Planetary Radio: Space Exploration, Astronomy and Science - Mars Exploration Rover Program Manager John Callas

Episode Date: November 19, 2007

John Callas provides a status report on Spirit and Opportunity. Emily Lakdawalla is looking at brilliant Comet Holmes in her Q&A report, and Bruce Betts also makes room for Holmes in his What's Up! review of the night sky.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Mars Rover Project Manager John Callis, this week on Planetary Radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan. Take your pick. You can celebrate two Martian years or almost four Earth ones. Either way, Spirit and Opportunity, the Mars Exploration Rovers,

have to be among the greatest successes in the history of space exploration. John Callis of JPL is at the heart of this success story. He'll share a progress report with us in just a couple of minutes. Emily Laktawalla and Bruce Betts both make time to talk about Comet Holmes, still lighting up a corner of the night sky.

Bruce and I will also offer your last chance to get in on Planetary Radio's fifth anniversary celebration when we talk about the new space trivia contest. Someone is going to win that little piece of Mars next week. A snapshot of our pale blue dot tops the space headlines. Kaguya, the Japanese lunar orbiter, has an HDTV camera on board. That camera caught a candid shot of you, me, and everyone else on Earth as our lovely planet rose over the cratered moon. You can see it at planetary.org. We've also got a pretty picture of next-door neighbor Venus on the site. This one came to us in a riot of false color from Venus Express, the European orbiter that just celebrated two years in space. The infrared image cuts

through the clouds to reveal the hot surface below. Hey, and while you're poking around planetary.org, you might want to check out the article Executive Director Lou Friedman penned for Professional Pilot magazine. Asked to write about the future of flight, Lou looked past our atmosphere to the solar sails that may someday lay courses between the stars. Here's Emily. I'll be right back with John Callis of JPL. Hi, I'm Emily Lakdawalla with questions and answers.

A listener asked, from Earth, we're looking at Comet Holmes straight down its tail. With the armada of spacecraft across the solar system, have any of them taken pictures of the comet from different angles? 17 P. Holmes is a Jupiter family comet, orbiting between Mars and Jupiter. In October 2007, the normally dim comet suffered an outburst, brightening by a factor of half a million times over a period of just two days. Observers around the world were able to look up with the naked eye and see the fuzzy blob of the comet sitting near the constellation Perseus. The brightening seems to be related to a sudden ejection of material from the comet's surface in all directions.

Very fortunately, the comet happened to be close to opposition when the outburst happened, meaning that Earth was between the comet and the Sun, very near the comet's closest approach to Earth. So Earth observers were in a great position to observe the coma expand and expand over many weeks. But our position between the comet and the Sun means that we're looking almost directly down the comet's tail. Are there any spacecraft out there that can get a side view on the tail? Stay tuned to Planetary Radio to find out. Can it really be almost four years since we held our breath, hoping that the Mars Exploration Rovers would successfully crawl out onto the surface of the red planet?

Now, after miles of trekking, nearly 200,000 images sent home, and gigabytes of terrific science, spirit and opportunity still struggle on. John Callis leads the teams of engineers that hope to keep them doing exactly that, possibly for many more months. But many challenges lie ahead. John is the MER Project Manager at the Jet Propulsion Lab near Pasadena, California. We talked last week about this continuing mission and how it has prepared us for future exploration of Mars. John, congratulations. What can I say? Five extensions of the Mars Exploration Rover mission, and this one could take you through 2009? That's right. For what was originally a three-month mission, we're now at 45 months,

so 15 times the original mission duration. And the rovers are still going. I mean, obviously they're showing signs of wear and age, but they're still very functional vehicles on the surface, and so there's a tremendous amount of exploration we can continue to do with these vehicles as they travel about the surface. Here's the question I know you get all the time, and so I don't even have to finish it. In your wildest dreams, did you imagine?

