UPDATE: Feb. 18, 2021, 4:10 p.m. EST NASA's Perseverance rover successfully landed on the surface of Mars.
UPDATE: Feb. 10, 2021, 11:43 a.m. EST The UAE's Hope orbiter entered Mars's orbit on Feb. 9. China's Tianwen-1 entered Mars's orbit on Feb. 10, and will make its attempt to reach the surface in May.
With missions from three nations expected to reach the Red Planet this month, 2021 might be the most illuminating year in the history of Mars research.
Earthlings have been sending probes and robots to and near Mars since the 1960s, and dozens have successfully captured images and data about the planet, gradually revealing its desert mysteries. We've learned a bit about its geology and atmosphere, found ice, and uncovered compelling evidence that Mars was once home to blue oceans.
Now, we're looking deeper. The looming missions will search for evidence of past life on Mars, gather a complete picture of the planet's weather systems, prepare soil samples to be picked up by a future mission, and even attempt the first flight on Mars (via a small helicopter).
From the United States comes Perseverance, NASA’s fifth Mars rover. In the country's first independent mission to Mars, China is sending Tianwen-1. And the Hope orbiter from the United Arab Emirates will be the first interplanetary mission from any Arab nation.
All three of these missions launched from Earth in July 2020. Hopefully, by the end of 2021, they’ll teach us plenty of new things about Mars.
The Perseverance mission
NASA's Perseverance is expected to land in Jezero Crater, just north of the Martian equator.
“We're going to a really old area of Mars and we expect that because the climate was warmer and wetter around 3.5 million years ago, which is the age of these rocks that we're looking at, if life had a chance to arrive, this might be a good place to search for that evidence,” said Mitch Schulte, Mars 2020 program scientist at NASA.
Once the rover lands, it will check to make sure its parts and scientific instruments are working, which can take a month or two. But once it’s ready, the search for past life can begin.
Perseverance is equipped with cameras, lasers, and other instruments to help it examine Mars and scan for traces of atoms left behind by tiny lifeforms.
Schulte was in charge of the process that determined what instruments would be included on the rover. That process wrapped up back in 2014, two years after the team started to develop this mission.
“Instruments on the rover's arm will be able to detect the presence of organic matter but we're not expecting, like, dinosaur bones or anything like that,” Schulte said. “We're really looking at fine detail in the environment that the organisms might have inhabited.”
Those instruments on the rover’s arm are called SHERLOC and PIXL. SHERLOC can hit surfaces two inches away with an ultraviolet laser to detect organic chemicals, and is partnered with a camera named WATSON.
PIXL uses an X-ray beam to search for organic material, traces of which can last millions of years after a microscopic organism lived.
Before its hunt begins, the rover will attempt to launch the first flight on Mars. Aboard Perseverance is Ingenuity, a roughly 4-pound drone equipped with a camera. It can fly for around 90 seconds, covering almost 1,000 feet at heights of 10 to 15 feet on pre-set paths. It's solar-powered and can recharge its own battery.
“This will be the first time flying anything on another planet. That's pretty spectacular,” said Michael Meyer, Mars Exploration Program lead scientist at NASA. As lead scientist, Meyer works with the global community of Mars scientists to determine what the next steps of Mars exploration should be and how missions should proceed in the future.
"This will be the first time flying anything on another planet. That's pretty spectacular."
If the test flight goes well, it might open a path for other drones in space exploration, which could survey planets between the far-out scale of orbiters and six-foot-high scale of rovers.
“It really does improve your possibilities for where you should go and take samples,” Meyer said. “That outcrop that you don't see from the rover or don't see from space, that could be the perfect place to take a sample. As you think more about this and we learn more about how to fly on Mars, you can start thinking about putting other things on it that might be able to pick up samples, do things for you that might be too dangerous or steep to get a rover.”
Mars has plenty of carbon dioxide, but little oxygen. So Perseverance will use a tool called MOXIE to “take carbon dioxide out of the atmosphere, compress it, and then use a solid oxide electrolysis cell to strip the oxygen” out of it, Schulte said.
