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Comment by prawks | Hacker News Reader

It is naive to ask why another? I was under the impression that Curiosity was supposed to be like the rover to end all Martian rovers. What else do they need? It seems like there must be something else to do aside from.... rove. Maybe not manned exploration, but something to push things further towards that?

Or are they still stuck on "We must make a final, irrefutable conclusion on whether life has or has not existed on Mars prior to introducing organisms to the planet"? Am I the only one who thinks that the search is kind of, well, silly at this point? How much of the surface have they covered with rovers? I'd imagine it would take much longer, and a much more exhaustive search to come to any sort of definitive conclusion.

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The reasons are likely more political than scientific. The rovers keep the money flowing. Rovers have a high chance of success and they are some of the last few remaining tangible results that NASA can point to to justify their budget in the public's eye. A new kind of mission is risky and would likely get bogged down in bureaucracy (see Orion).

The function of the rover isn't to drive around and map things. Its function to serve as a platform for a suite of scientific instruments to gather data. That suite of scientific instruments will be different for the next rover, adjusted based on what we now currently know (and didn't know the last time they chose instruments). So, yes, its "another" rover. But its what that rover is carrying that is different and interesting.

Having said that, I'm all for being a lot more ambitious, and sending people to Mars instead. But that's a different discussion.

>how much of the surface have they covered

Oh, right about 0%. And that was with rovers not properly equipped to find microscopic life.

I'm a fan of all the missions so far, but when I hear that none of the rovers have been "properly equipped to find microscopic life", I fear that some of the mission planning may be trying to "preserve the mystery", trickling out plot revelations to keep the viewers/funders hooked.

Couldn't Curiousity have had some agar plates and just dragged them through the dust, for subsequent observation over weeks? (Even if any organisms detected were eventually suspected to be earth-originated contaminants, their growth details would be new info, right?)

The problem with relying on that method is that finding life on mars could be like finding life at geothermal vents; deep down in hard-to-reach volcanic pockets. If you don't poke around some of those areas before bringing masses of earth contaminants to the surface, you could easily screw up future searching.

This makes no sense to me. You can't just test the soils and easy-to-reach places for microorganisms until you can also test the deep places?

And how do easy surface tests contaminate things any more than all the earth-originated equipment we've already dropped there?

Surface tests are perfectly fine, but they're not enough. prawks was talking about how we're wary of introducing Earth organisms to the planet. We should keep that attitude until we've done proper searching for life all over, not just the easiest tests.

> How much of the surface have they covered with rovers?

They've landed four successful rovers on the surface. One the size of a microwave oven, two the size of small golf carts, and one the size of a BMW Mini.

Meanwhile, Mars has approximately the same land area as all the continents of earth put together. It's a big place.

Feel free to do the math to answer your question, but there'll be an awful lot of zeros after the decimal place.

It was a rhetorical question, perhaps improperly phrased as such. The point being that they have barely even begun to attempt to scratch the surface. How effective are rovers at doing this? Shouldn't the ultimate goal to be to gather data to allow more extensive exploration (likely by humans)?

I saw a map of Mars landing sites, which I can't find anymore. The bulk were on a tiny sliver next to a mountain, and most landers were immobile. We've only had a good, constantly up to date map of Mars for a handful of years thanks to MRO. It takes time to plan new missions based on that data.

Mars has as much land area as Earth. So 1) we are nowhere near done searching it with robots, and 2) we will never search it completely with robots.

We really need to have humans on Mars to search for life.

How are humans better at searching for life than robots?

Humans seem to require much more onsite support infrastructure, including for activities (eating, sleeping, remaining social and sane) that are tangential to most exploration and life-detection experiments. Such an infrastructure also increases the magnitude of Earth-contamination of the Martian environment.

I'm all for having humans on Mars so we're a two-planet species... but I don't see boots-on-the-ground as offering a faster/better/more-complete search for life than the same resources sent as robots.

How long would would you have to search the rocky mountains with robots to find a dinosaur fossil?

Assuming terrain-optimized multipedal robots, with stereoscopic vision across a broader range of the light spectrum than human vision: less time than with humans.

Such robots should be available in the same timeframe as a human-supporting infrastructure could be delivered to the Martian surface. (In fact, building that infrastructure might require similarly-advanced robotics.)

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