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Mars Science Laboratory + Curiosity Rover: Interview with
NASA JPL's Ashwin VasavadaXeni Jardin at 8:00 AM Friday, Apr 8, 2011?
This week, Boing Boing visited NASA's Jet Propulsion Laboratory for a peek inside the clean room where NASA's next Mars rover, Curiosity, and other components of the Mars Science Laboratory spacecraft (MSL) have been built for launch in late 2011 from Florida. Our big photo gallery with first-ever media access for "hands-on" images is here. Spacecraft assembly and testing specialists showed Boing Boing the rover and the other spacecraft components, including the descent stage "sky crane." Shipment from the clean room to Florida is scheduled to begin within the next two months, with launch scheduled for late 2011 and landing on Mars in mid-2012.
Xeni spoke with Ashwin Vasavada, Deputy Project Scientist at JPL for the MSL mission, to understand more about how MSL works and what its creators hope to accomplish, how one scores a job designing interplanetary explorer robots, and how this updated Mars rover is (or is not) like an iPad.
Xeni Jardin, Boing Boing: So, the MSL and Curiosity unveiling this week represents a big milestone for you folks.
Ashwin Vasavada, NASA JPL: Right. The rover is almost complete. We've been working on for several years now, it has all come together and works great and we're putting the final touches on.
BB: So as I understand it, Curiosity will have a lot more science gathering capability than either Spirit or Opportunity.
Ashwin Vasavada: Yes. You can think of it as having nearly everything that Spirit and Opportunity had in the sense that it's a rover capable of driving over some pretty rough terrain, have cameras to look around at the landscape, had some instruments on the end of a robotic arm to look at rocks up-close and do some chemical analysis up-close on the rock. But in addition to that, it has a major new capability of being able to take samples of rocks and soils, and analyze those samples in instruments on board the rover itself.
BB: So much of the science and the public interest around Mars expeditions has been -- is there water on Mars, with the thought being that this would mean life on Mars. How does this change that question?
Ashwin Vasavada: Well, that definitely is the kind of overarching question in Mars exploration, is there life on Mars today? Was there ever life on Mars in the past? As we've tried to answer that question over the past two decades, we realized it's a pretty difficult question to answer. Not only do you need very sophisticated instruments to be able to detect microbial life, but that may not be the kind of life that we're used to on Earth.
But you also have to know a lot about Mars itself as a planet and where you might want to look for life, where the sort of environmental niches are on Mars. What the Mars Science Laboratory aims to do is not detect life directly, but ask those questions about the environment on Mars, and specifically early Mars, a period for which there's a lot of evidence that there were rivers and lakes and a much more kind of a life-friendly environment. So we're going to go to a place that dates back from Mars' early history, maybe three billion, four billion years ago and try to detect whether that environment at that time was an environment that could have supported life.
Video Link: Space reporter Miles O'Brien visited JPL in 2010 as Ashwin and colleagues prepared the "rover on steroids" for departure for the Red Planet.
BB: And the ability to gather and analyze soil samples, rocks is a big leap in that direction?
Ashwin Vasavada: That's correct. The signatures that we're looking for would be, for example, different minerals that might be present in the rocks and soils that only form in the presence of water. So for example, we've detected clays from orbiting spacecraft around Mars, clays on the surface. And clay minerals are pretty interesting because they form in the presence of water that's interacted with more pristine rock. They also form in the presence of water that's basically neutral in pH, in other words, neither too basic or too acidic.
So the presence of clay is a signature that there might be a life-friendly environment and we'll be able to confirm that on the surface.
BB: So let's talk about the rover itself. As I understand, it's simply too big to run on solar power. So instead, this one as I understand it will be equipped with a radioactive thermal generator that uses basically decaying plutonium to generate electricity.
Ashwin Vasavada: That's correct. That's the kind of device that we've used on missions to the outer planets for many years where the sunlight isn't strong enough to generate electricity through solar panels. But this time, we're using it on Mars mostly because Mars is a dusty place and solar panels tend to get covered up and degrade over time.
BB: So the choice to use nuclear power is not just because it's a really large craft, it's the fact that the environment is so full of dust.
Ashwin Vasavada: That's correct. It's primarily because of the dust but it's also the fact that this will be a very long-lived mission so we can't afford to have the dust accumulate and we wanted to design those vehicle to be able to go to higher latitudes if the science pushed us in that direction.
And at higher latitudes like on Earth, there's less sunlight as well. It turns out that where we're probably going to go is more near the equator, but we still will benefit from being free of any constraints due to dust.
BB: Who decides exactly where the rover will be aimed?
Ashwin Vasavada: Well, we try to involve pretty much everybody who knows anything about Mars is open to give us [Laughter] suggestions and help us understand these different sites. So we've had an open process where we've invited all -- basically, all working Mars scientists from around the world and we've gathered them together in hotel conference rooms now four times over the past four years and we have some very vigorous discussions and people share ideas and propose sites. We've narrowed it down to four final sites. And we're also in parallel with the scientific studies studying the safety of those sites whether we can actually land successfully on those sites and we'll deliver all information to NASA and NASA will make the decision.
