Astronomy

Some lizards dive into streams to escape predators, and a specialised bubble-breathing technique enables them to stay submerged for up to 18 minutes

A natural border between

In February 2016, scientists at the Laser Interferometer Gravitational-wave Observatory (LIGO) confirmed they made the first-ever detection of gravitational waves (GWs). These events occur when massive objects like neutron stars and black holes merge, sending ripples through spacetime that can be detected millions (and even billions) of light-years away. Since the first event, more than 100 GW events have been confirmed by LIGO, the Advanced VIRGO collaboration, and the Kamioka Gravitational Wave Detector (KAGRA).

Moreover, scientists have found numerous applications for GW astronomy, from probing the interiors of supernovae and neutron stars to measuring the expansion rate of the Universe and learning what it looked like one minute after the Big Bang. In a recent study, an international team of astronomers proposed another application for binary black hole (BBH) mergers: using the earliest mergers in the Universe to probe the first generation of stars (Population III) in the Universe. By modeling how the events evolved, they determined what kind of GW signals the proposed Einstein Telescope (ET) could observe in the coming years.

The study was led by Boyuan Liu, a postdoctoral researcher at the Center for Astronomy of Heidelberg University (ZAH) and a member of the Excellence Cluster STRUCTURES program. He was joined by colleagues from the ZAH and the Institut für Theoretische Astrophysik at Heidelberg University, the Cambridge Institute of Astronomy, the Institute for Physics of Intelligence, the Institut d’Astrophysique de Paris, the Centre de Recherche Astrophysique de Lyon, the Gran Sasso Science Institute (GSSI), the Kavli Institute for Cosmology, the Weinberg Institute for Theoretical Physics, and multiple universities.

From Cosmic Dark to Dawn

Population III stars are the first to have formed in the Universe, roughly 100 to 500 million years after the Big Bang. At the time, hydrogen and helium were the most plentiful forms of matter in the Universe, leading to stars that were very massive and had virtually no metals (low metallicity). These stars were also short-lived, lasting only 2 to 5 million years before they exhausted their hydrogen fuel and went supernova. At this point, the heavier elements created in their cores (lithium, carbon, oxygen, iron, etc.) dispersed throughout the cosmos, leading to Population II and I stars with higher metallicity content.

Astronomers and cosmologists refer to this period as “Cosmic Dawn” since these first stars and galaxies ended the “Cosmic Dark Ages” that preceded it. As Liu explained to Universe Today via email, the properties of Pop III stars were sensitive to the peculiar conditions of the Universe during Cosmic Dawn, which were very different from the present-day conditions. This includes the presence of Dark Matter Haloes, which scientists believe were vital to the formation of the first galaxies:

“The timing of Pop III star formation reflects the pace of early structure formation, which can teach us about the nature of dark matter and gravity. In the standard cosmology model, cosmic structure formation is bottom-up, starting from small halos, which then grow by accretion and mergers to become larger halos. Pop III stars are expected to be massive (> 10 solar masses, reaching up to 1 million solar masses, while present-day stars have an average mass of ~ 0.5 solar masses). So, many of them will explode as supernovae or become massive black holes (BHs) when they run out of fuel for nuclear fusion.”

These Pop III black holes are further believed to be where the first supermassive black holes (SMBHs) in the Universe came from. As astronomers have demonstrated, SMBHs play an important role in the evolution of galaxies. In addition to assisting in the formation of new stars and encouraging galaxy formation in the early Universe, they are also responsible for shutting down star formation in galaxies ca. 2 to 4 billion years after the Big Bang, during the epoch known as “Cosmic Noon.” The growth of these black holes and the UV radiation emitted by Pop III stars reionized the neutral hydrogen and helium that permeated the early Universe.

This led to the major phase transition that ended the Cosmic Dark Ages (ca. 1 billion years after the Big Bang), allowing the Universe to become “transparent” as it is today. However, as Liu stated, how this process started remains unclear:

“Generally speaking, Pop III stars mark the onset of cosmic evolution from a starless (boring) state to the current state with rich phenomena (reionization, diverse populations of galaxies with different masses, morphologies, and compositions, andquasars powered by accreting supermassive BHs). To understand this complex evolution, it isessential to characterize its initial phase dominated by Pop III stars.”

