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      Here’s how NASA’s Ingenuity helicopter has spent 1 year on Mars

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      One year ago, Ingenuity took its first flight on Mars. And its story since is that of a real-world little helicopter that could.

      Ingenuity traveled to the Red Planet attached to the belly of NASA’s Perseverance rover, and both arrived in Jezero crater last February (SN: 2/17/21). About six weeks later, the helicopter began what was meant to be only a 30-day technology demonstration to see if flight is possible in the thin Martian atmosphere.

      It proved it could fly — and then some (SN: 4/19/21). Over the next couple weeks, Ingenuity took four more flights, each time going a bit farther, a bit faster and a bit higher. After those first test flights, Ingenuity’s mission morphed from a technology demonstration to operations, helping Perseverance traverse the surface by scouting the terrain ahead (SN: 4/30/21; SN: 12/10/21).

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      Before the helicopter arrived, scientists had two perspectives of Mars. “We have pictures taken from orbit around Mars, and then we have pictures taken by rovers driving on the ground,” says planetary scientist Kirsten Siebach of Rice University in Houston, who is not part of the Ingenuity team. “But now this has opened up an entirely new perspective on Mars.” 

      Ingenuity has surpassed all expectations. It has shown not only that flight is possible but also what is possible with flight. Science News discussed the helicopter’s big moments, collaboration with the rover and upcoming flights with Håvard Fjær Grip. He’s Ingenuity’s chief pilot and an engineer at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. His answers were edited for length and clarity.

      SN: What does the “chief pilot” for a helicopter on another planet do?

      Grip: The biggest part of the job is planning the flights. Ingenuity doesn’t know where it is or where it wants to go when it wakes up, so all of those decisions are made here [on Earth]. Every maneuver that the helicopter makes during the flight is planned here on the ground first, and then we uplink the instructions to Ingenuity. When it comes time to fly, it uses its onboard software to follow our instructions as precisely as possible.

      On April 19, 2021, Ingenuity Chief Pilot Håvard Fjær Grip (pictured) logged the first flight on another world in an official logbook.JPL-Caltech/NASA

      SN: Ingenuity has completed 25 flights. Can you talk about how it’s exceeded expectations?

      Grip: It is pretty great. We came there expecting to perform at most five flights within the 30-day window. And all of that was going to happen within in a small area that we carefully selected. We spent weeks figuring out exactly where to place the helicopter, studying these tiny little rocks. Everything was mapped out. And then things went so well when we started flying that almost immediately people started thinking, “Wow, let’s try to make use of this beyond those five flights.”

      We started this next phase where, to be useful at all, we had to fly away from this carefully selected area. I’m really proud of that. We’ve been able to take this technology that was designed for this very limited mission and extend it to go and land different places on Mars and to travel across terrain that, originally, we had never planned on traveling across.

      It’s lasted now for over a year since we deployed it to the surface. I don’t think any of us had imagined that that would be possible.

      SN: Have there been any specific flights that have stood out to you?

      Grip: Obviously, the first flight. That was the most important flight; it still is. We had a more challenging [time on] flight six. It became exciting, because we had an anomaly during the flight. [A glitch led to navigation images being marked with the wrong time stamps, which caused Ingenuity to sway back and forth during its flight.] Ingenuity had to power through that and survive and get down on the ground in one piece.

      We’ve had some flights that have been dedicated to scouting activities. We went to an area where the rover was going to spend several months, and we went ahead of the rover and scouted [it] out so the rover drivers could be more efficient in finding safe ways to drive. Those were flights 12 and 13. Then some of these longer flights have been exciting. Flight No. 9, until a few days ago, was the biggest thing we’d ever done, at [a distance of] 625 meters. And with flight 25, we just beat that and flew more than 700 meters.

      SN: There was a flight recently that had to be postponed because of a dust storm, right?

      Grip: That’s correct. That was flight No. 19. With flying, whether it’s on Mars or here on Earth, you’re worried about weather. We always look at the weather before flying. And every time we’ve done that [on Mars], it had been more or less the same. Then the afternoon before we were about to open flight 19, we were notified that we had a dust storm. That delayed us by quite a bit. When we woke up from that, we had dust on our navigation camera lens, and sand covered our legs partially. We had to fly out of that, and it was a new challenge for the helicopter, but again, it tackled that perfectly.