BB: So you mentioned the landing. This CGI animation of what it will be like for this rover to land looks pretty Rube Goldberg! This is complicated and risky stuff, very far from home. Mars is a notoriously hard place to land a spacecraft, and the plan for how this one will get there is different than its predecessor rovers.
Ashwin Vasavada: Right, and that's mostly due to the size of the Mars Science Laboratory. So we've gotten used to seeing Mars spacecraft land with the airbags and that turned out to be a nice way to land, but we can't use it for a vehicle that's this heavy. We weigh a metric ton. We're about 900 kilograms and it would just require more airbags than we want to carry with us to Mars.
Because of this, we have gone back to the sort of the old school approach and landing with rockets firing and setting it down on the ground. But we've put in a little twist where the rockets are actually attached to what we call a "descent stage" that flies the rover down and the rover is attached to the underside of that stage.
And the very final 10 feet or so above the surface, that descent stage lowers the rover down on a series of tethers to the surface and lands the rover on its wheels. And that turns out to be the most economical and safest way to land this particular vehicle on Mars.
BB: I understand there is a James Cameron connection with the cameras on this rover?
Ashwin Vasavada: Yes, there is. He became involved when he hooked up with the camera team that proposed cameras for these rovers and there are 3D cameras that were capable of video and that seemed to be very much along the lines of his interest. So he became a co-investigator on the camera team for this rover. He had previously worked with the camera team which is in San Diego to develop not only 3D video cameras, but also zoom-cameras so you could really be cinematic with them. And unfortunately, the zoom capability didn't make it in time for us to go on this mission, but we still have the 3D video cameras.
BB: Will this basically be silent films or will there be audio gathering capability? Microphones?
Ashwin Vasavada: They will be silent. Yeah, that's something we haven't done yet on Mars, is actually listen to the sound of Mars. If we did listen, we'd probably hear ourselves mostly, because we think Mars is a pretty quiet place. [Laughter] So we'd probably mostly hear the wheels driving along.
BB: So the idea is that the data that's needed most right now, and the data that there's the most of, is visual data.
Ashwin Vasavada: Right. The visual data really gives the public a sense of being there, which is one of the main reasons we want to do the 3D and the video. But scientifically, any imaging of the landscape is extremely valuable for detecting things like whether water flowed across the surface and basically, doing a geologic study of the landing site.
BB: How soon will we here on Earth be able to see the footage that's gathered?
Ashwin Vasavada: We hope to take a few pictures the very day that we land on Mars, which is pretty much customary for spacecraft. We land and then we take a few pictures and then we spend a few hours making sure everything else is working, but we take sort of an insurance picture right after landing.
And then, in the next few days, we'll hopefully be able to send quite a few pictures back. We'll have a very good data link to Mars since we have some orbiters existing at Mars that will be relaying all the data for us.
BB: So the rover is headed to Florida within the next couple of months.
Ashwin Vasavada: That's right. BB:
And then, is there a sense of when it's likely to go up?
Ashwin Vasavada: Yeah. We have a fixed window which opens up on November 25th of this year and last until December 18th. And so, for about two hours, every day during that window, we have a chance to launch it to Mars and we'll launch at the first opportunity when everything seems to be ready to go.
BB: So you're basically planning not to sleep during that month?
Ashwin Vasavada: Well yeah. [Laughter] In fact, there's a lot of people who haven't slept in the past few months already.
BB: I remember talking to Steve Squyres about that, like his personal sleep schedule during the earlier mission, adapting his circadian rhythms to "Mars days" instead of "Earth days."
Ashwin Vasavada: Yeah. I mean when we land is when the scientists lose all the sleep because Mars has a twenty-four and a half hour day and to make the most out of the first few months on Mars, we actually start sleeping in sync with Mars. And so, we go to bed a half hour later everyday and that gets really fun after a month or two.
BB: Let's talk about the design. Who designs the Mars Rovers and what kind of background do you have to have to get that totally awesome job?
Ashwin Vasavada: JPL is a fantastic place to work exactly for that reason. We have some of the world's best engineers here who get to have the fun and really the challenge of designing these incredibly complex, but really cool vehicles. We have a lot of different kind of engineers. We need all the flavors, electrical, software, everything. And then, we have a few scientists like myself around to help the engineers understand the constraints of their designing, too, and what the eventual purpose of the rover is.
So I get to basically advice all these really amazing engineers as they're building these things in there. They're very clever and interesting people.
BB: Do the designs build off one another? So for instance, are these Mars Rovers sort of technological descendants of earlier models, like generations of iPhones, or iPads, or do you have to start more from scratch with each new series because it's doing different things than its predecessor?
Ashwin Vasavada: It's a little of both. We definitely build on proven technologies. So even the first rover from JPL, the Sojourner Rover in 1997, which was just a little bigger than a shoebox—that still had the six-wheel design and the kind of Rocker-Bogie suspension and we've used that same six-wheel Rocker-Bogie suspension on the Spirit and Opportunity Rovers, which are golf cart size and then MSL, which is a car size.