Probing the Early Universe

The confirmation of gravitational waves (GW) was revolutionary for astronomers, and many applications have since been proposed. In particular, scientists are eager to study the primordial GWs created by the Big Bang, which will be possible with next-generation GW detectors like the Laser Interferometer Space Antenna (LISA). As Liu explained, existing GW detectors are mostly dedicated to studying binary black hole (BBH) mergers. The same is true of detectors expected to be built in the near future. Said Liu:

“The GW emission from a BH binary is stronger when they are closer. The GW emission carries away energy and angular momentum from the system such that the two BHs will get closer over time and eventually merge. We can only detect the GW signal at the final stage when they are about to merge. The time taken to reach the final stage is highly sensitive to the initial separation of the BHs. Basically, they have to start close (e.g., less than ~ 10% of the earth-sun distance for BHs below 10 solar masses) to merge within the current age of the Universe to be seen by us.”

The question is, how do two black holes get so close to each other that they will eventually merge? Astronomers currently rely on two evolutionary “channels” (sets of physical processes working together) to model this process: isolated binary stellar evolution (IBSE) and nuclear star cluster-dynamical hardening (NSC-DH). As Liu indicated, the resulting BBH mergers have distinct features in their merger rate and properties, depending on the channel they follow. They contain valuable information about the underlying physical processes.

“Knowledge of evolution channels is necessary to extract such information to fully utilize GWs as a probe for astrophysics and cosmology,” he added.

Modeling BBH Evolution

To determine how black holes come to form binaries that will eventually merge, the team combined both channels into a single theoretical framework based on the semianalytical model Ancient Stars and Local Observables by Tracing Halos (A-SLOTH). This model is the first publicly available code that connects the formation of the first stars and galaxies to observations. “In general, A-SLOTH follows the thermal and chemical evolution of gas along the formation, growth, and mergers of dark matter halos, including star formation and the impact of stars on gas (stellar feedback) at the intermediate scale of individual galaxies/halos,” said Liu.

Current operating facilities in the global network and their planned expansion. Credit: Caltech/MIT/LIGO Lab

They also used the Stellar EVolution for N-body (SEVN) code to predict how stellar binaries evolve into BBHs. They then modeled the orbit of each BBH in their respective dark matter halos and during halo mergers, which allowed them to predict when some BBHs will merge. In other cases, BBHs travel to the center of their galaxies and become part of a nuclear star cluster (NSC), where they are subject to disruptions, ejections, and hardening by gravitational scattering. From this, they followed the evolution of internal binary orbits to the moment of merger or disruption.

Next-Generation Observatories

As Lui explained, their results had significant theoretical and observational implications:

“On the theory side, my work showed that the isolated binary evolution channel dominates at high redshifts (less than 600 million years after the Big Bang) and the merger rate is sensitive to the formation rate and initial statistics of Pop III binary stars. In fact, the majority (> 84%) of BH binaries, especially the most massive ones, are initially too wide to merge within the age of the Universe if they evolve in isolation. But a significant fraction (~ 45 – 64%) of them can merge by dynamical hardening if they fall into NSCs. These predictions are useful for the identification and interpretation of merger origins in observations.”

In terms of observational results, they found that the predicted detection of Pop III BBH mergers is not likely to be discernible by current instruments like LIGO, Advance Virgo, and KAGRA, which generally observe BBH mergers closer to Earth. “[A]ltough Pop III mergers can potentially account for a significant fraction of the most massive BH mergers detected so far (with BHs above 50 solar masses),” said Liu. “It is difficult to learn much about Pop III stars and galaxies in the early Universe from the existing data because the sample size of detected massive mergers is too small.”

However, next-generation detectors like the Einstein Telescope will be more efficient in detecting these distant sources of GWs. Once completed, the ET will allow astronomers to explore the Universe through GWs back to the Cosmic Dark Ages, providing information on the earliest BBH mergers, Pop III stars, and the first SMBHs. “My model predicts that the Einstein Telescope can detect up to 1400 Pop III mergers per year, offering us much better statistics to constrain the relevant physics.”

The paper that describes their findings recently appeared online and is being reviewed for publication in the Monthly Notices of the Royal Astronomical Society.

Further Reading: arXiv

The post Future Gravitational Wave Observatories Could See the Earliest Black Hole Mergers in the Universe appeared first on Universe Today.

