Universe Today

When we think of Jupiter-type planets, we usually picture massive cloud-covered worlds orbiting far from their stars. That distance keeps their volatile gases from vaporizing from stellar heat, similar to what we’re familiar with in our Solar System. So, why are so many exoplanets known as “hot Jupiters” orbiting very close to their stars? That’s the question astronomers ask as they study more of these extreme worlds.

It turns out that hot Jupiters don’t actually start life snuggled up so close. Instead, they form much farther away from their stars in the protoplanetary nebula. That leads to the question: how did they migrate inward? The answer has been “we aren’t sure” from the planetary science community. However, astronomers at MIT, Penn State University, and a host of other institutions think they’ve got a handle on a better answer. They’ve found a hot Jupiter “progenitor.” That’s a juvenile version of a Jovian world slowly turning from cold to hot. The clues lie in its orbit and may give insight into how other planets evolve.

Introducing a Proto Hot Jupiter

This new world is called TIC 241249530 b and it lies about 1,100 light-years away from us. Instead of circling its star in an almost circular elliptical orbit (our Jupiter does around the Sun), this one is in a highly elliptical orbit. That squished “egg-shaped” path takes it very close to its star (like about 10 times closer than the orbit of Mercury. Then, it heads out to about the distance that Earth lies from the Sun. Not only is that a weird orbit, but it gets weirder. The path is “retrograde”. That means its direction of travel is counter to the star’s rotation. Think of it like this: the star rotates one way and the planet orbits the opposite way.

Both the highly elliptical orbit and the retrograde path tell planetary scientists that the formerly “cool” Jupiter-like world is evolving into one of those hot Jupiters. Now, if that isn’t strange enough, the star the planet is orbiting is actually a binary star. That means it has a stellar companion. Over time, successive interactions between the two orbits—of the planet and its star—force the planet to migrate ever closer to its star. That forces its elliptical orbit to change to a tighter, more circular one. That’ll take about a billion years and that’s when the planet will be fully evolved into a Hot Jupiter.

An orbital comparison of this evolving hot Jupiter if it existed in our Solar System. Courtesy NOIRLab. How Do Hot Jupiters Fit Formation Theory?

The standard theory about planetary formation usually requires that rocky worlds form closer to their stars than the gas and ice giants. That’s because the heat of the newborn star vaporizes any “volatile” gases such as hydrogen away from newly forming planets. Worlds with a lot of those volatiles tend to form out where it’s cooler and those gases don’t get vaporized.

Artist’s conception of early planetary formation from gas and dust around a young star. Planets with large abundances of volatile elements (such as hydrogen) need cooler environments much further from their stars in order to maintain their volatiles. So-called “hot Jupiters” may form further away but then migrate closer to their stars. Credit: NASA/JPL-Caltech

So, does this new world fit into that theory? According to MIT’s Sarah Millholland, it does. “This new planet supports the theory that high eccentricity migration should account for some fraction of hot Jupiters,” said Millholland. “We think that when this planet formed, it would have been a frigid world. And because of the dramatic orbital dynamics, it will become a hot Jupiter in about a billion years, with temperatures of several thousand kelvin. So it’s a huge shift from where it started.”

So, this hot Jupiter (and many of the others seen in exoplanet surveys) started farther from its star. Then, through orbital interactions, it’s been getting closer. That may well explain many of the hot Jupiters seen in exoplanet discoveries.

Simulations of Orbital Dances

“It is really hard to catch these hot Jupiter progenitors ‘in the act’ as they undergo their super eccentric episodes, so it is very exciting to find a system that undergoes this process,” says Smadar Naoz, a professor of physics and astronomy at the University of California at Los Angeles, who was not involved with the study. “I believe that this discovery opens the door to a deeper understanding of the birth configuration of the exoplanetary system.”

Of course, tracking the changes in exoplanet orbits can take a long time, so Millholland and her colleagues ran computer simulations. Those allowed them to model how this particular Hot Jupiter could have evolved. The team’s observations, along with their simulations of the planet’s evolution, support the theory that hot Jupiters can form through high eccentricity migration, a process by which a planet gradually moves into place via extreme changes to its orbit over time.

“It’s clear not only from this, but other statistical studies too, that high eccentricity migration should account for some fraction of hot Jupiters,” Millholland said. “This system highlights how incredibly diverse exoplanets can be. They are mysterious other worlds that can have wild orbits that tell a story of how they got that way and where they’re going. For this planet, it’s not quite finished its journey yet.”

For More Information

Astronomers Spot a Highly Eccentric Planet on its Way to Becoming a Hot Jupiter
A Hot-Jupiter Progenitor on a Super-eccentric Retrograde Orbit

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Venus is known for being really quite inhospitable with high surface temperatures and Mars is known for its rusty red horizons. Even the moons of some of the outer planets have fascinating environments with Europa and Enceladus boasting underground oceans. Recent observations from the James Webb Space Telescope show that Ariel, a moon of Uranus, is also a strong candidate for a sub surface ocean. How has this conclusion been reached? Well JWST has detected carbon dioxide ice on the surface on the trailing edge of features trailing away from the orbital direction. The possible cause, an underground ocean!

Uranus is the seventh planet in the Solar System and has five moons. Ariel is one of them and is notable for its icy surface and fascinatingly diverse geological features. It was discovered back in 1851 by William Lassell who funded his love of astronomy from his brewing business! The surface of Ariel is a real mix of canyons, ridges, faults and valleys mostly driven by tectonic activity. Cryovolcanism is a prominent process on the surface which drives constant resurfacing and has led to Ariel having the brightest surface of all Uranus’ moons. 

Image of Uranus from Webb

Studying Ariel closeup reveals that the surface is coated with significant amounts of carbon dioxide ice. The trailing hemisphere of Ariel seems to be particularly coated in the ice which has surprised the community. At the distance of Uranian system from the Sun, an average of 2.9 billion kilometres, carbon dioxide will usually turns straight into a gas and be lost to space, it’s not expected to freeze!

Until recently, the most popular theory that supplies the carbon dioxide to Ariel’s surface is interactions between its surface and charged particles in the magnetosphere of Uranus. The process known as radiolysis breaks down molecules through ionisation. A new study just published in the Astrophysical Journal Letters suggests an intriguing alternative, the carbon dioxide molecules are expelled from Ariel, possibly from a subsurface liquid ocean!

A team of astronomers using JWST have undertaken a spectral analysis of Ariel and compared the results with lab based findings. The results revealed that Ariel has some of the most carbon dioxide rich deposits in the solar system. The deposits are not just wisps and trace amounts instead adding up to about 10 millimetres across the trailing hemisphere. Furthermore, the results also showed signals from carbon monoxide too which should not be there given the average temperatures. 

Illustration of James Webb Space Telescope

It is still possible that radiolysis is responsible for at least some of the deposits but the replenishment from the subsurface ocean is thought to be the main contributor. This hypothesis has been supported by the discovery of signals from carbonate minerals, salts that can only be present due to the interaction between rock and water. 

The only way to be absolutely sure is for a future space mission to Uranus. Such a mission will undoubtedly explore the moons of Uranus. Ariel is covered in canyons, fissures and grooves and it is suspected these are openings to its interior. A robotic explorer in the Uranian system will be able to uncover the origin of the carbon oxides on Ariel. Without such a mission we are still somewhat in the dark given that Voyager 2 only imaged around 35% of the moon’s surface. 

Source : Carbon Oxides on Uranus’ Moon Ariel Hint at Hidden Ocean, Webb Telescope Reveals

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When the James Webb Space Telescope was launched it came with a fanfare expecting amazing things, much like the Hubble Space Telescope. One of JWST’s most anticipated target was TRAPPIST-1. This inconspicuous star is host to seven Earth-sized planets, with at least three in the habitable zone. The two inner planets are airless worlds but so far there has been no word of the third planet, the first in the habitable zone. The question is why and what makes it so tricky to observe?

TRAPPIST-1 is a red dwarf star about 41 light years in the constellation Aquarius. The interest in the planets in the habitable zone is that the conditions could allow for the existence of liquid water. The seven planets were discovered through transit photometry where tiny drops in brightness of the star are observed due to the passage of the planets in front of the star.  The planets that orbit the star all have fairly short orbital periods from 1.5 days to 20 days. The result of this is that their transits across the stellar surface often overlap. 

The launch of the JWST in 2021 reignited the interest in exoplanet studies. Its predecessor the Hubble Space Telescope was never expected to last as long to JWST was able to complement the famous telescope. Setting itself apart from Hubble by its advanced infrared capability, JWST was ideally placed to study exoplanet atmospheres. Fundamental to the operation of the JWST is a large, multi-segment mirror measuring 6.5 metres in diameter and a whole host of sophisticated instruments. 

Artist impression of the James Webb Space Telescope

A team of astronomers have been studying TRAPPIST-1 and its system of planets using JWST, exploiting its infrared capabilities. Using a technique known as transmission spectroscopy the starlight is explored as it passes through the planetary atmospheres as they pass in front of the star. Studying the light in this way can reveal the elements in the atmosphere. Three years in though and challenges have slowed them down. 

Now, a paper published in Nature Astronomy highlights the challenges they faced and proposes how to overcome them. Top of the list relates to the non uniformity of a star. Those interested in solar astronomy will already be familiar with sun spots, flares and other solar phenomenon. These are seen on stars too and regions where cooler regions form can often harbour water vapour, playing havoc with transmission spectra and making it difficult to identify elements in the planetary atmosphere rather than in the star. This is known as stellar contamination. 

Previous issues like this have been seen by astronomers studying exoplanet atmospheres using Earth based telescopes like the Magellan Telescope in Chile. Previously however, these issues were often simply ignored but the greater sensitivity of JWST causes more of a problem. There is a relatively simple work around however by observing the star as it rotates to build a picture of the stellar surface, allowing a more accurate analysis of the planetary atmosphere. 

