Deborah Bass

Dr. Deborah S. Bass
Scientist, NASA/Jet Propulsion Laboratory

They went to Mars to look for signs of
'historic' water in the distant past.
Imagine their surprise when they found
evidence of current flowing water.

Interview by Leon Worden
Signal Senior Editor

Sunday, December 31, 2006
(Television interview conducted December 18, 2006)

Signal: How do you really know you found water on Mars?

Bass: The fact is that we have evidence that's consistent with water on Mars. It looks like we have a fluid that flowed. It looks like the conditions are such that it couldn't be carbon dioxide fluids. Frankly, the only thing it could be, given the conditions, is water.

Signal: There are photos that show a light sedimentary deposit. How do you know it's not just some dirt that the wind blew down the hill?

Bass: We have looked at dust streaks, as they're called, on Mars. Every place that we see dust streaks, they're dark. Now, there's this light layer of dust all over, covering Mars. Wherever that dust is removed, we see a dark streak. Wind streaks are almost entirely dark streaks, and this streak that we see is a light streak. So we don't believe it's a wind streak.

Signal: There are different frozen chemicals on Mars, right? There's frozen carbon dioxide and frozen water; what else is there? What else could it be?

Bass: Sure. There are plenty of chemicals on Mars. What we think this is, is a mineral that precipitated out of water. You know when you have a plant and you water it and water it and you get this crusty white stuff around the edge of the pot?

Signal: Unfortunately, yes.

Bass: This is probably the same kind of crusty white stuff. We think that this is some kind of sulfate mineral that has come out of the water, that has precipitated out of the water, and has been left behind, and the water itself has evaporated.

Signal: So there is water under the surface of Mars.

Bass: It seems that way. The evidence is consistent with that.

Signal: Would it be liquid water or frozen water under the surface?

Bass: There are several different hypotheses. It's possible that it's ground ice that is frozen under there, and when it comes to the surface, it actually liquefies. It's possible that it's a subsurface aquifer, which is actually water in porous space. There are a number of possibilities, and we're still struggling to figure that out. We have to get more information in order to establish that.

Signal: The satellites that are up there — there's a subsurface radar on at least one of them, right?

Bass: Yes.

Signal: Are you using that to look in the spot where this gully formed to see what is under there?

Bass: The Mars Reconnaissance Orbiter, MRO, has an instrument called CHARAD, and that is a radar instrument. I expect that there are individuals who are planning measurements to look at these gullies specifically.

Signal: What would have pushed the water out? Would it have taken something like a volcano or seismic event?

Bass: Probably not. It has probably built up under pressure just over time, sort of enough (pressure) pushing it toward the surface, at which point it sort of bursts out and catastrophically floods down, and then it evaporates over time.

Signal: I've heard the word "dam" used. Why are we hearing that word?

Bass: We think that the water is sort of ice-dammed beneath the surface, so that it's held up rigidly under the surface, and then when enough pressure gets to that point, it breaks through that dam and you get that flooding.

Signal: Like a frozen lake, where there's a layer of ice and water below?

Bass: Similar to that.

Signal: What would it be like if you're standing in that crater while this event is happening?

Bass: I think if you were actually in the crater — I've heard that there are about seven swimming pools worth of water that have been released in these gullies, and it could be a very dangerous place to be if you were in that dry lakebed at that time.

Signal: What are the dimensions of the flow? Evidently there are cameras on the satellites that couldn't see it, but then there's a 280-megapixel camera that did see it.

Bass: It's on the order of tens of meters long.

Signal: Why do we see it at all? Doesn't water instantly evaporate if it's on the surface?

Bass: That's what is so exciting about this discovery. The fact that we can see new evidence of water flowing on Mars in the last, say, seven years, is a phenomenal discovery.
    We took pictures of these same areas back in 1999 or thereabouts, with the same camera system, and then reimaged them more recently in 2005. And the team, the Malin Space Science Systems team with the Mars Orbiter Camera, MOC, saw this change in the surface and it made them scratch their heads and think: What the heck could this be?
    The conclusion that they've come to, kind of kicking and screaming, is that it's water. It's water that has recently flowed on Mars since they started making observations.

Signal: Was there a conscious effort to go back and look at some of the places that were imaged in 1999-2001 and check them out? Or is it just happenstance that somebody noticed there was a difference now?