In a survey of thousands of people, respondents underestimated the massive difference between the carbon footprints of the wealthiest and poorest individuals – and that’s bad for climate policy

In a survey of thousands of people, respondents underestimated the massive difference between the carbon footprints of the wealthiest and poorest individuals – and that’s bad for climate policy

A quantum computing protocol makes it possible to extract energy from seemingly empty space, teleport it to a new location, then store it for later use

A quantum computing protocol makes it possible to extract energy from seemingly empty space, teleport it to a new location, then store it for later use

On opposite sides of the Atlantic Ocean, Central Europe and North Carolina have both been drenched by torrential rains

A SpaceX Falcon 9 rocket launched two European navigation satellites tonight (Sept. 17) and then landed safely, acing its 22nd mission.

Americans are famously fond of their guns. So it should come as no surprise that a team of NASA scientists has devised a way to “shoot” a modified type of sensor into the soil of an otherworldly body and determine what it is made out of. That is precisely what Sang Choi and Robert Moses from NASA’s Langley Research Center did, though their bullets are miniaturized spectrometers rather than hollow metal casings. 

First, let’s look at the miniaturized spectrometers. Spectrometers have been a workhorse of space exploration for decades. They analyze everything from the surface of Enceladus to stars. However, they almost all use a type of spectroscopy known as Fraunhofer diffraction. Drs. Choi and Moses decided to use a different physical phenomenon in their invention, known as Fresnel’s diffraction.

In Fresnel diffraction, a spectral graph becomes very clear at much smaller distances than those created by Fraunhofer diffraction. Since the necessary distance between a “grating” and the sensor required by a spectrometer using Fraunhofer diffraction is one of the system’s design constraints, most spectrometers in use today are prohibitively large.

Fraser discusses the importance of the lunar south pole – which includes many permanently shadowed craters

Fresnel diffraction, however, allows for the creation of much smaller spectrometers. In the case of Dr. Choi and Moses’s invention, all of the necessary power, signaling, and analysis electronics can fit into a small cylindrical tube only slightly larger than a traditional bullet.

That was likely where the idea for shooting these sensors into the ground came from. If the “micro-spectrometers” were surrounded by regolith, whether the Moon, an asteroid’s, or Mars’, it would allow quick analysis of the composition of the soil wherever it is embedded. Since these sensors are easily deployed, if multiple of them were spread throughout a lunar crater, a single astronaut (or rover) could characterize the soil makeup of an entire area without hand-digging a space for each sample area.

This is where the “gun” comes in—a rover, or even an astronaut, could be fitted with a tube that “fires” the cylindrical micro-spectrometer into the ground, embedding it where it can do the best science. A single rover or astronaut could then distribute enough of these to collect data on an entire area, such as the permanently shadowed regions of a lunar crater.

Image of a prototype micro-spectrometer
Credit – Choi and Moses

Such a system could also be used on asteroids from an orbiter or even Mars. It could use telemetry back to a central connection point—potentially also carried by the astronaut or rover. Unfortunately, at least in the current iteration, it couldn’t be reused, though that could change in new designs.

This invention, which NASA has patented, could also be used on Earth if a mining or petroleum company wants to quickly sample an area’s geological makeup. But it is also useful in space—so much so that we might someday find astronauts shooting what look to be bullets but are actually miniaturized sensors directly into the ground.

Learn More:
Sang H Choi – Lunar, Mars, and Asteroid Exploration for Space Resources
Choi & Moses – Micro-Spectrometer for Resource Mapping in Extreme Environments
UT – The Darkest Parts of the Moon are Revealed with NASA’s New Camera
UT – Absorption Spectroscopy

Lead Image:
Depiction of the “bullets” being deployed in a lunar crater.
Credit – NASA

The post Could You Find What A Lunar Crater Is Made Of By Shooting It? appeared first on Universe Today.

Is it time for space lasers yet? Almost.

As time passes, ideas that were once confined to the realm of science fiction become more realistic. It’s true of things like using robots to explore other worlds. Space lasers are a well-used element in science fiction, and we’re approaching the time when they could become a reality.

Where would we put them, and what could we use them for?

In science fiction, lasers are predominantly used as powerful weapons. While some countries have investigated the idea of using lasers as space weapons, an international treaty limits their use.

A more realistic use for lasers is for deflecting incoming asteroids or as propulsion systems for spacecraft. In a new paper, a researcher examines where a giant laser array could be positioned in space to be of most use to humanity while at the same time minimizing risk.

The research is “Minimum Safe Distances for DE-STAR Space Lasers.” The paper is in pre-print, and Adam Hibberd from the Initiative for Interstellar Studies in London, UK, is the sole author.

While space lasers could also be used to utilize resources or in satellite laser ranging systems to control space traffic, Hibberd’s focus is on using them to protect Earth from impacts.