If the test is successful, MOXIE could be used to provide future astronauts with breathable air. Oxygen is also a vital component of rocket fuel. If spacecraft could launch from Earth with less fuel for the return trip, they would be able to carry more cargo with the same amount of fuel or alternatively need less fuel thanks to the lighter load.
Eventually, a mission will be sent to pick up 43 sample tubes that Perseverance will have filled and stored inside itself until they're ready to be left outside.
Scientists on Earth will have to determine where to collect the samples, and where and when to set them down. There is some debate on the timing of this. If the samples aren't deposited and something unexpected happens to the rover, they would be inaccessible to the pick-up mission, Meyer explained.
“The science community and the engineers will get nervous about having all those samples on board,” Meyer said. “When they're on board, they can't be accessed. They're in the trunk but the trunk is locked. At some point in time you have to decide to let those samples go, put them on the surface of Mars, so that the future mission can collect them.”
By the end of the year, we may have an idea of where the samples will be awaiting their ferry back to Earth.
Tianwen-1’s goals
While the China National Space Administration has not made much information publicly available about Tianwen-1, the agency did release its main goals and what it will be launching.
Between the orbiter and the rover, Tianwen-1 will use various cameras, radar, and other tools to examine the soil, structure, and climate of Mars, most notably looking at the presence of water and ice in the planet's soil, according to an article published in Nature Astronomy.
After the lander settles, a ramp will allow the rover to roll onto the surface of the Utopia Planitia, a broad plain hundreds of miles northwest of where Curiosity has explored and northeast of where Perseverance is headed.
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Despite having little information about the Tianwen-1 mission, Meyer said the fact the rover is going somewhere new is exciting.
“Let's face it, any time you send a rover and you land somewhere where you haven't landed before, you're going to learn something new, because now you're looking at a new place up close and personal,” he said.
Meanwhile, the orbiter will serve as a communications relay between the rover and Earth. It will also observe Mars to help analyze the planet's atmosphere and subsurface.
Sending Hope into orbit
The United Arab Emirates has much more information about its Hope orbiter mission, so named because the UAE Space Agency would like it to inspire people in the Middle East.
The Hope orbiter’s primary goal is to observe, measure, and analyze the Martian atmosphere. Onboard it has an infrared spectrometer, ultraviolet spectrometer, and imager for capturing high-resolution photos.
Its infrared spectrometer will be used to study the lower atmosphere, measuring dust, ice clouds, and water vapor distribution, as well as temperature. This will help give us an understanding of the planet’s atmospheric circulation and seasons.
Hope's UV spectrometer will measure gases in the thermosphere (the second-highest layer of the atmosphere), including carbon monoxide and oxygen. And it will create a 3D map of hydrogen and oxygen in the exosphere, the outermost layer of the atmosphere.
While there are other Mars orbiters, such as NASA’s MAVEN, Meyer said that Hope’s physical orbit is unique: it’s both very large and equatorial.
Other orbiters like MAVEN orbit around the poles of Mars, running north and south while the planet rotates underneath. They also stay much closer to the planet, which can give a more detailed look at the planet but limits their breadth, Meyer said.
“Because of the large orbit, it's something like 40,000 km the furthest away, [Hope is] going to be able to look at Mars kind of as an entire planet, this synoptic view,” Meyer said, noting that it will complement MAVEN and other missions very well.
Additionally, Hope will measure atmospheric escape, specifically looking at hydrogen and oxygen. Scientists know this happens, but haven't been able to accurately measure yet.
Once Hope reaches Mars, it won’t be long before Earth receives new images and measurements of Martian weather.
A long time coming
As Schulte and Meyer explained, reaching this level of Mars exploration has been a long process. The Perseverance mission is a step in an astrobiological strategy that was laid out back in 1995.
Earlier, NASA was “able to determine that there was liquid water scattered near Mars' surface,” Schulte said. “That led naturally into actually searching for signs in the rock records that life might have left behind on Mars.”
Now that technology has caught up to their curiosity, their hard work is paying off, despite the worst pandemic in a century.
“Everything is hard already and you throw in the pandemic where people have to isolate and people have to be away from their families for extended periods of time,” Meyer said. “It's pretty amazing the challenges people have overcome to make these missions successful.”
