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What a win or loss on Mars will mean

Anyone who's looked at the "Seven Minutes of Terror" trailer for next month's Mars landing might have wondered whether the planners behind NASA's $2.5 billion Mars Science Laboratory mission really knew what they were doing — and although the planners insist they're confident, they also say they're nervous.

"There's not a whole lot we can do about it at this point, except just be nervous," said Dave Beaty, chief scientist for the Mars Exploration Directorate at NASA's Jet Propulsion Laboratory.

You can test the mood for yourself by tuning in our "Virtually Speaking Science" talk show at 9 p.m. ET tonight, via BlogTalkRadio or the Second Life virtual world. Beaty and I will be talking about the buildup to the Aug. 5 landing, and taking your questions through Second Life, Twitter (use the hashtag #askvs) and the phone lines. If you can't make it, don't worry: You'll be able to listen to the hourlong podcast via BlogTalkRadio's archive or iTunes.

Falling into place

All the pieces are falling into place for the Mars Science Laboratory's landing sequence, aimed at putting the subcompact car-sized Curiosity rover down within Gale Crater. On Tuesday, NASA maneuvered its Mars Odyssey orbiter into the correct trajectory to pass over the landing site just in time to pick up telemetry from the probe.

The MSL spacecraft is currently within 2.2 million miles (3.6 million kilometers) of Mars and closing in fast. The big nail-biter is scheduled for just after 10 p.m. PT on Aug. 5 (1 a.m. ET Aug. 6), when the spacecraft is supposed to blaze through Mars' atmosphere, spring a parachute, pop off its heat shield and let loose a rocket-powered sky crane platform that will hover about 66 feet (20 meters) above the Martian surface and lower Curiosity on cables. Then the cables will cut loose and the sky crane will fly itself out of the way, leaving Curiosity to get down to business.

What were they thinking???

"I've met with the engineers," Beaty told me. "I've seen their presentations, and they can be very convincing. But you have to hold your breath a little bit and trust that they know what they're doing."

This multibillion-dollar mission depends on everything working right — and there's even more at stake than just the mission. If next month's landing fails, that could spark even more questions about the future of NASA's troubled Mars exploration effort. The failures of Mars Climate Orbiter and Mars Polar Lander in 1999 led to years of rethinking and retrenchment, and the soul-searching would probably go far deeper in this current age of tightened budgets and downscaled ambitions.

On the other hand, a successful landing would set a sunny tone for what's likely to be years of exploration by the most capable interplanetary robot ever created. During tonight's talk show, Beaty will probably be a lot more willing to talk about that type of scenario, just as he was when I interviewed him on Monday. Check out this edited transcript, and bring your follow-up questions to "Virtually Speaking Science" at 9 p.m. ET.

Cosmic Log: So, there's less than two weeks before the big Mars landing — what's going on there at JPL?

Dave Beaty: We're getting very nervous. There's not a whole lot we can do about it at this point, except just be nervous. But this is a significant thing. It's one of these points in history that may change the trajectory of things that happen afterward, whether we end up with a successful landing or an unsuccessful landing.

Q: What do you see as the outcome for failure, and the outcome for failure? What would that mean to the Mars exploration program?

A: Well, just having a successful landing, by itself, is of course huge good news. It enables the scientific return from the mission to happen, which will play out over the next Mars year — that's two Earth years, more or less. Once the rover lands, it has to raise its antenna, do some checkouts, get moving, and then drive over to this mountain that has the stratigraphy we're interested in.

It's sort of like the Grand Canyon way of looking at rock. You get this beautiful exposure of stratigraphy because of the erosion of this mountain. We want to climb up the side of the mountain and check the layering, like John Wesley Powell did just after the Civil War when he went one-arming up and down the Grand Canyon. That was one of the great geological expeditions of all time, as far as I'm concerned.