DE-STAR stands for Directed Energy Systems for Targeting of Asteroids and exploRation. Of all the space laser ideas that have been discussed, DE-STAR is probably the most well-studied and developed. It would consist of a modular phased array of lasers powered by solar cells. It could heat the surface of potentially hazardous objects (PHO) to approximately 3,000 Kelvin. That’s hot enough to melt all known constituents of PHOs. DE-STAR could also be used to propel spacecraft.

The idea originated in 2013 when a group of researchers published a paper titled “DE-STAR: Phased-Array Laser Technology for Planetary Defense and Other Scientific Purposes.” In their paper, they outlined the idea for DE-STAR, a stand-off laser array. In 2016, some of the same authors published another paper titled “Directed Energy Missions for Planetary Defense.” It expanded on DE-STAR and added DE-STARLITE, a stand-on system that would be sent to the vicinity of an approaching object to ward it off with lasers.

This artist’s illustration shows DE-STARLITE firing its lasers at a hazardous object. Image Credit: Lubin et al. 2016.

In either case, the system would be based on the Sun’s energy. “DE-STAR is a square modular design which exploits the energy created by banks of solar cells in space to generate and amplify the power of a laser beam,” Hibberd explains in his new paper. In literature, DE-STAR is typically referred to as DE-STAR n, where n is usually between 0 and 4 and denotes the size of the bank of lasers. The larger the array, the more powerful it is. The more powerful DE-STAR is, the more effective it will be at deflecting asteroids from greater distances.

While the merit of this idea is immediately clear, the problems follow soon after. A bank of powerful space lasers is every supervillain’s dream. Its destructive power could be immense. “With a DE-STAR 4
structure (10 km × 10 km square) capable of generating a laser beam on the order of tens of gigawatts,
clearly, there is the potential for such an asset to be deployed as a weapon by targeting locations on Earth,” Hibberd writes.

How can this risk be mitigated so that the system can be used to protect Earth rather than as a weapon?

The simple solution is to not deploy them in Earth’s orbit. The lasers lose energy with range, so they could be deployed at distances where they pose no threat. “Results indicate that given they should lie 1 au from
the Sun, there are feasible locations for DE-STAR 0-2 arrays where there is no danger to Earth,” Hibberd writes.

This table from the paper shows the specs adopted in this paper for different-sized DE-STAR arrays. The clip ratio affects beam quality, energy efficiency, how well it propagates through space, and how well it handles heat generation. Smaller is generally better, and 0.9 is the ratio adopted by other researchers. Optimizing the clip ratio is an important part of designing an effective array. Image Credit: Hibberd 2024.

Of course, the more lasers there are in the array, the greater the safe minimum distance.

For DE-STAR 4 or even 5, that distance wouldn’t be enough. Instead, these lasers would need to be much further away or at positions in the Solar System with no direct line of sight to Earth. These systems would need to correct their positions regularly with an on-board propulsion system “or preferably using push-back from the laser itself,” Hibberd explains.

The minimum safe distance also changes depending on the wavelength of the DE-STAR system. Hibberd defines minimum safe distance as a single laser with a maximum intensity on Earth’s surface of 100 Wm-2. “Or on the order 10 % of the Solar Constant at Earth (1 au from the Sun),” Hibberd writes. For an infrared system, the minimum safe distance is just beyond geosynchronous Earth orbit (GEO). At the more powerful end of the scale, a UV laser would need to be beyond cis-lunar space.

This figure from the research shows the Dependence of the Minimum Safe Distance of any Unphased DE-STAR Array with the Wavelength of the Laser. Image Credit: Hibberd 2024.

There’s another factor to consider. Since DE-STAR gets its energy from the Sun, its power decreases the further away from the Sun it is. “This reduction is a consequence of the decrease in solar flux intensity on the photovoltaic cells, where an inverse square law is followed,” Hibberd explains.

This figure shows how the laser’s power diminishes with distance from the Sun for four different array sizes. “We find that a DE-STAR n at 90 au from the Sun is approximately equivalent to a DE-STAR n-1 at 10 au and a DE-STAR n-2 at 1 au,” Hibberd writes. Image Credit: Hibberd 2024.

For DE-STAR 1 and 2 Arrays, the minimum safe distances are not that great. Hibberd points out that for a DE-STAR 2 Array, Sun/Earth Lagrange 4 and 5 points would be suitable and require no propulsion. L4 and L5 are about 400,000 km from Earth.