      During Ingenuity’s 22nd flight, on March 19, 2022, the helicopter captured a picture of its own shadow on the ground below.JPL-Caltech/NASA

      SN: Ingenuity has flown through two seasons on Mars. As seasons change, so does air pressure. Does that affect the helicopter?

      Grip: Yeah, that’s a pretty big deal. We knew, for several years before launch, exactly when we were going to land and where we were going to land. Our design was geared towards the first few months after landing, and that coincided with a particular season [spring] in Jezero crater on Mars. We could [ahead of launch] predict reasonably well what the air density would be. And when we extended [the mission] beyond that, the air density started dropping. To be able to keep flying, we had to increase our rotor speed. In fact, we increased it above anything we tested on Earth. Now we’ve come out of summer, the density has started climbing again, and we’ve been able to go back to our original rotor speed and also extend our flight time.

      SN: What comes next? Are there any big flights planned soon?

      Grip: We’re going to make our way over to the river delta that Perseverance is headed toward. We’ve just completed the biggest obstacle to doing that, flight 25, which was getting across this region called Séítah, which has a lot of sand and varied terrain. And when we get to the river delta, there are a few different options on the table: to help the rover drivers, to scout out targets, or even potentially to do some scouting on behalf of the next Mars mission. Perseverance is the first part of a sample return campaign. It’s sampling right now. And those samples will be left on the surface and will be eventually picked up — that’s the plan anyway — and sent back to Earth.

      SN: What does Ingenuity mean for future exploration?

      Grip: This is a new era. Aviation in space is now a thing. We can’t think about Mars exploration without aerial assets as part of that. I think that’s the most exciting thing. More

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      Crumbling planets might trigger repeating fast radio bursts

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      Fragmenting planets sweeping extremely close to their stars might be the cause of mysterious cosmic blasts of radio waves.

      Milliseconds-long fast radio bursts, or FRBs, erupt from distant cosmic locales. Some of these bursts blast only once and others repeat. A new computer calculation suggests the repetitive kind could be due to a planet interacting with its magnetic host star, researchers report in the March 20 Astrophysical Journal.

      FRBs are relative newcomers to astronomical research. Ever since the first was discovered in 2007, researchers have added hundreds to the tally. Scientists have theorized dozens of ways the two different types of FRBs can occur, and nearly all theories include compact, magnetic stellar remnants known as neutron stars. Some ideas include powerful radio flares from magnetars, the most magnetic neutron stars imaginable (SN: 6/4/20). Others suggest a fast-spinning neutron star, or even asteroids interacting with magnetars (SN: 2/23/22).

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      “How fast radio bursts are produced is still up for debate,” says astronomer Yong-Feng Huang of Nanjing University in China.

      Huang and his colleagues considered a new way to make the repeating flares: interactions between a neutron star and an orbiting planet (SN: 3/5/94). Such planets can get exceedingly close to these stars, so the team calculated what might happen to a planet in a highly elliptical orbit around a neutron star. When the planet swings very close to its star, the star’s gravity pulls more on the planet than when the planet is at its farthest orbital point, elongating and distorting it. This “tidal pull,” Huang says, will rip some small clumps off the planet. Each clump in the team’s calculation is just a few kilometers wide and maybe one-millionth the mass of the planet, he adds.

      Then the fireworks start. Neutron stars spew a wind of radiation and particles, much like our own sun but more extreme. When one of these clumps passes through that stellar wind, the interaction “can produce really strong radio emissions,” Huang says. If that happens when the clump appears to pass in front of the star from Earth’s perspective, we might see it as a fast radio burst. Each burst in a repeating FRB signal could be caused by one of these clumps interacting with the neutron star’s wind during each close planet pass, he says. After that interaction, what remains of the clump drifts in orbit around the star, but away from Earth’s perspective, so we never see it again.

