Space

The NASA Artemis missions aim to send astronauts to the moon by 2024. But to succeed, they’ll need to solve big problems caused by some tiny particles: dust.
Impacts on the moon’s surface have crushed lunar rock into dust over billions of years (SN: 1/17/19). The resulting particles are like “broken shards of glass,” says Mihály Horányi, a physicist at the University of Colorado Boulder. This abrasive material can damage equipment and even harm astronauts’ health if inhaled (SN: 12/3/13). Making matters worse, the sun’s radiation gives moon dust an electric charge, so it sticks to everything.
Horányi and colleagues have discovered a new method for combatting lunar dust’s static cling, using a low-powered electron beam to make dust particles fly off surfaces. It complements existing approaches to the sticky problem, the researchers report online August 8 in Acta Astronautica.

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During the Apollo missions, astronauts relied on a low-tech system to clean lunar dust off their spacesuits: brushes. Such mechanical methods, however, are thwarted by the electrically charged nature of lunar dust, which clings to the nooks and crannies of woven spacesuit fabric.
The newly described method takes advantage of the dust’s electrical properties. An electron beam causes dust to release electrons into the tiny spaces between particles. Some of these negatively charged electrons are absorbed by surrounding dust specks. Because the charged particles repel each other, the resulting electric field “ejects dust off the surface,” says Xu Wang, a physicist also at the University of Colorado Boulder.
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Abrasive, electrically charged lunar dust clings to surfaces and could wreak havoc on equipment and astronaut well-being during missions to the moon. An electron beam may aid future cleaning efforts. As shown here, when a beam hits artificial lunar dust on a glass plate, particles leap off the surface.
“This is a very unique idea,” says mechanical engineer Hiroyuki Kawamoto of Waseda University in Tokyo, who was not involved in the new work. Kawamoto and colleagues have developed their own dust-busting technologies, including a layer of electrodes that can be built into materials. When embedded in a spacesuit or on the surface of equipment, the electrodes generate electrostatic forces and fling away charged dust particles. Such systems are more complex than shooting an electron beam at surfaces, Wang says. But a potential downside to the simpler electric beam idea, Kawamoto says, is that it would require a robot or some other external means to direct it.
Another limitation of the electron beam is that it left behind 15 to 25 percent of dust particles. The researchers aim to improve the cleaning power. The team also envisions the electron beam as one of multiple approaches that future space explorers will take to keep surfaces clean, Horányi says, in addition to suit design, other cleaning technologies and, one day, even lunar habitats with moon dust mudrooms. More

Venus’ clouds appear to contain a smelly, toxic gas that could be produced by bacteria, a new study suggests.
Chemical signs of the gas phosphine have been spotted in observations of the Venusian atmosphere, researchers report September 14 in Nature Astronomy. Examining the atmosphere in millimeter wavelengths of light showed that the planet’s clouds appear to contain up to 20 parts per billion of phosphine — enough that something must be actively producing it, the researchers say. 
If the discovery holds up, and if no other explanations for the gas are found, then the hellish planet next door could be the first to yield signs of extraterrestrial life — though those are very big ifs.
“We’re not saying it’s life,” says astronomer Jane Greaves of Cardiff University in Wales. “We’re saying it’s a possible sign of life.”