Magellan Telescope

Using TRAPPIST-1 as a test bed, it is hoped that other challenges and their solutions can be tested before being applied to other, less easy to observe explanatory systems. The team propose that the exoplanet and JWST community work together on research projects to maximise efficiency in driving out solutions to other challenges in the road ahead. 

Source : Roadmap details how to improve exoplanet exploration using the JWST

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The extrasolar planet census recently passed a major milestone, with 5500 confirmed candidates in 4,243 solar systems. With so many exoplanets available for study, astronomers have learned a great deal about the types of planets that exist in our galaxy and have been rethinking several preconceived notions. These include the notion of “habitability” and whether Earth is the standard by which this should be measured – i.e., could there be “super habitable” exoplanets out there? – and the very concept of the circumsolar habitable zone (CHZ).

Traditionally, astronomers have defined habitable zones based on the type of star and the orbital distance where a planet would be warm enough to maintain liquid water on its surface. But in recent years, other factors have been considered, including the presence of planetary magnetic fields and whether they get enough ultraviolet light. In a recent study, a team from Rice University extended the definition of a CHZ to include a star’s magnetic field. Their findings could have significant implications in the search for life on other planets (aka. astrobiology).

The research team consisted of Anthony S. Atkinson, a graduate student with the Department of Physics and Astronomy at Rice University, Professor David Alexander, the director of the Rice Space Institute and member of the Texas Aerospace Research and Space Economy Consortium, and Alison O. Farrish, a NASA Postdoctoral Program Fellow at NASA’s Goddard Space Flight Center. The paper describing their findings, “Exploring the Effects of Stellar Magnetism on the Potential Habitability of Exoplanets,” appeared on July 9th in The Astrophysical Journal.

Artist’s impression of exoplanets orbiting different types of stars. Credit: NASA/W. Stenzel

On Earth, the presence of an intrinsic magnetic field has been vital to the emergence and evolution of life as we know it. Without it, our atmosphere would have been stripped away long ago by energetic particles emanating from the Sun – which was the case with Mars. In addition to Earth’s atmosphere, our planet’s magnetic field ensures that a limited amount of solar radiation and cosmic rays reach the surface. For this reason, astrobiologists consider a planetary magnetic field essential for determining whether or not an exoplanet is habitable.

Another factor is how the strength of a planet’s magnetic field and its interaction with its parent star’s magnetic field affect habitability. Not only does an exoplanet require a strong field to shield it against stellar activity (solar flares, etc.), but it must also orbit far enough to avoid a direct magnetic connection with its star. “The fascination with exoplanets stems from our desire to understand our own planet better,” said Prof. Alexander in a recent Rice University press statement. “Questions about the Earth’s formation and habitability are the key drivers behind our study of these distant worlds.”

The magnetic interactions between planets and their parent stars are known as “space weather.” For their study, the team examined 1,546 exoplanets to determine if they orbited inside or outside their host star’s Alfvén radius – the distance where stellar wind decouples from the star. This consisted of characterizing the stars’ activity known using their Rossby number (Ro) – the ratio between a star’s rotational period to their convective turnover time.

Planets orbiting within this radius would directly interact magnetically with the star’s corona, leading to significant atmospheric stripping, ruling them out as viable candidates for habitability. This phenomenon has been observed with TRAPPIST-1 and its system of seven exoplanets. After examining the exoplanets in their study, they found that only two planets met all the conditions for potential habitability. These were K2-3 d and Kepler-186 f, two Earth-sized exoplanets 144 and 579 light-years from Earth (respectively).

Illustration of Kepler-186f, a possible Earth-like exoplanet that could be a host to life. Credit: NASA Ames, SETI Institute, JPL-Caltech, T. Pyle

These planets orbit within their stars’ CHZ, lie outside their Alfvén radius, and have strong enough magnetic fields to protect them from stellar activity. “While these conditions are necessary for a planet to host life, they do not guarantee it,” said Atkinson. “Our work highlights the importance of considering a wide range of factors when searching for habitable planets.”

These findings highlight the need for continuous observation when studying exoplanet systems and considering what factors have led to the emergence of life here on Earth. They are also indicative of current efforts among astronomers and astrobiologists to refine the definition of “Habitable Zone” and create a more nuanced understanding. In so doing, this research could help refine the search for extraterrestrial life by allowing scientists to further constrain where they should be looking.

Further Reading: Rice University, The Astrophysical Journal

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Supermassive Black Holes are Nature’s confounding behemoths. It’s difficult for Earth-bound minds to comprehend their magnitude and power. Astrophysicists have spent decades studying them, and they’ve made progress. But one problem still baffles even them: the Final Parsec Problem.

New research might have solved the problem, and dark matter plays a role in the solution.

Supermassive Black Holes (SMBHs) can be billions of times more massive than our Sun. Evidence shows that they may reside at the center of all large galaxies. The Milky Way has one and it’s named Sagittarius A* (Sgr A*).

SMBHs grow so massive by merging with other SMBHs when their host galaxies merge. But there’s a problem. Astrophysicists don’t understand how the two SMBHs can close the final parsec that separates them.

When black holes merge, they begin as a binary object. They spiral around each other, each carrying their own momentum. To merge, the black holes need to shed energy. To do this, they shed energy to the surrounding gas and dust which then dissipates. But when they get about three light-years away from one another, or about one parsec, there simply isn’t enough gas and dust to absorb the necessary energy.

Yet SMBHs do merge, so somehow, nature overcomes the Final Parsec Problem (FPP).

New research published in the journal Physical Review Letters presents a solution to the FPP. The research is titled “Self-Interacting Dark Matter Solves the Final Parsec Problem of Supermassive Black Hole Mergers.” The first author is Gonzalo Alonso-Álvarez, a Postdoctoral Fellow in the Department of Physics at the University of Toronto, Canada.

“Our work is a new way to help us understand the particle nature of dark matter.”

Gonzalo Alonso-Álvarez, Department of Physics, University of Toronto

There’s no question that stellar-mass black holes can merge. LIGO/Virgo has sensed the gravitational waves coming from many mergers between stellar-mass black holes, which is direct evidence that black holes can merge. However, evidence for SMBH mergers is elusive.

In 2023, scientists announced the detection of a persistent background hum of gravitational waves. That detection came from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav.) NANOGrav gathered gravitational wave data for 15 years using pulsar timing.

Different groups of researchers hypothesized that the hum comes from the mergers of SMBHs. In one paper, researchers said the hum comes from hundreds of thousands of pairs of merging SMBHs. Somehow, these SMBHs are overcoming the FPP.

In their new paper, Alonso-Álvarez and his co-researchers show how dark matter allows SMBHs to merge despite the Final Parsec Problem. “We show that including the previously overlooked effect of dark matter can help supermassive black holes overcome this final parsec of separation and coalesce,” said Alonso-Álvarez. “Our calculations explain how that can occur, in contrast to what was previously thought.”

Astrophysicists have been working on the FPP for a long time. Different researchers have developed different models to try to explain how SMBHs merge, and those models include dark matter. However, previous merger models showed that the dark matter near the spiralling black holes is thrown clear of the merger area by the gravity created by the inspiralling holes. Without that dark matter to absorb energy, the pair of SMBHs can’t overcome the FPP.

But in this new research, dark matter interacts with itself and ‘spikes’ instead of being dispersed. Dark matter spikes are theoretical concentrations of dark matter around a black hole. As an SMBH grows, it draws regular matter towards itself. The same process could lead to a spike in dark matter around the black hole. Its density remains high enough that it can absorb enough energy for the pair of SMBHs to continue their inspiralling. Eventually, they overcome the FPP and coalesce into one.

This figure from separate research shows a spike in dark matter near a black hole. The vertical axis shows the dark matter’s density in solar masses per cubic parsec, and the horizontal axis shows the distance to the black hole center in parsecs. The black line shows the initial distribution of dark matter, and the pink line shows the spike that occurs due to adiabatic growth. Image Credit: Wierda 2023.

It all depends on dark matter self-interacting.

“The possibility that dark matter particles interact with each other is an assumption that we made, an extra ingredient that not all dark matter models contain,” said Alonso-Álvarez. “Our argument is that only models with that ingredient can solve the final parsec problem.”

Physicists aren’t certain that dark matter can interact with itself, though. The Standard Model says that dark matter interacts primarily through gravity. But newer evidence is accumulating that it can interact with itself, and physicists call this the Self-Interacting Dark Matter theory.

Other research has looked at dark matter spikes near merging black holes. According to that research, dynamical friction between the black holes and the DM spike could dissipate the spike. However, this new research argues that only SIDM can effectively move the heat outwards and replenish the DM spike. Contrary to collisionless dark matter, an SIDM spike maintains itself and allows the inspiralling black holes to shed enough energy and cross the final parsec problem.

More support for this hypothesis comes from the nature of the background gravitational wave hum that scientists announced in 2023. It was measured by pulsar timing and the waves displayed a softening at low frequencies. According to Alonso-Álvarez, their model predicts this phenomenon, lending credence to their work.

“A prediction of our proposal is that the spectrum of gravitational waves observed by pulsar timing arrays should be softened at low frequencies,” said co-author Professor James Cline from McGill University and the CERN Theoretical Physics Department in Switzerland. “The current data already hint at this behavior, and new data may be able to confirm it in the next few years.”

This research reaches beyond SMBH mergers to the nature of dark matter itself. The self-interactions the researchers modelled can help explain the shape of dark matter haloes around galaxies.

“Our work is a new way to help us understand the particle nature of dark matter,” said Alonso-Álvarez. “We found that the evolution of black hole orbits is very sensitive to the microphysics of dark matter and that means we can use observations of supermassive black hole mergers to better understand these particles.”

“Despite astrophysical uncertainties about their detailed nature, there is no doubt that dark matter spikes exist around supermassive black hole binaries and thus contribute to the dynamical friction accelerating the decay of their orbit,” the authors write in the conclusion of their paper.