      Comparing the calculated bursts to two known repeaters — the first ever discovered, which repeats roughly every 160 days, and a more recent discovery that repeats every 16 days, the team found the fragmenting planet scenario could explain how often the bursts happened and how bright they were (SN: 3/2/16).

      The star’s strong gravitational “tidal” pull on the planet during each close pass might change the planet’s orbit over time, says astrophysicist Wenbin Lu of Princeton University, who was not involved in this study but who investigates possible FRB scenarios. “Every orbit, there is some energy loss from the system,” he says. “Due to tidal interactions between the planet and the star, the orbit very quickly shrinks.” So it’s possible that the orbit could shrink so fast that FRB signals wouldn’t last long enough for a chance detection, he says.

      But the orbit change could also give astronomers a way to check this scenario as an FRB source. Observing repeating FRBs over several years to track any changes in the time between bursts could narrow down whether this hypothesis could explain the observations, Lu says. “That may be a good clue.” More

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      This is the biggest known comet in our solar system

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      The nucleus of a comet discovered in 2014 is the largest ever spotted.

      The “dirty snowball” at the center of comet C/2014 UN271 is about 120 kilometers across, researchers report in the April 10 Astrophysical Journal Letters. That makes this comet — also known as Bernardinelli-Bernstein, after its discoverers — about twice as wide as Rhode Island, says David Jewitt, an astronomer at UCLA.

      Though the comet is big — and vastly larger than Halley’s comet, which measures a little more than 11 kilometers across — it will never be visible to the naked eye from Earth because it’s too far away, Jewitt says (SN: 12/14/15). The object is now about 3 billion kilometers from Earth. At its closest approach in 2031, the comet will come no closer to the sun than 1.6 billion kilometers, about the same distance as Saturn.

      Jewitt and colleagues sized up the comet with the help of new images from the Hubble Space Telescope, combined with images taken by another team at far-infrared wavelengths. The analysis also revealed that the comet’s nucleus reflects only about 3 percent of the light that strikes it. That makes the object “blacker than coal,” Jewitt says.

      Comet Bernardinelli-Bernstein takes about 3 million years to circle the sun in a highly elliptical orbit. At its farthest, the comet may reach about half a light-year from the sun — about one-eighth of the distance to the next nearest star.

      The comet is likely “just the tip of the iceberg” as far as undiscovered comets of this size go, Jewitt says. And for every comet this size, he suggests, there could be tens of thousands of smaller objects circling the sun undetected.

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      New thermal maps of Neptune reveal surprising temperature swings

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      Neptune’s atmospheric temperature is on an unexpected roller-coaster ride, and it could take decades for scientists to piece together what’s happening at the distant planet.

      The ice giant’s global temperature dropped about 8 degrees Celsius between 2003 and 2012 at the start of Neptune’s summer, researchers report April 11 in Planetary Sciences Journal. Then from 2018 to 2020, thermal images show that the planet’s south pole brightened dramatically, indicating a spike of 11 degrees C (SN: 10/2/07).

      Naomi Rowe-Gurney, a planetary scientist at NASA Goddard Space Flight Center in Greenbelt, Md., and colleagues looked at 17 years of mid-infrared data from ground-based telescopes and the no-longer-functioning Spitzer Space Telescope (SN: 7/18/18; SN: 1/28/20). The researchers used infrared light to pierce Neptune’s top cloud layer and peer at its stratosphere, where the planet’s atmospheric chemistry comes into view.

      Each Neptune year lasts 165 Earth years, so the time period analyzed — from 2003 to 2020 — is essentially equivalent to five weeks on Earth. The wildest temperature shift occurred from 2018 to 2020, when the atmospheric temperature at Neptune’s south pole rose from –121° C to –110° C.

      “We weren’t expecting any seasonal changes to happen in this short time period, because we’re not even seeing a full season,” says Rowe-Gurney. “It’s all very strange and interesting.”

      The researchers don’t yet know what’s causing the temperature changes. The sun’s ultraviolet rays break up methane molecules in the stratosphere, so that chemistry or even the sun’s activity cycle could be a trigger. Nailing down specifics requires more observations. “We need to keep observing over the next 20 years to see a full season and see if something else changes,” says Rowe-Gurney.

