Astronomy

One underappreciated aspect of the current flood of exoplanet discoveries is the technical marvels that enable it. Scientists and engineers must capture and detect minute signals from stars and planets light years away. With the technologies of even a few decades ago, that would have been impossible – now it seems commonplace. However, there are still some technical hurdles to overcome before finding the “holy grail” of exoplanet hunting – an Earth analog. To help that discussion, a team of researchers led by Bertrand Mennesson at NASA’s Jet Propulsion Laboratory has released a paper detailing the current experimental and theoretical work around one of the most critical technical aspects of researching exoplanet atmospheres – starshades.

In particular, the paper discusses the technical hurdles of one of the most interesting upcoming space technology concepts. The Habitable Worlds Observatory (HWO) was called for as part of NASA’s recent decadal survey. While it is still early in its development cycle, the general outlines of how the HWO will work are evident, even if some technical details aren’t. And those general outlines point to the need for a starshade or coronagraph – or both.

The paper details the difference between a starshade and a coronagraph. By its definition, a starshade is a filter placed between the primary telescope mirror and the object it is observing. In contrast, a coronagraph is a filter placed between the primary mirror and the telescope’s sensor. Both methods have advantages and disadvantages regarding the data they allow the telescope to collect, but they can also be combined.

Starshades aren’t only useful for space telescopes, as Fraser discusses with Dr. Markus Janson in this video.

Several labs worldwide have been working on developing starshade and coronagraph technology. However, several nuances to the test set-ups affect their work’s applicability to the HWO project. Some tests are performed in a vacuum, while others are performed in air. Some tests are performed on monolith mirrored telescopes, while others are performed on segmented mirrors. Currently, the baseline operational mode of HWO is a space-based telescope, which, given current launch size constraints, also means it has to be segmented. So, only some tests performed to validate coronagraph and starshade technologies apply to the HWO use case.

For the relevant tests, there are three particular “key performance parameters” (KPPs), as the paper calls them, which can impact the technology’s viability. These are the image’s “raw” contrast, the “post-calibration” contrast, and the “off-axis throughput.” Each of these has thoroughly technical definitions described in the paper. But the first two can be thought of as how easy it is to see an exoplanet before (“raw”) and after (“post-calibration”) an image is run through a data processing algorithm. Off-axis throughput is the percentage of light from the planet through the starlight suppression system.

Each of these three KPPs represents a trade-off with the other two. Optimizing a starlight suppression system, such as a coronagraph or starshade, requires understanding and validating those design trade-offs. The paper mentions that the details of the HWO are still in flux, so it is impossible to determine what trade-offs must be made to have a fully functional system. Factors such as the number of exoearths the HWO is expected to observe, their orbital parameters, and how long the observatory will be allowed to capture data on any particular planetary system will all feed into the simulated trade-offs considered in the paper.

The Nancy Grace Roman Space Telescope is another candidate for exoplanet hunting with an advanced starlight suppression system, as Fraser discusses in this video.

Most importantly, the paper’s authors stated they intended to inform the technical committees of the HWO project about these trade-offs and to help guide the selection of mission parameters that might fit in with the current (or near-term) state of technical development of one of the most critical technologies for the optimal operation of the system. HWO is still in the early planning stages and has no expected launch date. Work has started around defining the teams that will make the technical determinations to inform the selection of a starlight suppression system for the HWO. Dr. Mennesson, the paper’s lead author, also happens to be one of the co-chairs of one of the committees.

But for now, there is plenty of time to flesh out the HWO design and continue developing and testing different starlight suppression technologies. If the remarkable pace of exoplanet discovery is any indication, with a little more time and attention, the telescope development community will develop an optimally designed system to help find one of the most sought-after discoveries in modern science.

