>> Rebecca Boyle and David W Brown, The New York Times
Published: 2020-07-28 10:08:10 BdST
The planetary science community will cheer these missions. But many researchers have started asking, more loudly than usual, why we’re going back to Mars yet again. So we invited David W Brown and Rebecca Boyle, two journalists who have devoted a fair share of their careers to interviewing space researchers at NASA and in academia, to discuss why Mars, a planet that lost its atmosphere long ago, seems to absorb so much of the oxygen — and budgetary resources — in the rooms where exploration of our solar system are decided.
Rebecca Boyle: So we’re going back to Mars. Again, with another rover. Two, perhaps, if both NASA and China’s space agency succeed.
It’s not that this is disappointing. But there’s a certain level of déjà vu with NASA’s Perseverance mission, modelled so closely after the successful Curiosity rover in 2011. I have written a lot about the value of exploring Mars and the particularly Earthlike qualities that endear it to us. But even I can’t help but wonder what’s next in our quest to explore the solar system, and whether so many journeys to Mars are blocking other important science.
David W Brown: There’s an entire solar system waiting to be explored. Since 2001, NASA has flown eight consecutive successful missions to Mars, including five landers. Humanity now has a library of Mars data sitting on servers that no one has had a chance to study. Data collected from brief encounters by spacecraft with the moons of Jupiter, on the other hand, or the ice giants, Uranus and Neptune, have been squeezed dry.
RB: And that has made the story of Mars exploration a self-fulfilling one. The robots we’ve sent to Mars have been, on balance, exceptionally successful, and have told us about vast waters in Mars’ distant memory, including floodplains where life might have burbled to the surface. They have told us about Martian ice caps, carbon dioxide snow, inner geology, tenuous atmosphere and wind-eroded surface.
Every discovery about Mars brings new questions, which cultivates a healthy ecosystem of Mars researchers. Some of those researchers wind up at academic institutions, where they have funding for graduate students and postdoctoral researchers who continue asking more Mars questions. And so the search continues.
But the past few years have seen an increasingly loud chorus calling for NASA to turn its sights elsewhere. Maybe Venus, maybe Saturn’s moon Titan, maybe the distant, faceless turquoise orb of Uranus — just not Mars, anywhere but Mars, where we’ve been driving wheeled robots for nearly two decades.
DWB: For many years, Mars was treated by NASA almost as its own space program with its own mission lines and priorities. Every two years, something would launch there.
But then in 2010, in part because of budget cuts, the Mars program was integrated into NASA’s overall planetary exploration portfolio. Suddenly other worlds were being annihilated by a crimson Death Star.
The Curiosity rover went over budget by almost $1 billion, eating into other projects. Perseverance went wildly over budget as well, and if the pattern holds, the eventual mission to collect the samples gathered by the rover would do the same.
While much remains uncertain about the particulars of the sample return sequence — will the next be a joint mission with the Europeans, for example, or will it be NASA astronauts going it alone, or will we pay SpaceX to do it — it was deemed by the planetary science community to be a multibillion-dollar “flagship” mission of the highest priority.
That decision killed off a spacecraft that would have orbited Europa, Jupiter’s ocean moon. (A less expensive design, Europa Clipper, is to launch this decade.) While the shock was still fresh, NASA selected the Mars InSight lander over a well-regarded mission in its less expensive Discovery class that would have landed a boat on Titan, Saturn’s largest moon, to sail its seas of liquid methane.
RB: Rest in peace, Titan Mare Explorer. Meanwhile, as planetary scientists debated how to pay for their missions, some geologists salivate for a second look at Venus, the second planet from the sun.
Venus is about the same size as Earth, it’s rocky, it has an atmosphere. And, it orbits the sun in a zone where temperatures are just right for liquid water — and maybe life.
“I got my PhD. on Mars volcanoes. I am on three Mars proposals. It’s not like I don’t value Mars — it’s an amazing world,” said Paul Byrne, a planetary scientist at North Carolina State University. “But it’s not the only amazing world.”