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Venus has roughly the same mass and size as Earth, so, from far away, the neighboring planet might look like a habitable world (SN: 10/4/19). But up close, Venus is a scorching hellscape with sulfuric acid rain and crushing atmospheric pressures.
Still, Venus might have been more hospitable in the recent past (SN: 8/26/16). And the current harsh conditions haven’t stopped astrobiologists from speculating about niches on Venus where present-day life could hang on, such as the temperate cloud decks.
“Fifty kilometers above the surface of Venus, the conditions are what you would find if you walk out of your door right now,” at least in terms of atmospheric pressure and temperature, says planetary scientist Sanjay Limaye of the University of Wisconsin–Madison, who was not involved in the new study. The chemistry is alien, but “that’s a hospitable environment for life.”
Previous work led by astrochemist Clara Sousa-Silva at MIT suggested that phosphine could be a promising biosignature, a chemical signature of life that can be detected in the atmospheres of other planets using Earth-based or space telescopes.
On Earth, phosphine is associated with microbes or industrial activity — although that doesn’t mean it’s pleasant. “It’s a horrific molecule. It’s terrifying,” Sousa-Silva says. For most Earthly life, phosphine is poisonous because “it interferes with oxygen metabolism in a variety of macabre ways.” For anaerobic life, which does not use oxygen, “phosphine is not so evil,” Sousa-Silva says. Anaerobic microbes living in such places as sewage, swamps and the intestinal tracts of animals from penguins to people are the only known life-forms on Earth that produce the molecule.  
Still, when Greaves and colleagues searched Venus’ skies for signs of phosphine, the researchers didn’t expect to actually find any. Greaves looked at Venus with the James Clerk Maxwell Telescope in Hawaii over five mornings in June 2017, aiming to set a detectability benchmark for future studies seeking the gas in the atmospheres of exoplanets (SN: 5/4/20), but was startled to find the hints of phosphine. “That’s a complete surprise,” Greaves says. When she was analyzing the observations, “I thought ‘Oh, I must have done it wrong.’”
Signs of phosphine first showed up in data taken with the James Clerk Maxwell Telescope in Hawaii.Will Montgomerie/JCMT/EAO
So the team checked again with a more powerful telescope, the Atacama Large Millimeter/submillimeter Array in Chile, in March 2019. But the signature of phosphine — seen as a dip in the spectrum of light at about 1.12 millimeters — was still there. The gas absorbs light in that wavelength. Some other molecules also absorb light near that wavelength, but those either couldn’t explain the whole signal or seemed improbable, Greaves says. “One of those is a plastic,” she says. “I think a floating plastic factory is a less plausible explanation than just saying there’s phosphine.”
Phosphine takes a fair amount of energy to create and is easily destroyed by sunlight or sulfuric acid, which is found in Venus’ atmosphere. So if the gas was produced a long time ago, it shouldn’t still be detectable. “There has to be a source,” Greaves says.
Greaves, Sousa-Silva and colleagues considered every explanation they could think of apart from life: atmospheric chemistry; ground and subsurface chemistry; volcanoes outgassing phosphine from the Venusian interior; meteorites peppering the atmosphere with phosphine from the outside; lightning; solar wind; tectonic plates sliding against each other. Some of those processes could produce trace amounts of phosphine, the team found, but orders of magnitude less than the team detected.
“We’re at the end of our rope,” Sousa-Silva says. She hopes other scientists will come up with other explanations. “I’m curious what kind of exotic geochemistry people will come up with to explain this abiotically.”
The idea of searching for life on Venus “has been regarded as a pretty out-there concept,” says Planetary Science Institute astrobiologist David Grinspoon, who is based in Washington, D.C. Grinspoon has been publishing about the prospects for life on Venus since 1997, but was not involved in the new discovery.
“So now I hear about this, and I’m delighted,” he says. “Not because I want to declare victory and say this is definite evidence of life on Venus. It’s not. But it’s an intriguing signature that could be a sign of life on Venus. And it obligates us to go investigate further.”
Because of the planet’s acidic atmosphere, extreme pressures and lead-melting temperatures, sending spacecraft to Venus is a challenge (SN: 2/13/18). But several space agencies are considering missions that could fly in the next few decades.
In the meantime, Greaves and colleagues want to confirm the new phosphine detection in other wavelengths of light. Observations they had planned for the spring were put on hold by the coronavirus pandemic. And now, Venus is in a part of its orbit where it’s on the other side of the sun.
“Maybe when Venus comes around on the other side of the sun again,” Greaves says, “things will be better for us here on Earth.” More

