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Fri September 14, 2012
Mars Rover May Be Contaminated with Earth Microbes
Originally published on Fri September 14, 2012 2:04 pm
IRA FLATOW, HOST:
This is SCIENCE FRIDAY. I'm Ira Flatow.
In a few weeks, NASA's Curiosity rover may use its powerful drill for the first time on Mars, and that has been a cause of a concern - not because the drill may be malfunctioning, but because the drill bit might be contaminated with germs from Earth.
Several months before Curiosity was launched into space, mission planners made a last-minute decision to open one of the rover's compartments to attach a bit onto the end of Curiosity's drill. And the work was done in a standard clean room, but the change of plan violated NASA's procedures for extra-planetary protection.
So was Curiosity facing a contamination risk? And if so, does it jeopardize the rover's science mission? Catharine Conley is the planetary protection officer at NASA Headquarters. Her job is to ensure that all spacecraft meet the agency standards of cleanliness before they are sent to study other worlds.
Welcome to the program.
CATHARINE CONLEY: Thank you very much.
FLATOW: Can you give us a blow-by-blow of what actually happened there?
CONLEY: Well, first, I'd like to say that there have not been any violations of the planetary protection requirements by the Curiosity rover. As it turns out, the Gale Crater landing site is a place where rovers - or any spacecraft - would need to be clean, but they don't actually need to be sterile. The requirement for sterility is in order to be able to touch ice, and we don't expect there to be ice at the equator of Mars.
So that was, if you will, a sort of saving grace of this whole procedure. It turned out, yes, there was this problem with the communication, that the mission planners did take the drill out of the box and put it in the drill. But as it turned out, with the Gale Crater landing site, there is no violation, and so no effect on the science operation. It should be really exciting to see what they get.
FLATOW: No foul, no penalty.
CONLEY: Pretty much. Exactly.
FLATOW: Well, you mentioned something there that sort of connected the dots for us. You said there was a miscommunication. What did you mean - how did that affect what happened there?
CONLEY: Well, the Curiosity mission, the (unintelligible) Mars Science Laboratory mission is a huge mission. It's a very complex mission. It had a two-year delay because it is such a complex mission. And so there were lots of things that needed to be paid attention to, and planetary protection is only one of them.
So as the mission planners were determining what they were going to do with the mission, my office heard about this plan to put the drill bit in the drill a little bit late in the game. But soon enough, we were able to take care of everything, and they're fully compliant and doing well.
FLATOW: In other words, they should have consulted with you and your office first before they opened the box.
CONLEY: That is the standard practice. It doesn't always happen that way, but we much prefer it to be able to do that so that I can have all my paperwork done and submitted to the international community to make sure that everybody knows that we're complying with the requirements.
FLATOW: So if the rover should be - accidentally get to a spot where it might find water or touch water, you say that's probably not going to happen. But if it did, that might be a problem.
CONLEY: Well, it would actually be an incredibly exciting scientific result, because all of the data that we have from our orbiters and from the other rovers suggest that there should not be water. So if we find water at Gale Crater, that's really amazingly cool.
FLATOW: So you would be worried about contamination at that point?
CONLEY: Well, in that case, what we would do is we would take a step back, and we would convene a panel of scientific experts to review the whole procedure, look at the amount of ultraviolet light that might've been hitting the drill bit that would be burning, you know, giving all those organisms sunburn. There are a small number of organisms on the rover, many, many fewer than there are on the palm of your hand. But there are a few.
So we would convene this panel of experts. We'd look at the conditions at Gale Crater. We'd consider what the characteristics of this potential water or ice might be, and then that panel would decide how we should proceed with the potential to study that. There is a laser onboard, so we could certainly shoot the laser at the ice.
FLATOW: And to vaporize it, melt it or...
CONLEY: They - what they got out of those rocks was vaporizing the rocks to get an indication of what chemical compound elements are released when the laser hits the rocks.
FLATOW: You're the planetary protection officer. Please take this in the spirit. It sounds like something out of "Men in Black."
CONLEY: I do tend to wear black, and I do have a badge. It was given - I got the sunglasses my first day on the job. But, you know, I don't ever remember getting that flashy thing.
FLATOW: Well, I think it's still waiting for you in your pick-up box.
FLATOW: It must be a cool job, though, to be there.
CONLEY: Well, it's a very interesting job. It's pretty diverse, because on the one hand, I talk with the international community about making sure that the United States and NASA in particular complies with the Outer Space Treaty. On the other hand, I get to go into spacecraft clean rooms and watch spacecraft being assembled, take samples from them. I actually got to touch the - I got to touch the Phoenix lander and take the final samples the day that it launched down at the Cape.
So - and then in between there, I, of course, talk to different scientists, mission planners. I have to have a research program to understand how Earth organisms might be able to survive on Mars. It's a pretty diverse job.
FLATOW: Yeah. And it's a great title, too, for the (unintelligible).
CONLEY: Well, thank you. I always say it's the second-best title at NASA. There used to be somebody who was director of the universe, and that really is kind of a little bit better.
FLATOW: Director of the universe?
CONLEY: Yeah. It's now called astrophysics - not quite as cool.
FLATOW: That person would sit in a big chair up there on that...
CONLEY: I would imagine. Exactly.
FLATOW: So tell us why - what's so bad about having brought - if we did bring microbes to Mars, what is the problem with that?
CONLEY: Well, if we want to find life on Mars, we really want to find Mars' life, if we bring Florida with us and then find Florida instead, that's kind of waste of taxpayer dollars.