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      Mars has two speeds of sound

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      On Mars, the speed of sound depends on its pitch.

      All sound travels slower through Mars’ air compared with Earth’s. But the higher-pitched clacks of a laser zapping rocks travels slightly faster in the thin Martian atmosphere than the lower-pitched hum of the Ingenuity helicopter, researchers report April 1 in Nature.

      These sound speed measurements from NASA’s Perseverance rover are part of a broader effort to monitor minute-by-minute changes in atmospheric pressure and temperature, like during wind gusts, on the Red Planet.

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      “The wind is the sound of science for us,” says astrophysicist Baptiste Chide of Los Alamos National Laboratory in New Mexico.

      To listen to the wind, Perseverance carries two microphones. One was meant to record audio during the mission’s complex entry, descent and landing, and while it didn’t work as hoped, it is now turned on occasionally to listen to the rover’s vitals (SN: 2/22/21; SN: 2/17/21). The other microphone is part of the rover’s SuperCam instrument, a mast-mounted mishmash of cameras and other sensors used to understand the properties of materials on the planet’s surface.

      But these microphones also pick up other sounds, such as those made by the rover itself as its wheels crunch the surface, and by Perseverance’s flying companion, the robotic helicopter Ingenuity. The SuperCam instrument, for example, has a laser, which Perseverance fires at interesting rocks for further analysis (SN: 7/28/20). The microphone on SuperCam captures sounds from those laser shots, which helps researchers learn about the hardness of the target material, says planetary scientist Naomi Murdoch of the Institut Supérieur de l’Aéronautique et de l’Espace in Toulouse, France.

      Murdoch, Chide and their colleagues listened to the laser’s clack-clack when zapping rocks. (“It doesn’t do, really, ‘pew pew,’” Murdoch says). When the laser hits a target, that blast creates a sound wave. Because scientists know when the laser fires and how far away a target is, they can measure the speed at which that sound wave travels through the air toward the SuperCam microphone.

      The speed of this sound is about 250 meters per second, the team reports. That’s slower than on Earth, where sound travels through the air at about 340 m/s.

      The slower speed isn’t surprising. What we hear as sound is actually pressure waves traveling through a medium like air, and the speed of those waves depends on the medium’s density and composition (SN: 10/9/20). Our planet’s atmosphere is 160 times as dense as the Martian atmosphere, and Earth’s air is mostly nitrogen and oxygen, whereas the Martian air is predominately carbon dioxide. So sound on Mars travels slower in that different air.

      The team also used the SuperCam microphone to listen to the lower-pitch whirl of Ingenuity’s helicopter blades (SN: 12/10/21). From this lower-pitched sound, the researchers learned that there is a second speed of sound at the Martian surface at frequencies below 240 hertz, or slightly deeper than middle C on a piano: 240 m/s.

      In contrast, at Earth’s surface, sound moves through the air at only one speed, no matter the pitch. The two speeds on Mars, the researchers say, are because of its carbon dioxide–rich atmosphere. Carbon dioxide molecules behave differently with one another when sound waves with frequencies above 240 hertz move through the air compared with those below 240 hertz, affecting the waves’ speed.

      “We’ve proved that we can do science with a microphone on Mars,” Chide says. “We can do good science.”

      The SuperCam microphone captures thousands of sound snippets per second. Those sounds are affected by air pressures, so the researchers can use that acoustic data to track detailed changes in air pressures over short timescales, and, in doing so, learn more about the Martian climate. While other Mars rovers have had wind, temperature and pressure sensors, those could sense changes only over longer periods.

      “Listening to sounds on another planet is another way that helps all of us place ourselves as if we were there,” says Melissa Trainer, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md., who was not part of this work.

      The team is focusing on next collecting acoustic data at different times of day and different seasons on Mars.

      “The pressure changes a lot on Mars throughout the year with the seasons,” Trainer says. “I’m really excited to see how the data might change as it gets collected through proceeding seasons.” More

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      A star nicknamed ‘Earendel’ may be the most distant yet seen

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      A chance alignment may have revealed a star from the universe’s first billion years.

