Science: Search for Life on Mars

Washington Post Staff Writer Marc Kaufman was online Monday, May 19 at 1 p.m. ET to discuss his Monday Science Page article about NASA's Phoenix spacecraft, which is scheduled to land next Sunday on Mars.

Read today's story: An Icy Dig in Search of Signs of Life on Mars.

The transcript of the discussion follows.

Kaufman discussed discoveries on Mars last month. Read the transcript here.

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Marc Kaufman: Good afternoon. Nasa's Phoenix lander is scheduled to touch down near the North Pole of Mars on Sunday. It's on a search for ice, water and ultimately signs of past (or conceivably current) life. This search for life forms beyond Earth is a major emphasis of NASA and the relatively new science of astrobiology is growing fast. We can never tell what missions like Phoenix will find -- or if the lander will even land safely -- but the science is certainly compelling and possibly quite important.

On to your questions.

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Blacksburg, Va.: Hello Marc,

What happens if the results for organic carbon beneath the surface come back negative? Will the Mars Science Laboratory still be sent to a similar area or will it be sent someplace else with a different objective?

Thanks,

Nick Wigginton, Ph.D.

Blacksburg, VA

Marc Kaufman: There's a saying in science, and especially space science, that "An absence of evidence is not evidence of absence." There are so many possibly confounding issues involved in a mission like this that -- unless it unexpectedly gets a very strong signal of organic life -- it will be hard to say that it's conclusive. The Viking missions to Mars, after all, did not find organic matter, and we are back again looking elsewhere and in some different ways. So this is definitely the beginning of a process, and many possibilities and approaches remain on the table.

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Århus, Denmark: Although remote experiments performed automatically by the probes themselves are without a doubt extremely useful, they do seem very narrowly focused and rather limited in scope.

What are the prospects for a mission that endeavors to return samples to Earth? Would the scope of such a mission be to land, pick up the nearest pebble and fly home, or could it conceivably include rovers that collect more varied specimens?

Marc Kaufman: NASA is seriously discussing, along with the European space agency, an unmanned mission to Mars to collect and bring back samples. I believe this is proposed for 2014 or 2015, and would involve some serious technical challenges. It also raises some complicated questions involving possible contamination of Mars (from a spacecraft) and equally possible contamination of Earth if there are life forms in a Mars sample. Nonetheless, I believe there is a consensus that we won't have a clear idea of the possibilities of life on Mars until either samples are recovered, humans explore the surface, or many new ways of collecting data are developed and tried. We know that the surface of Mars seems to be barren and inhospitable, but there are hints that liquid water could exist below the surface, and suggestions that it existed on the surface in eons past.

We do have numerous samples of moon rocks, and a Japanese spacecraft is heading back from taking rock samples from an asteroid. Indeed, a number of other nations have said they intend to send future sample-gathering missions to Mars, including the Russians.

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Washington, D.C.: I am very excited for the landing on Sunday and I hope everything goes according to plan with it.

I know missions like Phoenix are very expensive and take a lot of planning and organizing long before the vehicle is even built. These missions are never really developed to do a single task - even one as exciting as searching for life.

What other goals do the Phoenix mission planners hope to accomplish besides these tests for life and scouting the pole for water that may be less exciting for the public to hear about but may be just as important in terms of scientific research and discovery?

Marc Kaufman: Other goals include the setting up of a Canadian-made weather station -- the first at such a high latitude on Mars. Researchers hope to the station will help them better understand how water cycles seasonally between ice on the ground and vapor in the atmosphere. There will also be numerous soil tests that do not focus solely on water. These include efforts to test for soil pH, and for sulfates, carbonates and other soluble salts. In addition, Phoenix has a number of sophisticated microscopes that will be used to study soil samples.

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Chicago: I need your help to resolve the following....

Here's a true story... in college, one of my best friends (someone whom I consider a bright, well-read, responsible person, and today the father of 3) arranged to swap-out his license plates.

His new tags read: "MARS IN 93" reflecting his belief that by 1993 (this was 1991), we would make contact with life forms on Mars.

In more recent years, he has claimed that the 1996 discovery of the meteorite ALH84001 in the arctic means that his prediction was indeed correct, and that he was only 3 years off the mark.

I believe that this is revisionist history (regardless of the timing) and that his prediction was predicated on finding life "ON" Mars...not Martian life "AWAY" from Mars, as was the case with the microbes found on the meteorite.

Could you please weigh in on this? (there's a small wager riding on your answer). Thanks.

Marc Kaufman: Turns out your friend was off in several ways. Most important, the famous ALH84001 meteorite -- which was hailed as carrying the first detected signs of fossilized organic life-- is no longer considered to have carried such a cargo. The scientific consensus, I'm told, is that while the meteorite may have contained some of the building blocks of life, it did not have in it anything that was ever alive.

Another interesting point: Meteorites like this one arrive regularly on Earth, and many contain carbon in them. Yet Mars scientists have never detected any samples of carbon on the planet's surface. Carbon dioxide is in the atmosphere and we can assume carbon is somewhere underground, but it has never been conclusively found on the Mars. Intruiging...

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BC: A couple of quick questions:

Is NASA looking at the site and the condition of the water ice as factors for manned missions later? Seems like there would be a big advantage to mission profiles that require less water to be transported from Earth to Mars; both for human consumption and thrust/reaction mass...