Dark matter just got even more puzzling.
This unidentified stuff, which makes up most of the mass in the cosmos, is invisible but detectable by the way it gravitationally tugs on objects like stars. (SN: 11/25/19). Dark matter’s gravity can also bend light traveling from distant galaxies to Earth — but now some of this mysterious substance appears to be bending light more than it’s supposed to. A surprising number of dark matter clumps in distant clusters of galaxies severely warp background light from other objects, researchers report in the Sept. 11 Science.
This finding suggests that these clumps of dark matter, in which individual galaxies are embedded, are denser than expected. And that could mean one of two things: Either the computer simulations that researchers use to predict galaxy cluster behavior are wrong, or cosmologists’ understanding of dark matter is.
Very high concentrations of dark matter can act like a lens to bend light and drastically alter the appearance of background galaxies as seen from Earth — stretching them into arcs or splitting them into multiple images of the same object on the sky. “It’s totally cool. It’s like a fun house mirror,” says astrophysicist Priyamvada Natarajan of Yale University.

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Judging by computer simulations of galaxy clusters, clumps of dark matter around individual galaxies that are dense enough to cause such dramatic gravitational lensing effects should be rare (SN: 10/4/15). Based on cluster simulations run by Natarajan and colleagues, “we would expect to see 1 [strong lensing] event in every 10 clusters or so,” says study coauthor Massimo Meneghetti, an astrophysicist at the Astrophysics and Space Science Observatory of Bologna in Italy.
But telescope images told a different story. The researchers used observations from the Hubble Space Telescope and the Very Large Telescope in Chile to investigate 11 galaxy clusters from about 2.8 billion to 5.6 billion light-years away. In that set, the team identified 13 cases of severe gravitational lensing by dark matter clumps around individual galaxies. These observations indicate there are more high-density dark matter clumps in real galaxy clusters than in simulated ones, Meneghetti says.
The simulations could be missing some physics that leads dark matter in galaxy clusters to glom tightly together, Natarajan says. “Or … there’s something fundamentally off about our assumptions about the nature of dark matter,” she says, like the notion that gravity is the only attractive force that dark matter feels.
Richard Ellis, a cosmologist at the University College London who was not involved in the work, thinks the crux of the problem is more likely in the computer simulations than in the nature of dark matter. “A cluster of galaxies is a very dangerous place. It’s like the Manhattan of the universe,” he says — busy with galaxies whizzing past one another, colliding and getting torn up. “There’s awful physics that goes into predicting how many of these little lensed things they should find,” Ellis says, so the new result “is intriguing, but my suspicion is that there’s something in the simulations … that isn’t quite right.”
Future observations with the upcoming Euclid space telescope (SN: 11/14/17), the Nancy Grace Roman Space Telescope and Vera C. Rubin Observatory (SN: 1/10/20) could help clear matters up, says Bhuvnesh Jain, an astrophysicist at the University of Pennsylvania who was not involved in the work. “These three telescopes are going to produce extremely large samples of galaxy clusters,” he says. That may lead to a new understanding of the physics in these turbulent environments, and help determine whether unrealistic simulations are to blame for this dark matter mystery. More

In one of the most complex cosmic dances astronomers have yet spotted, three rings of gas and dust circle a trio of stars.
The star system GW Orionis, located about 1,300 light-years away in the constellation Orion, includes a pair of young stars locked in a close do-si-do with a third star making loops around both. Around all three stars is a broken-apart disk of dust and gas where planets could one day form. Unlike the flat disk that gave rise to the planets in our solar system, GW Orionis’ disk consists of three loops, with a warped middle ring and an inner ring even more twisted at a jaunty angle to the other two.
The bizarre geometry of this system, the first known of its kind, is reported in two recent studies by two groups of astronomers. But how GW Orionis formed is a mystery, with the two teams providing competing ideas for the triple-star-and-ring system’s birth.
In a Sept. 4 study in Science, astronomer Stefan Kraus of the University of Exeter in England and colleagues suggest that gravitational tugs and torques from the triple-star ballet tore apart and deformed the primordial disk. But in a May 20 study in the Astrophysical Journal Letters, Jiaqing Bi of the University of Victoria in Canada and colleagues think that a newborn planet is to blame.
“The question is how do you actually form such systems,” says theoretical physicist Giuseppe Lodato of the University of Milan, who was not on either team. “There could be different mechanisms that could do that.”

