NASA’s most sophisticated rover has yet to launch into Mars on a mission to answer one of the deeper questions: did life arise on another planet?
Mission controllers have set their sights on the 28-mile-wide (45 km) Jezero crater north of the planet’s equator. The landing site is one of the most promising places for any microbial Martian to have been preserved on a rock formed when the crater supported a lake nine times larger than Loch Ness.
The $ 2.7 billion (£ 2.1 billion) rover carries a set of instruments to analyze rocks for “bio-signatures”, the chemical characteristics of life, but will cache other samples on the surface for collection and return to Earth aboard a future mission.
The bad weather and technical glitches aside, the Perseverance mission will embark on its half-trillion-kilometer journey at 12.50 p.m. BST on Thursday when the engines of the Atlas V rocket hitch up to ignite in Cape Canaveral, Florida.
With the coronavirus in the southern state, few scientists and engineers will be in Florida to witness the launch and follow the events online.
“It is an early launch for us,” said Ken Williford, the project’s assistant scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California. “I will have to get up around 3am, although I don’t know if I will be able to sleep.
“Our plan was to have thousands of people there. Our scientific team is only 400 people and all were going to be invited. It’s very different. We will be celebrating remotely.
Even without the pandemic to face, the mission has been challenging. Beyond developing powerful new instruments and an updated autopilot system, engineers built a helicopter for the rover to deploy, the first to take off on another planet.
Called Ingenuity, the 1.8-kg helicopter will be a “pioneer” for future rotorcraft to explore ahead of mobile robots, and perhaps even astronauts, and explore terrain beyond the reach of any one of them, said MiMi Aung, the manager of the Ingenuity project. If Perseverance lands safely, Ingenuity will attempt up to five flights over 30 days, scratching the thin Martian air with four 1.2-meter-long carbon fiber blades that spin at 2,400 rpm.
“Nervousness and nail biting will come to the surface,” Aung told the Guardian. “Surviving the first night for us will be huge.”
But first you have to get there. Trips to Mars are daunting feats and the recent successes of NASA’s Mars Insight and Curiosity missions do nothing to change that. Low Martian gravity and a rarefied atmosphere make entry, descent, and landing so complicated that flight engineers are prone to using the word “terror.”
After seven months of interplanetary travel, in February 2021 the spacecraft will hit the Martian sky at such a speed that its heat shield will burn at 2,370C (4,298F). Using thrusters for control, the probe will head toward its landing site, blow up a parachute, and then release it, descending the last 10 km to the surface in eight retro-rockets.
All right, perseverance will land in Jezero crater on the western edge of Isidis Planitia, a giant impact basin north of the Martian equator. The site was chosen from more than 60 candidates because of its promise to preserve signs of life. The crater was home to an ancient lake and river delta that may have collected and buried Martian microbes and enclosed them in rocks made of mud or compacted mud.
Mounted on the end of his robotic arm are two instruments that Perseverance will use to look for signs of past lives or promising rocks to return to Earth. The Pixl (planetary instrument for X-ray lithochemistry) can fly rocks with a small but powerful beam to reveal its elemental composition. Another tool, called Sherloc, will scan rocks for organic and mineral molecules. The hints of life may not only be in the organics, but also in the textures and patterns of the compounds that scientists see in the rocks.
“Any sign of life we find is very likely to be very ambiguous, very difficult to interpret, and difficult or impossible to reach a true scientific consensus,” Williford said. “We have very good capabilities at finding possible signs of life, but we will need to retrieve those samples and have many different people study them with many different techniques over the years to achieve something like scientific consensus.”
Mark Sephton, an astrobiologist at Imperial College London, is part of the team that will decide what half a kilo of rocks he will bring back to Earth, an unprecedented feat that NASA can accomplish with the European Space Agency in 2031.
“We may be about to cross a fairly deep threshold,” he said. “We talked about the possibility of finding life on Mars, but people forget that if that happens and is conclusive, that is a radical change. That is a line that you cross and never return. It tells us that everywhere in the universe, where you have the right conditions, the right raw materials and a little time, that life should emerge.
“I’m excited, but nervous that something might happen that stops the opportunity of a lifetime. It is a privilege to be involved. It is historical. I do not want anything to go wrong “.
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