“We found that the final parsec problem can only be solved if dark matter particles interact at a rate that can alter the distribution of dark matter on galactic scales,” said Alonso-Álvarez. “This was unexpected since the physical scales at which the processes occur are three or more orders of magnitude apart. That’s exciting.”

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Our CO2 emissions are warming the planet and making life uncomfortable and even unbearable in some regions. In July, the planet set consecutive records for the hottest day.

NASA is mapping our emissions, and while what they show us isn’t uplifting, it is visually appealing in a ghoulish way. Maybe the combination of visual appeal and ghoulishness will build momentum in the fight against climate change.

NASA’s Scientific Visualization Studio has released a video showing how wind and air currents pushed CO2 emissions around Earth’s atmosphere from January to March 2020. The video’s high-resolution zooms in and sees individual sources of CO2, including power plants and forest fires.

“As policymakers and as scientists, we’re trying to account for where carbon comes from and how that impacts the planet,” said climate scientist Lesley Ott at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “You see here how everything is interconnected by these different weather patterns.”

Credit: NASA’s Goddard Space Flight Center

The video starkly shows that it doesn’t matter where CO2 emissions come from; we all deal with the outcomes. Yet there are some interesting global differences.

Above the USA, South Asia, and China, most of the carbon comes from industry, power plants, and transportation. But over Africa and South America, most of the emissions come from burning, including forest fires, agricultural burning, and land clearing. Emissions also come from fossil fuels like oil and coal.

via GIPHY

The image pulses for a couple of reasons. Forest fires tend to flare during the day and then slow down at night. Also, trees and plants photosynthesize during the day, releasing oxygen and absorbing CO2. The land masses and the oceans act as carbon sinks.

There’s more pulsing in South America and the tropics because the data was collected during their growing season.

In this version, the video zooms in on the USA, showing individual CO2 sources.

via GIPHY

These visualizations are based on GEOS, the Goddard Earth Observing System. GEOS is an integrated system for modelling Earth’s coupled atmosphere, ocean, and land systems. NASA calls it a “high-resolution weather analysis model,” and it uses supercomputers to show what’s happening in the atmosphere. GEOS is based on billions of data points, including data from the Terra satellite’s MODIS and the Suomi-NPP satellite’s VIIRS instruments. GEOS has a resolution that’s more than 100 times greater than typical weather models.

Interested users can download the visualizations at the Scientific Visualization Studio.

Image Credit for all videos, images, and clips: NASA’s Goddard Space Flight Center

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We take high definition streaming for granted in many parts of the world. Even now, as I type this article, I have the Martian streaming in high definition but until now astronauts on board the Space Station have had to accept low definition streaming. A team of researchers at NASA have developed and used a new system using an aircraft as a relay. A laser terminal was installed on a research aircraft and data was sent to a ground station. The signals were sent around the Earth and beamed to a relay satellite which then sent the signal on to the Space Station. What the astronauts will actually use it for is less likely to be streaming HD movies but will certainly be able to take advantage of the high bandwidth for science data and communications. 

Over the years, space travellers from all countries have had to rely upon radio waves to transfer data and information to and from space. This has meant reliable communication but low quality video. Alternative technologies have been available but these are generally limited to Earth-based activity. Laser is an obvious alternative which uses infrared light to transmit 10 to 100 times more data transfer than radio based systems. 

A team of researchers based at the Glenn Research Centre, part of NASA’s Cleveland presence has succeeded in establishing sufficient bandwidth to stream 4K video to the ISS using laser communications. The study was part of a series of tests of new technology that could provide high quality live video coverage of the Artemis lunar landing missions. 

The International Space Station (ISS) in orbit. Credit: NASA

The team worked closely with the Air Force Research Laboratory and NASA’s Small Business Innovation Research program. Together they installed a temporary laser terminal on the bottom of a Pilatus PC-12 aircraft. The pressurised single engined aircraft then flew over Lake Erie in Cleveland sending data to a ground station nearby. The next hop was for the data to be sent over Earth-based infrastructure to White Sands, the NASA test facility in New Mexico where it was translated to an infrared signal. 

Orbiting Earth at an altitude of about 35,000 kilometres is NASA’s experimental Laser Communications Relay Demonstration satellite which received the infrared signal and then relayed it to the ISS via the Illuma-T, the Integrated LCRD LEO User Modem and Amplifier Terminal. A new system known as High-Rate Delay Tolerant Networking was integrated into the transfer and helped to deal with cloud penetration more efficiently. 

Multiple flights were completed by the Pilatus aircraft and after each test, the functionality was improved. It’s far easier to identify issues and subsequent enhancements during aeronautical testing than during ground testing. 

NASA’s Space Launch System rocket carrying the Orion spacecraft launches on the Artemis I flight test, Wednesday, Nov. 16, 2022, from Launch Complex 39B at NASA’s Kennedy Space Center in Florida. Credit: NASA/Joel Kowsky.

The upcoming Artemis missions to the Moon and beyond are a real driving force behind developing high bandwidth data transfer not just for streaming video but to provide full video conferencing abilities to the astronauts. This will not only aid mission efficiency but also help to maintain astronaut morale and wellbeing. The drive too for the capture of high quality video data along with vast amounts of scientific data will benefit this high bandwidth technology as NASA embraces laser communications as a core part of their future projects. 

Source : NASA Streams First 4K Video from Aircraft to Space Station, Back

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Check any container of over-the-counter medicine, and you’ll see its expiration date. Prescription medicines have similar lifetimes, and we’re told to discard old medications rather than hold on to them. Most of them lose their effectiveness over time, and some can even become toxic. We’re discouraged from disposing of them in our wastewater because they can find their way into other organisms, sometimes with deleterious effects.

We can replace them relatively easily on Earth, but not on a space mission beyond Low Earth Orbit.

A round trip to Mars takes about three years. A lot can happen in that time. Important medical supplies, including medicines, might not remain as effective for that long.

That could create problems for astronauts who make the journey.

New research in Nature’s npj Microgravity examines the lifetimes of medicines and how they could affect astronauts on long-duration space missions. It’s titled “Expiration analysis of the International Space Station formulary for exploration mission planning,” and the senior author is Daniel Buckland. Buckland is from the Department of Emergency Medicine at the Duke University School of Medicine and is an aerospace medicine researcher. The lead author is Thomas Diaz, a pharmacy resident at The Johns Hopkins Hospital.

Getting sick in space isn’t rare. Canadian astronaut Chris Hadfield talked about the problem in 2013. “When we first get to space, we feel sick. Your body is really confused. And so, you know, you’re dizzy, your lunch is floating around in your belly ’cause you’re floating, and what you see doesn’t match what you feel.” NASA calls it ‘space adaptation syndrome,’ and motion sickness and anti-nausea medications can help.

Research also shows that astronauts’ immune systems are weakened in space. Weaker immune systems raise the risk of infections. Humans carry latent viruses that can become active when immune systems are weakened, and the entire problem is amplified on longer missions.

When used properly and early enough, common medications can prevent relatively simple afflictions, such as a minor infection, from growing into more dangerous problems. Expired medications can create a problem because their effectiveness is often diminished over time.

“Effective medications will be required to maintain human health for long-duration space operations,” the authors write in their paper. “Previous studies have explored the stability and potency of several of the medications used on the International Space Station (ISS).”

However, this is the first time researchers have compared medications used in space with drug expiration dates in four different international drug registries.

Lead author Thomas Diaz got the idea for this work and then contacted Buckland.

Daniel Buckland, MD, PhD, is an emergency medicine physician at Duke School of Medicine and a NASA affiliate. He studies the risk of spaceflight on humans, including using robotics to deliver care in space. (Photo by Eamon Queeney.)

“Tom reached out with the idea, knowing my work on risk mitigation for extended spaceflight,” said Buckland. “He was concerned that not enough research addressed the problem of medication longevity on a Mars mission.”

NASA doesn’t reveal what medicines it stores on the ISS. For this research, Diaz used a Freedom of Information Act Request to get the list of medicines. The researchers assumed that the formulary would be the same or at least similar for a Mars mission.

The ISS carries 111 medications, divided among five different colour-coded kits. Each kit holds medicines pertinent to its designated use.

• Convenience kit: 23 medications.
• Emergency/Advance Life Support: 4 medications.
• Oral Medication: 36 medications.
• Topical and Injectable: 37 medications.
• Vascular Contingency: 11 medications.

Some medications are duplicated in multiple kits, and two of them are diluents for other medications.

This table from the research shows the four medications in the Advanced Life Support kit, along with their expiry dates in different jurisdictions. Some have a range of dates because of different manufacturers making the same drug. Image Credit: Diaz et al. 2024.

The ISS’s formulary, a list of drugs stocked on the station, contains 106 medications, excluding multiples and diluents. The most common issues that need to be addressed with medicines are motion sickness, allergies, minor pains, and infections. The list of medicines includes antibiotics, sleep aids, pain relievers, and allergy medicines. The drugs are chosen because they are effective in microgravity environments and because they have longer shelf lives than similar medications.

The research shows that over half of the medicines stocked on the ISS would expire on a Mars mission before astronauts returned to Earth.

“Of the 106 medications in the ISS formulary, shelf-life data was found in at least 1 of the registries for 91 (86%) medications,” the authors write in their research. “Of these 91 medications, 54 have an estimated terrestrial shelf-life of less than or equal to 36 months when stored in their original packaging. 14 will expire in less than 24 months.”

This graph from the research shows the survival percentage of ISS medicines by mission length for a lunar mission (Moon image) and a Mars mission (Mars image.) After five years, all medicines would expire. Image Credit: Diaz et al. 2024.

“It doesn’t necessarily mean the medicines won’t work, but in the same way you shouldn’t take expired medications you have lying around at home, space exploration agencies will need to plan on expired medications being less effective,” said Buckland.

