Can we learn all we need to know without sending humans there?
Absolutely, as long as we have sample returns. Multiple rover missions with sample returns could adequately explore the planet and at far less expense than sending humans.
You’ve worked on a lot of Mars missions. Do you have a favorite?
I had a much bigger responsibility for Viking, so I was sort of much more deeply and emotionally involved with that one. I had a central role as leader of the Viking orbiter imaging team. I was young and enthusiastic. We worked long days, but I was so excited, I was sleeping in the office at JPL. For me, that was a special time.
What was the proudest moment for the Viking team? And how have other projects built on its foundation?
The proudest moment was undoubtedly the successful landing. This was the first successful landing on Mars. Everything had to go right, and there was that communications gap during descent. So when there were indications of success and the first pictures came in, that was a special moment. As for building on that success, much of the technology used in subsequent landed missions is Viking-derived.
What stands out as a key difference in the way missions are run today?
The data gets distributed so much more efficiently. On Viking, we had to store everything on tape and we made hard copies and photographs that were then distributed to the team members. There wasn’t the computer distribution network then that there is now. That’s a huge difference. I’ve been involved with a German camera [for Mars] and I can get the data here in my office just as well as someone sitting in Berlin.
What’s been the biggest surprise about Mars?
The initial recognition that water played such a prominent role in sculpting the surface. That goes back a long way [to Mariner 9 in 1972] and that was absolutely a total surprise. Along that same theme, a major surprise was when Opportunity landed [in 2004] and saw that outcrop of hydrated salts just next to it. That was kind of amazing. All this data that’s come back now about water ice, all these hydrated minerals, it just keeps coming. We see deltas, embedded sediments, lake sediments, evidence for the whole hydrological cycle. It’s a very exciting planet.
How much remains unknown?
Life is absolutely the central question, and there are two aspects to that. Did it ever start, and is it there now? The probability is much higher that it could have started very early and perhaps survived for a time. But the probability that there is present-day life has got to be much less because the surface is pretty hostile. From a scientific point of view, that’s what’s driving the program. That’s why we’ve got to have these samples back on Earth and look for details of any organics.
Paul Hoversten is the Air & Space executive editor.