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Because even if life exists, we do not yet know where to look for it, or what we would be looking for. The surface is bombarded by UV and radiation, so very unl

Because even if life exists, we do not yet know where to look for it, or what we would be looking for. The surface is bombarded by UV and radiation, so very unlikely. Should we look in cliff shadows? Near ice deposits? The bottoms of craters? Near the equator where it is warmer? Or near the poles where there might be water? We could look a long time without ever learning whether or not life exists. Instead, we look for things associated with life. Methane can be produced by life, so let's see where it's coming from first and then worry about whether we can send a probe there. Maybe look for organic molecules, then try to see if there is a trail to life. Try to figure out where on Mars liquid water exists, since that is a prerequisite for life as we know it. And in the meantime, there's plenty of basic science to be done. Geology teaches us about what Mars was like a long time ago. That too can give us a hint towards whether life was possible, and where. Understanding the atmosphere and its routine seasonal swings helps us understand the environment so that later, when looking for life, we don't get excited and confuse a weather phenomena with evidence of life. Lastly, physics of our probes dictates where we can send them. For our best, heaviest probes, we don't have room on the rocket for a lot of fuel to slow down. So sites need to have low elevation to give parachutes a chance to slow us down. If we want the probe to be powered by solar, we need to be near the equator. Even if not powered by solar, we probably want to avoid being near the poles where winter can last a whole Earth year.

pmoriarty 7y ago
"Should we look in cliff shadows? Near ice deposits? The bottoms of craters? Near the equator where it is warmer? Or near the poles where there might be water? We could look a long time without ever learning whether or not life exists." Somewhere near water might be a good start. There are plenty of candidates for this on Mars already. Also, I'm sure plenty of people at NASA and other space agencies have thought of this, and there are probably some good reasons for not doing it, but why not take some deep core samples and look through them with a microscope for anything moving? Not that creatures that can be seen moving under a microscope would exhaust all possible forms of life, but wouldn't it be a good start rather than looking for traces of what might have existed on Mars millions or billions of years ago? Looking for basic components of or traces of life and only then later starting to look for existing life itself seems like the going the long way around. Why not just go for the gold from the start?
- TeMPOraL 7y ago
  > Also, I'm sure plenty of people at NASA and other space agencies have thought of this, and there are probably some good reasons for not doing it, but why not take some deep core samples and look through them with a microscope for anything moving? I would guess the difficulty of taking that sample would be one reason - in particular, the difficulty of building, shipping and operating necessary hardware. The best we've done so far is AFAIK the 5m thermometer-tipped drill on the Insight lander, which drilled ~30cm down and broke. We really need cheaper access to Mars for such missions, so that we could send more and heavier hardware for less.
  - busymom0 7y ago
    I am probably the least knowledgeable on this subject, especially compared to the NASA scientists but why don't they send more "complex/capable" robots like the ones from Boston Dynamics instead of their rovers? I feel like a human type of robot mechanically would be much more capable of doing such tests than a rover with limited range of motion. The rovers already have a continuous wear and tear to their wheels (something I will guess the Boston Dynamics might be a bit better at as there is lesser surface area and rolling friction)?
    - jacobush 7y ago
      Because for science per kilogram sent there, you'd get very little from such a robot. Hence very little science per dollar. (Also, I'd expect such a robot to break in short order.)
    - trickstra 7y ago
      here is a talk about the architecture of a Mars rover: https://media.ccc.de/v/35c3-9783-the_mars_rover_on-board_computer https://media.ccc.de/v/35c3-9783-the_mars_rover_on-board_com... Boston Dynamics Atlas probably wouldn't survive the journey, nor the radiation, nor the heat swings. Mars rover is specifically designed to do handle crazy unknown failures, that's what makes it complex. Having a complex robot and trying to make it resistant to all those failure modes is simply too difficult for today's engineering.

pmoriarty 7y ago

"Should we look in cliff shadows? Near ice deposits? The bottoms of craters? Near the equator where it is warmer? Or near the poles where there might be water? We could look a long time without ever learning whether or not life exists." Somewhere near water might be a good start. There are plenty of candidates for this on Mars already. Also, I'm sure plenty of people at NASA and other space agencies have thought of this, and there are probably some good reasons for not doing it, but why not take some deep core samples and look through them with a microscope for anything moving? Not that creatures that can be seen moving under a microscope would exhaust all possible forms of life, but wouldn't it be a good start rather than looking for traces of what might have existed on Mars millions or billions of years ago? Looking for basic components of or traces of life and only then later starting to look for existing life itself seems like the going the long way around. Why not just go for the gold from the start?

TeMPOraL 7y ago
> Also, I'm sure plenty of people at NASA and other space agencies have thought of this, and there are probably some good reasons for not doing it, but why not take some deep core samples and look through them with a microscope for anything moving? I would guess the difficulty of taking that sample would be one reason - in particular, the difficulty of building, shipping and operating necessary hardware. The best we've done so far is AFAIK the 5m thermometer-tipped drill on the Insight lander, which drilled ~30cm down and broke. We really need cheaper access to Mars for such missions, so that we could send more and heavier hardware for less.
- busymom0 7y ago
  I am probably the least knowledgeable on this subject, especially compared to the NASA scientists but why don't they send more "complex/capable" robots like the ones from Boston Dynamics instead of their rovers? I feel like a human type of robot mechanically would be much more capable of doing such tests than a rover with limited range of motion. The rovers already have a continuous wear and tear to their wheels (something I will guess the Boston Dynamics might be a bit better at as there is lesser surface area and rolling friction)?
  - jacobush 7y ago
    Because for science per kilogram sent there, you'd get very little from such a robot. Hence very little science per dollar. (Also, I'd expect such a robot to break in short order.)
  - trickstra 7y ago
    here is a talk about the architecture of a Mars rover: https://media.ccc.de/v/35c3-9783-the_mars_rover_on-board_computer https://media.ccc.de/v/35c3-9783-the_mars_rover_on-board_com... Boston Dynamics Atlas probably wouldn't survive the journey, nor the radiation, nor the heat swings. Mars rover is specifically designed to do handle crazy unknown failures, that's what makes it complex. Having a complex robot and trying to make it resistant to all those failure modes is simply too difficult for today's engineering.