Bass: There has been an interest in these Martian gullies for quite some time. So the MOC team, the Mars Orbiter Camera team, has been imaging gullies for quite some time. But one particular individual, Dr. Kenneth Edgett — I think it was happenstance that he was looking at these gully pictures and just noticed that there was a change in one from another. So we really owe this discovery to Ken.

Signal: How many people at JPL and other places are looking at what's being found on Mars?

Bass: Well, there are about 5,000 scientists and engineers at the Jet Propulsion Laboratory in Pasadena. However, there are subcontractors all over the world that are connected with NASA and connected with missions to Mars at JPL. So I would say there are tens of thousands of individuals looking for water on Mars.

Signal: You actually found signs of flowing water in two different places, right? There are sets of photos from Terra Sirenum and the Centauri Montes region. So there are two different locations where this same kind of thing happened?

Bass: Those are two locations where they have "before" and "after" pictures. There are at least 150 other places on Mars where the MOC camera has taken pictures of gullies where they've seen these light streaks. So they're all over the place.
    They happen to be in particular bands of latitude. They're about 30 to 70 degrees north and south latitude. And frankly, in a different location than the wind streaks that we were talking about earlier.

Signal: Beyond the fact that you went there to see if you could find water and now you've found it, what does it mean? Does it mean there's life on Mars?

Bass: All of NASA's Mars missions have been trying to follow the water in one way or another. The water that we've talked about for years has always been water in the past -- water millions and billions of years ago. This is current water. This is water now.
    So the question is, could the water that we found now, more recently, have been long-lived enough to form a habitat where life might form? That question is still open, I believe.
    Is there life on Mars now? I don't think we have enough information yet, still, to answer that question.

Signal: You can have water without having life, but you can't have life without having water, right?

Bass: Wherever on Earth we find water, we seem to find evidence of life. So, finding water on another planet makes the likelihood of finding life on another planet so much more probable. It's just tremendously exciting.

Signal: So this was a complete surprise? You were looking for "historic" water from a long time ago and this came out of nowhere?

Bass: This is a blow-your-mind kind of discovery for the scientists. We are absolutely floored and thrilled by this discovery. We're scratching our heads and we're trying to figure out, how do we put this new discovery into the plans for future Mars missions?
    In fact, we have a mission coming up called the Astrobiology Field Laboratory, which is a rover, and that rover will have equipment on it that could perhaps go up to that gully and understand what those chemicals are all about.

Signal: When does that one happen?

Bass: I think that one is scheduled to launch in 2013.

Signal: Now, much sooner than that, come August, you're scheduled to launch the Phoenix.

Bass: Yes.

Signal: What is your relationship with this next Mars project?

Bass: I'm working on the Phoenix Scout mission. I am the deputy project scientist for the Phoenix mission, which is headed to the north polar highlands of Mars.
    We, too, are looking to follow the water. Odyssey, which is another spacecraft orbiting Mars, has found evidence for subsurface hydrogen, which we believe — hydrogen, H20; we think that this subsurface hydrogen is evidence of a huge amount of water frozen into the ground. So Phoenix is going to land in the north polar highlands where all of this hydrogen is and see if we can provide what we call "ground truth." Find, actually touch, the water that Odyssey found.

Signal: The north polar region is one of your specialties. What's your background?

Bass: I have a Ph.D. from UCLA in planetary geology, and I specialized in Mars polar water and Mars polar atmospheric science. So the fact is that getting the opportunity to participate in this Phoenix mission is amazing to me. I feel incredibly privileged and fortunate.

Signal: What are the polar caps made of? Is the ice that we see in the photographs anything other than water ice?

Bass: We believe that at least the visual layer of the north polar cap is water ice, H20 ice, as well as sand and dust from the surrounding environment sort of captured into that ice. It's a mixture of the two, because we see layers. It's got bubbles; it's got contaminants of the sand and dust that floats around in the atmosphere.
    Every winter, the cap gets covered up by CO2, which precipitates out of the atmosphere and sits on top of this water icecap.

Signal: So there is some atmosphere.

Bass: There is. There is some atmosphere. It's very thin, but we see clouds on Mars, we have dust storms on Mars; we have enough air to blow things around. It's just very thin, so that the puff is very weak.

Signal: How close were these recent flows to the poles?

Bass: Not that close. They're more equator-ward than where Phoenix is going to land.

Signal: If there were some kind of life on Mars, it would be microbial, right?

Bass: Yes. Pond scum. We'd have pond scum on Mars, if anything.

