Are Nuclear Powered Mars Rovers a Good Idea?

meatybeans writes "NASA officials are meeting today, with concerned residents around Cape Canaveral, regarding the power system for the upcoming Mars Science Lab mission. MSL is going to be like our current rovers on steroids. The plans call for a larger, heavier rover with a lot more juice for gadgets. This meeting however brings to light the issue of the power system for the MSL. The Mars Science Lab originally called for a nuclear power source, much like the Cassini and New Horizon missions use. Some vocal opposition to this has been voiced in the past. As a result, NASA has backup plans to employ solar power and small amounts of RTG's ^? if arguments against straight nuclear for MSL win out. As with most, things 'NIMBY' ^? seems to be in full effect when it comes RTG's. Does the recent success of the rovers show us that RTG's are not needed for Mars exploration? Are 1:420 odds of an accident that bad? Finally, are the hearings that are taking place between NASA and the public really just a formality in the name of public relations?"

Yes, of course

[Anonymous Coward]

Yes, of course they're a good idea. People should get over their irrational fear of decaying nuclei.

RTGs are not dangerous

[SirBruce]

As I pointed out in the Victoria Crater story, there are places a solar-powered rover can't really explore effectively, or for very long. You can't just land the current MER rovers "anywhere" on Mars and expect them to work. An RTG-powered rover will work longer and better than a MER rover, assuming all other things are equal (not breakdowns elsewhere). Suppose instead Spirit and Opportunity had been RTG-powered... would we now be saying, "Hey, these RTGs work great, so why bother with solar probes anymore?"

But the real answer to your quest is that RTGs aren't dangerous, so the entire premise of the question is flawed. A launch failure isn't going to make Florida a radioactive wasteland. We've launched dozens of RTGs in past missions. The last big "outcry" was over the Cassini mission, and NASA made the correct decision and launched anyway. Hopefully they'll make the correct decision again and use RTGs for the future rovers like MSL. Bottom line: it's not any more risky to launch an RTG powered probe than a solar powered one, so you use RTG power for the missions that need it and solar power for the missions that need it.

Bruce

wrong question

[192939495969798999]

the correct quesion should be, 'what's wrong with continuing to build solar rovers that we need a nuclear one? So far, the solar ones haven't stopped running, so I'd say that solar is a home run.

Whose backyard?

[brunes69]

My question is, why are these people afraid of a *single* launch malfunctioning and scattering waste in their area, when the US Air Force still has planes launched 8all the time* from *all over the country* that have strategic nuc lear weapons on them? They are never fired, for sure, but any plane accident could cause just as much damage as an accident with one of these NASA launches. In fact the weapons likely have even more dangerous material in them, for obvious reasons.

They're Not a Good Idea

[turgid]

They're a brilliant idea.

Seriously, educate yourself of RTGs if you're worried about launch safety.

Secondly, as others have pointed out, they're an excellent, long-lasting, power source.

A thought just struck me. For much more additional cost, you could make the robots bigger and heavier with much bigger solar panels. They could have batteries big enough to hold several days' charge.

I'll go with the RTGs, which last decades and result in a smaller, more reliable, and more manoeverable vehicle.

Anyway, I'm sure the Martians are more radiation-hardened than we are, what with that thin atmosphere.

Re:Result of accident?

[Shakrai]

Great. What are the arguments against the use of a RTG then? If there isn't any "real" damage aven locally why does it seem to such a big issue?

Because tree huggers have an irrational fear of anything called "nuclear"?

I'm an environmentalist and I realize that the future of mankind lies in the atom. Be it fission or fusion, unless we are prepared to accept a major reduction in our standard of living, we will need something to replace fossil fuels.

Re:RTGs are not dangerous

[theCoder]

On the other hand an RTG powered rover would be really heavy, for about the same amount of power you would get from solar cells (assuming illumination is available).

[emphasis added]

I don't know how well RTGs compare to solar cells for power production (I would expect they produce more, but maybe not), but the crucial point is that there isn't sufficient illumination on many parts of Mars for solar power to be workable. There is only a narrow latitude band near the Martian equator that can support the solar powered rovers. Using an RTG, much more of Mars would be open to exploration.

Re:They'll be perfectly fine

[budgenator]

In nuclear engineering, a fissile material is one that is capable of sustaining a chain reaction of nuclear fission. ... Fissile" is distinguished from "fissionable". "Fissionable" are any materials with atoms that can undergo nuclear fission. "Fissile" is defined to be materials that are fissionable by neutrons with zero kinetic energy. "Fissile" thus, is more restrictive than "fissionable" -- although all fissile materials are fissionable, not all fissionable materials are fissile. Some authorities even restrict the term fissionable to mean only non-fissile materials. ...
        * Uranium-233.
        * Uranium-235.
        * Plutonium-239.

All these have been used successfully as fission fuels. Plutonium-241 and Neptunium-237 are also fissile but have not been used as a nuclear fuel. Several other transuranic isotopes are known to be fissile, all of them having both even atomic numbers and odd atomic mass numbers. These include:

        * Neptunium-237[1]
        * Curium-244[2]
        * Americium-241 ...

so sayeth wikipedia [wikipedia.org]
  even atomic numbers and odd atomic mass numbers lets out Pu238 due to even atomic mass.

The answer the "old" NASA would give....

[argStyopa]

Are they safe? Yes. Shutup. We're launching.
If you long haired hippy freaks don't like it, tough.