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Astronomers have seen tilted disks of gas and dust around binary star systems, but not systems of more than two stars (SN: 7/30/14). Around half of the stars in the galaxy have at least one stellar companion, and their planets often have tilted orbits with respect to their stars, going around more like a jump rope than a Hula-Hoop (SN: 11/1/13). That misalignment could originate with the disk in which the planets were born: If the disk was askew, the planets would be too.
About a decade ago, astronomers first realized that GW Orionis has three stars and a planet-forming disk, and the scientists scrambled to get a closer look. (At the time, it was impossible to tell if that disk was a single loop or not.) Bi’s team and Kraus’ team aimed the Atacama Large Millimeter/submillimeter Array in Chile at the triple-star system.
Both groups spotted the trio of stars: one about 2.5 times and another about 1.4 times the sun’s mass orbiting each other once every 242 days, and another 1.4 solar mass star orbiting the inner pair about every 11 years.
The observations also revealed three distinct rings of dust and gas encircling the stars. The closest ring to the star trio lies about 46 times the distance from Earth to the sun; the middle one about 185 times the Earth-sun distance; and the outermost ring about 340 times that distance. For perspective, Neptune is about 30 times the distance from Earth to the sun.
That innermost ring is strongly misaligned with respect to the other rings and the stars, the teams found. Kraus’ group added observations from the European Southern Observatory’s Very Large Telescope to show the shadow of the inner ring on the inside of the middle loop. That shadow revealed that the middle ring is warped, swooping up on one side and down on the other.
Astronomers looked at GW Orionis with the ALMA telescope array (left, blue) and the SPHERE instrument on the Very Large Telescope (right, red), both in Chile. The ALMA observations revealed the disk’s tri-ringed structure, while the SPHERE images showed the shadow cast by the innermost ring, allowing scientists to describe the rings’ deformed shapes in detail.Left image: ALMA/ESO, NAOJ, NRAO; Right image: ESO, S. Kraus et al, Univ. of Exeter
Next, both groups ran computer simulations to figure out how the system formed. This is where their conclusions begin to differ, Bi says. His team suggests that a newly formed, not-yet-discovered planet cleared its orbit of gas and dust, splitting the inner ring off from the rest of the disk (SN: 7/16/19). Once the disk was split, the inner ring was free to swing around the stars, settling into its skewed alignment.
Simulations from Kraus’s team, though, found that the chaotic gravity from the triple stars’ orbital dance alone was enough to break up the disk, a phenomenon called disk tearing. Each star tends to keep the disk aligned with itself, and the tug-of-war warped and sheared the disk, and twisted the inner ring even further. Theoretical studies had suggested disk tearing might happen in multiple star systems, but this is the first time it’s been seen in real life, Kraus contends.
“I think it’s plausible that there could be planets somewhere in the system, but they’re not needed to explain the misalignment,” he says. “We don’t need to invoke undiscovered planets to explain what we see.”
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A trio of stars in GW Orionis are surrounded by an enormous, warped disk of gas and dust, new observations reveal. This animation, which is based on computer simulations and observational data, shows the complex geometry of the deformed and broken-apart disk.
The difference may lie in the assumptions that the groups made about the disk’s properties, in particular its viscosity, says astrophysicist Nienke van der Marel, Bi’s colleague at the University of Victoria. A more viscous disk would tear like how Kraus and colleagues propose, but a less viscous disk needs a planet to break apart, she says. She thinks her team’s work is more realistic based on observations of other star systems. But with current technology, there’s no way to tell what the properties of GW Orionis’ disk are really like.
And neither group could explain what made the disk split into three. “We don’t really know what’s causing the outer ring,” Klaus says.
Lodato, who predicted the disk-tearing effect in 2013, thinks GW Orionis is proof that the phenomenon really exists. Back then, Lodato and colleagues were “very worried” that their simulations showed an effect that was introduced by the computations, not real physics, he says. “Now observations tell us that it does happen in reality.”
Future telescopes may also be able to spot the planet if it exists, van der Marel says. More