Well, originally we were concerned that the winter, the first Martian winter, would have been the end point for the rovers. That dust would have accumulated on the solar arrays. It would have been too dark and too cold for the rovers to have survived that first winter, and they would have died there. And so the mission would have been 120 days, 180 days, something like that. But the reality is that Mars has blessed us. We had these wind events that blew some of the dust off the solar arrays, which gave the rovers more power going into the winter. They then continued on in the spring and summer. The second Martian winter was a little tougher for Spirit because there was more dust on the arrays, but we got her through that. And now we're looking ahead to our third Martian winter,

which will be even tougher still for Spirit because there's now a lot more dust on the arrays, and we have to take some special measures to make sure that she gets through the winter. So you must be hoping for a good windstorm down there in the south. Well, we're not banking on that. We can't predict these. We can't anticipate them. And so we're assuming a worst-case dust accumulation continuing through the winter

and estimating what we think our power levels will be. And they will be very low. We'll see power levels that Spirit has never seen before in terms of how low they are. And we're going to have to take some special measures to manage the rover's power utilization during that time. And we will park the rover with its solar arrays pointed towards the northern sky, which is where the sun will be in the wintertime, and we hope to get the rover tilted by as much as 25 degrees towards the north to maximize the solar array energy production of the arrays.

I guess it was a pretty careful search for this resting place where Spirit will weather this winter? That's right. It was a compromise between finding a place where we could do new science, go to a new location we've never visited before, versus finding the location that maximizes the survivability of the rover. I mean, there's a real risk here that the rover won't make it through this winter. The estimates are that it will, but that's based on estimates. So we wanted to do everything we possibly could to maximize the likelihood that Spirit will go through the winter.

And so we did a search of different locations. And remember, Spirit does have one wheel that no longer functions. And so it's a five-wheel driving rover, not a six-wheel driving rover. And so its ability to climb up onto slopes is compromised. So we had to find a steep slope to the north that the rover could get onto. And so that limited our choices pretty much to the north side of home plate, which is the geologic feature where the rover is right now. And we needed to get there in enough time to make sure we could get into place before the energy levels get too low and we lose the ability to drive effectively each day. Now, are you going to be able to do some science

while Spirit is parked there? I know that last winter, last Martian winter, you actually still got a fair amount of science done. Yeah, we were quite busy. I mean, the situation with last Martian winter is since we weren't driving around, we did all the other stuff that we've been putting off. You know, it's kind of like farmers in the winter. They have time to, you know, do the furniture making and the knitting and the quilting because they don't have to worry about taking care of the fields and the crops outside. So it's the same thing for us. Since we weren't driving, we had time to focus on more of the stationary, long-term science observations. And we will do that again this winter.

There is a possibility that we actually may be able to move the rover some during the wintertime to put additional or new targets within the reach of its robotic arm. So we expect the rover to be busy up to the point where energy levels start to get very marginal, and there we'll have to then have the rover to be quiescent, almost hibernating during the deepest part of the winter. Of course, we have been anthropomorphizing these two plucky rovers, there I go again, since the beginning of this mission. But you really have to admire Spirit for what it has gone through.

The bad wheel, its rock abrasion tool went bad quite a while ago. It's dealing with this dust now. And I guess the dust storms have taken their toll. The dust storms really took their toll on both rovers. I know you've had to shut down the mini test units or the thermal emission spectrometers. That's right. The dust storm we went through was dramatic. It was probably the greatest threat to the survivability of the rovers since landing.

It was a rover-killing dust storm, but through careful power management, we were able to get both rovers to survive. You know, the atmospheric opacity, how dark the sky gets, was tremendous. I mean, the rovers were almost in the equivalent of nighttime during the day, and so they had very little energy. And we had to manage that very, very carefully to get them through that. And then one of the results of the dust storm was that it dumped all this dust onto the rovers. All the high-altitude atmospheric dust that gets kicked up as part of one of these large global dust storms eventually rains out of the sky. And so the rovers got not only their solar arrays, but some of the camera optics. And we

believe the mini-test on both rovers has been affected by dust, by wind blowing dust into the viewing aperture and obscuring the optical mirrors inside. And so we haven't used the mini-test lately because we're concerned about continued contamination. And so we're in the process of developing ways to try to shake some of the dust off the internal mirrors to return those instruments to functionality. That's John Callis, project manager for the Mars Exploration Rovers. He'll tell us more right after a break. This is Planetary Radio.