Also, has NASA considered the idea of Martian water as a source of funding? If people pay for water shipped from France or the Alps, think about what they'd pay for a bottle - or perhaps even a hot tub full of healthy iron-rich Martian water. This could be a great way to have the sample return missions pay for themselves... "Ares Strain H20 - It's Out of This World, and It'll Take You There, Too!"

Seriously, I hope this all goes well, and I'm looking forward to further coverage on this, Marc.

BC

Marc Kaufman: To your first question, yes the condition of the water ice is definitely a potential factor for future manned missions to Mars (and to the moon as well.) In addition to the possibility that it holds clues about past or current life, the ice is also a possible energy source and, I guess, could be used by astronauts.

It is, however, very cold at the Martian (or lunar) poles -- with Martian temperatures going down to minus 100 F in the area where Phoenix will land.

As for selling Martian water, I think it might be a good two-fer for selling shares of the Brooklyn Bridge.

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Vienna, Va.: Mr. Kaufman: Today's WP article stated that the success rate for landing probes on Mars is only 50%. The descent procedure for Phoenix is more of a traditional descent, whereas the Spirit and Opportunity rovers both successfully used the bouncing "balloon" method for touchdown. To your knowledge, what parameters were considered in the use of one method over the other for Phoenix? Thanks.

Marc Kaufman: If I understand correctly, the size and weight of the rover/lander determines whether the descent will be with thrusters or the bouncing balloons. Beyond a certain size, I believe the balloons don't work, and so they have to go back to more traditional methods.

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Savannah, Ga: I have observed , in the images of Mars from our orbiting space craft , certain seasonal changes of color on the planet "surface" and I put surface in quotes because I really don't know if these changes are on the surface. I have seen images of the Sahara showing stream and river basins that one could not detect if one was walking on the planet surface, but because the imager penetrates the sands, we see another older viewpoint. On our planet , seasonal changes are actually a series of interactive "living events" that produce color changes on our planet, and my question is ," are these color changes possibly an indication of some sort of "Living " process?

Marc Kaufman: Interesting observation, but afraid not something I'm aware of on the Mars. The planet is covered with a layer of dust and, as far as I know, there have not been pronounced color variations.

However, I know of some recent research into the release of methane - an organic compound -- from the surface of Mars. The gas is only released at certain times and in certain places. This could be a sign of life, in that a life form could produce the methane as a byproduct. Or it could be the result of a chemical reaction below the surface of the planet. The methane could be locked below the surface during the coldest season, but then released when some surface ice melts. Either way, it would be a very interesting development if fully confirmed.

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Gaithersburg, Md.: How much potential exists for contamination of Mars or other explored planets by the spacecraft or other equipment? Microscopic spores, bacteria, mites, etc are everywhere on Earth. Some spores are very resistant to extreme temperature fluctuations and chemical treatments and it seems remotely possible that some would be able to survive interplanetary travel, and either provide false positive results when searching for life or possibly even gain a foothold in the new environment and begin to grow and eventually thrive there.

What are your thoughts on this?

Marc Kaufman: The field of "planetary protection" is definitely growing in importance because of these issues you raise. It seems to me improbable that spores or microbes on a spacecraft sent from Earth would survive the trip to Mars, but you're correct that the possibility cannot be ruled out. And as we are finding on Earth, life can survive in environments we long assumed would immediately kill them.

Two interesting sidelight to this: Some believe that if we do some day find life on Mars or the moon, that it will have been carried there by man. The only way to determine whether that is correct, I believe, is to test the DNA and see if it is any different than what exists on Earth. Also, there is a serious theory that life on Earth was seeded from Mars via a long-ago asteroid. If true, I guess we would all be Martians.

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Panama City, Fla.: Thanks for your reporting.

As a result I've marked my calendar and told numerous friends of Sunday's landing.

I tell them that this has the potential to be a very historic mission(not that it isn't already), should it detect any signs of past or present life.

How soon will the results of these tests be made public?

Marc Kaufman: I believe Phoenix will begin sending photos quite soon after touching down, but the other data will take a while. The researchers I spoke with said it would be a week or two before they started getting good information. No word yet on how quickly they will release their information, but I see no reason why it won't be quite soon.

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Bronx, N.Y.: Are there any considered plans to land on Phobos and Deimos to set up observation/jump-off missions?

Marc Kaufman: None that I'm aware of. I believe the Russians tried to land on Phobos some years ago and missed. All the information I've read and discussions I've had about a future manned mission to Mars involved a direct flight from Earth -- or from a jump-off station on the moon -- to Mars.

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Washington, D.C.: Many people have given very similar details when reporting UFO sightings. Might this be more proof, or at least, equal suggestion of life outside earth?

In fact, several friends of mine and I have seen similar phenomenon first hand, but we refrain from telling anyone for fear of looking foolish.

Thanks.

Marc Kaufman: I personally see no reason to believe that UFOs exist and have visited Earth. Indeed, I think the UFO phenomenon has confused people about the possibility of life beyond Earth -- making it appear that life would be intelligent, or even super-intelligent. Today, most astrobiologists think that if life -- or remnants of life - are found elsewhere, they will be microbes or tiny, simple organisms, rather than fully evolved creatures or beings. That's why missions such as Phoenix test for these most basic forms of life.

Many thanks for your questions...

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