These figures show the minimum safe distance for DE-STAR 1 and 2 Arrays by wavelength. Image Credit: Hibberd 2024.

However, as the arrays become larger, the minimum safe distance quickly increases. Conversely, the available solar energy decreases.

A DE-STAR 3 would have to be placed somewhere beyond the asteroid belt. If it were ultraviolet, it would have to be beyond Jupiter.

A DE-STAR 4 phased array would have to be much further away. It would have to be about 30 ? 40 au away, and even further for an ultraviolet system, about 70 au from the Sun.

These figures show the minimum safe distance for DE-STAR 3 and 4 Arrays by wavelength. Image Credit: Hibberd 2024.

The tables above assume a direct line of sight to Earth. But there are locations where there is no direct line, and they could be used as locations for powerful arrays. Hibberd explains that the Earth/Moon Lagrange 2 point and the Sun/Earth Lagrange 3 point both lack direct lines of sight but, unfortunately, are unstable. “In both cases, the instability of these points will result in the DE-STAR wandering away and potentially becoming visible from Earth, so an on-board propulsion would be needed to prevent this,” Hibberd writes. It’s possible that an array could be built that is physically prevented from pointing at Earth, but the author doesn’t tackle that aspect of the problem.

Sun-Earth Lagrange Points. Credit: Xander89/Wikimedia Commons

Nobody’s building a DE-STAR phased array, but that doesn’t mean it’s too soon to think about it. This type of technology is on the horizon, and it’s difficult to predict which nation or nations might be the first to build one. Treaties are in place to prevent the weaponization of space, but not everybody signed them. Some nations are known to sign treaties and then break them, in any case. Also, an argument could be made that this isn’t a weapon.

It likely won’t be long before serious talk about such a system begins to surface in wider public discussions. That will surely generate a lot of political difficulty and wrangling as nations argue over what constitutes a weapon and what doesn’t.

If civilization is to survive, we will eventually need a way to protect the entire globe from asteroid strikes, whether it’s phased laser arrays or some other system.

The post There are Plenty of Uses for Powerful Lasers in Space. But Where Should We Put Them? appeared first on Universe Today.

Even though the strange behaviour we observe in the quantum realm isn’t part of our daily lives, simulations suggest it is likely our reality could be one of the many worlds in a quantum multiverse

Even though the strange behaviour we observe in the quantum realm isn’t part of our daily lives, simulations suggest it is likely our reality could be one of the many worlds in a quantum multiverse

If microscopic black holes born a fraction of a second after the Big Bang exist, then at least one may fly through the solar system per decade, generating tiny gravitational distortions that scientists can detect.

The FAA has proposed fining SpaceX more than $630,000 for allegedly failing to comply with regulations on two launches in 2023.

"I would say family and part of that 'first-gen experience' [shaped me]...It shaped me to be a hard worker and to aspire to large things because not only was it my goal at this point, but it was also my parents' aspiration." – Zaida Hernandez, Engineer, Lunar Architecture Team, NASA's Johnson Space Center

Comet Tsuchinshan-ATLAS will sweep around the sun on Sept. 27 to make a brief foray into the morning sky. Will it be a bright naked-eye object with a significant tail? Here's where and when you might be able to see it.

Billions of dollars of observatory spacecraft orbit around Earth or in the same orbit as our planet. When something wears out or goes wrong, it would be good to be able to fix those missions “in situ”. So far, only the Hubble Space Telescope (HST) has enjoyed regular visits for servicing. What if we could work on other telescopes “on orbit”? Such “fixit” missions to other facilities are the subject of a new NASA paper investigating optimal orbits and trajectories for making service calls on telescopes far beyond Earth.

Some of the most productive orbiting telescopes operate at the Sun-Earth Lagrange points L1 and L2. Currently, those positions afford us some very incredible science. What they can’t afford is easy access for repairs and servicing. That limits the expected lifetime of facilities such as JWST to about 10-15 years. In the future, more missions will be deployed a Lagrange points. These include the Nancy Grace Roman Telescope, ESA’s PLATO and ARIEL missions, and the Large Ultraviolet Optical Infrared Surveyor (LUVOIR).

Artist’s impression of the Nancy Grace Roman Space Telescope, named after NASA’s first Chief of Astronomy. This spacecraft will orbit at SEL2, far from Earth. Credits: NASA

These observatories need propellants for attitude thrusters to help them stay ‘in place’ during their observations. There’s only so much “gas” you can send along with these observatories. In addition, components wear out, as they did with HST. So, people are looking at ways to extend their lifetimes through servicing missions. If failing components can be replaced and propellant delivered, the lifetimes of these observatories should be extended quite a bit, giving astronomers more bang for the observational buck.