Learn More:
Mennesson et al. – Current laboratory performance of starlight suppression systems, and potential pathways to desired Habitable Worlds Observatory exoplanet science capabilities
UT – Astronomers Identify 164 Promising Targets for the Habitable Worlds Observatory
UT – The Habitable Worlds Observatory Could See Lunar and Solar ‘Exo-Eclipses’
UT – Planning is Underway for NASA’s Next Big Flagship Space Telescope

Lead Image:
Image of exoplanets

The post Suppressing Starlight: How to Find Other Earths appeared first on Universe Today.

Back in December, NASA officials, space industry experts, members of the academic community, and science communicators descended on Washington, D.C., for the Achieving Mars Workshop X (AM X). This workshop is hosted by Explore Mars Inc., a non-profit organization dedicated to bringing leading experts from disparate fields together to contribute to creating the first crewed missions to Mars. On May 17th, the results of this year’s workshop were summarized in a report titled “The Tenth Community Workshop for Achievability and Sustainability of Human Exploration of Mars.”

Erik Antonsen, Bruce Jakosky, and Lisa May co-chaired the workshop, which took place from December 5th to 7th at George Washington University. Antonsen is the CTO of Advancing Frontiers, a consulting company providing spaceflight integration services, and an Associate Professor of Space Medicine and Emergency Medicine with the Center for Space Medicine at the Baylor College of Medicine (BCM). Jakosky is a Professor Emeritus of Geological Sciences and the Associate Director of the Laboratory for Atmospheric and Space Physics (LASP) at UC Boulder. May is the Chief Technologist for Lockheed Martin’s Commercial and Civil Space Advanced Programs.

As always, the workshop featured presentations and discussions that addressed the challenges, benefits, and ongoing efforts to realize the human exploration of Mars. But this year was special in several ways, not just because it was the tenth anniversary of the AM series. In addition, AM X took place during an auspicious time for NASA, space agencies, international organizations, and commercial space companies supporting human spaceflight. Between the impending return to the Moon through the Artemis programs and uncertainties about the first crewed missions to Mars, there was a lot to discuss!

For instance, last year’s workshop (AM IX) addressed the pressing question of whether NASA would be able to mount a crewed mission to Mars by 2033. This has been a key aspect of NASA’s Moon-to-Mars (M2M) mission architecture, detailed in the agency’s annual Architecture Concept Reviews (ACRs). It is also in keeping with Explore Mars’ goal of advancing the “human exploration of Mars and beyond no later than the 2030s.” Alas, in recent years, there has been growing skepticism that several key technologies will be ready to meet this deadline.

As Universe Today reported at the time, these doubts were raised at AM IX, and there was no consensus regarding potential solutions. This included the possibility of a flyby mission by 2033 and whether or not a nuclear-thermal propulsion (NTP) system, which can potentially reduce transit times to Mars (45 to 100 days), would be ready in time. In addition, there were the comments of Deputy Administrator Jim Reuters, who acknowledged that sending astronauts to Mars by 2040 was “an audacious goal for us to meet… It may sound like a lot, but it is [a] very short time to develop technologies we need to develop.”

As with previous AM workshops, cooperation and effective communication were emphasized. This includes coordinating robotic and human spaceflight missions and broader cooperation between space agencies, government, and industry. A key concern that was identified was the process through which NASA’s mission architecture evolves. While participants agreed that the M2M ADD “provides a strong starting point for an iterative architecture process,” they also concluded that the development process was insufficient. As stated in the AM X Report:

“Participants observed that despite recent progress, existing channels were insufficient to adequately integrate human capabilities and limitations as well as science objectives into the architecture development process. Similarly, sustainable human exploration of the Moon and Mars will not occur unless science and human exploration objectives are infused early and continuously into the systems engineering processes.”

Artwork for the AM X Workshop Report. Credit: Explore Mars Inc.

To address these concerns, the workshop participants came up with four recommendations for improving existing channels and the architecture development process. They include:

Public Outreach & Involvement

First, the AM X Workshop Report recommended that public interactive forums be more frequent to develop inputs to NASA’s Architecture Definition Documents. The communities emphasized for engagement include operations, human research, science, international organizations, and others “that empower cross-disciplinary teaming, welcome broad participation from external experts, and provide a pathway to incorporate community recommendations and findings into Mars mission planning.”