Observations of thousands of white dwarf stars have confirmed a decades-old theory about the relationship between their masses and sizes. More

Small, frequent lightning storms zip across Jupiter’s cloud tops. NASA’s Juno spacecraft spotted the flashes for the first time, scientists report August 5 in Nature.
“It’s a very exotic thing that doesn’t exist on Earth,” says physicist Heidi Becker of NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
Previous spacecraft have revealed high-energy “superbolts” on Jupiter. That lightning originates 50 to 65 kilometers below Jupiter’s cloud tops, where liquid water droplets form. Scientists think superbolts form like lightning on Earth does: Colliding ice crystals and water droplets charge each other up, then stretch the charge between them when they separate (SN: 6/25/20).
Juno, which arrived at Jupiter in 2016, got much closer to the giant planet’s cloud tops than previous missions. Becker and her team turned the spacecraft’s navigation camera — which normally observes stars to track Juno’s position — on Jupiter’s nightside in February 2018. To the team’s surprise, the clouds crackled with electricity.
Newly observed lightning showed up as bright dots (indicated with arrows) on Jupiter’s nightside, seen in this composite image from two of Juno’s cameras. The insets are pixelated representations of the events’ brightness (yellow is more bright; blue is less bright).H.N. Becker et al/Nature 2020
Superbolts are up to 100,000 times as strong as these small flashes. But the cloud-top lightning is 10 times as frequent. Strangely, the smaller bolts appeared to come from just 18 kilometers below the cloud tops, where it’s too cold for liquid water to exist alone.
Shallow lightning must have a different origin than the deeper lightning, Becker says. Perhaps ammonia in the upper cloud decks acts as antifreeze, creating droplets of ammonia and water combined. Juno has also seen evidence that violent storms in deeper cloud layers sometimes toss ice crystals high above where they’re normally found. When those crystals collide with the ammonia-water droplets, they may charge up and create lightning, Becker and her colleagues reason.
Similar small lightning storms may happen on other planets, including exoplanets, Becker says (SN: 5/13/16). “Every time you have a new realization, it feeds into new theories that will be developed not only for our solar system but for other solar systems.” More