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The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. Welcome back to Planetary Radio. I'm Matt Kaplan. We're visiting with John Callis, Mars Exploration Rover Project Manager at the Jet Propulsion Lab in Southern California. He was just telling us about Rover Spirit's somewhat delicate situation as it faces another long, cold, Martian winter. But there's more to the story than Spirit's many trials and tribulations. Before we move north and to the other side of the planet, up to the Meridiani Planum, where Opportunity is, of course,

if you could talk a little bit more about the actual science that Spirit has managed to accomplish. The most exciting discovery in the past few months with Spirit, which may be one of the biggest discoveries that Spirit has made, is the discovery of this high concentration of amorphous silica. This is basically silicon dioxide, but it's an amorphous phase. And the geologists say that this formed, this amorphous silica formed from a hot spring or a volcanic fumarole with the presence of water, or maybe even a deep ocean volcanic vent. So it was an aqueous environment where there was an energy source.

We know here on Earth, wherever we have those, those are thriving ecosystems. And so we believe that on Mars there was some sort of an environment that was like that at this particular site. of an environment that was like that at this particular site. The other tantalizing thing about the formation of the amorphous silica is as it forms, it tends to entrap or entomb whatever may be in that solution. And so on Earth, once again, the amorphous silica contains the fossilized remains of living systems, bacteria, single-celled animals. And so we've been speculating that this amorphous silica we found on Mars may be the ideal sample you want to bring back because there may be something trapped in it, something from billions of years ago.

Is it significant, this additional discovery, looking at these sulfur-rich samples that may contain up to 16% water, I read. Well, it's all part of the same story that Mars had a watery past. We had an environment that was more Earth-like. You know, to have liquid water on the surface, Mars would have had to have had a thicker atmosphere. I mean, today the atmosphere of Mars is only about 1% of the Earth's atmosphere. So water can't exist as a liquid. It's either frozen as an ice or it exists as a vapor.

So the fact that there was liquid water means that Mars had to have a thicker atmosphere. And, of course, liquid water means that the temperatures had to be somewhere between freezing and boiling, so much warmer than they are today on Mars, which gets down to minus 100 degrees Celsius at night for the rovers. So the fact that Mars had a warmer, wetter environment sometime in the ancient past is very intriguing because it means that it was a Earth-like environment. So the natural question is, we had these two bodies, Earth and Mars, that were very much alike. Life started on one. Did it start on the other one? And can we find evidence of either past life or even current life on Mars? Let's quickly turn to Opportunity up there on the Meridiani Planum.

I guess it's proving to be quite sure-footed on the sides of Victoria Crater. That's right. Our objective for close to two years has been to arrive at Victoria Crater and to descend down into it. You know, the science team loves craters because they're giant holes in the ground. And we know that the deeper down you go, the older the geology. You know, much like when you go to the Grand Canyon and you look at the various layers of the rock, you know that the rocks down at the bottom are older than the rocks up at the top. So by going down into a crater, we essentially are going back in Martian history, going back in time, and we're reading the geological record.

And we can read the record in sequence, much like reading the chapters of a book in order. So we've, for a long time, been very excited about getting to Victoria because it's so big, it's so deep, it goes further back in time. And it took quite a bit to get there. I mean, we had to cross kilometers of Martian terrain. We had several, we had a couple of what we call embedding events where the rover was partially stuck in soil that we had to carefully extract ourselves. We had the degradation of the robotic arm because of its age. And then we had this

rover-killing dust storm that we had to get through. And then through all that, we finally had our chance to go down into Victoria Crater. And we selected a spot that not only can we get down in, but we can get back out again to eventually continue exploration elsewhere once we're done with our work inside Victoria. But the rover has been climbing down steep slopes. We've been on a slope of about 25 degrees and doing some careful measurements of some of the exciting geology inside the crater. It really is a heroic story. These little rovers have certainly made their mark in space exploration history. I wonder, though, as you look forward, people are already getting excited about the next step on the surface of Mars. Not just Phoenix, that's really the next step, I guess, but the next rover, the Mars Science Laboratory.