The need to coordinate with diverse science communities to prioritize and narrow science objectives was also noted, as was the possible need for certification paths for external groups “to provide input in
smaller settings and more frequently than once a year at the ACR.”

The Report also emphasizes the need for initiatives and workshops that focus on the development and integration of “intelligent systems” and “data analytics” that will be critical for missions operating farther from Earth for extended periods. According to NASA’s mission architecture, this applies to Phase III of the Moon to Mars plan (aka. “Earth Independent”), where operations will shift from cislunar to deep space. This will include transits to and from Mars using the Deep Space Transport (DST) and science operations on the Martian surface.

Risk Mitigation

Second, the Report acknowledges the historical trend where certain priorities (like discovery science, technology, and infrastructure development) are often sacrificed for short-term needs. To this end, it is recommended that NASA acknowledge and address tensions between scientific investment for “risk mitigation purposes and investment for discovery science in planning for M2M missions.” While there is no reference to the sacrifices made to realize the Artemis Program and a return to the Moon by 2024, there are some hints that this could be the case.

An illustration of the Gateway’s Power and Propulsion Element and Habitation and Logistics Outpost in orbit around the Moon. Credits: NASA

The shifting priorities brought about by the expedited timetable have led to the deprioritizing of mission elements crucial to reaching Mars by the 2030s – like the Lunar Gateway. As acting Deputy Administrator Doug Loverro explained in March of 2020 during a NASA Advisory Council science committee, the Gateway was deprioritized to “de-risk” Artemis so NASA could focus on meeting the mandatory goals of Artemis and its 2024 deadline. Meanwhile, no design or feasibility studies have been performed for the DST or a Mars orbital habitat (a la the Mars Base Camp) since 2018/19, coinciding with the Artemis “shake-up.”

Regardless, the Report cites the need for increased funding to ensure “technology maturation, demonstration, and infusion to incorporate capabilities.” This is understandable, given that budget concerns have been an issue since NASA began planning missions to the Moon and Mars. In addition to speeding the development of technology, an increase in funding is also desirable to incorporate rapidly advancing technologies such as “artificial intelligence, data management, in-space manufacturing,” and others that are still relatively early in the development process.

Another important factor emphasized here is Health and Human Performance (HPP), which clearly refers to strategies for mitigating the health risks associated with deep space transits. These include extended periods spent in microgravity and long-term exposure to elevated levels of solar and cosmic radiation. To date, NASA has explored multiple possibilities for addressing these concerns, but no concrete plans have emerged just yet.

Evolving Architectures

Further to Recommendation I, the Report states that NASA and commercial companies invested in Mars exploration should continue designing “evolvable mission and campaign architectures.” The purpose of this is to allow for new technologies to be incorporated along the way and prevent the current state of technology from limiting plans. As per the Report, this will help ensure that “we do not design architecture and hardware applicable only for the first mission without allowing both to evolve for subsequent missions.” To this end, NASA and commercial industries are encouraged to:

• Develop common standards, requirements, and interfaces to allow the incorporation of multiple technologies, capabilities, and/or solutions as technology progresses over the next two decades.
• Create and implement a Human and System Readiness Level verification process to assess if the human, hardware, software, and planning systems are sufficiently mature as an integrated system.
• Ensure that the architecture is sufficiently flexible that it can address a wide range of missions beyond the first one.

Artist’s representation of NASA’s “Moon to Mars” mission architecture. Credit: NASA Commercial Partnerships

Finally, the Report encourages NASA to continue investing and cooperating with commercial partners to realize lunar capabilities and technologies that will help them reach Mars. This goes to the heart of the M2M mission architecture, which prioritized a return to the Moon during the 2020s to develop the necessary technologies, systems, and expertise to create a pathway to Mars by the 2030s. “The Moon is how we learn to get to Mars,” it reads, “and we want companies thinking not just about getting to the Moon but, at the same time, how getting there prepares us for the more challenging missions to Mars.”