On Earth, different medications become less effective at different rates after expiration. However, the effects of space flight on their effectiveness are largely unknown. Space is a harsh environment, and radiation could have a pronounced effect on medications. Increasing the amount of each medication carried on a Mars mission could help deal with the problem, but it’s a rather clumsy solution.

“Hopefully, this work can guide the selection of appropriate medications or inform strategies to mitigate the risks associated with expired medications on long-duration missions,” Buckland said.??

“Prior experience and research show astronauts do get ill on the ISS, but there is real-time communication with the ground and a well-stocked pharmacy that is regularly resupplied, which prevents small injuries or minor illnesses from turning into issues that affect the mission,” he said.??

In their conclusion, the researchers note that pharmaceutical drugs will be the cornerstone of astronaut health on long missions. They also point out a gap in data regarding the shelf lives of the drugs in the ISS’s formulary. For example, 14% of the medicines in the formulary lack expiration data. “It is imperative to know and understand these pharmacologic parameters in order to supply a safe and effective astropharmacy,” they write.

If medicines become unstable sooner on long space missions, it’s a problem that needs to be addressed.

“Ultimately, those responsible for the health of spaceflight crews will have to find ways to extend the expiration of medications to the complete mission duration or accept the elevated risk associated with administration of an expired medication,” they conclude.

The post The Shelf Life of Many Medications Is Shorter Than A Round Trip To Mars appeared first on Universe Today.

There’s a burgeoning arms race between Artificial Intelligence (AI) deepfake images and the methods used to detect them. The latest advancement on the detection side comes from astronomy. The intricate methods used to dissect and understand light in astronomical images can be brought to bear on deepfakes.

The word ‘deepfakes’ is a portmanteau of ‘deep learning’ and ‘fakes.’ Deepfake images are called that because they’re made with a certain type of AI called deep learning, itself a subset of machine learning. Deep learning AI can mimic something quite well after being shown many examples of what it’s being asked to fake. When it comes to images, deepfakes usually involve replacing the existing face in an image with a second person’s face to make it look like someone else is in a certain place, in the company of certain people, or engaging in certain activities.

Deepfakes are getting better and better, just like other forms of AI. But as it turns out, a new tool to uncover deepfakes already exists in astronomy. Astronomy is all about light, and the science of teasing out minute details in light from extremely distant and puzzling objects is developing just as rapidly as AI.

In a new article in Nature, science journalist Sarah Wild looked at how researchers are using astronomical methods to uncover deepfakes. Adejumoke Owolabi is a student at the University of Hull in the UK who studies data science and computer vision. Her Master’s Thesis focused on how light reflected in eyeballs should be consistent, though not identical, between left and right. Owolabi used a high-quality dataset of human faces from Flickr and then used an image generator to create fake faces. She then compared the two using two different astronomical measurement systems called the CAS system and the Gini index to compare the light reflected in the eyeballs and to determine which were deepfakes.

CAS stands for concentration, asymmetry, and smoothness, and astronomers have used it for decades to study and quantify the light from extragalactic stars. It’s also used to quantify the light from entire galaxies and has made its way into biology and other areas where images need to be carefully examined. Noted astrophysicist Christopher J. Conselice was a key proponent of using CAS in astronomy.

The Gini index, or Gini coefficient, is also used to study galaxies. It’s named after the Italian statistician Corrado Gini, who developed it in 1912 to measure income inequality. Astronomers use it to measure how light is spread throughout a galaxy and whether it’s uniform or concentrated. It’s a tool that helps astronomers determine a galaxy’s morphology and classification.

In her research, Owolabi successfully determined which images were fake 70% of the time.

These eyes are all from deepfake images with inconsistent light reflection patterns. The ones on the right are coloured to highlight the inconsistencies. Image Credit: Adejumoke Owolabi (CC BY 4.0)

For her article, Wild spoke with Kevin Pimbblet, director of the Centre of Excellence for Data Science, Artificial Intelligence and Modelling at the University of Hull in the UK. Pimblett presented the research at the UK Royal Astronomical Society’s National Astronomy Meeting on July 15th.

“It’s not a silver bullet, because we do have false positives and false negatives,” said Pimbblet. “But this research provides a potential method, an important way forward, perhaps to add to the battery of tests that one can apply to try to figure out if an image is real or fake.”

This is a promising development. Open democratic societies are prone to disinformation attacks from enemies without and within. Public figures are prone to similar attacks. Disturbingly, the majority of deepfakes are pornographic and can depict public figures in private and sometimes degrading situations. Anything that can help combat it and bolster civil society is a welcome tool.

But as we know from history, arms races have no endpoint. They go on and on in an escalating series of countermeasures. Look at how the USA and the USSR kept one-upping each other during their nuclear arms race as warhead sizes reached absurd levels of destructive power. So, inasmuch as this work shows promise, the purveyors of deepfakes will learn from it and improve their AI deepfake methods.

Wild also spoke to Brant Robertson in her article. Robertson is an astrophysicist at the University of California, Santa Cruz, who studies astrophysics and astronomy, including big data and machine learning. “However, if you can calculate a metric that quantifies how realistic a deepfake image may appear, you can also train the AI model to produce even better deepfakes by optimizing that metric,” he said, confirming what many can predict.

This isn’t the first time that astronomical methods have intersected with Earthly issues. When the Hubble Space Telescope was developed, it contained a powerful CCD (charge-coupled device.) That technology made its way into a digital mammography biopsy system. The system allowed doctors to take better images of breast tissue and identify suspicious tissue without a physical biopsy. Now, CCDs are at the heart of all of our digital cameras, including on our mobile phones.

Might our internet browsers one day contain a deepfake detector based on Gini and CAS? How would that work? Would hostile actors unleash attacks on those detectors and then flood our media with deepfake images in an attempt to weaken our democratic societies? It’s the nature of an arms race.

It’s also in our nature to use deception to sway events. History shows that rulers with malevolent intent can more easily deceive populations that are in the grip of powerful emotions. AI deepfakes are just the newest tool at their disposal.

We all know that AI has downsides, and deepfakes are one of them. While their legality is fuzzy, as with many new technologies, we’re starting to see efforts to combat them. The United States government acknowledges the problem, and several laws have been proposed to deal with it. The “DEEPFAKES Accountability Act” was introduced in the US House of Representatives in September 2023. The “Protecting Consumers from Deceptive AI Act” is another related proposal. Both are floundering in the sometimes murky world of subcommittees for now, but they might breach the surface and become law eventually. Other countries and the EU are wrestling with the same issue.

But in the absence of a comprehensive legal framework dealing with AI deepfakes, and even after one is established, detection is still key.

Astronomy and astrophysics could be an unlikely ally in combatting them.

The post Astronomers Have Tools That Can Help Detect Deepfake Images appeared first on Universe Today.

Characterizing near-Earths asteroids (NEAs) is critical if we hope to eventually stop one from hitting us. But so far, missions to do so have been expensive, which is never good for space exploration. So a team led by Patrick Bambach of the Max Planck Institute for Solar System Research in Germany developed a mission concept that utilizes a relatively inexpensive 6U CubeSat (or, more accurately, two of them) to characterize the interior of NEAs that would cost only a fraction of the price of previous missions. 

The mission, known as the Deep Interior Scanning CubeSat mission to a rubble pile near-Earth asteroid, or DISCUS, was initially floated in 2018. Its central architecture involves two separate 6U CubeSats equipped with a powerful radar. They would travel to opposite sides of an NEA and direct a radar to pass through the NEA’s interior.

To understand more about the mission architecture, it’s best to look at the type of asteroid best suited to being visited by DISCUS. The authors suggest one about the size of Itokawa, the target of the first Hayabusa mission. It’s about 330 meters in diameter, right in the size range the mission planners were looking for, and is designated as a “rubble pile,” meaning the interior is relatively sparse.

Understanding how to stop an asteroid strike is one of DISCUS’s primary mission drivers. Fraser discusses how we can do it.

A sparse interior is critical to the mission objectives, as an asteroid’s density can dramatically impact the scientific toolkit needed to characterize it. For DISCUS, the mission team plans a radar antenna known as a half-dipole. This would transmit at a relatively low frequency, which is more likely to pass through larger objects. Additionally, they plan to use a radar technique known as stepped-frequency modulation, which changes the radar’s frequency to allow for the broadest range of characterizations.

The opposing spacecraft on the other side of the asteroid would then receive these radar signals, analyze whatever waveform deformations occurred, and correlate that to the materials the radar had to pass through. Calculations show that this technique should enable a resolution of a few tens of meters for the interior of an asteroid about the size of Itokawa.

However, they also have to be run through another spectral analysis technique called computed radar tomography. This technique is often used in radiology diagnoses on Earth—the name CT scan comes from—but it can also be used to analyze the interiors of solid objects in the solar system.

The radar techniques DISCUS uses are also used on Earth, as described in this video on bistatic radar.
Credit – Nicole Bienert YouTube Channel

However, the science payload is only one part of the DISCUS package and would ideally only take up 1U of the 6U allotted on each probe. The other five would be taken up by a series of off-the-shelf components, including a propulsion system (2U), communication system (1U), and avionics suite (1U). The dipole antenna and solar panels would deploy outside the standard CubeSat housing, allowing for better power collection and signal strength.

One of the most critical selections is the propulsion system, which would enable an acceleration of around 3.2 km/s, allowing DISCUS to match speeds with at least some NEAs. Alternatively, the mission plans to slingshot the craft around the Moon to get a boost of up to 4 km/s and gain access to even more asteroids.

A particular asteroid stood out to the team as they developed the mission design in 2018. Asteroid 1993 BX3 came within 18.4 times the distance to the Moon back in 2021 and was traveling at a speed that DISCUS could match, so the mission design team was hoping to have a prototype up and running to allow for a launch to that particular asteroid.