The site we want to look at is great. It's a little hard to predict exactly what we're going to see inside those rocks if we end up on the success pathway. We know what we're looking for: What are the rocks? What is the nature of the layering? Are there signals that the layers were "habitable" — i.e., had the potential for a life form to have lived there, had a life form been present. If there's a positive outcome on that, then we would definitely want to send another mission — either back to the same place, to check out whether there's any sign of something actually there; or potentially to another place that has the same kind of layering, but some other kind of characteristic.

Here on Earth, one of the big issues we face is that the preservation of the signs of life is very uneven. We know that there's life everywhere on Earth, right? And it's been here in sort of the form that we see it when we look out our windows, back to the time of the Cambrian, which is 600 million years ago. But if you look at the sedimentary rocks, they don't all contain fossils, they don't all contain pollen. You've got to look carefully to understand what has happened to the rock since its formation, and whether it would have included the signs of life, and whether those signs would have survived through all the subsequent things that happened to the rock.

It's not a guarantee that we would go back to exactly the same place, but we would certainly want to go back somewhere if we received this encouragement.

Q: And the implications of failure?

A: If it's a bad landing, the question would be, what is the reason why? In my experience, the public and Congress and all the people surrounding us would be accepting of a failure that was just a bad weather day, or if you land sideways on a rock, or some other sort of bad luck that happens because of what Mars has done to us. They tend to be less forgiving of a mistake made by a human being here on Earth. So, those are two very different kinds of scenarios. Just the fact of a bad day doesn't tell you enough to know what the implication might be. 

Q: A lot of people wonder about how the sky crane is going to work, or whether the heat shield will work properly — the "seven minutes of terror." Is that what you have in mind? Everything that could be done has been done, of course, but if something goes wrong, I suspect people will want to focus on the process for doing something that's never been done before.

A: Almost everything we do at Mars has never been done before. That's what makes this exciting from the point of view of the engineers. They're here to do the impossible. That sky crane landing has some very powerful advantages, if it works. I've met with the engineers, I've seen their presentations, and they can be very convincing. But you have to hold your breath a little bit and trust that they know what they're doing.

Q: If everything works nominally, will we see the sky crane become the main method for getting large payloads down to the surface of Mars?

A: I absolutely think so. For the robotic exploration missions, the bigger question is, do we want the payloads to keep getting bigger? We know for sure that the pathway to eventual human missions has to involve bigger and bigger payloads, because the humans and all their support systems are heavy. This particular landing system will land a payload that's bigger than can be landed with airbags. The airbag would not survive. So it is heading in the direction that we need to follow if we believe in eventual human exploration. Whether the next robotic mission needs to be the same size as MSL — that's an interesting question. We may want to get it smaller, in part to bring the cost down.

Q: What's your role going to be on the night of the landing?

A: I just got my assignment. I will be at Beckman Auditorium at Caltech, with an audience of 1,136 people, which is the auditorium's capacity. I'll be standing in front of them with the NASA feed on the screen behind me, and my instructions are to narrate it like a tennis match. You can interject a little bit of commentary, but you don't want to detract from the main show, which is what's on the screen.

Q: So when will you know if the landing's been successful?

A: The landing itself is at 10:32 p.m. Pacific time, and we've placed both orbiters [Mars Odyssey and Mars Reconnaissance Orbiter] so they will be in position to watch the descent as it comes down. By 10:32 or 10:33, they should have the data to know whether the landing was successful. They may get an ambiguous answer and not know for sure whether it was successful or not successful. That may take a little while longer to sort that out. It's hard to end up with a for-sure crash scenario quickly, because the signals are likely to be less than obvious. But if it's successful, we'll know very quickly.

Tune in "Virtually Speaking Science" on BlogTalkRadio or in Second Life. Dave Beaty and I will be at the StellaNova Small Auditorium, courtesy of the Meta Institute for Computational Astrophysics, at 9 p.m. ET (6 p.m. PT/SLT) tonight. If you miss the live event, don't worry: It'll be archived by "Virtually Speaking" on BlogTalkRadio as well as iTunes.

Previous episodes of "Virtually Speaking Science":

Alan Boyle is's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.