Planning Future Spacecraft Servicing Missions

Researchers at the Satellite Servicing Capability Office (SSCO) at the Goddard Space Flight Center (GSFC) investigated the possibilities for servicing missions to distant space telescopes. In a recently released paper, they focus on the feasibility of on-orbit refueling missions for space telescopes orbiting at Sun-Earth Lagrange 2 (SEL2).

There are many challenges. For one thing, present-day launch technologies are (at this writing) inadequate to do that kind of mission at such distances. Clearly, the technology has to advance for servicing visits to take place. In addition, it’s important to remember that current telescopes, such as Gaia and JWST, weren’t designed for such access. However, future telescopes can be fitted with servicing ports, etc. to enable servicing. Finally, there are the challenges of actually getting the servicing missions to the observatories.

Illustration of OSAM-1 (bottom) grappling Landsat 7. This servicing mission concept was discontinued by NASA, but remains a good example of what’s needed to perform repairs and refueling to orbiting spacecraft. Credits: NASA

The Goddard team focused on this final issue by computing models of various launch and orbital solutions for such missions. Not only did they take into account the launch trajectories themselves, but also Sun-Earth-Lagrange point dynamics, plus the relative positions of observatories at SEL2. In addition, the team considered the stability of the observatories during and after rendezvous and attachment. All of these factors count when planning whether or not a servicing vehicle can be launched at a reasonable cost to extend the lifetime of the observatory enough to make the effort worth the time and expense.

Getting a Spacecraft Refuelling Mission Underway

The team created models for a theoretical mission for on-orbit fuelling at SEL2. That’s where JWST and Gaia are sitting, for example, along with WMAP, Planck, and others. The paper examines robotic refueling missions out to SEL2 for modeling purposes.

To do that, however, there must be an optimal trajectory for the robotic spacecraft to take out to SEL2. They need to be able to perform autonomous navigation to the correct point in space. Once at the target observatory, the refueling robot would then need to make a careful approach for its docking maneuvers. That requires on-orbit assessment of the target’s motion in space with respect to the Sun as well as its position in its SEL2 orbit. Docking itself can affect the observatory’s position and motion and the robot needs to take that into account, as well. The idea is to keep the observatory in the same position after docking.

However, the big question is: how do we get it out there inexpensively, fast, and safe?

The Goddard team primarily investigated the best and most efficient trajectories to get to SEL2. In particular, they looked at the best approaches to get to the Gaia spacecraft, which will run out of its propellant sometime in the next year. They also examined JWST as a possible target for such a mission. If such a mission was possible today, those observatories would gain years of “point and shoot” access to the Universe.

How to Get There

In their paper, the team looks at two approaches to the SEL2 refueling mission. One is a direct launch trajectory from Earth and the other is a spacecraft leaving from a geostationary transfer orbit (GTO). They assumed that the point of the mission was the fastest possible restoration of telescope operation. That dictates the shortest and safest possible trajectory along which the spacecraft can maintain constant thrust.

The Goddard team created a “forward design” approach for computing low-energy and low-thrust transfers from an Earth departure orbit to a space telescope orbiting the SEL2 point. Then they did the same for a servicing spacecraft leaving from a point in geostationary space. Essentially, either an Earth-departure or GTO-centric departure will work. Once the robotic servicing mission leaves Earth orbit, it travels at low thrust during a spiraling transit to SEL2. Once there, it does a rendezvous with the target, matches its motion in space, and then “locks on” to perform its delivery mission.

It’s important to remember that a launch from Earth or GTO is part of several solutions to SEL2 servicing missions. The team’s analysis resulted in a simplified process of generating possible orbits and trajectories for such activities. You can read the full text of their detailed analysis of the different trajectory solutions at the link below.

For More Information

Mission Design for Space Telescope Servicing at Sun-Earth L2
JWST Home Page
Gaia Telescope

The post There Could be a Way to Fix Spacecraft at L2, Like Webb and Gaia appeared first on Universe Today.

Maternity services need to educate parents-to-be on how pregnancy will affect their brain - their life could depend on it, says Helen Thomson

Maternity services need to educate parents-to-be on how pregnancy will affect their brain - their life could depend on it, says Helen Thomson