Unfortunately, that didn’t happen, and there hasn’t been much work on the mission concept since the paperback in 2018. However, more and more missions are targeting NEAs, and CubeSats are becoming increasingly popular. Eventually, a CubeSat mission will visit one of these objects and likely will be based at least partially on some ideas from DISCUS.

Learn More:
Bambach et al. – DISCUS – The Deep Interior Scanning CubeSat mission to a rubble pile near-Earth asteroid
UT – Swarms of Orbiting Sensors Could Map An Asteroid’s Surface
UT – Swarming Satellites Could Autonomous Characterize an Asteroid
UT – Asteroid Samples Were Once Part of a Wetter World

Lead Image:
This illustration shows the ESA’s Hera spacecraft and its two CubeSats at the binary asteroid Didymos. Image Credit: ESA

The post A Pair of CubeSats Using Ground Penetrating Radar Could Map The Interior of Near Earth Asteroids appeared first on Universe Today.

Think about background radiation and most people immediately think of the cosmic background radiation and stories of pigeon excrement during its discovery. That’s for another day though. Turns out that the universe has several background radiations, such as infrared and even gravitational wave backgrounds. NASA’s New Horizons is far enough out of the Solar System now that it’s in the perfect place to measure the cosmic optical background (COB). Most of this light comes from the stars in galaxies, but astronomers have always wondered if there are other sources of light filling our night sky. New Horizons has an answer. No!

Ok lets talk pigeon excrement.  Back in 1965 two telecommunication engineers were exploring signal interference at the Bell Laboratory. Penzias and Wilson detected a faint ‘hum’ in all directions and initially put it down to pigeon excrement as they nested in the horn of the radio receiver. Instead, what they had discovered was the cosmic background radiation, the faint glow that permeates the entire universe and is the thermal radiation left over from the Big Bang. Studying it allows us to understand more about the Universe when it was 380,000 years old. 

The full-sky image of the temperature fluctuations (shown as color differences) in the cosmic microwave background, made from nine years of WMAP observations. These are the seeds of galaxies, from a time when the universe was under 400,000 years old. Credit: NASA/WMAP

In the late 80’s a different type of background radiation was detected; the infrared background radiation. It consists of the diffuse infrared glow that fills the universe coming from numerous sources throughout the history of the universe. It is mostly from thermal emissions from dust grains heated by stellar radiation. In addition to this is the gravity wave background although this has yet to be detected. 

Another hotly debated background is the cosmic optical background (COB), a diffuse light which originates from stars and galaxies and spans the whole of the visible spectrum. There has been gathering momentum in its study however with observations from Hubble Space Telescope and the Spitzer Infrared Telescope. The studies however revealed that a large contribution to a general background optical glow come from faint unresolved galaxies. The study of the COB allows us to explore the total energy output of the universe, about galaxy and star formation across the history of the cosmos. 

The detection of the COB is a challenging one however with Earth based instruments or even those in Earth orbit plagued by interference. The zodiacal light for example is the result of sunlight scattered by interplanetary dust, it is dominant in the inner solar system  and makes studies of the COB difficult. The New Horizon probe is ideally positioned out beyond the orbit of Pluto over 8 billion kilometres away from interference. On board New Horizons is the LORRI (Long Range Reconnaissance Imager) camera which was identified as an ideal platform to begin a search. 

The New Horizons instrument payload that is currently doing planetary science, heliospheric measurements, and astrophysical observations. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Using images from the LORRI camera, a team of astronomers led by Marc Postman from the Space Telescope Science Institute attempted to measure the COB over the range 0.4 to 0.9 micrometers. The images were from high galactic latitudes to ensure no diffuse light from the Milky Way or scattered light from bright stars. Isolating the COB contribution to the total sky brightness levels required digitally subtracting the scattered light from bright stars and galaxies and from faint stars within the field that were fainter than that detectable by LORRI. Interestingly, the results showed that, based on the estimated galaxy counts in the sampled regions the COB is the result of light from all the galaxies within our observable region of the universe.

Source : New Synoptic Observations of the Cosmic Optical Background with New Horizons

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The prospect of actually resolving the event horizon of black holes feels like the stuff of science fiction yet it is a reality. Already the Event Horizon Telescope (EHT) has resolved the horizon of the black holes at the centre of the Milky Way and M87. A team of astronomers are now looking to the next generation of the EHT which will work at multiple frequencies with more telescopes than EHT. A new paper suggests it may even be possible to capture the ring where light goes into orbit around the black hole at the centre of the Milky Way. 

Black holes are strange objects that are the powerhouses of many galactic phenomenon. They have a complex anatomy with a singularity at the centre, a point of infinite density where gravity is so intense that the laws of physics cease to work. Surrounding the singularity is the event horizon, the boundary beyond which, nothing, not even light can escape. Just outside the event horizon is the photon ring and it is here that light is bent into a circular orbit around the singularity. Further out than this is the accretion disk but the focus of the next generation Event Horizon Telescope will be the photon ring. 

The Event Horizon Telescope name is a little misleading for it is not one telescope but a global network of radio telescopes that work together to act as a virtual Earth-sized radio telescope. The technology that makes this happen is known as interferometry where the telescopes are all connected together. The very long baseline of the telescope or put more simply the fact it is virtually VERY big means it has incredible resolution capabilities allowing it to capture the event horizon around Sagittarius A at the centre of the Milky Way and also of the black hole at centre of M87.

The ALMA array in Chile. Once ALMA was added to the Event Horizon Telescope, it increased the EHT’s power by a factor of 10. Image: ALMA (ESO/NAOJ/NRAO), O. Dessibourg

The EHT was launched in 2009 but now attention is turning to the next generation. The addition of ten new dishes and a whole host of new technology will transform EHT. Modern high-speed data transfer protocols will speed up transfer times and the addition of new dishes and technology will mean EHT will be able to observe at 86, 230 and 345 GHz simultaneously. This allows for the utilisation of frequency phase transfer techniques where lower frequency data can be used to supplement higher frequency. Using this will mean integration times of minutes at 345 GHz rather than seconds opening up a whole universe of new observations such as, the photon rings of black holes. 

Studies of the supermassive black hole at the centre of M87 and Sagittarius A suggest a magnetically arrested accretion disk. In this accretion model, the accretion disk forms a series of irregular spiral streams and a vertical magnetic field, which is split into separate field lines, pokes through the accretion plane. As the disk rotates the material spirals inward, dragging the field lines and twist them around the axis of rotation leading to the formation of jets. These magnetically arrested disks exhibit symmetrically polarised synchrotron emissions which were used by a team of astronomers to study the detectability of the photon ring using next generation EHT.

M87 and the jet streaming away from its central supermassive black hole. Credits: NASA, ESA and the Hubble Heritage Team (STScI/AURA); Acknowledgment: P. Cote (Herzberg Institute of Astrophysics) and E. Baltz (Stanford University)

The paper authored by Kaitlyn M. Shavelle and Daniel C. M. Palumbo from the Princeton University and Harvard & Smithsonian (respectively) show through simulations that the planned enhancements to the EHT are likely to enable the detection of photon rings. In the analyses of the enhancements they find that the higher sensitivity of the new EHT will likely be more critical than better processing techniques in the detection of the photon ring.

Source : Prospects for the Detection of the Sgr A* Photon Ring with next-generation Event Horizon Telescope Polarimetry

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The field of extrasolar planet studies has grown exponentially in the past twenty years. Thanks to missions like Kepler, the Transiting Exoplanet Survey Satellite (TESS), and other dedicated observatories, astronomers have confirmed 5,690 exoplanets in 4,243 star systems. With so many planets and systems available for study, scientists have been forced to reconsider many previously-held notions about planet formation and evolution and what conditions are necessary for life. In the latter case, scientists have been rethinking the concept of the Circumsolar Habitable Zone (CHZ).

By definition, a CHZ is the region around a star where an orbiting planet would be warm enough to maintain liquid water on its surface. As stars evolve with time, their radiance and heat will increase or decrease depending on their mass, altering the boundaries of the CHZ. In a recent study, a team of astronomers from the Italian National Institute of Astrophysics (INAF) considered how the evolution of stars affects their ultraviolet emissions. Since UV light seems important for the emergence of life as we know it, they considered how the evolution of a star’s Ultraviolet Habitable Zone (UHZ) and its CHZ could be intertwined.

The research team was led by Riccardo Spinelli, an INAF researcher from the Palermo Astronomical Observatory. He was joined by astronomers from the National Institute of Nuclear Physics (INFN), the University of Insubria, and the Astronomical Observatory of Brera. Their paper, “The time evolution of the ultraviolet habitable zone,” recently appeared in the Monthly Notices of the Royal Astronomical Society: Letters.

This infographic compares the orbit of the planet around Proxima Centauri (Proxima b) with the same region of the Solar System. Credit: ESO

As Spinelli told Universe Today via email, the UHZ is the annular region around a star where a planet receives enough UV radiation to trigger the formation of RNA precursors but not so much that it destroys biomolecules. “This zone primarily depends on the star’s UV luminosity, which decreases over time,” he said. “As a result, the UV habitable zone is farther from the star during the early stages of the star’s evolution and gradually moves closer to the star as time progresses.”

As astronomers have known for some time, CHZs are also subject to evolution, owing to changes in the star’s luminosity and heat output, which increase or decrease over time depending on the mass of the star. Addressing the interaction of these two habitable zones could shed light on which exoplanets are most likely to be “potentially habitable” for life as we know it. As Spinelli explained:

“We still do not know precisely how life originated on Earth, but we have some clues suggesting that ultraviolet (UV) radiation may have played a crucial role. Experimental studies, such as the one conducted by Paul Rimmer and John Sutherland in 2018, provide significant insights. In their experiment, Rimmer and Sutherland exposed hydrogen cyanide and hydrogen sulfite ions in water to UV light and discovered that this exposure efficiently triggered the formation of RNA precursors.