As usual, the prospect of sending crewed missions to Mars raised many concerns at this year’s workshop. This should come as no surprise, as the goal itself is incredibly ambitious and presents many major challenges. If there is a takeaway from this year’s workshop, it is that there is plenty of work to be done before a mission can be realized. This work must take place at the architectural level, emphasizing wider public engagement, advancing technologies, and a commitment to long-term goals.

Further Reading: Explore Mars

The post Highlights from the 10th Achieving Mars Workshop appeared first on Universe Today.

SpaceX plans to launch its huge Starship rocket on Thursday (June 6), provided it clears the required regulatory hurdles.

The Martian surface shows ample evidence of its warm, watery past. Deltas, ancient lakebeds, and dry river channels are plentiful. When the Curiosity rover found organic matter in ancient sediments in the Jezero Crater paleolake, it was tempting to conclude that life created the matter.

However, new research suggests that non-living processes are responsible.

There are three carbon isotopes on Earth: carbon-12 (12C), carbon-13 (13C), and carbon-14 (14C). Earth’s carbon is almost entirely carbon-12. It makes up 99% of the carbon on Earth, with carbon-13 making up the other 1%. (14C is extremely rare and unstable, so it decays into nitrogen-14.)

In 2022, MSL Curiosity took an inventory of organic carbon in sediments at Gale Crater. Organic carbon is usually described as carbon atoms bonded covalently to hydrogen atoms and is the basis for organic molecules. The carbon in organic carbon can be either carbon-12 or carbon-13, and the amounts are important. At Gale Crater, Curiosity found about 200 to 273 parts per million of organic carbon. “This is comparable to or even more than the amount found in rocks in very low-life places on Earth, such as parts of the Atacama Desert in South America, and more than has been detected in Mars meteorites,” said Jennifer Stern, a Space Scientist at NASA’s Goddard Space Flight Center when the results came in.

This is the Stimson sandstone formation in Gale Crater on Mars. This is where the Curiosity Rover drilled the Edinburgh hole and found enriched Carbon 12. Image Credit: NASA/Caltech-JPL/MSSS

This carbon is important evidence in understanding Mars’ history. It can tell scientists about the planet’s atmospheric processes and environmental conditions and even shed light on potential life. In fact, understanding Martian carbon can aid our understanding of habitability and prebiotic chemistry on distant exoplanets. The isotope ratio in this carbon is different than on Earth. It has a lower amount of carbon-13 relative to carbon-12 compared to Earth. Why the discrepancy?

In recent research in Nature Geoscience, a team of researchers tried to understand the difference between Earth’s and Mars’s carbon isotope ratios. The work is titled “Synthesis of 13C-depleted organic matter from CO in a reducing early Martian atmosphere.” The lead author is Yuichiro Ueno, a biogeochemist in the Department of Earth and Planetary Sciences at the Tokyo Institute of Technology.

“Strong 13C depletion in sedimentary organic matter at Gale crater was recently detected by the Curiosity rover,” the authors write. “Although this enigmatic depletion remains debated, if correct, a mechanism to cause such strong 13C depletion is required.” 

The amount of carbon-13 in the Martian sediments is far lower than in Earth’s sediments.

“On measuring the stable isotope ratio between 13C and 12C, the Martian organic matter has a 13C abundance of 0.92% to 0.99% of the carbon that makes it up,” lead author Ueno explained in a press release. “This is extremely low compared to Earth’s sedimentary organic matter, which is about 1.04%, and atmospheric CO2, around 1.07%, both of which are biological remnants and are not similar to the organic matter in meteorites, which is about 1.05%.”