So that's been something we're not going to change, but we do have to invent new things every once in a while like a new landing system or this sampling system we have for MSL, which is the first time we are doing that.
BB: And how difficult is it to build advanced technology that can do all the jobs you needed to do, but also be durable enough to survive in such an unforgiving environment where you can't just go fix it. What are some of the factors that you have to take into account and that make a robot built for Mars different from a robot you've built for here on Earth?
Ashwin Vasavada: That's a great question. There are a lot of different factors. You have to choose the materials that you work with very carefully, things that won't wear down in the environment on Mars that can take the hundred degree fluctuations in temperature that you see on the surface every day. That's can actually be a hundred degrees centigrade. On Earth, you might see a few tens of degrees from day to night and you still wouldn't want to leave your laptop outside overnight. We're talking a couple hundred degrees of change each day. On Mars with these vehicles, they're just as complex as that and they're out in the environment all the time. Now fortunately, it doesn't rain, so we don't have to worry about water too much, but we have to worry a lot about temperature and ultraviolet light and the fact that we have moving parts. We have as few as possible, but we can't avoid having things like wheels and arms that move. We can't lubricate them once we launched them, so we have to design things where things will work as we -- after we finished them, they'll last for three or four years being used every single day.
BB: Could the rovers ever be built to fix themselves?
Ashwin Vasavada: We haven't tried that. We saw that in the Disney movie WALL-E, where he screwed on a couple of new --
BB: How did you know that's what inspired my question!
Ashwin Vasavada: I remember seeing that,the robot screwed on a couple of new cameras when his eyes broke. Man, I wish we could do that, but what we do instead is, on these NASA spacecraft including MSL, we send redundant parts that we can switch to. So there's actually a good amount of electronics in the rover that are basically a spare and we can switch to a spare computer, we can switch to an entirely spare new circuits and that gives us some flexibility if something breaks.
Other things like the robotic arm and the wheels itself and that sort of thing, we only have one set. Now, Spirit and Opportunity have each had one wheel fail and they can just sort of limp along by dragging that wheel along. And so, it doesn't necessarily mean the mission is over if these things break. But we basically do a mixture of trying to be very careful about having redundant parts and very robust software, and then just hoping nothing goes wrong.
BB: Are these parts made in a factory, or sort of "made by hand" at JPL?
Ashwin Vasavada: At the part level, we do make use of commercially available or at least space-qualified parts when we can. If we were building everything from scratch, it would be an enormously expensive and horribly long process. But at the macro level, the rover itself, it's definitely a prototype kind of process. This is the first and only of its kind and we invent a lot of things as we go along and do a lot of testing and experimentation.
It's incredibly complex and there are many different aspects of it in terms of the mechanical work, then building the entire thermal system for the rover to work correctly. And it's all sort of a unique design. We build upon past experience, but this rover is new in a lot of ways and nothing else exists like it.
BB: Well, and then with that in mind, so we talked a lot about the way technology that was originally developed for NASA has worked its way down to the commercial sector, Tang, there's the archetypal example.
Ashwin Vasavada: Right, yeah. [Laughs]
BB: Both of us can think of many, many other examples. Now, how has that played out with the different generations of Mars Rovers? What are some examples of technologies or ideas that originated with this program, but eventually became incorporated into commercial products, or perhaps if that hasn't happened, maybe you could venture a guess as to what might come out of this.
Ashwin Vasavada: When I first started working on these spacecraft, there definitely was a lot more of that in the direction that NASA was inventing things for this spacecraft, but then would go out into society. And now, that society itself has become so driven by electronics and computers and things, the flow works in both directions.
So we benefit a lot from the fact that other companies are spending a lot of resources making faster computers and 3D imaging technology and things like that, and so, there's kind of a partnership. We invent things here that go out and then we borrow a lot from other companies as well.
BB: Any final thoughts for the space-loving audience at Boing Boing? Anything in particular that you would make sure that people not miss about this story?
Ashwin Vasavada: I hope that people follow along as we launch in November and land in August of 2012. I think what will be really unique about this mission is the fact that we'll have these HD color video cameras on Mars and really for the first time, we'll be able to see Mars the same way that we see things on Earth in HD, in color and moving a little bit.
BB: This is the first time ever that we'll have that opportunity with a NASA exploratory mission, right? This is it.
Ashwin Vasavada: That's right. And so, we really hope to bring as best as we can a virtual presence to people on Earth to be exploring Mars with us. That alone is really exciting, but then we have an incredibly deep and rich science to deal with this rover as well: ten instruments, some of which are as complex as spacecraft themselves.
We think we're just going to have a really great, hopefully a decade long mission if we're lucky. We're planning for two years, but we're hoping for ten.
[ Editor's note: Special thanks to space journalist Miles O'Brien for guidance with this feature, and to Boing Boing science editor Maggie Koerth-Baker. Photos in this post courtesy Joseph Linaschke. ]
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