Ever since the Viking Mars missions, NASA seems to be making every possible attempt to avoid directly searching for life on Mars. Oddly, the emphasis seems to be on the search for “conditions” that would sustain life, but never the direct search for life itself. Come on NASA, we all know that’s your number one mission objective when it comes to Mars so why not put a super sophisticated microscope and other scientific devices on Mars and directly search for life in situ? You know, the microscopic little critters that move around, eat, poop and do other unmentionable things? Is it because a definitive answer might doom future missions and funding?
How, exactly do you propose they ‘directly search for life’? Use a microscope to look closely at the surface? They’ve done that - both Spirit and Opportunity had microscopic imaging cameras that they used to look at the surfaces and interior of rocks. Neither of them saw any little critters crawling around.
If there’s life on mars, it’s not wandering around the surface where it can simply be photographed. It’s underground, in brine deposits or rare volcanic vents or something. We need to know where to look for it before we can go looking, and to do that we need to learn more about the geology and chemistry of Mars first.
First off, let’s say your search for life on Earth started in the Sahara or on Antarctica. You’d discover that Earth had little liquid water and supported nothing more than a few microbes. We live here, and know that these are bad places to look for life on Earth, but an alien life form from very far away would need to do some research to determine that. This is especially important when you consider the limited ranges of the rovers. They’re not sampling thousands of miles of Mars; we’re testing one postage stamp at a time. It could be that Mars was teeming with life just over that hill…
Second, the search for life on Mars isn’t just about finding life today. There might not be any today. But if we can identify likely places for life to exist or have existed, then we might find evidence of former life. The testing equipment for former life is going to be different than tests for current life.
Third, as the previous poster answered, the rovers are doing direct tests for life. However, they’ve found nothing so there’s not much to talk about in that respect. What we can talk about are the things we’re learning about conditions for life - things like the fact that Mars has underground ice we can’t see from Earth.
Other issues:
- In order of expense, it goes flyby > orbiter > probe > rover. NASA isn’t exactly a funding priority right now. Nobody wants to blow however many billion dollars on a project that would take years to get concrete results, especially not when the most possible result is “Mars possibly maybe had life once upon a time, but not any more”.
- Earth probes are full of Earth germs, no matter how much we try to scrub and disinfect before launching. This may generate false positives.
- Whatever we find there, if it’s still alive, we may not want to bring back to avoid killing it in Earth conditions or causing the Martian Zombie Apocalypse. (This is hyperbole, but you get the idea.)
I think we’ve fairly well established that there aren’t elephants roaming the planet, or pine trees growing on the surface, or any lifeforms of that size. The Mariner missions established that in the 1960s by taking photos from above. But you don’t have to look for elephants to determine there aren’t any there. You can look for other signs. Like the existence of CO2, or the presence of water. That’s how you do it.
Forty years of searching have found no biomarkers, nor have they found any of the conditions necessary to support life as we know it.
Funding for NASA to continue its Mars programs is very much in jeopardy, and any signs of life there would provide a huge boost. The OP’s suggestion that NASA has an incentive to not find anything is wacky.
Also, how do we know, for certain, that any life which evolved on Mars is going to be identical to life which evolved on Earth? If our probes and rovers are constrained to look for only those forms of Carbon-based, Oxygen-breathing life which we have here on Earth, they might overlook some form of life we had absolutely no idea existed.
Any form molecular processes could take which may be referred to as “Life” should have some similarities to the metabolism and respiration of Earth organisms. By looking for these “markers” we should be able to detect Life, no matter what form it may take in an alien environment like the surface of Mars.
This blog post (comparing Viking to the soon-to-be-launched MSL/Curiosity) explains it well
The book, 13 Things That Don’t Make Sense (Michael Brooks), mentions that one instrument actually detected signs of life, but another didn’t.
I don’t have the book with me right now but you can read a snippet from http://www.newscientist.com/article/mg18524911.600-13-things-that-do-not-make-sense.html?page=2 (6 Viking’s methane)
My takeaway from this is there is no easy, accurate, remote way to detect life.
