Planetary Radio: Space Exploration, Astronomy and Science - John Rummel: Protecting the Planets from Earth Invaders

Episode Date: July 10, 2006

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Inviters from Earth, 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. John Rummel is NASA's Planetary Protection Officer. We'll talk with him about how he and his staff work to defend our own planet from extraterrestrial infection, and more importantly, how the space agency attempts to keep places like Mars and Europa safe from microscopic Earth tourists. It's a job as big as the solar system. Later today, Bruce Betts will remind us that there's

plenty to see in the night sky, including a minor meteor shower. And he'll bring along a new space trivia question that could win you a Planetary Radio t-shirt. Think of it as our own multi-world cup. The big space headlines this week are owned by Space Shuttle Discovery, now docked at the International Space Station. A couple of the astronauts rode on the low Earth orbit equivalent of a crow's nest. Their seven and a half hour spacewalk put them not just at the end of the robotic arm, but at the end of a 50 foot boom held by the equally long robotic arm. The contraption was more stable than expected as the pair practiced the kinds of maneuvers that might be required to repair a shuttle. As we finish this week's show, Discovery has been cleared

for return to Earth. We've heard from many of you about our satellite telephone conversation with Stephen Grasby last week. Well, Stephen managed to get his Internet connection working on Ellesmere Island above the Arctic Circle, you can ooh and ah over some of the great photos he has taken by visiting Emily Laktawalla's blog at planetary.org. By the way, Stephen and his three colleagues have successfully completed their expedition to that sulfur-laden spring coming up through the glacier. He looks forward to going back in April. And while you're at planetary.org, you can read Emily's big announcement. I tell you what it is, but you really should hear it from her.

In the meantime, let her tell you about the discovery of another moon with a belly band and where that thing may have come from. I'll be right back with John Rummel. Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, On a previous show, you said Iapetus's belly band is unlikely to be caused by sweeping up ring material. It looks like Pan has a belly band, too. Could that one be caused by sweeping up ring material? Unlike Saturn's outermost large moon, Iapetus, the inner small moons of Saturn very likely owe their shapes

to their collection of stray material from other parts of Saturn's system. Beyond Saturn's rings orbit lots of moons that are spherical worlds in their own right. Mimas, Enceladus, Tethys, Dione, Rhea, Titan, Iapetus, and Phoebe. But inside the orbits of these moons are several smaller bodies that are intimately connected with the rings, Janus, Epimetheus, Pandora, Prometheus, Atlas, Daphnis, and Pan. These ring moons, as they are called, are small and have lumpy shapes. Some, notably Atlas, Daphnis, and Pan, look almost like flying saucers

spreading out toward their equators. Cassini scientists have concluded that not only do the ring moons show signs of picking up ring material, they may be made entirely of ring rubble. How do they know that? Stay tuned to Planetary Radio to find out. And you thought a defense secretary or minister has a big job. They only have to protect nations. What if your assignment was to protect the entire solar system?

That is the charge NASA gave John Rummel, its planetary protection officer. He's been at it since 1998, although he also worked for the agency from 1986 to 1993 researching extraterrestrial life. The astrobiologist and commander in the U.S. Naval Reserve recently took our call at his Washington, D.C. office. John Rommel, thanks very much for joining us on Planetary Radio. You know, you are definitely in the running for world's greatest job title. Well, it's always nice to have a distinctive title, but I do remember a popular science piece that suggested it was one of the 18 or 20 worst jobs in science as well.

Now, why is that? Why would it be one of the worst? I would think it would be fascinating. Well, it is fascinating, but, of course, because part of what we're protecting against is unknown, or at least that's the back contamination concern. At this point, you're putting requirements on people without any evidence, but if something does happen, then they'll say you didn't put enough requirements on,

and it'll be your fault. I see. Well, so that if by chance somebody accidentally opens up the canister full of Andromeda strain, they're going to call your office to complain. Damned if you do, damned if you don't. How did planetary protection get started as really a worldwide priority? Are we looking back to Apollo days? Well, actually, it's pre-Apollo in the late 1950s when the National Academy of Sciences in the U.S.

and a group of international scholars elsewhere were thinking about what to do in space exploration. It was brought to the attention of most people by Josh Lederberg and some others that if we were going to look for evidence of life elsewhere, that it was best not to take it there ourselves and discover that. And as a way to preserve the investment in the scientific discovery related to the origin and evolution of life and chemical evolution, it was best not to introduce earth microbes in the places where they could grow and thrive.