An observatory in the heart of Antarctica could have the world’s clearest views of the night sky.
If an optical telescope were built on a tower a few stories tall in the middle of the Antarctic Plateau, it could discern celestial features about half the size of those typically visible to other observatories, researchers report online July 29 in Nature. The observatory would achieve such sharp vision by peering above the atmosphere’s lowermost layer, known as the boundary layer, responsible for much of the undulating air that muddles telescope images (SN: 10/4/18).
The thickness of Earth’s boundary layer varies across the globe. Near the equator, it can be hundreds of meters thick, limiting the vision of premier optical telescopes in places like the Canary Islands and Hawaii (SN: 10/14/19). Those telescopes usually cannot pick out celestial features smaller than 0.6 to 0.8 arc seconds — the apparent width of a human hair from about 20 meters away.
“But in Antarctica, the boundary layer is really thin,” says Bin Ma, an astronomer at the Chinese Academy of Sciences in Beijing, “so it is possible to put a telescope above.”
Ma and colleagues took the first-ever measurements of nighttime atmospheric blur from the highest point in East Antarctica, called Dome A. From April to August 2019, instruments on an 8-meter-tall tower at China’s Kunlun research station tracked how Earth’s atmospheric turbulence distorted incoming starlight. A nearby weather station also monitored atmospheric conditions, such as temperature and wind speed. Using these observations, researchers characterized the boundary layer at Dome A and its effect on telescope observations.
From April to August 2019, instruments atop an 8-meter-tall tower at China’s Kunlun research station in East Antarctica observed how the local atmosphere distorted light from celestial objects.Zhaohui Shang
The boundary layer was, on average, about 14 meters thick; as a result, the light sensors at the top of the 8-meter tower were completely free of boundary layer blur only about one-third of the time. But when these instruments were above the layer, atmospheric interference was so low that a telescope could pick out details on the sky 0.31 arc seconds across, on average. The best recorded atmospheric conditions would let a telescope see features as small as 0.13 arc seconds.
“One-tenth of an arc second is extremely good,” says Marc Sarazin, an applied physicist at the European Southern Observatory in Munich who was not involved in the work. This is “really something you rarely achieve in Chile or on Mauna Kea” in Hawaii.
Researchers have found similarly excellent visibility above the boundary layer at another spot on the Antarctic Plateau, known as Dome C. But the boundary layer there is around 30 meters thick — making it more difficult to build an observatory above it. An optical telescope planned for construction on a 15-meter tower at Kunlun could take advantage of Dome A’s stellar views above the boundary layer, Ma says. Such crisp telescope images could help astronomers study a range of celestial objects, from solar system bodies to distant galaxies.

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Megan Barrington watched the sun rise over the rocky outcrop. When light struck at exactly the right angle, she mounted a gizmo that looked like eye exam equipment on a tripod and aimed it at the spot. The goal: gather evidence that this windswept wilderness once teemed with life, and then beam the information to her colleagues back home.
Soon, a version of that setup (minus Barrington) will be deployed on Mars. The state-of-the-art, zoomable, multispectral camera is part of the toolkit on NASA’s Perseverance rover (SN: 7/28/20). “That instrument is going to allow me to look at the mineralogy of Mars at Jezero crater,” the rover’s landing spot, says Barrington, a planetary scientist at Cornell University.
The rover is scheduled to launch to Mars on July 30. A February role-playing exercise in the Nevada desert by Barrington and six colleagues was a kind of dress rehearsal for the rover’s various instruments. Another 150 team members around the world played the “Earth” team during those two weeks, sending commands from remote mission control and receiving data as it would appear coming from the real rover.
“We’re not just simulating a Mars mission,” says engineer Raymond Francis of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., who organized and led the trip. “We’re simulating a specific Mars mission by presenting data … to the people who designed the instrument that will take that data. So the standard is high not to look like clowns.”