      If confirmed, this star would be the most distant one ever seen, obliterating the previous record (SN: 7/11/17). Light from the star traveled for about 12.9 billion years on its journey toward Earth, about 4 billion years longer than the former record holder, researchers report in the March 30 Nature. Studying the object could help researchers learn more about the universe’s composition during that early, mysterious time.

      “These are the sorts of things that you only hope you could discover,” says astronomer Katherine Whitaker of the University of Massachusetts Amherst, who was not part of the new study.

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      The researchers found the object while analyzing Hubble Space Telescope images of dozens of clusters of galaxies nearer to Earth. These clusters are so massive that they bend and focus the light from more distant background objects, what’s known as gravitational lensing (SN: 10/6/15).

      In images of one cluster, astronomer Brian Welch of Johns Hopkins University and colleagues noticed a long, thin, red arc. The team realized that the arc was a background galaxy whose light the cluster had warped and amplified.

      Atop that red arc is a bright spot that is too small to be a small galaxy or a star cluster, the researchers say. “We stumbled into finding that this was a lensed star,” Welch says.

      The researchers estimate that the star’s light originates from only 900 million years after the Big Bang, which took place about 13.8 billion years ago.

      Welch and his colleagues think that the object, which they poetically nicknamed “Earendel” from the old English word meaning “morning star” or “rising light,” is a behemoth with at least 50 times the mass of the sun. But the researchers can’t pin down that value, or learn more about the star or even confirm that it is a star, without more detailed observations.

      The researchers plan to use the recently launched James Webb Space Telescope to examine Earendel (SN: 10/6/21). The telescope, also known as JWST, will begin studying the distant universe this summer.

      JWST may uncover objects from even earlier times in the universe’s history than what Hubble can see because the new telescope will be sensitive to light from more distant objects. Welch hopes that the telescope will find many more of these gravitationally lensed stars. “I’m hoping that this record won’t last very long.” More

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      Binary stars keep masquerading as black holes

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      As astronomy datasets grow larger, scientists are scouring them for black holes, hoping to better understand the exotic objects. But the drive to find more black holes is leading some astronomers astray.

      “You say black holes are like a needle in a haystack, but suddenly we have way more haystacks than we did before,” says astrophysicist Kareem El-Badry of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. “You have better chances of finding them, but you also have more opportunities to find things that look like them.”

      Two more claimed black holes have turned out to be the latter: weird things that look like them. They both are actually double-star systems at never-before-seen stages in their evolutions, El-Badry and his colleagues report March 24 in Monthly Notices of the Royal Astronomical Society. The key to understanding the systems is figuring out how to interpret light coming from them, the researchers say.  

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      In early 2021, astronomer Tharindu Jayasinghe of Ohio State University and his colleagues reported finding a star system — affectionately named the Unicorn — about 1,500 light-years from Earth that they thought held a giant red star in its senior years orbiting an invisible black hole. Some of the same researchers, including Jayasinghe, later reported a second similar system, dubbed the Giraffe, found about 12,000 light-years away.

      But other researchers, including El-Badry, weren’t convinced that the systems harbored black holes. So Jayasinghe, El-Badry and others combined forces to reanalyze the data.

      To verify each star system’s nature, the researchers turned to stellar spectra, the rainbows that are produced when starlight is split up into its component wavelengths. Any star’s spectrum will have lines where atoms in the stellar atmosphere have absorbed particular wavelengths of light. A slow-spinning star has very sharp lines, but a fast-spinning one has blurred and smeared lines.

      “If the star spins fast enough, basically all the spectral features become almost invisible,” El-Badry says. “Normally, you detect a second star in a spectrum by looking for another set of lines,” he adds. “And that’s harder to do if a star is rapidly rotating.”

      That’s why Jayasinghe and colleagues misunderstood each of these systems initially, the team found.

      “The problem was that there was not just one star, but a second one that was basically hiding,” says astrophysicist Julia Bodensteiner of the European Southern Observatory in Garching, Germany, who was not involved in the new study. That second star in each system spins very fast, which makes them difficult to see in the spectra.