“Without UV light, the same mixture resulted in an inert compound that could not form the building blocks of life. Furthermore, RNA demonstrates a resistance to damage from UV radiation, indicating that it likely formed in a UV-rich environment. Indeed, UV radiation was one of the most abundant sources of chemical-free energy on the surface of the early Earth, suggesting it might have played a crucial role in the emergence of life.”

For their purposes, Spinelli and his colleagues sought to determine if (and for how long) the CHZ and the UVZ would overlap – thus facilitating the emergence of life. To this end, the team analyzed data from NASA’s Swift Ultraviolet/Optical Telescope (UVOT) to measure the current UV luminosity of stars with exoplanets that reside in the “classical” HZ. They then consulted data from NASA’s Galaxy Evolution Explorer (GALEX), an orbiting space telescope that has been observing galaxies up to 10 billion years away in the UV wavelength.

Illustration of the Trappist-1 system. Credit: NASA/JPL-Caltech

From GALEX, they incorporated how moving groups of young stars evolve in terms of their near-UV luminosity. “To estimate the evolution in time of the ultraviolet habitable zone, we used the results obtained by Richey-Yowell et al. 2023,” said Spinelli. “In this work, the authors derived an average UV luminosity evolution for each type of star. In our work, we reconstructed the evolution of the UV brightness of stars hosting planets in the classical habitable zone by combining the average evolution derived by Richey-Yowell et al. 2023 and the measurements carried out with the Swift Telescope.”

From this, they determined there is an overlap between the evolution of CHZs and UHZs. These results were especially significant for M-type (red dwarf) stars, where many rocky planets have been found orbiting within their CHZs. Previous research, which includes a 2023 paper by Spinelli and many of the same colleagues, has suggested that M-dwarf stars are not currently receiving near-UV radiation to support the prebiotic chemistry necessary for the emergence of life. However, their conclusions in this latest paper contradicted their previous findings. Said Spinelli:

“We assert that, when examining the evolution of NUV luminosity in M-dwarfs, most of these cool stars are indeed capable of emitting an appropriate amount of NUV photons during the first 1–2 billion yr of their lifetimes to trigger the formation of important building blocks of life. Our results suggest that the conditions for the onset of life (according to the specific prebiotic pathway we consider) may be or may have been common in the Galaxy. Indeed, in this work, we demonstrated that an intersection between the classical habitable zone and the ultraviolet habitable zone could exist (or could have existed) around all stars of our sample at different stages of their life, with the exceptions of the coolest M-dwarfs (temperature less than 2800 K, notably Trappist-1 and Teegarden’s star).”

While they may be a bit of a letdown for those hoping to find life on some of TRAPPIST-1s seven rocky planets, it bodes well for other M-type stars hosting rocky planets in their HZs. This includes the closest exoplanet to the Solar System (Proxima b), Ross 128 b, Luyten b, Gliese 667 Cc, and Gliese 180 b, all of which are within 40 light-years of Earth. These findings could have significant implications for exoplanet and astrobiology studies, which have been transitioning from discovery to characterization in recent years.

These fields will benefit from next-generation telescopes like Webb, the Nancy Grace Roman Space Telescope, and ground-based observatories that will enable Direct Imaging studies of exoplanets.

Further Reading: MNRAS

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On May 30th, the Mars Curiosity rover was just minding its own business exploring Gediz Vallis when it ran over a rock. Its wheel cracked the rock and voila! Pure elemental sulfur spilled out. The rover took a picture of the broken rock about a week later, marking the first time sulfur has been found in a pure form on Mars.

After Curiosity’s encounter with the broken rock and its pure sulfur innards, the rover trundled over to another rock, called “Mammoth Lakes” for a little drilling session. Before it left to explore other rocks, the rover managed to cut into that rock and take samples for further study to find out its chemical composition.

It’s not that sulfur isn’t prevalent on Mars. It is, but in different forms. The stuff is highly abundant in the Solar System, so this find isn’t as surprising as you’d think. However, Curiosity finding pure sulfur in the middle of broken rocks is a new experience in Mars exploration. So, of course, that’s raising questions about how it got there and its implications for habitable environments in Mars’s long history.

Curiosity’s Peregrinations

At the moment, the Curiosity rover is making its way through the Gediz Vallis. That’s a flow channel winding its way down a section of Mount Sharp (aka Aeolis Mons). That’s the central peak of Gale Crater. The rover has been heading up since 2014, charting different surface layers as it goes. Each layer was put down during a different era of Mars’s history. They could contain clues to the planet’s habitability in the past.

NASA’s Curiosity Mars rover captured this view of Gediz Vallis channel on March 31. Floods of water and debris piled rocks and sand into mounds within the channel. The rock the rover broke lies in a channel in this region.
 Credit: NASA/JPL-Caltech/MSSS 

Fast-moving liquid water raged over the surface and carved Gediz. The floods carried a lot of rocks and sand and deposited them all along the way. Other piles of flood debris lie around the region, bearing witness to other ancient floods and landslides. “This was not a quiet period on Mars,” said Becky Williams, a scientist with the Planetary Science Institute in Tucson, Arizona, and the deputy principal investigator of the Mast Camera, or Mastcam on Curiosity. “There was an exciting amount of activity here. We’re looking at multiple flows down the channel, including energetic floods and boulder-rich flows.”

Understanding Sulfur’s Presence

The surface materials in Gediz contain high amounts of sulfates. Those are sulfur-bearing salts that appear as water evaporates. They are a chemical clue that water existed in the region. Judging by some parts of the surface, it also appears the water ponded at some times, in addition to the floods that scoured the landscape and then deposited debris.

Now the planetary science team has to explain how a pure form of elemental sulfur got stuck in the middle of rocks, according to project scientist Ashwin Vasavada. “Finding a field of stones made of pure sulfur is like finding an oasis in the desert,” said Vasavada. “It shouldn’t be there, so now we have to explain it. Discovering strange and unexpected things is what makes planetary exploration so exciting.”

Putting Sulfur in Context

Sulfur, of course, exists on Earth, which helps scientists understand its behavior and the environments where it’s found. The presence of sulfur can be a result of various geological processes. The sulfur “cycle” includes the flow of sulfur from the core to the surface through volcanism. That’s not unusual. Sulfur commonly appears around volcanic vents. Mt Ijen in Indonesia is a good example. It sports extensive elemental sulfur deposits that are mined.

Traditional sulfur mining at Ijen. Candra Firmansyah. CC BU-SA 4.0.

The volcanic moon Io in the Jupiter system features patches of different allotropes of sulfur. They’re also volcanic in origin, spewed out along with widespread lava flows. This moon has more than 400 volcanic features, making it the most volcanically active (and sulfurous) place in the Solar System.

The Jovian moon Io is seen by the New Horizons spacecraft. The mission’s camera caught a view of one of this moon’s volcanos erupting. The region that Curiosity is investigating shows evidence of different kinds of sulfur-bearing minerals. Courtesy: NASA Goddard Space Flight Center Scientific Visualization Studio.

The pure sulfur in the Mars rock most likely came from volcanic processes. They occurred sometime in the past, but that doesn’t answer how the crystals got inside the rock it crushed. Scientists have known for years that Mars was extremely volcanically active in the past. For a long time, they also thought it was dead, or at least dormant. The planet has no plate tectonics like we see on Earth, either. However, the Mars InSight mission found evidence of some seismic activity on the planet in 2021.

In 2023, planetary scientists at the University of Arizona offered up evidence of a giant mantle plume under Elysium Planitia that drove some kinds of activity in the more recent past. Gale Crater lies in this region and could well have experienced related volcanic and seismic activity during the recent geologic past. If so, that could help explain the presence not only of pure sulfur but also the flood-related sulfates deposited on the surface.

For More Information

NASA’s Curiosity Rover Discovers a Surprise in a Martian Rock
Recent Volcanism on Mars Reveals a Planet More Active than Previously Thought
Sulfur on Mars from the Atmosphere to the Core

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One of the challenges engineers face when developing technologies for use in space is that of different gravities. Mostly, engineers only have access to test beds that reflect either Earth’s normal gravity or, if they’re fortunate, the microgravity of the ISS. Designing and testing systems for the reduced, but not negligible, gravity on the Moon and Mars is much more difficult. But for some systems, it is essential. One such system is electrolysis, the process by which explorers will make oxygen for astronauts to breathe on a permanent Moon or Mars base, as well as critical ingredients like hydrogen for rocket fuel. To help steer the development of systems that will work in those conditions, a team of researchers led by computational physicist Dr. Paul Burke of the Johns Hopkins University Applied Physics Laboratory decided to turn to a favorite tool of scientists everywhere: models.

Before we explore the model, examining the problem they are trying to solve is helpful. Electrolysis immerses an electrode in a liquid and uses an electrical current and subsequent chemical reaction to split atoms apart. So, for example, if you put an electrode in water, it would separate that water into hydrogen and oxygen.

The problem comes from reduced gravity. As part of electrolysis, bubbles form on the surface of the electrode. On Earth, those bubbles typically detach and float to the surface, as the density difference between them and the remaining liquid forces them to.

Dr. Burke presented alongside other experts at the Space Resources Week Workshop back in March.
Credit – ESRIC YouTube Channel

However, in reduced gravity, the bubbles either take much longer to detach or don’t do so at all. This creates a buffer layer along the electrode’s length that decreases the electrolysis process’s efficiency, sometimes stalling it out entirely. Electrolysis isn’t the only fluidic process that has difficulty operating in reduced gravity environments – many ISS experiments also have trouble. This is partly due to a lack of complete understanding of how liquids operate in these environments – and that in itself is partly driven by a dearth of experimental data. 

Which is where the modeling comes in. Dr. Burke and his colleagues use a technique known as Computational Fluid Dynamics to attempt to mimic the forces the fluids will undergo in a reduced gravity environment while also understanding bubble formation.