Similarly, if there's something alive out there, we don't want to bring it back and spread it around without knowing something about it. Upon visiting your website, and we'll put the link to that website up at planetary.org, I was really interested to see how very sophisticated this area is now and that, among other things, you have five different categories, beginning with Category 1 where really no particular effort is needed? Well, we've got four outbound categories and one return category with two subdivisions. So that's something that we've done because there are different places in the solar system.

What's really fun in terms of the whole breadth of solar system exploration missions that have been undertaken is that we now know the difference between some of these places. And in fact, on a planet like Mars, we know the difference between different places on Mars. And we can see that there are some areas there that don't need the same kind of protection as some others probably do. So we're really getting into a point where we're learning enough to be both dangerous

but also distinctive. So have we learned a lot since Viking 30 years ago? Well, in some ways we have. Certainly our understanding of the environments of Mars have come a long way. Our understanding of places like Europa, which in the Viking time frame were only conjectured to have the potential for something other than completely frozen water. Europa, of course, is one of my favorite small bodies because as it goes around Jupiter with the rest of the Galilean satellites,

they warm each other up. And having the potential for a large ocean and possibly life under the surface of Europa is exciting, but you don't want to smash a spacecraft into it. In terms of killing off microbes, in fact, Viking did a very good job. And we can kill off microbes without killing off spacecraft in a similar fashion. And we haven't really improved the state of the art there because of both the microbes being more hardy and the spacecraft being just about the same. With this interest in Europa, I've got to guess that your office probably had a role

in making sure Galileo didn't run into any of those moons. Well, that was actually one of the fun things I did when I first took on this job back in the late 1980s. It was 1988, actually, subsequent to the Challenger disaster, that the whole Galileo mission had to be replanned. And with the replanning, we were able to write a new planetary protection plan that would take into things that hadn't been included by my predecessor. And what we ended up with was a paragraph that suggested that if Galileo were to learn something new and different about the Jovian system, they would have to, A, provide the information to the Planetary Protection Officer, and then, B, we would negotiate an end of mission which would protect whatever bodies might have been discovered. Of course, I knew that people had conjectured about the possibility of liquid water under

the surface of some of the Galilean satellites and wanted to make sure that we had a way to deal with it when we made the discoveries that we did. So in 1988, I put that in. They launched in 1989. And then in 1993, I left NASA for the first time and didn't think that I'd have anything more to do with it. But in 1997, I came back to NASA, and I was very pleased to be able to be the one who negotiated the end of mission to preclude hitting Europa. So let's take up the topic of a lander like the Mars Exploration Rovers. How did your office get involved with those?

Well, the Mars Exploration Rovers were put on Mars under the same requirements that obtained for Pathfinder and were the requirements that were recommended by the National Research Council, the Space Studies Board in 1992, in their task force on preventing the biological contamination of Mars. Essentially, they acknowledged that the Mars of Viking was much different than the pre-Viking Mars, Essentially, they acknowledged that the Mars of Viking was much different than the pre-Viking Mars, and that it was unlikely that anywhere on the surface of Mars that was then known about in 1990, 1991, the report was published in 92, that there was anything that could be contaminated easily. Nonetheless, being conservative and also being appropriately concerned about the potential for contamination,

they had made it possible to send a spacecraft to Mars without full system-level dry heat microbial reduction, which was done on Viking. So when the MERs were put together, they were put together under a specification that required them to be very, very clean but not sterilized or treated with any kind of major efforts the same way Viking was. And they landed successfully, of course, but before they took off, we, of course, checked the work of the project. So we monitored their implementation all the way along and then gave them a final exam before they could take off. And your folks actually go out and try and pick up cultures from spacecraft like the rovers? Oh, absolutely.

I've got a slew of pictures that show people doing that. We do it both on our own with some highly trained specialists that we have who are available, as well as have the project people make certain kinds of examinations under our direction. And those are what we call the qualification analyses or the final analyses that we do on microbial reduction. But, of course, the project has been doing this all the way along to make sure that they can pass this test and that the spacecraft is clean enough. And we examine those data, too.