The only real ‘direct’ way to search for life on Mars is to send astronauts to check it out.
As others have mentioned, Viking detected ‘life signs’ and then the scientists said, "No, that’s a false positive.’ That’s likely to happen with any future rover missions as well due to rivalries and competition in the scientific community.
So the only effective method would be to send astronauts, and that is VERY expensive (unless we adopt Robert Zubrin’s Mars Direct proposal, in which case it’s ONLY expensive).
That said, I will say I believe Martian life exists right now, just beneath the surface. We know water ice exists under the soil because the Phoenix lander photographed it and documented it as it sublimated away.
When the first astronaut bears down on a shovel with his boot and scoops up a pile of dirt, the life on Mars question will be answered.
An astronaut digging a shovel in won’t do anything more than a robot digging a shovel in. Once you have that spadeful of dirt, what do you do with it? We already know there aren’t any big wiggly worms in there-- We’re really asking about things like bacteria. You can try looking at samples of the dirt under a microscope to see if you see anything, but what if you just don’t recognize it? You can try putting the samples in some nutritious medium and seeing if anything grows, but how do you know what’s nutritious for any hypothetical Martian life? Really, anything that a human could do, a robot could, too, and already is.
I beg to differ. If you look at the “shovels” we’ve sent so far, they are wholly insufficient. Viking, Pathfinder/Sojourner, Phoenix, Spirit, and Opportunity sport small little scoops – a symptom of the expense of sending even a robotic probe. Everything is small and lightweight. We’ve never dug a hole on Mars deeper than an inch or two.
An astronaut with a big shovel, and the strength to bear down on it, would be an entirely different story.
Left out of the discussion but worth noting is the ease with which an astronaut can travel compared to a rover, the human element which would allow for improvisation on a moment’s notice, and the ability to immediate return the samples to a hab unit where the soil can be analyzed immediately and the results transmitted to Earth.
I probably won’t convince you, but please just remember this discussion when it happens. The first manned mission to Mars will discover microscopic living organisms in the soil. I highly doubt we’ll have any such discovery until we send people.
“The shovel is too small” is a completely different complaint from “it’s not a human pushing it”. You could probably send an entire robotic backhoe for less than the cost of sending a living human with an idiot stick.
Well now you’re just being deliberately obtuse aren’t you? You’re saying we should send a robotic backhoe to do one job? Just dig? And it would cost less than sending a human mission? How much less? Got any figures? Where humans are capable of doing millions of jobs… it would make more sense to send a robotic backhoe? What rocket do you propose we use to launch a robotic backhoe?
Rovers weigh very little. They do not have the digging power to do the job. The size of the shovel is directly proportional to the size and weight of the rover and the weight allowance of the mission.
The Mars Direct mission was initially priced out at 80-billion.
Sounds like you’ve bought into the standard NASA line… the line they use to appease those of us who understand… there is no substitute for manned exploration of the solar system and beyond.
Discovering life of any kind is not the primary goal of any interplanetary missions. It may be one of a number of different mission goals when exploring a planet that has conditions that could potentially harbor life, but the primary mission goals with planetary exploration is planetolgy; study of the planet’s atmosphere and composition. The potential for life gets amplified in the media because it attracts more attention than rocks and wind, but exobiology is really a very minor portion of NASA research efforts. And the discovery of life, far from “dooming future missions and funding” would virtually ensure greater funding for more elaborate future missions. For note, the Mars Science Laboratory as a sample analysis suite of instruments that are, among other tasks, designed to discriminate organic molecules and analyze their structure to see if they are from a natural origin or could be the product of life processes.
This is patent nonsense. First of all, there is nothing that astronauts can do in terms of exploration that cannot be done more cheaply by robotic probes and landers. People are useful when it comes to complex mechanical tasks like assembling hardware (although when confined by a pressure suit and in low gravity or freefall even this becomes highly challenging) but for taking samples, performing repeated analyses, functioning for hours or days on end without break, et cetera robotic exploration is superior.