Electrolysis on Earth is typically done with water, but why stop there? The team used their CFD to model two other liquids that might be used in electrolyzers – molten salt (MSE) and molten regolith (MRE). Molten salt is used on Earth, but less commonly than regular water, and has successfully produced oxygen. However, molten regolith electrolysis is still somewhat of a novel use case and has yet to be thoroughly tested. MOXIE, the experiment that famously created oxygen on Mars in 2021, used the carbon dioxide in Mars’ atmosphere and a solid-state electrode – neither representative of molten regolith.

Fraser discusses MOXIE electrolysis with Dr. Michael Hect.

Dr. Burke and his team found that, computationally, at least, MRE has the most challenging conditions in reduced gravity. It has also never been tested in any reduced gravity environment, so for now; these simulations are all engineers have to go on with if they are going to design a system.

There were a few key takeaways from the modeling, though. First, engineers should design horizontal electrodes into MRE systems, as the longer a bubble spreads across an electrode (i.e., as it goes “up” it), the longer it takes for that bubble to detach. In a horizontal configuration, the electrode has less surface area to attach to, making it more likely for the bubbles to detach and float to the surface.

Additionally, the amount of time bubbles remain attached to an electrode scales exponentially with decreasing gravity. That means bubbles on the Moon will take longer to detach than those on Mars, which will take longer than those on Earth. Consequently, electrolysis on the Moon will be less efficient than that on Mars, which will again be less efficient than that on Earth, and mission planners will need to account for these discrepancies if they plan on getting something as mission-critical as oxygen from this process. The smoothness of the electrodes also seems to matter, with rougher electrodes more likely to hold onto their bubbles and, therefore, end up less efficient.

SciShow Space explores the world of MRE.
Credit – SciShow Space YouTube Channel

Other engineering solutions can overcome all these challenges, such as a vibratory mechanism on the electrode to shake the bubbles loose. However, it’s a good idea to consider all the additional complications operations in a reduced gravity environment have before launching a mission. That’s why modeling is so important, but humanity will ultimately have to experimentally test these systems, perhaps on the Moon itself, if we plan to utilize its local resources to sustain our presence there.

Learn More:
Burke et al. – Modeling electrolysis in reduced gravity: producing oxygen from in-situ resources at the moon and beyond
UT – NASA Wants to Learn to Live Off the Land on the Moon
UT – What is ISRU, and How Will it Help Human Space Exploration?
UT – A Robotic Chemist Could Whip up the Perfect Batch of Oxygen on Mars

Lead Image:
Graphic showing the difference in bubble accumulation in low and high gravities.
Credit – Burke et al.

The post Producing Oxygen From Rock Is Harder In Lower Gravities appeared first on Universe Today.

Why July 2024 is a prime time to see distant Pluto before it fades from view.

Lots of the ‘wow factor’ in astronomy revolves around knowing just what you’re seeing. Sure, a quasar might be a faint +14th magnitude point of light seen at the eyepiece, but it’s also a powerful energy source from the ancient Universe, billions of light-years distant.

The same case is true for finding Pluto. Though its 0.1” disc won’t resolve into anything more than a speck in even the most powerful backyard telescope, knowing just what you’re seeing is part of the thrill of finding the distant world.

Pluto in 2024

The good news is, Pluto reaches opposition for 2024 this week on July 23rd. This means it rises when the Sun sets, and is highest in the sky and well-placed for observation around midnight. 2024 sees Pluto loitering in the zodiacal constellation of Capricornus the Goat, just across the border from its former decade-long residence in Sagittarius.

A wide field finder chart for Pluto in July 2024. Credit: Stellarium

Fun fact: on a leisurely 248-year orbit, Pluto has only moved from the constellation Gemini where it was first discovered by astronomer Clyde Tombaugh in 1930, to its present position.

At the eyepiece, Pluto presents a +14th magnitude dot. You’ll have to star hop through the dense star field to locate the distant world. Sketching or photographing the region to cinch the sighting. Your watching for the slight but discernible motion of the world from one night to the next. Heavens-Above can give you the right ascension/declination search coordinates for Pluto for a given night.

The path of Pluto through late July into August. Stars are plotted down to +14th magntude. Credit: Starry Night.

I remember showing off Pluto to viewers at the Flandrau Observatory in Tucson with the 14” telescope… the world was an easy catch, even from bright downtown urban skies. Use a 6” or larger aperture telescope in your quest.

A Receding World

Pluto passed perihelion on September 5th, 1989. It is now headed out to a distant aphelion 49.3 Astronomical Units (AU or 7.4 billion kilometers) from the Sun next century in February 2114. This means that Pluto varies in brightness from an apparent magnitude of +13.7 near perihelion, to 16 times fainter at magnitude +16.3 near aphelion. Clyde was fortunate that Pluto was headed towards perihelion in the mid-20th century. Otherwise, it might well have eluded discovery (!) Pluto is getting successively fainter with each opposition in the 21st century, so the time to see it for yourself is now.

Pluto from 2016. Credit: Sharin Ahmad From a Dot to a World

Until less than a decade ago, we knew of Pluto’s brightness, distance and orbit… and not much else. One inside joke among astronomers was that Pluto’s size and mass estimates were shrinking at such a rapid rate, that by 1980 it would disappear altogether (spoiler alert: it didn’t). Charon was discovered by astronomer James Christy as a fuzzy blob peeking out from behind its parent body in images. The large moon was found using the 61-inch telescope at the Flagstaff Observatory in 1978. Since then, Hubble revealed four more moons, named Styx, Nix, Kerberos and Hydra.

At +16th magnitude, Charon should be in range of a large dedicated amateur telescope. To date, I’ve only ever seen one convincing potential capture of the large moon. Orbiting once every six days, Charon reaches a separation of about 1”… certainly, near opposition is a key time to try and carry out this extremely challenging observation. Bizarre fact: if astronauts make it to the surface of Pluto by 2107 AD, they can witness a cycle of solar eclipses, courtesy of Charon.

NASA’s New Horizons really opened up the frontier on Pluto and its moons during its historic flyby in 2015. The mission revealed the worlds in dramatic detail. Nearly a decade later, new research is still coming out on the results from the flyby. We now live in an era where we can discuss the formation of Charon, or the geology of Pluto…

New Horizons’ view of Pluto. Credit: NASA/APL/New Horizons

Good luck, on your quest to cross Pluto off of your astronomical life list.

The post Astro-Challenge: Catching Pluto at Opposition 2024 appeared first on Universe Today.

Craters are a familiar sight on the lunar surface and indeed on many of the rocky planets in the Solar System. There are other circular features that are picked up on images from orbiters but these pits are thought to be the collapsed roofs of lava tubes. A team of researchers have mapped one of these tubes using radar reflection and created the first 3D map of the tube’s entrance. Places like these could make ideal places to setup research stations, protected from the harsh environment of an alien world. 

Lava tubes have been hotly debated for the last 50 years. They are the result of ancient volcanic activity and develop when the surface of a lava flow cools and hardens. Below this, the molten lava continues to move and eventually drains away leaving behind a hollow tunnel. Exploring these tunnels can mean we can learn more about the geological history of the Moon from the preserved records in the rocks. 

The lava tubes have been the subject of analysis by NASA’s Lunar Reconnaissance Orbiter (LRO) which began its journey in 2009. It’s purpose was to gather information about the Moon’s surface and environment and to that end has a plethora of scientific equipment. LRO has been mapping the lunar surface using high resolution imagery capturing temperature, radiation levels and water ice deposits. All with a view to identifying potential landing sites for future missions.

Artist’s rendering of Lunar Reconnaissance Orbiter (LRO) in orbit. Credit: ASU/LROC

A team of scientists from around the world have been working together to make a breakthrough in the quest to understand these tubes. The research was led by the University of Trento in Italy and the results published in Nature Astronomy. They have identified the first, confirmed tunnel just under the surface of the Moon that seems to be an empty lava tube. Until now, their existence was just a theory, now they are a reality. 

The discovery would not have been possible without the LRO and its Miniature Radio-Frequency instrument. In 2010 it surveyed Mare Tranquilitatis – location for Apollo 11’s historic lunar landing in 1969 – capturing data which included the region around a pit. As part of this new research the data was reanalysed with modern complex signal processing techniques. The analysis revealed previously unidentified radar reflections that can best be explained by an underground cave or tunnel. Excitingly perhaps is that this represents an underground tunnel on the surface of the Moon but it is an accessible tunnel too.

Buzz Aldrin Gazes at Tranquility Base during the Apollo 11 moonwalk in an image taken by Neil Armstrong. Credit: NASA

The discovery highlights the importance of continued analysis of historical data, even from decades ago for hidden information that modern techniques can reveal. It also highlights the importance of further remote sensing and lunar exploration from orbit to identify more lava tubes as potential safe havens for lunar explorers. 

Travellers to the Moon can experience temperatures on the illuminated side of 127 degrees down to -173 degrees on the night time side. Radiation from the Sun can rocket – pardon the pun – to 150 times more powerful than here on Earth and that’s not even considering the threat of meteorite impacts. We are protected from thousands of tonnes of the stuff thanks to the atmosphere but there is no protective shield on the Moon. If we build structures on the surface of the Moon then they must be built to withstand such a hostile environment but look to lava tubes and many of the problems naturally go away making it a far safer and cheaper prospect to establish a lunar presence. 

Source : Existence of lunar lava tube cave demonstrated

The post The Entrance of a Lunar Lava Tube Mapped from Space appeared first on Universe Today.

Water purification is a big business on Earth. Companies offer everything from desalination to providing just the right pH level for drinking water. But on the Moon, there won’t be a similar technical infrastructure to support the astronauts attempting to make a permanent base there. And there’s one particular material that will make water purification even harder – Moon dust. 

We’ve reported plenty of times about the health problems caused by the lunar regolith, so it seems apparent that you don’t want to drink it. Even more so, the abrasive dust can cause issues with seals, such as those used in electrolyzers to create rocket fuel out of in-situ water resources. It can even adversely affect water purification equipment itself. 