I'll be back with John Rummel, NASA's Planetary Protection Officer, in just a minute. This is Buzz Aldrin. When I walked on the moon, I knew it was just the beginning of humankind's great adventure in the solar system. That's why I'm a member of the Planetary Society, the world's largest space interest group. The Planetary Society is helping to explore Mars. We're tracking near-Earth asteroids and comets. We sponsor the search for life on other worlds, and we're building the first-ever solar sail.

We didn't just build it. We attempted to put that first solar sail in orbit, and we're going to try again. You can read about all our exciting projects and get the latest space exploration news in-depth at the Society's exciting and informative website, planetary.org. You can also preview our full-color magazine, The Planetary Report. It's just one of our many member benefits. Want to learn more? Call us at 1-877-PLANETS. That's toll-free, 1-877-752-6387. The Planetary Society, exploring

new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. John Rummel is our guest this week. NASA's Planetary Protection Officer was just telling us about how the agency's engineers and scientists work to minimize the number of stowaway microbes that are carried by spacecraft to places like Mars. I wondered if sterilization technology has changed much in the three decades since a couple of famous probes set down on the red planet. There's a great shot on your website of the Viking spacecraft in its shroud being rolled into an oven for this heat sterilization that you mentioned.

But I guess nowadays you've got other techniques, including stuff as prosaic as hydrogen peroxide. Well, those are certainly things that are under examination for future missions. The nice thing about dry heat microbial reduction, which is the beginnings of the Viking casserole dish, as I like to call it, the BioShield being a very light, nice kind of casserole dish for a spacecraft. The nice thing about dry heat microbial reduction is that it's something experienced by lots of the spacecraft before it's put together anyway. A modern spacecraft typically has parts that are burned in at high temperatures and will kill off microbes that way without killing off the parts.

Hydrogen peroxide can be used for surface sterilization, but unlike dry heat, doesn't get to what we call the mated or buried bioburden. And so we have to use a combination if we're going to go after hydrogen peroxide as a sterilant. It may have some benefits in breaking down organics and other things, but the jury's still out as to whether or not that will be in common use. You mentioned microbial reduction, not elimination, and it makes me think of a magazine I found. Actually, it was a French magazine,

kind of like the Discover magazine here in the United States, and it had a cover article that basically said, it's too late for Mars, we've already infected it. Is that really a concern that you have? Oh, I love this. That issue of Sion Seville was a very good one and a lot of fun for my European colleague, Gerhard Kominik, to deal with since his picture was in the magazine.

But no, it's not too late for Mars by any means. Mars is an extremely cold place, and even when it gets warmer, it's still very cold. And the microbes that are on Mars today, other than the ones that are associated with crash sites, Mars Polar Lander comes to mind as a potentially difficult crash site, are still very limited in what they can do. The surface is flooded with ultraviolet radiation. It's cold and extremely dry, drier than any place on Earth, including the Atacama, where currently there's education and outreach activity going on

with Chris McKay, who's one of the people in the Planetary Society. Well, the bottom line is that microbes on Mars aren't going to get along all that well unless they get into environments that are much more Earth-like. We think those environments can exist below the surface, significantly below the surface. And we're concerned that they might exist in sites close to gullies. None of the spacecraft that we've sent to Mars so far have gotten close to the gully systems, and I think that there may indeed be microbes alive within spacecraft on the surface of Mars today. In fact, I'd bet on it, but I don't think they're going anywhere.

And unlike the, I guess they had syringes injecting microbes into Mars, we're not able to actually get that far beneath the surface on Mars. So I think they're way out of scale. Of course, there are a few voices out there. I think of Bob Zubrin of the Mars Society who say, the heck with anything that might be alive on Mars. If our stuff beats it, well, that's fair game in evolution. Do you ever think about the more philosophical side of planetary protection?

Well, that's the first time I've heard Bob Zubrin and philosophical in the same sentence. But as it turns out, I mean, Bob is willing to make a lot of bets with other people's money, but the prime reason for forward contamination control is to protect the science value of what we do for the American taxpayer and for the world scientific community. So I'm not too worried about Martian microbes at this point in time because I don't know anything about them, but I'm definitely concerned about our ability to learn the lessons that we're investing in. I mean, it's not a cheap program. It's something that we do with a significant investment of the taxpayers' money, and I want to make sure that when we learn something from Mars exploration that it's something

real and not something that we find is contaminated by microbes from Florida or Uzbekistan or wherever. At the same time, of course, if there is life on Mars, it would be fascinating to make sure that we can learn those lessons, but I don't want to be affected by it if it happens to come back in an unknown fashion. And I kind of laugh at Bob when he says things like that. We know that there are microbes on Earth that are not particularly nice to have in freshwater systems or saltwater systems, et cetera, and that represent a danger to us.