FLATOW: There are so many things I can say to that...
FLATOW: ...bringing Florida - if we find Florida on Mars. Some of the - I'm not playing a straight man on this one.
FLATOW: In other words, if you found something that looks like it was on Mars, it might actually come from Earth. And you want to...
CONLEY: Right. We want to understand life in the universe. And if we all see is Earth life, that doesn't tell us much about anywhere else. The problem, of course, I mentioned that the total number of organisms on the Curiosity rover are fewer than the numbers that are on the palm of your hand. The problem is that life on Earth is everywhere, and there's lots and lots of it. So to be able to go to a place like Mars where we really don't think there would be very much life, if your instruments are covered with Earth life, you'll never be able to see what might be there in the sample that you collect.
FLATOW: Let's go to the phones. Let's go to Bill in Fair Grove, Missouri. Hi, Bill.
BILL: Hello. Thanks for taking my call.
FLATOW: You're welcome. Go ahead.
BILL: Just a quick question regarding any kind of microbial life or germs or organisms, anything of that nature hitchhiking a ride on the Mars' Curiosity rover, I would think that it would be highly unlikely because of the - no heat or moisture or anything of the - in space would sustain any kind of microbial life. And I think anything that would be, you know, impinging on the surface of the rover would be gone by the time it reached Mars, long before.
CONLEY: Well, it'd actually turn...
BILL: Is that right?
CONLEY: It actually turns out that we have put organisms on the outside of the International Space Station. And as long as they're protected from sunburn, as they're shielded from the ultraviolet light, they can actually survive up there for years. So...
FLATOW: You put them out there on purpose to see how long they'd live?
CONLEY: That is something that NASA and the European Space Agency have both done, and I believe also Roscosmos has done it. So international experiments all of which confirmed this, that Earth organisms can, in fact, survive in space.
FLATOW: Wasn't there a case in one of the Apollo missions where contamination was brought back?
CONLEY: That's a very interesting question, and my office actually recently funded a study to look - this is Surveyor three camera, and there were some concern at that time or some claims at that time. They took sample - the camera set up on the Surveyor 3 spacecraft, was retrieved by the Apollo program, brought back down. And then samples were taken in a lab at, I think, Kennedy Space Center or Johnson Space Center to try and understand whether there were organisms on that camera. It turns out that the way they were taking those samples was about the same level of - sterility level of cleanliness, aseptic technique, as you do in surgery. And, of course, when you're doing surgery, you've got a human with an immune system.
So they had short-sleeved scrubs. They didn't really have good masks. So the samples that were contaminated were taken at the very end of this experiment, of this whole sampling process and just after somebody had breathed right on that location on the camera. So it probably was contamination after the camera got brought back and not contamination that went the whole round trip. But that's a very important lesson, exactly with this problem. When you find life or if you're looking for life, you really have to be careful how you do it and make sure you don't screw up your own results.
FLATOW: Well, when - at what point at NASA did you go from, you know, the short sleeves, just some sterile face masks to really go to a real high-level clean room and understand that you might be bringing stuff with you?
CONLEY: That was actually in the assembly of Mars missions, between the Viking missions and the Pathfinder mission. There was a big gap there because, of course, at some point after the Viking missions, it was concluded that there probably wasn't life on Mars, and therefore, Mars wasn't interesting. And then people decided it was interesting again and wanted to send the Pathfinder. And so as we assemble the Pathfinder mission and then the Spirit and Opportunity rovers, and now the Mars Science Laboratory rover at the Jet Propulsion Lab, they have developed techniques for keeping spacecraft more clean. They assembled them in clean rooms. They tape the gloves to the clean room suits to prevent, you know, (unintelligible) hairs from coming out and falling on the spacecraft.
And the Curiosity rover and the Mars Science Laboratory, really, they did a marvelous job of keeping that spacecraft clean. It's - the same number of organisms, approximately, as were on the Curiosity rover is the number that was on each of the Exploration rovers. Remember how much smaller they are.
CONLEY: That's about the same number as on the Pathfinder rover, which was really tiny. So over time, the Jet Propulsion Lab has really developed excellent techniques for keeping spacecraft clean.
FLATOW: Can you actually count the number of germs?
CONLEY: Well, the - we count a subset of them. We count only the ones that you can wipe off the spacecraft, and then you put them in warm water for a little while. And then you grow them on a particular kind of Petri dish. That's not all of them, but it's the subset that we use as a sort of a test case, the measure of cleanliness, a proxy to evaluate how clean they are.
FLATOW: One quick, last question to you. Would it be - you talked about using the laser. Could you use the laser to sterilize the drill bit at all pointed at it?
CONLEY: That may be one of the options that we consider if we have to look into that. It's - that would be for the scientific panel to decide, and that certainly will be an option.
FLATOW: Well, I'm rooting that you find water.
CONLEY: It would be cool. It would be really exciting to find water at (unintelligible).
FLATOW: Yeah. You'd like to have that kind - to consider that option, wouldn't you?
CONLEY: I would love to have that problem, absolutely.
FLATOW: Right. Catharine Conley, thank you very much for taking time to be with us.
CONLEY: Thank you.
FLATOW: She is the planetary protection officer. She's got her black clothing and waiting for that little flashy thing as Will Smith said in "Men in Black" at NASA headquarters. Thanks again.
CONLEY: Thank you. Transcript provided by NPR, Copyright National Public Radio.