Unfortunately, this contamination is inevitable. Lunar dust is far too adhesive and electrostatically charged to be kept completely separate from the machinery that would recycle or purify the water. So, a group of researchers from DLR in Germany decided to test what would happen if you intentionally dissolved lunar regolith.

Fraser interviews Dr. Kevin Cannon, an expert in lunar dust mitigation.

The short answer is, unsurprisingly, nothing good. Dissolved lunar regolith causes pH, turbidity, and aluminum concentrations all exceed World Health Organization benchmarks for safe drinking water. This happened even with short exposure times (2 minutes) and static pH values, as they used a 5.5 pH buffer in part of the experiments. 

They didn’t use actual lunar dust for these experiments, but a simulant modeled on the regolith returned during the Apollo 16 mission. It mimics the regolith that is thought to be most similar to the Artemis landing sites. In addition to the pH changes and the amount of exposure time (which went up to 72 hours), the authors also varied the amount of dissolved oxygen in the system and the particle size of the simulant.

Those negative results occurred for every test variation, no matter what combination of the four control variables was used. Ultimately, that means engineers will have to devise a system to filter the water from these deposits before it can be recycled into the overall water system.

After taking the first boot print photo, astronaut Buzz Aldrin moved closer to the little rock and took this second shot. His boot was already completely covered in adhesive dust.
Credit: NASA

The paper explored some potential solutions for that water purification system. Each of the limits that were violated requires its purification methodology. In the author’s estimation, lowering the turbidity is the first requirement. To do so, they suggest doing standard filtration or allowing the dust particles to settle. 

Removing aluminum is next in importance, with another experiment showing that plants that grew in lunar soil showed signs of aluminum toxicity. Additional ions, including calcium, iron, and manganese, also need to be removed, as they were above acceptable levels in some test batches but not all. Removing these ions would require a reverse osmosis process or ion exchange. Ion removal is vital to a fully functional electrolyzer system as well. 

The authors seemed to be ultimately going after a platform to test and validate water purification processes for future lunar exploration missions. Given the results from their experimentation, there will undoubtedly be future rounds of testing and plenty of technology development to work on solving these technical challenges. Ultimately, astronauts will have to drink water on the Moon – and it won’t be coming just from bottles from Earth.

Learn More:
Freer, Pesch, & Zabel – Experimental study to characterize water contaminated by lunar dust
UT – The Moon Is Toxic
UT – Astronauts Will Be Tracking Dust Into the Lunar Gateway. Is This a Problem?
UT – Lunar Dust is Still One of The Biggest Challenges Facing Moon Exploration

Lead Image:
Turbidity samples of some of the dissolved regolith.
Credit – Freer, Pesch, & Zabel

The post Moon Dust Could Contaminate Lunar Explorers’ Water Supply appeared first on Universe Today.

The International Space Station (ISS) has been continuously orbiting Earth for more than 25 years and has been visited by over 270 astronauts, cosmonauts, and commercial astronauts. In January 2031, a special spacecraft designed by SpaceX – aka. The U.S. Deorbit Vehicle – will lower the station’s orbit until it enters our atmosphere and lands in the South Pacific. On July 17th, NASA held a live press conference where it released details about the process, including a first glance at the modified SpaceX Dragon responsible for deorbiting the ISS.

As usual, the company shared details about the press conference and an image of the special Dragon via their official X account (formerly Twitter). As they indicated, SpaceX will deploy a modified spacecraft that will have six times the propellant and four times the power of “their “today’s Dragon spacecraft.” The image shows that the U.S. Deorbit Vehicle will have a robust service module in place of the trunk used by the standard Crew Dragon vehicle. This module is larger and has additional fold-out solar arrays in addition to hull-mounted solar panels.

With 6x more propellant and 4x the power of today’s Dragon spacecraft, SpaceX was selected to design and develop the U.S. Deorbit Vehicle for a precise, controlled deorbit of the @Space_Station https://t.co/GgtuplTwqQ pic.twitter.com/E23sS7CE4U

— SpaceX (@SpaceX) July 17, 2024

It also appears to have more Draco engines than the standard Crew Dragon vehicle – which has 18 engines capable of generating 400 Newtons (90 lbf) each – for a total of 7,200 N (360 lbf) of thrust. Presumably, this means the U.S. Deorbit Vehicle will have 72 Draco thrusters (arranged concentrically) and be capable of generating close to 30,000 Newtons (1,440 lbf) of thrust. The image also shows the spacecraft docking with the Kibo module operated by the Japan Aerospace Exploration Agency (JAXA).

NASA announced the selection of SpaceX in late June to develop the vehicle as part of a single-award contract with a total potential value of $843 million. While SpaceX is responsible for developing the spacecraft, NASA will take ownership once it is complete and operate it throughout the mission. Both the spacecraft and ISS are expected to break up during re-entry, and the remains will land in the “spacecraft cemetery” in the South Pacific. The contract for the launch services has not yet been awarded but is expected to be announced shortly.

SpaceX is also responsible for developing the Human Landing System (HLS) – the Starship HLS – that will transport astronauts to the lunar surface as part of the Artemis III and IV missions. SpaceX has also been contracted to launch the core elements of the Lunar Gateway – the Power and Propulsion Element (PPE) and the Habitation and Logistics Outpost (HALO) – into lunar orbit using a Falcon Heavy rocket in November 2025.

The International Space Station (ISS) in orbit. Credit: NASA

Since 1998, the ISS has served as a unique scientific platform where crew members from five space agencies – including NASA, the Canadian Space Agency), the European Space Agency (ESA), JAXA, and the Russian State Space Corporation (Roscosmos). During its operational lifetime, crew members have performed experiments ranging from the effects of microgravity and space radiation on human, animal, and plant physiology. This research will play a vital role as NASA and its international partners conduct long-duration missions to the Moon and Mars in the coming decades.

The station has also allowed for extensive research into space science, biology, the physical sciences, and technology demonstrations that are not possible on Earth. Above all, the ISS has served as a symbol of international cooperation, consistent with the Outer Space Treaty and its core philosophy of “space is for all.” NASA, the CSA, the ESA, and JAXA have all committed to operating the station through 2030, while Roscomos has committed to continue operations until 2028 at least. The safe deorbit of the ISS is the responsibility of all five space agencies.

Further Reading: NASA

The post SpaceX Reveals the Beefed-Up Dragon That Will De-Orbit the ISS appeared first on Universe Today.

For over ten years, the ESA’s Gaia Observatory has monitored the proper motion, luminosity, temperature, and composition of over a billion stars throughout our Milky Way galaxy and beyond. This data will be used to construct the largest and most precise 3D map of the cosmos ever made and provide insight into the origins, structure, and evolutionary history of our galaxy. Unfortunately, this sophisticated astrometry telescope is positioned at the Sun-Earth L2 Lagrange Point, far beyond the protection of Earth’s atmosphere and magnetosphere.

As a result, Gaia has experienced two major hazards in recent months that could endanger the mission. These included a micrometeoroid impact in April that disrupted some of Gaia‘s very sensitive sensors. This was followed by a solar storm in May—the strongest in 20 years—that caused electrical problems for the mission. These two incidents could threaten Gaia‘s ability to continue mapping stars, planets, comets, asteroids, quasars, and other objects in the Universe until its planned completion date of 2025.

Micrometeroids are a common problem at the L2 Lagrange Point, roughly 1.5 million km (932,057 mi) from Earth, so engineers designed Gaia with a protective cover. Unfortunately, the particle was traveling at a very high velocity and struck the cover at precisely the wrong angle, causing a breach. This has allowed stray sunlight to interfere with Gaia’s ability to simultaneously collect light from so many distant stars. Gaia‘s engineering team was addressing this issue the moment the solar storm hit, adding electrical issues to their list of problems.

Gaia’s all-sky view of our Milky Way Galaxy and neighboring galaxies, based on measurements of nearly 1.7 billion stars. Credit: ESA

Mission controllers first noticed signs of disruption in May when Gaia began registering thousands of false detections. They soon realized that this may have been due to the solar storm that began on May 11th, which could have caused one of the spacecraft’s charge-coupled devices (CCDs) to fail, which converts light gathered by Gaia’s billion-pixel camera into electronic signals. The observatory relies on 106 CCDs, each playing a different role. The affected sensor was vital for Gaia’s ability to confirm the detection of stars and validate its observations.

While the spacecraft was built to withstand radiation, it has been operating in space for almost twice as long as originally planned (6 years) and may have been pushed to its limits. As Edmund Serpell, Gaia spacecraft operations engineer at ESOC, explained in an ESA press release:

“Gaia typically sends over 25 gigabytes of data to Earth every day, but this amount would be much, much higher if the spacecraft’s onboard software didn’t eliminate false star detections first. Both recent incidents disrupted this process. As a result, the spacecraft began generating a huge number of false detections that overwhelmed our systems. We cannot physically repair the spacecraft from 1.5 million km away. However, by carefully modifying the threshold at which Gaia’s software identifies a faint point of light as a star, we have been able to dramatically reduce the number of false detections generated by both the straylight and CCD issues.”

Meanwhile, the Gaia teams at ESA’s European Space Operations Centre (ESOC), the European Space Research and Technology Centre (ESTEC), and the European Space Astronomy Center (ESAC) have spent the past few months investigating these problems. They have also worked closely with engineers from Airbus Defence and Space (the spacecraft’s manufacturer) and payload experts at the Data Processing and Analysis Consortium. Thanks to their efforts, the Gaia Observatory recently returned to regular operations.

Illustrated effects of Space weather. Credit: ESA/Science Office

In addition, the engineers used the opportunity to refocus the optics on Gaia’s twin telescopes one last time, which has led to some of the best-quality data Gaia has ever produced. As a result, we can expect that Gaia’s final Data Release (DR5)—which will include the full mission data—will be even more poignant!

Further Reading: ESA

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