Why would we want to take things to Mars willy-nilly and find out later that that wonderful aquifer that we found that can support a human colony is contaminated by Earth microbes that we took by mistake. Great point. So you've got plenty of practical and scientific reasons. You don't even have to get into philosophy. Well, good. In that environment, that's probably not all that useful. John, we've only got about a minute left,

and we haven't even talked about protecting Earth in that Category 5, I guess you would call it the backward contamination of a sample return mission. Maybe we can get into that another time. But one last question. We've talked to the curator of astromaterials at the Johnson Space Center. I take it that there the challenge, once again, is still more protecting those materials from Earth than us from them. Well, Earth life is pervasive, and something that we deal with in every walk of life.

And, of course, when you try to study the material that you brought back and look for signs of life, you want to make sure that you're not looking at things that you have here already. At the same time, when we talk about bringing things back from a body like Mars, Europa, that might have life, time, when we talk about bringing things back from a body like Mars, Europa, that might have life, we want to provide an environment where we can do that without allowing either the back contamination concern or the contamination from Earth microbes in the forward direction. So you have to be very careful about mixing and matching different kinds of issues. And that's going to be a challenge for future Mars sample returns. Luckily, it's not a back-contamination control problem for Stardust or Genesis, those sorts of missions, and we have a list of six questions that we typically apply, recommended by the

National Research Council, to determine whether or not something is a restricted Earth return mission or an unrestricted Earth return mission. As yet, we haven't had any restricted Earth return missions, but we have had them proposed under the Mars Scout program, and we may get one sooner than we think. I'll look forward to that if we do, and there are many fun challenges in the future. Well, I look forward to you having that challenge, and congratulations on the good work. We haven't caught any interplanetary bugs yet so you must be doing your job well if we have it may be us so look at that man i mean if we're uh

we represent mars contamination after uh three and a half billion years um i'll leave it to somebody else to judge whether that's a good thing or a bad thing thanks very much john thanks very much john rummel is the Planetary Protection Officer in the Science Directorate at NASA headquarters in Washington, D.C. He is a commander in the U.S. Naval Reserve and an astrobiologist who spent a few years in between stints at NASA working at the Marine Biological Laboratory in Woods Hole, Massachusetts. And I'm glad he's on our side emily locked wall is on our side as well she is going to be back with a bit more of this week's q and a followed by a visit with bruce betts and what's up

i'm emily locked a wall of back with q and a how do cassini scientists know that that Saturn's inner moons have collected ring material? The so-called ring moons of Saturn have notably flattened shapes. Seen up close by Cassini, they also have strangely smooth surfaces. So it seems probable that they've collected ring particles that have coated their surfaces. But the key piece of information that Cassini scientists figured out was the masses of these bodies. Mass divided by volume gives you density. So once they knew the mass, they could do the math and find out that these moons are far less dense than the icy

material they are presumably made of. They can't be made of coherent, solid chunks of icy material broken off from some past moon. Instead, they have to be rubble piles made up of agglomerated boulders, gravel, and dust, which would have collected slowly by the influence of the minuscule gravity of a small solid core. As a matter of fact, the innermost moons seem to have accreted stuff until the collected rubble filled the entire Roche zone of the moon. The surfaces of those moons are shaped by the delicate balance of force between the moon's tiny gravity and the tidal forces imposed by the presence of giant Saturn. 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 Bruce Betts and this week's edition of What's Up on Planetary Radio. He is the director of projects for the Planetary Society. Like every other week, he's joining us to tell us about the night sky and a new space trivia contest and other cool stuff. Hi. Hey, we got cool stuff. But our little friends, the planets, a lot of them are running away from us right now.

Saturn's pretty much lost below the horizon, but maybe you can see it just after sunset in the west. Don't worry. It'll pop up in the pre-dawn sky in a month or so. Okay. It just went on vacation. in a month or so. Okay. It just went on vacation.

