NASA is about ready to send its largest and most capable rover to Mars. With a mass of 1.025 metric tons, the Perseverance rover is about 14 percent more bulky than its predecessor, Curiosity, which landed on Mars in 2012.

Because the two rovers are similar in size and appearance, it would be easy to dismiss Perseverance as a copy of Curiosity. But that would be doing a disservice to the newer rover, which is carrying some unique experiments and hardware to Mars. With these, NASA will dare to try new things on another planet and jumpstart the search for ancient life.

In short, this is an exciting mission.

NASA and its science division, led by Thomas Zurbuchen, deserve credit for pulling together this latest $2.4 billion Mars mission amidst a pandemic, with the coronavirus striking almost precisely at the moment when preparations for launch were most frenetic. “Together,” Zurbuchen said, “We have persevered.”

So here we are, on the eve of launch of the latest mission to Mars. A two-hour launch window for Perseverance opens on Thursday at 7:50am ET (11:50 UTC). The mission will launch on an Atlas V rocket, built by United Launch Alliance, from Cape Canaveral Air Force Station. Weather looks good—and it’s a good time to go, what with a tropical system potentially bearing down on Florida this coming weekend.

Human tech

Like a number of increasingly capable rovers that NASA has dispatched to Mars over the decades, Perseverance will study the geology of the Red Planet to better understand its past and how it went from a warm, wet place to the cold, dry world we know today.

However, this rover will carry some new experiments that may help inform NASA as it plans for eventual human missions to Mars. To be clear, NASA does not currently have the funding or technology to send astronauts to Mars or get them home. Making such a mission affordable will likely require a new generation of reusable, low-cost, and capable vehicles—perhaps something like the Starship launch system SpaceX is developing.

Getting to Mars will require more than rockets and spacecraft, however. It will require a better understanding of the resources available on Mars and how humans might tap into them to make such expeditions more sustainable. For this purpose, Perseverance will carry an experiment named “MOXIE,” which will seek to produce oxygen from Mars’ thin atmosphere, 96 percent of which is composed of carbon dioxide. If this experiment is successful, it will demonstrate the potential for deriving liquid oxygen for rockets launching from the surface of Mars. The potential for mass savings is huge: oxidizer typically accounts for about three-quarters of the mass of rocket propellant, and being able to produce this locally would be a huge boon.

Perseverance will also carry spacesuit-material samples to the surface of Mars. The goal is to assess how these materials perform over time in the harsh conditions of the Red Planet. This will help engineers design hardy spacesuits for eventual human missions to Mars. “To my knowledge, this is the first human spaceflight hardware to actually fly to Mars,” said Amy Ross, a NASA spacesuit engineer, during a news briefing this week.

Helicopter

The rover will also bring a small helicopter to Mars for the first time. Named Ingenuity, the 1.8kg helicopter is about a half-meter tall, with two pairs of counterrotating blades that span 1.2 meters. “This is a Wright Brothers moment, but on another planet,” said MiMi Aung, the helicopter project’s manager. “It adds an aerial dimension to exploration.”

Because the Martian atmosphere is so thin (about 1 percent the thickness at the surface of Earth’s atmosphere), Ingenuity must be both really light and have blades that spin really fast. They rotate at a speed of 2,400 revolutions per minute. The vehicle’s solar-powered lithium-ion batteries have to provide enough energy for about a 90-second flight.

Aung and her team have flown the helicopter in simulated Martian environments on Earth, but replicating those conditions is difficult. And then there is the challenge of needing to fly Ingenuity entirely autonomously, due to the lag in communications between Earth and Mars.

This small vehicle will attempt five flights within 30 days, seeking to go farther and higher with subsequent flights. It’s a grand experiment in flight on another world. “It’s truly the high-risk, high-reward phase of our mission,” Aung said.

Astrobiology

Scientists have long dreamed of studying actual rock and soil samples from Mars in their labs, akin to the opportunities researchers enjoyed with the hundreds of kilograms of Moon rocks brought back by the Apollo program. Perseverance will take the first step toward doing that with a mechanism to collect and stash promising samples.

The rover has a special drill to cut intact cores of Martian rock, each about the size of a chalk stick, and store them. NASA hopes to collect 30 samples from areas the space agency deems geologically interesting or sites where life may once have existed.

While this is technically challenging, it is only the first step of an ambitious and as-yet-unfunded robotic plan to return these samples to Earth. Still to be designed, funded, built, and launched are two more missions, neither of which is simple or cheap.

The first spacecraft would include a lander, a “fetch” rover to retrieve the samples collected by Perseverance, and a “Mars Ascent Vehicle” to launch the samples into orbit. There, they would link up with the second spacecraft, an orbiter that would find and dock with the samples. The spacecraft would then move the samples into a small capsule with a heat shield, return to Earth, and jettison the samples for reentry through Earth’s atmosphere.

NASA and the European Space Agency are talking about jointly developing different elements of this mission, possibly for a launch as early as 2026. While there is some limited funding in NASA’s budget for a new Mars orbiter, at present the complex plan to retrieve and bring the samples home seems more aspirational than real—we are hopeful that it comes to pass, but not expectant.

Listing image by Trevor Mahlmann

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