How have Spirit and Opportunity forged a path, been pathfinders, if you'll pardon the expression, for that even more powerful rover. Well, we certainly have benefited from the fact that you have a roving surface vehicle. And what's been remarkable about the Mars Exploration Rovers is that our extended missions are not a repeat of the previous mission. They're like brand new missions, the fact that you can travel to new locations and see totally new terrain and make new discoveries. So the ability to rover, to travel, is phenomenal. And the advantage that the next rover, Mars Science Laboratory, will have is that it's a bigger rover. And when it comes to rover size, it does matter. A bigger rover can travel faster, it can travel

farther, and it can go over more challenging obstacles. So we expect the Mars Science Laboratory to do more traveling. And it also carries a larger science payload, more instrumentation. Where we'd like to think of the Mars Exploration Rovers as robotic geologists, we think of the Mars exploration rovers as robotic geologists. We think of the Mars Science Laboratory as a mobile analytical chemistry lab. It's going to do the next set of investigations where we've been doing a geological survey. The Mars Science Laboratory will do the analytical chemistry survey of Mars. And that's sort of the next level that we need to go to to start to probe many of these questions about the past environment on Mars. Are there organics? Can we understand the nature of those organics? How are they distributed? How are they associated with geology? And wouldn't it be

exciting if when MSL sets down on Mars and begins to explore on its own, if Spirit and or Opportunity were still doing their part on other parts of the red planet? Well, my job is to see that that happens. I would love to keep these rovers going as long as possible. I mean, they continue to be productive assets. And so while they're there, we should maximize their use. I mean, we really want to wear them out. We want to use every little bit of their capability on Mars.

John, we're out of time. Happy second anniversary in Martian years, and looking forward to a fourth anniversary of the Mars Exploration Rovers on the surface of Mars for Earth years, that is, far, far beyond anything that a lot of sensible people thought that they'd be able to achieve. I've enjoyed my time with you. John Callas is the project manager for the Mars Exploration Rovers, still doing an amazing job there on the surface of Mars. We'll be right back with Bruce Betts, who will do a terrific job

exploring the night sky with us on this week's edition of What's Up. That'll be right after a return visit by Emily. I'm Emily Lakdawalla, back with Q&A. As we observe the outburst of comet 17P Holmes from Earth, we are staring directly down its tail. Can we get a better view of the tail from spacecraft? Unfortunately, as it turns out, all the inner planets where there are active spacecraft, Venus, Earth, and Mars, are presently on the same side of the Sun. So the Mars and Venus orbiting spacecraft would also be looking straight down the comet's tail.

We'll have to look into deeper space. There are only two spacecraft in deeper space with cameras, New Horizons and Cassini. New Horizons just passed by Jupiter, which is practically on the opposite side of the Sun from the comet, so that's little help. The last spacecraft out there is Cassini at Saturn, the only deep space mission with a side view of the comet a billion and a half kilometers away. Cassini could take that picture, but the Cassini mission normally plans its science observations months or even years in advance. Trying to hurry up a new sequence of commands for Cassini to photograph this comet while it's active could be risky.

So we may have to remain satisfied with the amazing photos of comet homes that are being taken from Earth. Got a question about the universe? Send it to us at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio. Time for What's Up with Bruce Betts, the Director of Projects for the Planetary Society, joins us by phone this pre-holiday weekend.

And unfortunately, I have not been out to see that big comet, which I bet you're going to mention again. Oh, I am so into the comet now. Yeah, I've been showing people, showing the kids, showing the Cub Scouts, anyone I can. So yeah, Comet Holmes, it is up there. It is still bright for a comet. Now, realize I'm talking, when you find it, you successfully see a fuzzball,

so don't get overly excited. But we don't get to see these cometary fuzzballs very often, especially not with the naked eye. You can see it without binoculars right now, even from the light-polluted L.A. area, although it's a little on the edge. But with binoculars, it just leaps out as a nice fuzzy ball. So I encourage you all to check it out. It's easiest to find a finder chart to help you out.

But right around now it's in Perseus, and it's right near the star we mentioned before. Now it's pretty much almost on top of Mirafak. Good old Mirafak. Our friend Mirafak in Perseus. So it's going to be in the north. It's going to be easy pretty much all night for Northern Hemisphere listeners and probably kind of a bummer for those of you in the Southern Hemisphere. But good up here, and the best we've had in an awful long time for checking out a comet.