Second, while the problem of ensuring that contamination with Earth-based bacteria is challenging enough with unmanned probes, doing so with astronauts is virtually impossible. Human beings naturally carry bacteria on and inside of them, and this will inevitably result in some bacteria transferring to pressure suits, tools, and sampling apparatus. Placing astronauts in the exploration system increases the chances of false positives.
Third, Zubrin’s Mars Direct proposal substantially undermines the challenges and difficulty of getting people to Mars and back. It involves durations spent in freefall and low gravity that exceed existing experience, virtually neglects the problems of radiation exposure, and doesn’t account for any of a number of contingencies that could occur on the 27 month mission duration that could result in loss of mission and crew for which no extant mitigation exists. Even optimistic estimates of a manned mission put a minimum cost at in the hundreds of billions of dollars to place a handful of explorers at one location on the surface of Mars. For the same cost one could litter the surface of Mars with unmanned probes like the Mars Science Laboratory that can cover more ground, perform a greater scope of work, and operate for a much longer mission duration than a team of astronauts, plus not have to be recovered (nor tears shed if they are damaged on descent or fail prematurely).
There may be valid reasons for manned space exploration (though most current rationales devolve into “so we can get better at putting people in space”) but the costs, limitations, and liabilities for planetary exploration are prohibitive, and no significant advantages exist to offset these.
Stranger
While I disagree with much of what you’ve said, we may have to just agree to disagree. I could spend hours here rebutting every point you’ve made (like your contention that Zubrin made no provisions for radiation exposure – false, or that Mars Direct would cost hundreds of billions – again false – the Space Exploration Initiative mission was estimated at 500 billion and was outlandishly ambitious by comparison) but I’m not going to convince many of you.
At any rate, I’m getting sidetracked. The original question was “why avoid directly searching for life on Mars?” And my answer is “because it’s expensive”. The most direct way to search for life on Mars is to send astronauts. In 50 years of spaceflight, with hundreds of missions, we have yet to make this breakthrough. And I would argue it’s because of an over-reliance on robotic probes and a lack of political will to do the hard (expensive) things.
Think about it this way: An astronaut with a backhoe is always more expensive to send than a remote-operated backhoe. Same with an astronaut + microscope vs. a remote-operated microscope. Same with an astronaut + rover vs. a similar sized automated rover. (Recall that Apollo astronauts didn’t get very far from the landing sites until they started riding around on rovers.)
And not just because an astronaut needs supplies (food, water, air), additional safety considerations, etc. It’s also because an astronaut needs to be returned to earth safely after the mission is over, while unmanned equipment can be left abandoned on Mars.
Of course eventually there would be benefit to sample-return missions, because labs on earth have far more capabilities than any automated analysis equipment we can send to Mars. But then again, any equipment astronauts can take to Mars wouldn’t be any better. Why send astronauts to go to Mars and bring back soil samples when a robot can do it for a fraction of the cost?
Curiosity weighs 2000 pounds; even larger rovers are under study.
No, others have answered this already. To put it simply, (1) there’s no “direct” way to look for something when we don’t know what that something looks like and where it is, and (2) we are already searching as “directly” as we know how.
I happen to have more than a passing familiarity with Zubrin’s “Mars Direct” proposal, both the original 1990 study and the later modified version that was used as a design reference mission for several nascent Mars exploration studies by NASA. I’ve also heard Dr. Zubrin speak at a conference once. Bob Zubrin is clearly a smart guy, an enthusiastic speaker, a dyed-in-the-wool space exploration advocate, and completely lacking in any practical experience in the development, testing, and acquisition of aerospace and spacecraft propulsion systems. Just in listening to him it is clear that his knowledge of actually propulsion and space systems development comes out of a textbook.
