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Phoenix Mars Lander Deploys Robotic Arm, Possibly Finds Ice
The Phoenix Mars Lander has successfully deployed its robotic arm and tested other instruments including a laser designed to detect dust, clouds, and fog. The arm will be used to dig up samples of the Martian surface, which will be analyzed as a possible habitat for life. A camera on the arm will allow pictures to be taken of the ground directly beneath the lander. The camera has already seen what may be ice, which was exposed when the soil was disturbed by the landing. The data collected by the arm will be compared to recent findings which suggest that water on Mars may have been too salty for most known forms of life.
The rovers can't dig as deep, nor could they have survived more than a season at these polar latitudes either. There isn't as much ice (or for that matter, any ice that we've been able to find) at the latitudes where the rovers are operating.
As for what we already have on Mars, we have rovers that have amazingly gone almost 10km each. That's about 1% of the distance they'd have to cover to get to where this one is. So in terms of "what we have on mars" that "are capable of finding out what the polar ice caps are like", we currently had nothing until Phoenix.
Because other than the "gee, that's pretty" factor, a color image doesn't have as much significance as a grayscale image that has been taken through specific filters. The probe has multiple filters so they can take images that are sensitive at different wavelengths (depending on what they want to "see").
If they want a standard color image, they can take three pictures with R, G, B filters and combine them. It's not like anything they're (likely) going to take a picture of is going to move anyway, so taking 3 sequential images won't be a problem.
Grayscale images are also smaller (bandwidth-wise) so they can transmit faster. No use wasting time transmitting a larger image if your camera is pointed at the wrong thing.
I took a course with Steve Squyres (the principal investigator for the rover mission) in the fall semester. According to him, you can't look to Earth extremophiles as evidence that life can arise in these conditions. Extremophiles apparently all have adaptations such that, inside their cells, they can do their chemistry in 'normal' (non-acidic, non-salty, ...) conditions. If life were to arise in extreme conditions, they'd probably need totally different chemistry.
There's certainly a possibility of some exotic form of life arising in extreme (for us) conditions, but we shouldn't be expecting it to be possible, as there's no evidence that it can happen.
Yes. The chances of destroying life that can withstand extremely high radiation levels, a virtual vacuum, and living in frozen C02 is unlikely to be bothered by a little bit of ammonia steam for a few seconds. Additionally the design intentionally spreads the plume over a wide area to lower the local heating, pressure, or contamination effects. Melting ice isn't likely given the small heat input and short duration, but it's not clear that melting a little bit of ice for a few seconds before it refreezes actually hurts anything much.
Brett