It is quite far away from us. It's about one-and-a-half AU, one-and-a-half the distance between the Earth and the sun, astronomical units, and you see coma, basically, the fuzzy outside. But we'll get back to that. In the meantime, let me tell you what planets are up there right now. We've also, in addition to our friend Comet Holmes and its buddy Murphak, we have in the evening sky, Mars rising earlier and earlier, coming up on opposition in the end of December, looking bright, like a very bright reddish star, getting kind of hard to miss, rising in the early, very early evening in the east and

then high overhead by late evening. And we also have in the pre-dawn sky, we've got Saturn coming up kind of in the middle of the night, early morning, also rising in the east, of course. And then Venus, the extremely bright Venus, still up in the pre-dawn sky. And if you're up in the middle of the night, early morning, also rising in the east, of course, and then Venus, the extremely bright Venus, still up in the pre-dawn sky. And if you're up in the pre-dawn, you can check out Venus in the east and then go up and check out Saturn high overhead and keep going over and you'll see Mars heading towards setting in the west all along that ecliptic, the plane of the planets. And that's what's going on with our planet.

You might still catch Jupiter in the evening in the west just after sunset, but it's going to be tough. Keep on trucking through the universe there. All right, I'm trucking on to random space facts. It's really going to be random space facts this week because it's comet time. As I said, I'm enthused. I already told you the fuzzy gas and dust around comet homes or any comet, the kind of blobby area around the nucleus is called the coma. And then comets often have two tails.

In the case of homes, they're not well-developed, but in other cases, they're very well-developed. One a dust tail, one a gas tail. And my favorite little random space fact, and I've probably mentioned it before, is that the comet tails always point away from the sun, even when they lead the comet when it's heading away from the sun. The comet tails are out in front because they're pushed back by processes coming out from the sun. There you go. There's your random space fact. And I think that leads us into trivia land.

We'll come back to comma-related items and future trivia questions. But for now, let's check out that past trivia question. We asked you, what is the escape velocity from Jupiter? What's the escape velocity from Jupiter? I didn't state it. People pointed out. But basically, from the cloud tops, we're looking for ballpark figures. So it won't vary a whole lot, depending on where you're doing it

from. But how do we do, Matt? You know, a lot of people did figure that out, that we needed to talk about how high above the center of Jupiter. Most of them came up with the cloud tops, and sure enough, came up with the same figure 59 and a half kilometers per second that's what we got from edward lupin edward lupin not far from us in san diego long time listener i think a first time winner said jupiter's escape velocity from its cloud tops is that their number it's also about almost 37 miles per second we had a few people who actually derived it, like Tom O'Reilly. Brownie points. Yeah, isn't that something?

And then we had two or three people, Kevin Hecht was one of them, who said, you know, you'd have a really hard time if you lived on Jupiter, if there was something to live on, exploring the solar system because you'd have to build such big rockets. And I pointed out, this is why you run into so few Jovians. Yeah, it's true. It's very true. So anyway, we're going to send out a T-shirt to Edward there. Tell us what we got next week and point out that this is the last chance

that people have to enter the fifth anniversary contest. Oh, that's cool. The fifth anniversary contest. Win a piece of Mars. Win other cool stuff. You can tell them about the cool stuff. I'll give them a question. The question is about our friend Murphak, the star Murphak and Perseus, also known as Alpha Perseae. Why is it called Murphak, and where's

it derived from, and what's it mean? Go to planetary.org slash radio, find out how to enter. When do they need to get that in by, Matt? By the 26th. the 26th of November, which is also when we will start to celebrate our fifth anniversary. They'll need to do that by Monday, the 26th, at 2 p.m. And those other prizes that you mentioned? Well, of course, our grand prize is that fragment of a Mars meteorite, your own piece of Mars. Then we've got a signed limited edition poster courtesy of Mike Okuda and CBS,

a limited edition poster for Star Trek Remastered, and then a couple of copies of a really fun game, Space Station Sim from Vision Video Games. So we're going to have at least four winners. That's very cool. And so every time they enter, they're getting entered. And that's your last chance. And also you're competing for this week's Planetary Radio t-shirt, of course. Of course.

Which is far more exciting, I'm sure, for most people than a piece of Mars. Keeps you warmer than the piece of Mars. Well, that's true. We're out of time. All right, everybody, go out there. Look up the night sky and think about pieces of wood and what you might do with them right now. Thank you, and good night. But we don't, we're not giving away any wood. Oh, I see.

It's just something to think about. He's Bruce Betts. He's the director of projects for the Planetary Society, always swimming against the grain here with us on What's Up. You're a naughty boy. We also want to thank our friends at spaceflory.com, purveyors of fine space memorabilia.

For that little piece of Mars, someone will be winning next time we get together. Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week. Thank you.