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Perseverance has the most demanding and ambitious to-do list of any rover yet: seek signs of past Martian life, prepare the way for future human missions and collect at least 20 samples of Martian rock for eventual return to Earth. And that’s just in its first two years. For contrast, Curiosity rover has drilled a few dozen holes over eight years on Mars, and didn’t store any of those samples for later (SN: 7/7/18, p. 8).
The dress rehearsal in the desert will help ensure that when Perseverance lands on the Red Planet in February 2021, its handlers on Earth can get straight to the science.
“We don’t want to get there and learn how to explore Mars while on Mars,” Francis says. “We want [team members] to be ready when the rover hits the ground.”
Water marks the spot
The first order of business was to find the right spot for the dry run. “We had to pick a site that kind of looked like Mars,” Francis says. “The parking lot would not do.” The team wanted the site to look as Mars-like as possible, no factories, footprints or foliage to break the illusion.
An ideal site would have geology that echoed Jezero crater, which is thought to be the remnants of an ancient lakebed and river delta (SN: 11/19/18). It also had to be within a few hours’ drive of JPL, and not totally off the grid — the rover team slept in hotels, ate dinner in restaurants and had reliable Wi-Fi to send data to the Earth team every night.
The final requirement was that it be someplace the Earth team hadn’t seen before. If mission control members recognized the site, they could bias their findings with what they already knew.
Engineer and team leader Raymond Francis gets up close with the rocks to make a measurement.JPL-Caltech/NASA
“Most of the popular Mars analogs are already well known to the Mars community,” Francis says. “So we had to be a little sneaky.”
Previous exercises, in November 2017 and February 2019, were run in the Mojave Desert in California. For 2020, the rover team headed to Walker Lake in western Nevada. The lake’s water has been receding for a thousand years, so there are spots near the ancient shoreline where the present-day lake is invisible.
Walker Lake’s rocks preserved a cornucopia of biological signals for the ground team to discover: fossilized fish bones and shells of tiny shrimplike crustaceans called ostracods, which are not expected on Mars; and microbial fossils called stromatolites, which could plausibly be found in Jezero crater (SN: 10/17/18).
Toolkit
Francis and his team brought handheld versions of almost all the rover’s instruments to gather whatever data the Earth team requested. They had a drill, handheld spectrometers, lasers, a ground-penetrating radar that they transported in a jogging stroller, plus several elaborate camera setups to represent the rover’s navigation, hazard avoidance and zoomable 3-D science cameras.
Perhaps the most important piece of equipment was the broom used for sweeping away footprints. It became a running joke, Francis says: “We’ve got all this equipment, a multibillion-dollar mission, and it’s all hinging on this 99-cent broom.”
Almost everything went smoothly. But a few days into the mission, Barrington’s zoomable camera had “a major malfunction,” she says. She framed her shot, and…. nothing happened. The camera wasn’t getting any power, she realized. “I took it apart and rewired many pieces, to no avail,” she says.
She and her teammates finally realized one of the power adapters had completely blown. She had to drive two hours to the nearest city to get a new one.
Of course, driving into town to get a new part won’t be an option on Mars. The real camera, called Mastcam-Z, has been through weeks of rigorous testing and calibration, and is probably up to the task. But “we all go into missions knowing that sometimes irreversible mistakes occur,” Barrington admits. “All we can do at that point is use the instruments to the fullest capacity of which they are capable of operating.”
Planetary scientist Megan Barrington adjusts her instrument, a multispectral, zoomable camera standing in for Perseverance’s Mastcam-Z.JPL-Caltech/NASA
Signs of life, big and small
There was one major giveaway that the team was actually on Earth. “This is very much middle-of-nowhere desert, which is good,” Francis says. But the rover site was mere steps from a U.S. Department of Defense munitions facility, one of the largest in the world.
“It was really something to behold,” Barrington says. “They had hundreds of bunkers lined up in rows as far as you could see…. All of that was one very crooked metal fence away from us.”
More than once, military police showed up to check the team’s credentials. “I had to approach them and say, hello, people with the guns, I need you to stop walking now,” Francis says. “We’re running a Mars rover simulation and we don’t want you to put your footprints in this sand.”
Despite Francis and colleagues’ best efforts, the bunkers showed up in a few photos. The ground team gamely ignored them, apart from a few jokes about SpaceX founder Elon Musk building a Martian city.
By the end of the two-week exercise, the remote science team reviewing the data had noticed the ostracods and fishbones, and started exploring the stromatolites. “They were doing a good job of finding the biomarkers,” Francis says, who now has hope that “if Mars is hiding stromatolites, maybe we’ll see them.”
Coming home to quarantine
The field trip ended on February 27, just as awareness of the novel coronavirus SARS-CoV-2 was rising in the United States. By March 15, JPL told employees to work from home. “We only had a few days together before we were all on remote work,” Francis says.
The pandemic has already contributed to the delay of the launch of the European and Russian ExoMars rover, which was also supposed to launch in July (SN: 3/12/20).  If Perseverance misses the late July to early August launch window, the rover can’t head to Mars until 2022.
If the pandemic is still an issue by the time the rover lands in February, Francis doesn’t know what the team will do. “But,” he says, “the good news is the mission is designed for remote operations.” More