How Mars 2020 Became the Last Defense of the Martian Past
published during a waning gibbous moon.

It’s not that Mars 2020 was ever unimportant, exactly. Its prime objective was the top endorsement of the most recent Planetary Decadal Survey—essential, said the report, for “understanding Mars in the context of solar system evolution and for addressing the question of whether Mars has ever been an abode of life.”

Moreover, Mars 2020 would be one of those tectonic firsts in space that the public loves and that only NASA can do: it would perform wild west geology, moseying across the red Martian landscape, a lone wanderer against the world. It would bottle pristine samples of Martian soil, leaving them prepped for a follow-on mission to gather the tubes and launch them back to Earth.

Mars 2020 was inexpensive, relatively speaking. The rover would use parts left over from the colossally expensive Curiosity, meaning a lot of the hard work was already done. Anyway, there are no unimportant missions to Mars. Each orbiter, lander, and rover advances our understanding of the fourth rock in some key way—atmosphere, soil composition, topography, and so on—and consequently, our understanding of the solar system as a whole.

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This artist’s concept shows the sky crane maneuver during the descent of NASA’s Curiosity rover to the Martian surface. Credit: NASA

The problem facing Mars 2020 is literally one of now or never.

But the thing about Mars that we’ve always been able to depend upon is that it can wait. Mars went 4.5 billion years without being poked, prodded, and sniffed by robotic ambassadors from the blue marble next door, and if NASA padlocked the doors of the planetary science division tomorrow, Mars could wait another 4.5 billion. And yet today, Mars will soon be unable to wait another day, leaving Mars 2020 imbued with astonishing importance hardly imagined at its conception. The mission, indeed, will soon face the sort of demand for a timely launch not seen by NASA engineers since the Voyager missions, whose launch window opened only once every 173 years.

No. Mars 2020’s urgency is even more pronounced than that. Had the Voyagers each blown up on the launch pad, successors could always launch in 2153 (or more likely, new trajectories, albeit much slower ones, could have been plotted). The problem facing Mars 2020 is literally one of now or never. If it blows up on the launch pad, or faces prolonged delays, or is canceled by an anti-science president, what science will lose, it will lose forever.

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A prototype of the Lander Vision System for NASA’s Mars 2020 mission was tested in this Dec. 9, 2014, flight of a Masten Space Systems “Xombie” vehicle at Mojave Air and Space Port in California. Credit: NASA/Tom Tschida

To understand the sudden urgency, consider the premise of Mars 2020. To find Martian life, existing or extinct, we have to bring pristine samples of Martian soil to Earth, open the canisters in a laboratory, and poke around in the dirt until we answer some pretty big questions. But the entire mission rests on one big assumption: that Martian soil will be pristine in the first place. Should Mars 2020 experience the same sorts of setbacks that plagued the Mars Science Laboratory, there is a chance that the Mars it eventually lands on will no longer be an unspoiled world.

Mars 2020, you see, is racing against Elon Musk.

Mars 2020, you see, is racing against Elon Musk. The SpaceX CEO is determined to make humans a multi-planet species, and his company has a plan to make that happen. In the very long term, it involves the development of a massive Interplanetary Transport System whose rocket dwarfs even the massive Space Launch System now under development by NASA. In the short term, however, he intends to send landers to Mars during each available launch window, which opens roughly every two years when Mars is nearest to Earth.

The first flight to Mars will be in 2018. On that mission, SpaceX will attempt a graceful landing of its Red Dragon capsule on the Martian surface. In 2020, they intend to continue the cadence, sending dropships of supplies for an eventual crewed mission, and again in 2022. The big year in Musk’s ambitious schedule is 2024: that is the earliest that SpaceX might send human beings to the Martian surface. (This is at least ten years in advance of NASA’s own proposed human expedition to the red planet.) Once this happens, Mars as we know it will be over.

Maybe Mars is lifeless today. Maybe it isn’t. Maybe it was a billion years ago. Maybe it wasn’t. But one thing will be certain: once human beings, teeming with bacteria, set foot on Mars, it will no longer be a lifeless world. Casting aside the implied pejorative, Mars will be contaminated, which means Mars 2020 will no longer a mission of analysis, but rather, one of preservation. The Martian soil diligently bottled by the rover will be the only unsullied, pre-human Martian soil in existence. The sample tubes will be our only pristine link to the Mars of the last 4.5 billion years. That’s why the mission has to launch on time and perform flawlessly when it arrives one planet over.

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These eight places on Mars are potential landing sites under consideration as the destination for the Mars 2020 rover. Credit: NASA/JPL-Caltech

“Having some kind of sample as a backup before we have humans trampling all over the place is actually really important to understanding the history of the planet before we mess things up,” says Tanya Harrison, a research scientist for the NewSpace Initiative at Arizona State University.

Historically, planetary protection protocols with respect to a Mars surface sample have placed special interest on protecting this planet’s ecosystem from the introduction of some unknown and extant critter of Mars. With the certainty of humans one day walking on Mars, and the possibility of them doing so before a sample canister might be rocketed back to Earth, scientists have a relatively new and interesting problem to solve. To that end, the Committee on Space Research and NASA’s Office of Planetary Protection have worked to develop protocols to minimize the contamination of Mars that might be caused by the human biome. They have set guidelines for go and no-go areas for human and robotic exploration, and have commissioned studies on how the Martian wind might sweep Earth-brought microbes across the Martian dunes and around the world. (Bacteria aren’t like loyal puppies yapping at our feet. Once they are airborne, it’s off to the races.)

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This shows one prototype for hardware to cache samples of cores drilled from Martian rocks for possible future return to Earth. Credit: NASA/JPL-Caltech

Once on Mars, the rover will be looking specifically for ancient life, and NASA will likely send it somewhere with very old rock exposure. Earlier this month, scientists convened a workshop near Jet Propulsion Laboratory in California to narrow down the possible landing sites for the new rover. Three targets on Mars were chosen, including Columbia Hills in the Gusev Crater, best known as the resting spot for the NASA rover Spirit, whose mission ended in 2010. None of these sites are likely home to life today.

“The places where you would be more likely to find life—if there was life on Mars today—you can’t actually send anything there right now,” says Harrison. “Those sites are all on the planetary protection restriction list.” To visit a site on that list, NASA would first have to spend a fortune sanitizing a spacecraft to an almost ridiculous degree. Planetary protection is an all or nothing affair. Either the life is Martian, or it hails from Earth, and there’s no way to know for sure. Thus the human problem.

Though they don’t compare to the walking bacterial ecosystems that are homo sapiens, there is a good chance that previous NASA landers have brought along wiggly Earth-born friends. “We’ve probably already sent microbes to Mars on things like Viking and Spirit,” says Harrison. One argument for having Mars 2020 visit the rover Spirit is to search for signs of microbial life brought along when that rover landed in 2004. NASA works hard to sterilize their spacecraft, and in any event, the robots are irradiated as they fly through space. The flickering candle of life is not so easily extinguished, however. “It’s probably dormant, but we’ve probably sent stuff to Mars already, but it’s not taken hold. It’s not taken over the planet,” Harrison says with a laugh.

Which means there’s still a chance to bottle fragments of Mars for preservation and study. Human exploration should not stop, but the robots must act quickly. Once Old Mars is lost, there is no bringing it back.