Signal: But frozen pond scum under the surface?

Bass: Potentially, yes. Frozen pond scum under the surface.

Signal: You're not expecting to find any pond scum above the surface.

Bass: Probably not, because the Martian atmosphere doesn't have much ozone. Ozone is what protects us from the UV radiation that the sun puts out, and the UV radiation sterilizes the surface of Mars. So we don't believe that the pond scum could survive. It needs a little protective layer. It needs a little raincoat, or sunscreen.

Signal: A lot of the images were captured by the Mars Global Surveyor satellite. But it's not sending back any more photos now?

Bass: No, unfortunately. Since about Nov. 4, Mars Global Surveyor has been silent. There has been a team trying to investigate and understand what happened to it and whether it has really gone silent for good, but NASA has not made an official announcement yet.

Signal: That's a job for the engineers to figure out, not the scientists.

Bass: That is true, although the scientists help by looking at the data and trying to understand what's going on, as well.

Signal: How well do the scientists get along with the engineers? Isn't it kind of like the scientists want everything, and the engineers have to go figure out how to make it happen?

Bass: We'd better work together, you know? Because that's the way this world works.

Signal: When I think of a scientist, I think of a 70-year-old white guy who looks Albert Einstein. How easy is it for a woman to break in and become a scientist for NASA?

Bass: I think that it's very important for young girls out there to know that you can make a meaningful contribution to NASA and still like nice shoes.
    NASA is a great place to work. I love working there, and I think if you have an interest in NASA, there's a role for you.

Signal: So there is no longer any great barrier to pursuing the sciences and similar fields?

Bass: It's getting better and better. I'll tell you — here's a funny little anecdote — when I was a young graduate student, I would go to conferences and you would see there was a line for the men's room, but there was no line for the women's room. Now when I go to conferences, I have to stand in line, too.

Signal: The U.S. has spent several billion dollars in the last decade, sending stuff to Mars. Are we getting our money's worth?

Bass: I would agree that we absolutely have gotten our money's worth, our taxpayer dollars, out of these spacecraft we've been sending to Mars.
    For example, the Mars Exploration Rovers were supposed to operate only 90 days — three months — and yet they're going on three years’ worth of operations. That's phenomenal. I mean, truly. If my car worked three times the (expected) lifetime, I think I would have gotten my money's worth.

Signal: You mentioned the rovers. Didn't you have something to do with designing the rovers’ space mission?

Bass: I worked on the Mars Exploration Rovers in the development phase as well as operating them, yes.

Signal: What were you doing? Creating projects for it to look for historic water?

Bass: I did some of that, so when the Mars Exploration Rover was on the surface in the primary mission, I took measurements. I helped aim the cameras and so forth.
    But in the development phase, what I did was design the process by which the team was going to figure out how to get those measurements. What I say I do is, I design car washes, where the ideas are the cars. What we try to do is figure out, how many towels do you need and how much soap do you need, and how many pieces of software do you need to move an idea from a mental concept all the way to a set of computer instructions that the spacecraft can understand? There are lots and lots of little hand-offs along the way, just like in a car wash. So I helped design that process.

Signal: If you'd always been looking for signs of historic water in the past, now that you found this current water, are you changing the mission of Phoenix? Do you want Phoenix to do something different from when it was initially planned?

Bass: Phoenix has always been geared toward looking for water. Phoenix is going to be looking for chemical evidence of water as well as rounding of grains and so forth, consistent with water, as well.

Signal: So how does this discovery impact what you'll be doing with Phoenix?

Bass: I think it lends credence to what we're doing with Phoenix, and makes the Phoenix mission much more exciting and compelling. Because what we know is that there's a high likelihood that water will be close to the surface, so we may very well find something really easily with the Phoenix mission that we were not so sure about before.

Signal: The Phoenix program manager is Barry Goldstein, who lives here in Stevenson Ranch. He'll be here in a few weeks to discuss the Phoenix project in more detail, but briefly, how does Phoenix differ from the rovers?

Bass: With the Mars Exploration Rovers, they move laterally across the surface. We talk about Phoenix moving vertically. Phoenix has a robotic arm, and we're going to dig beneath the surface—

Signal: Core borings?

Bass: Well, we don't have a core (drill); what we have is a robotic arm with a big scoop. We have a big shovel. We can dig out piles of sand and see down into the surface. We're going to take a look at whatever kinds of layering we see, and use our chemistry experiments that we're taking with us to understand what we see there.