      What’s more, the lines in the spectrum of a star orbiting something will shift back and forth, El-Badry says. If one assumes the spectrum shows just one average, slow-spinning star in an orbit — which is what appeared to be happening in these systems at first glance — that assumption then leads to the erroneous conclusion that the star is orbiting an invisible black hole.

      Instead, the Unicorn and Giraffe each hold two stars, caught in a never-before-seen stage of stellar evolution, the researchers found after reanalyzing the data. Both systems contain an older red giant star with a puffy atmosphere and a “subgiant,” a star on its way to that late-life stage. The subgiants are near enough to their companion red giants that they are gravitationally stealing material from them. As these subgiants accumulate more mass, they spin faster, El-Badry says, which is what made them undetectable initially.

      “Everyone was looking for really interesting black holes, but what they found is really interesting binaries,” Bodensteiner says.

      These are not the only systems to trick astronomers recently. What was thought to be the nearest black hole to Earth also turned out to be pair of stars in a rarely seen stage of evolution (SN: 3/11/22).

      “Of course, it’s disappointing that what we thought were black holes were actually not, but it’s part of the process,” Jayasinghe says. He and his colleagues are still looking for black holes, he says, but with a greater awareness of how pairs of interacting stars might trick them. More

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      When the Magellanic Clouds cozy up to each other, stars are born

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      Like two great songwriters working side by side and inspiring each other to create their best work, the Magellanic Clouds spawn new stars every time the two galaxies meet.

      Visible to the naked eye but best seen from the Southern Hemisphere, the Large and Small Magellanic Clouds are by far the most luminous of the many galaxies orbiting the Milky Way. New observations reveal that on multiple occasions the two bright galaxies have minted a rash of stars simultaneously, researchers report March 25 in Monthly Notices of the Royal Astronomical Society: Letters.

      Astronomer Pol Massana at the University of Surrey in England and his colleagues examined the Small Magellanic Cloud. Five peaks in the galaxy’s star formation rate — at 3 billion, 2 billion, 1.1 billion and 450 million years ago and at present — match similarly timed peaks in the Large Magellanic Cloud. That’s a sign that one galaxy triggers star formation in the other whenever the two dance close together.

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      “This is the most detailed star formation history that we’ve ever had of the [Magellanic] Clouds,” says Paul Zivick, an astronomer at Texas A&M University in College Station who was not involved in the new work. “It’s painting a very compelling picture that these two have had a very intense set of interactions over the last two to three gigayears.”

      Even as the two galaxies orbit the Milky Way at 160,000 and 200,000 light-years from Earth, they also orbit each other (SN: 1/9/20). Their orbit is elliptical, which means they periodically pass near each other. Just as tides from the moon’s gravity stir the seas, tides from one galaxy’s gravity slosh around the other’s gas, inducing star birth, says study coauthor Gurtina Besla, an astrophysicist at the University of Arizona in Tucson.

      During the last encounter, which happened 100 million to 200 million years ago, the smaller galaxy probably smashed right through the larger, Besla says, which sparked the current outbreak of star birth. The last star formation peak in the Large Magellanic Cloud occurred only in its northern section, so she says that’s probably where the collision took place.

      Based on the star formation peaks, the period between Magellanic encounters has decreased from a billion to half a billion years. Besla attributes this to a process known as dynamical friction. As the Small Magellanic Cloud orbits its mate, it passes through the larger galaxy’s dark halo, attracting a wake of dark matter behind itself. The gravitational pull of this dark matter wake slows the smaller galaxy, shrinking its orbit and reducing how much time it takes to revolve around the Large Magellanic Cloud.

      The future for the two galaxies may not be so starry, however. They recently came the closest they’ve ever been to the Milky Way, and its tides, Besla says, have probably yanked the pair apart. If so, the Magellanic Clouds, now separated by 75,000 light-years, may never approach each other again, putting an end to their most productive episodes of star making, just as musicians sometimes flounder after leaving bandmates to embark on solo careers. More