One key to the low cost of the original “Mars Direct” program was minimal testing, and no full up system testing or pathfinding activies. His argument for this is that we’re all so smart now that we’ve flown the Saturn V and Space Transportation System that we can avoid mistakes of the past, design a spacecraft on paper, “test” it via computer simulation, fab the hardware, bolt it together, and launch it direct to Mars. This approach is direct in opposition to standard engineering development practice and has been a complete disaster everytime someone has tried to put it into practice. See the Soviet N1 rocket (0 for 4 launch successes) or the Space Exploration Falcon 1 (first two launches failed to orbit, third failed the orbital objective). “Mars Direct” also hinged on production of methane as a fuel and propellant from Martian sources, which is unproven both from a resource extraction and long duration spacecraft propulsion standpoint. I don’t question that both can be done (and even make sense to do) but developing the technology to do that is not a matter of pulling an existing system off the shelf and modifying it.
I would agree that the NASA program estimates were not realistic in their basis, but even a low ball estimate for a realistic effort that is consistent with prudent engineering practice comes out at a couple hundred billion dollars for a single one-off mission. You could cut that by almost half by adopting a large amount of risk, but then you are still left with a high price tag, an enormous liability should the mission fail, and the question of what you are really going to achive by putting people on the surface in one or two locations for a few weeks instead of planting rovers and probes in disparate locations that don’t have to be fed, comforted, or returned.
As for radiation, although Zubrin had provisions for protection against transient solar charged radiation from coronal mass ejections which consisted of essentially turning the propulsion system and fuel tankage toward the Sun and moving the crew into a protected compartment, he had no scheme for protection against galactic cosmic rays which cause cummulative genetic damage and increase risk of cancer. Zubrin’s argument was that the then-current thresholds were simply too conservative and that space physiology from Space Station Alpha/Freedom Station would allow raising of the exposure threshold. In fact, research in the two decades since, while still inconclusive about what appropriate exposure should be, have significantly lowered thresholds. The Russians, who have even more cummulative space habitat time than the United States, have come to similar conclusions. There is no practical way to protect against this high energy radiation except to place a lot of mass between the crew and the radiation, which is coming in from every direction. On the Earth, this is the 100 km of atmosphere which renders cosmic radiation nearly harmless; in space, there is no practical way to carry that much mass, and carrying a little bit is not only not an effective mitigation, it will actually make for a greater hazard, as the high energy rays that might pass straight through an astronaut will now be converted into lower (but still very high) energy charged particles and ionizing radiation that is more likely to affect an astronaut.
Zubrin is also dismissive of the effect of long duration freefall and self-induced biological hazards (don’t get me started on spacecraft human waste disposal systems), although he has done significant research into the psycho-social aspects of long duration mission. However, even by his own admission, there are serious problems with long term isolation that remain unresolved, and experiements to simulate those conditions in volunteer “crews” have produced a lot of adverse results, as even a casual perusal of NASA and university studies will show.
You have still failed to make a clear or persuasive argument for why astronauts are of any particular value in looking for signs of life, and have totally ignored the points made previously as to why the presence of astronauts and the maintenance requirements of them are actually detrimental.
Stranger
Stranger, a real life rocket scientist (I know, I know, propulsion systems, etc etc) is one of the biggest reasons I hang out here. 
If you’re a real life rocket scientist, Stranger, then I’m not surprised that you believe EVERYTHING can be done cheaper and just as efficiently by robots. And there’s nothing I can say that will convince you otherwise.
I disagree. Humans are a better choice.
They’re not even cheaper and here’s why…
The Phoenix lander was sent with specific goals, one of which was to scrape a trench in the soil and look for subsurface ice (which it found). But ask Phoenix to rove like Spirit and Opportunity… it can’t do that. We have to actually send Spirit and Opportunity.
Spirit and Opportunity can rove all over an area of a couple hundred square miles, but they can’t dig themselves out of the sand when they get stuck. If we want a sand rover, we have to send a different mission.
And if we want a robot that can dig deeper, we have to send yet another mission.
And if we want a rover that will explore Martian lava tubes, we have to send another mission.
And if we want to explore Valles Marineris, we have to send another mission with an entirely different piece of hardware.
And on and on and on…
So lets add up the cost of all these missions and see what’s cheaper when ONE human mission could do ANY of these tasks.
I’ll be waiting with eager anticipation for a robot to prove there’s life on Mars.