The meteorite data is important because a four billion-year-old Martian meteorite named ALH 84001 is enriched in carbon-13, adding to the enigma of Mars’ carbon. Somehow, carbon-13 became depleted in the intervening billions of years. Solar escape is one possible reason for the carbon-13 depletion, but the authors discount that. There likely wasn’t enough time for enough carbon-13 to escape. “Furthermore, based on geomagnetic observations, early Mars probably had a geomagnetic field before 4?Ga,” the authors write. That field would’ve prevented solar escape.

To determine what’s behind this discrepancy, Ueno and his co-researchers simulated different Martian atmospheric conditions to see what would happen.

Their results show that isotope fractionation by solar UV light is responsible for Mars’ 13C depletion.

This graphic outlines the process that creates atmospheric organic matter that finds its way into the Martian sediments sampled by MSL Curiosity. Image Credit: Ueno et al. 2024.

Carbon-12 and carbon-13 respond differently to UV light. Carbon-12 preferentially absorbs UV, which dissociates it into carbon monoxide that’s depleted in carbon-12. What’s left behind is CO2 enriched with carbon-13.

Scientists have observed this process in the upper atmospheres of Earth and Mars. In Mars’ reducing atmosphere, where oxygen was depleted, the CO2 enriched with carbon-13 would’ve transformed into formaldehyde and possibly methanol. But those compounds didn’t remain stable. In Mars’ early days, the surface temperature was close to the freezing point of water, and it never exceeded about 27 Celsius (80 F.) In that temperature range, the formaldehyde and other compounds could’ve dissolved in water. From there, they gathered in sediments.

But that’s not the end of Mars’ carbon isotope story.

The researchers used models to show that in a Mars atmosphere with a CO2 to CO ratio of 90:10, 20% of the CO2 would have converted to CO, leading to the sedimentary carbon isotope ratio we see today. The remaining atmospheric CO2 would be higher in C-13, and both values are in line with what Curiosity found, and with the ancient Martian meteorite ALH 84001.

This is a plausible scenario that can explain Curiosity’s curious carbon findings.

The team’s study also includes some other important details. For instance, atmospheric CO may not have come solely from photolysis by UV light. Some could have come from volcanic eruptions. And atmospheric CO may not have been the sole source of organics that found their way into the sediments. But either way, the results tell scientists something about Mars’ carbon cycle.

It also tells us to expect to find more organics in Martian sediments in the future.

“If the estimation in this research is correct, there may be an unexpected amount of organic material present in Martian sediments. This suggests that future explorations of Mars might uncover large quantities of organic matter,” said Ueno.

While the research shows us that life needn’t be present to produce these organics, it can’t rule life out. Nobody can, at least not yet.

The research also shows how complex atmospheric chemistry can be and how difficult it can be to draw conclusions from atmospheric studies of exoplanets. The JWST has examined several exoplanet atmospheres and found some interesting results. But there’s so much we don’t know. This research is a reminder that any conclusions are likely premature.

The post Life Probably Played No Role in Mars’ Organic Matter appeared first on Universe Today.

Mice that exercised soon after waking up had stronger and longer bones than those that exercised later in the day  

Mice that exercised soon after waking up had stronger and longer bones than those that exercised later in the day  

India's Agnikul Cosmos successfully launched a test vehicle powered by a homegrown 3D printed rocket engine.

The Chang’e 6 mission is China’s second to touch down on the lunar far side and will retrieve samples for analysis on Earth

This year's U.S. Astronaut Hall of Fame induction ceremony was a reunion of sorts, as honorees David Hilmers and Marsha Ivins took the stage under Atlantis, the shuttle on which they crossed paths.

A small South Pacific fern boasts more than 50 times as many base pairs as the human genome

A rare sighting of a giant pangolin revives hopes for the species' survival in West Africa, despite threats from poaching and deforestation

A rare sighting of a giant pangolin revives hopes for the species' survival in West Africa, despite threats from poaching and deforestation

A Russian military satellite with a "history of unusual maneuvering" was spotted as it approached a satellite in geostationary orbit in April 2024.