DWB: Airships sniffing around the upper atmosphere of Venus are overdue. Certainly since the retirement of the space shuttle, nothing in the NASA portfolio, save the recent SpaceX launch to the International Space Station, has generated the excitement of the planetary science program.
The New Horizons flyby of Pluto, the Cassini mission to Saturn, Juno’s stunning images of a Jupiter dipped in blue — to the extent that people talk about NASA “moments,” they’re likely talking about planetary science.
The exception is perhaps the Hubble Space Telescope, which delivers so many stunning images that it’s become a kind of ever-present Technicolor cultural static. We don’t even notice it anymore, which is a testament to its success.
RB: I think this also applies to images from Mars, in a certain sense. We’ve been receiving them in living color since the late 1990s, and they’ve become a kind of static too. Curiosity has a high-resolution camera, and people were captivated by its incredible images after it landed in August 2012, yet barely notice anymore.
Curiosity was the first Mars mission to land in the era of social media, and people around the world watched on Twitter and live on TV in Times Square. That was electrifying. But the attention has faded.
Is it because Mars looks so familiar? For now, we’ll have to be content with wondering what the public response would be to something like a boat on Titan.
DWB: At least there’s a Titan quadcopter in the works. The problem for the rest of the solar system is that the S in NASA doesn’t stand for “science.” The agency is first and foremost a human spaceflight organisation. That’s where its real money goes, and robotic Mars missions are the natural beneficiaries. Astronauts can’t get to Europa with current technologies, and can’t land on Venus. But humans in spacesuits can survive on Mars, which means every robotic Mars mission is more than abstruse geology or aeolian physics. No, every Mars mission is a human precursor mission. Every dollar spent on Mars rovers reduces the inherent risk of future astronaut adventures.
Culturally, Mars is deeply important to NASA, and has been since its infancy. A humans-to-Mars program, conceived before Apollo, was the lunar program’s natural successor. To become multi-planetary, NASA identified the need for reusable space shuttles, a space station, rockets at least as powerful as the Saturn V and other space-based infrastructure. Though the glory days of Apollo funding died, the fundamental elements of Mars exploration did not: All of those things were built, though across a much longer timeline.
RB: The confusion and frustration surrounding the Mars program is a manifestation of NASA’s core existential struggle. As you pointed out, it’s always been an astronaut agency, with human exploration in its DNA. But when presidential administrations change exploration objectives every four to eight years, it’s harder to plan for the long term. NASA needs a place to go, and Mars has been the obvious next step since the moon.
But the agency and country should probably be asking: What is the actual future we want? What’s the endgame? Is it a returned chunk of rock that could tell us more about Mars’ early history? Or maybe we get extremely lucky and bring back a rock that has evidence of fossil bacteria? Or is it just about adding layers, like Martian sedimentary rock, of evidence that Mars is interesting enough for humans to risk walking there one day?
DWB: “Long term” is the strength of Mars exploration overall, and the great mystery of this mission. No one knows when the samples bottled up by Perseverance will be brought back to Earth. They might collect red dust for fifteen years before another robot snatches them up and rockets them here for study. The possibility of life on Mars, extant or extinct, has been raised and dashed and rendered inconclusive going back to the Viking landers in 1976 through Curiosity’s methane detection in 2019.
Maybe the samples will answer that question, or maybe, as Dr Tim McCoy, the curator of the meteorite collection at the Smithsonian Institution, tells me, the samples now being targeted by NASA might ultimately not be too scientifically useful.
“How do you know that those are going to address the pressing questions that are going to exist 15 or 20 years from now?” he asked, explaining that the planetary science community may have moved on to a completely different set of questions by the time Mars dirt reaches labs on Earth.
RB: When Perseverance starts exploring Mars, I hope it squirrels away the most interesting rock in the solar system. But while we wait to find out, there are so many other places we haven’t even been.
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