It would be below the redder Mars, which you still have a decent shot at seeing as soon as it gets dark in the West, but it's pretty darn low. Saw Mars last night, just in the sky in the desert where my parents live because I was visiting them, and it just looked great. Very, very red.

Very red orange. Really pretty. Good. I'm glad you're taking it to heart. Did you also see Jupiter? Hard to miss. Incredibly bright. I did. Not far from the moon, at least when I looked.

When other people look, you know, that pesky moon, it's moving. I mean, so is Jupiter, but relative in the sky, not moving that fast. Yeah, Jupiter, brightest object in the evening sky. Can't miss it, but it also is dropping farther towards the west, but still pretty high in the sky. Shortly after sunset, and then headed over to the west, brightest object in the evening sky in the pre-dawn sky, Venus. Also dropping lower, but really, really bright, so can't miss it. Look into the east if you have a good view to the horizon. We also have a kind of run-of-the-mill meteor shower coming up. The Southern Delta Aquarids meteor shower, usually producing about 20 meteors per hour.

But I particularly mention it because it nicely peaks during a very low moon period, particularly after the crescent moon sets. It peaks on July 28th, although it's pretty dispersed. So for many days before and after, you may get some increased activity. From a dark site, you may see about 20 meteors per hour. So go out there, sit back, and stare at the sky. We do have a little bit farther on the horizon, the Perseids, traditionally the second best of the year, with about 60 per hour coming up in mid-August. However, it's going to conflict with a really bright moon,

so it's going to be a little tougher this year. Let's go to this week in space history, shall we? 1965, Mariner 4, first Mars flyby, first successful one. Ten years later, Apollo-Soyuz was launched, a great American-Soviet hookup in space. Handshake in space. And then Skylab reentered and splattered all over Australia and out back in the ocean in 1979. On to Space Fact!

In honor of the space shuttle discovery, up and playing in space, we take you to space shuttles thrust. The solid rocket boosters, the SRBs, each of them on the space shuttle stack, 3,300,000 pounds of thrust come out of those bad boys when it's launching. But both of them together, still not equal to a Saturn V. Ha. Ha. Ha. Right.

And sadly, we don't have one of those to pull out, but still. Impressive. Very impressive. Okay, fine. Great Roman candles. No, no, I'm sorry. What's the thrust of a Saturn V?, but still. Impressive. Very impressive. Okay, fine. Great Roman candles. No, no, I'm sorry. What's the thrust of a Saturn 5? Seven and a half million pounds. Ha ha! Oh!

The kid comes through. Yeah. It's your show. You take it from here. Go! Bruce! That's impressive. Let's go on to the trivia contest. We asked, name the four so-called, so-called by NASA, great observatories. The NASA great observatories.

How'd we do? Terrific. Absolutely terrific. Good work, folks. And our winner is in Mannheim, Germany. It's Atanas, I hope I have that correct, Atanas Kumbarov. Atanas, let us know that it's, what are they? Hubble Space Telescope, Compton Gamma Ray Observatory,

Chandra X-ray Observatory, and the Spitzer Space Telescope. The big four partying up in space, providing unbelievable views of our universe in multiple wavelengths, each of them covering a different wavelength of band. Moving right along. How wonderful, how wonderful. Mrs. Hulligans, on to this trivia contest. Once again, for Space Shuttle fans, Space Shuttle being up there,

what is the Space Shuttle Discovery's vehicle number? You know, the vehicle ID if you look right below the windshield on the dashboard. A lot shorter on Space Shuttles, though, than for most cars. But what is Discovery's vehicle number. Go to planetary.org slash radio. Find out how to get us your answer and compete in the Planetary Radio Trivia Contest for a T-shirt. When do they have to get that in by, Matt? The deadline is July 17 at 2 p.m. Pacific time. July 17, 2 p.m. Pacific. That's when you need to get it in to us. All right, everybody.

Hey, go out there, look up at the night sky, and think about something Matt loves so very much, electrical cords. I hate cords. I hate all cords and cables. I'm sorry. And with that, thank you, and good night. Good night to you, too. He's Bruce Betts, the Director of Projects for the Planetary Society. He joins us every week here with What's Up. Join us next week for a conversation with astronomer and planetary scientist Heidi Hamel. We'll talk about a couple of planets in our solar system that don't get the respect they deserve, Uranus and Neptune. Planetary Radio is produced by the Planetary Society in Pasadena, California.

Have a great week, everyone. Thank you.