"Twisted Tatooine" binary star systems could be a major player in ejecting rogue planets that go on to drift through the Milky Way without a stellar parent to heat or illuminate them.

As we discover more and more exoplanets – and the current total is in excess of 5,200 – we continue to try to learn more about them. Astrobiologists busy themselves analysing their atmospheres searching for anything that provides a sign of life. It is quite conceivable of course that the Universe is teeming with life based on very different chemistry to ours but we often look to life on Earth to know what to look for. On Earth for example, ozone forms through photolysis of molecular oxygen and is an indicator of life. Using the James Webb Space Telescope astronomers are searching stars in the habitable zone of their star for the presence of ozone and how it impacts their climate.

It’s tantalising that 425 of the exoplanets detected so far, exist in their stars habitable zone. It is in this region where the climate on the planet may well be suitable to sustain life. A significant subset of those planets are Earth-like in nature and will therefore have a fairly temperate climate. In addition, they all seem to orbit M-dwarf type stars which means they are likely to be impacted by tidal spin-synchronisation (due to the effects of the tides, one face of the planet may well be kept facing the star). One impact of this is the potential for large contrast in daytime and night-time irradiation which can drive strong convection on the day side of the planet.  

The strong convection can drive winds around the equatorial region that are persistently higher faster than the rotation of the planet. It can also create Rosby Waves which naturally occur in the Earth’s ocean and atmosphere – in any rotating fluids or gas. Together these can control the distribution of chemicals in the atmosphere, in particular ozone. 

In Earth’s atmosphere the presence of molecular oxygen is an indicator of life since it is produced largely from photosynthesis in plants. The molecular oxygen collides with nitrogen in the atmosphere to produce ozone so the presence of the latter is an indicator of biological processes. There is a chance though that the molecular oxygen in exoplanet atmospheres are the result of different ratios of near and far UV that can drive a non-biological build up. 

In a new piece of research reported in a paper by lead author Paolo De Luca and team, they report their findings having leveraged climate model simulations on Proxima Centauri b. The Earth-sized exoplanet orbits the red dwarf star Proxima Centauri, the closest star to our own at a distance of 4,.2 light years. 

An artist’s conception of a violent flare erupting from the red dwarf star Proxima Centauri. Such flares can obliterate atmospheres of nearby planets. Credit: NRAO/S. Dagnello.

They report that the analysis of atmospheres of tidally locked Earth-like exoplanets received a massive boost as a result of the development of the James Webb Telescope. The team reveal that their climate modelling (including the use of interactive ozone) globally increases temperature in the stratosphere. This in turn induces regional variations of surface temperature and also reduces the temperature contrast between day and night side. 

Whilst the team have not been able to identify life on exoplanets, that was not their intention. What they have achieved is the ability to understand the exoplanet atmospheres using the James Webb Space Telescope, some of the processes that lead to atmospheric ozone and the impacts on temperatures. 

Source : The impact of Ozone on Earth-like exoplanet climate dynamics: the case of Proxima Centauri b

The post What Impact Does Ozone Have on an Exoplanet? appeared first on Universe Today.

Strange solids called temporal metamaterials finally make it possible to investigate the controversial idea of quantum friction – and push special relativity to its limits

Strange solids called temporal metamaterials finally make it possible to investigate the controversial idea of quantum friction – and push special relativity to its limits

China Chang’e 6 mission has landed on the Moon and is now set to perform another first: a sample return from the lunar farside.

The post Whirlwind Chang’e 6 Mission Collects Lunar Samples, Heads Back Home appeared first on Sky & Telescope.

A rare fossil skull provides strong evidence that the Dromornithidae, an extinct group of Australian flightless birds, were related to geese and ducks

A rare fossil skull provides strong evidence that the Dromornithidae, an extinct group of Australian flightless birds, were related to geese and ducks