Signal: They say mankind's knowledge expands exponentially — everything we've learned as a species in the last five years is probably equal to the amount we learned in the last 20 years, and everything we learned in the last 50 years is probably comparable to how much we learned in the last 400. You said we've gotten our money's worth out of these missions, but in the last, say, seven years since we've been intensely looking at Mars, have we really, dramatically altered our understanding of Mars?

Bass: Absolutely. I believe we have altered our understanding of Mars and our understanding of the solar system and our understanding of what it takes to create a planetary body, based on the discoveries that we found on Mars in the last, I would say, four or five years.

Signal: In what ways has our understanding changed? What do we know now that we didn't know seven years ago?

Bass: (I've) got to go back to this water thing. Water is much more prevalent on Mars than we thought possible. The Mars Exploration Rovers found evidence of standing bodies of liquid water, oceans, big lakes of water, in Meridiani Planum — a place that we didn't think we'd find a lot of water. Mars Odyssey, which is an orbiter, found all this subsurface hydrogen, frozen water, yet again.
    Mars has a ton of water all over the place. And again, wherever we find water on Earth, we find evidence of life. So, you can fill in the blank there.

Signal: It wasn't terribly long ago that we thought Mars was a totally dead planet.

Bass: Exactly. We thought Mars was a totally dead planet recently. But the fact that we found this water gushing out of the surface in the last seven years implies that this place is not as static as we thought it was.

Signal: Another thing the cameras picked up is recent impact craters. Why are we seeing recent, current impact craters on Mars and not on Earth?

Bass: We are seeing impact craters on Mars but not necessarily on Earth because Mars has a much thinner atmosphere than we have on Earth.

Signal: So we're getting hit with the same stuff, but it's burning up.

Bass: Yes.

Signal: Are there current impact craters like that on the moon?

Bass: There are absolutely current impact craters on the moon.

Signal: Do they occur with the same frequency?

Bass: They occur with the same frequency, which is really great, because what we've been able to do with getting these craters on Mars and craters on the moon is, we can validate our models of cratering rates and figure out, how many big ones do we get over what period of time? How many small ones do we get over what period of time? That is useful information, because it helps us predict big ones — really, really big ones.

Signal: OK, so if we're going to have a space station on the moon in the next 20 years and then Mars after that, isn't there a risk that they'll get bombarded by asteroids?

Bass: I think it's something that the team that's studying putting a station on Mars is absolutely going to consider. NASA employs a tremendous number of very, very intelligent people. I am convinced they'll come up with something to make it OK.

Signal: According to your bio, you have a number of hobbies, and one of them is hiking.

Bass: Yes.

Signal: As a geologist, do you find things on your hikes that you can relate to your work? Are there things you notice in our terrain here in Southern California that translate to the way you think about things on Mars?

Bass: Absolutely. Hiking anywhere gives you a better appreciation for what you're seeing in these orbital images. When you're hiking up and down a canyon and you go through what's called a horizon — the dirt beneath your feet will change color, and that means that you've actually gone from one kind of rock to another kind of rock. We see that same sort of thing in pictures on Mars. I've hiked on glaciers, and glacier ice is great fun because you can see all the layers and I think: Boy, that stuff is what's on Mars. It's just fabulous.

Signal: Beyond the raw pursuit of knowledge, why is it important to us here in Santa Clarita and California and the United States and the world to know whether there was water on Mars?

Bass: Well, certainly I think the raw pursuit of knowledge is important. I think that's why Californians, in particular, are out here — for the gold rush, to find something new. That pioneering spirit is very important to Californians, in particular.
    I do believe, though, that NASA's contribution to technology across the world is another important contribution. There have been an awful lot of useful medical inventions, for example, that have come out of the NASA program, as well.

Signal: Any parting thoughts? What will you be looking for next?

Bass: Certainly trying to find water on Mars and find chemistry on Mars. But my final thoughts are that if you want to work for NASA, you can be an animator, you can be an educator, you can be a scientist, you can be an engineer. NASA has room for all different kinds of people.

    See this interview in its entirety today at 8:30 a.m., and watch for another "Newsmaker of the Week" on Wednesday at 9:30 p.m. on SCVTV Channel 20, available to Time Warner Cable subscribers throughout the Santa Clarita Valley.

©2006 SCVTV.
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