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Are Nuclear Powered Mars Rovers a Good Idea?

Cliff posted more than 7 years ago | from the got-any-better-ideas dept.

173

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?"

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173 comments

Yes (4, Funny)

6Yankee (597075) | more than 7 years ago | (#16242783)

Of course it's a good idea! Ship all the evil nukuler stuff to Mars and the terrrrrists can't get their hands on it!

For now.

Re:Yes (2, Funny)

Chelloveck (14643) | more than 7 years ago | (#16243571)

Of course it's a good idea! Ship all the evil nukuler stuff to Mars and the terrrrrists can't get their hands on it!

Yeah, we tried that seven years ago, and ended up blowing the moon clear out of its orbit. Now you want the same for Mars?

Re:Yes (1)

webmistressrachel (903577) | more than 7 years ago | (#16243995)

"... ended up blowing the moon clear out of it's orbit ..."

Citation needed. I just can't swallow this.

Thanks.

Re:Yes (1)

Ash Vince (602485) | more than 7 years ago | (#16244097)

It was a Space 1999 reference, that crappy SciFi show from the 70s where Moonbase Alpha (and the entire moon) was sent drifting off through the universe by load of nuclear waste we stored there going critical and forcing it out of orbit.

Unnecessary (4, Funny)

tygerstripes (832644) | more than 7 years ago | (#16242789)

Why don't they just use batteries? I hear Sony has a surplus.

Re:Unnecessary (1)

jamesh (87723) | more than 7 years ago | (#16243013)

I wonder what Sony is doing with all of their unexploded batteries? I hope they aren't stored too close to each other. Sending them into space would be a good way to dispose of them...

Maybe they could use them as rocket fuel? Strap a few to the underside of the probe and bring it along to a Linux conference where Alan Cox is present. That's sure to send it on its way.

Re:Unnecessary (3, Funny)

ultranova (717540) | more than 7 years ago | (#16243993)

I wonder what Sony is doing with all of their unexploded batteries? I hope they aren't stored too close to each other. Sending them into space would be a good way to dispose of them...

Sell them to terrorists, of course. "Nobody move, he has a Sony battery! Now calm down, son..."

Yes, of course (5, Insightful)

Anonymous Coward | more than 7 years ago | (#16242809)

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

Re:Yes, of course (2, Informative)

ozmanjusri (601766) | more than 7 years ago | (#16244517)

People should get over their irrational fear of decaying nuclei.

They already use some nuclear power. Each rover has eight Radioisotope Heater Units, powered by Plutonium 238, so it's not fear that's preventing the use of RTGs.

My guess is that weight is the problem. NASA's standard General Purpose Heat Source RTG generates about 290W and weighs about 60Kg, while the rover's existing power system weighs about a third of that.

RTGs are not dangerous (5, Insightful)

SirBruce (679714) | more than 7 years ago | (#16242853)

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

Re:RTGs are not dangerous (1)

MichaelSmith (789609) | more than 7 years ago | (#16243353)

As I pointed out in the Victoria Crater story, there are places a solar-powered rover can't really explore effectively

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). Getting into Victoria may be a case of sliding down those sandy slopes into the crater with no possible chance of getting out. A much heavier rover may well get bogged on the way down and either get stuck or turn over.

On sandy surfaces it pays to be light.

Re:RTGs are not dangerous (2, Insightful)

theCoder (23772) | more than 7 years ago | (#16243509)

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:RTGs are not dangerous (4, Informative)

AKAImBatman (238306) | more than 7 years ago | (#16243365)

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.

Don't forget that we've blown up a few of them, too. The original RTGs were designed to be burned up in the atmosphere. (Russia even burned one up over Canada.) So far, there are no nuclear wastelands because of it. NASA quickly figured out, however, that burning up expensive nuclear fuel in the atmosphere was probably not the best idea. So they started cladding the fuel in tough containers designed to withstand a launch failure.

Those containers have been proven twice. Once on the Nimbus launch vehicle (which was destroyed by the range officer) and the other was the emergency landing of Apollo 13. The Nimbus RTG was recovered from the sea bed, washed off and resused. The Apollo 13 unit fell in the Troga Trench and has been sitting there unpenetrated.

Re:RTGs are not dangerous (3, Informative)

Anonymous Coward | more than 7 years ago | (#16244327)

If you are referring to Cosmos 954 crashing in the Northwest Territories, that wasn't a RTG. It was a nuclear reactor on a satellite. From Wikipedia, it is a BES-5 reactor fueled with U-235. According to one source (http://www.svengrahn.pp.se/trackind/RORSAT/RORSAT .html [svengrahn.pp.se]), there was 30 kg of 90+% enriched U-235 (as U-Mo alloy) in the core. Power output was 3kW, obtained by thermoelectric generators. The heat source is fission, not decay heat.

Re:RTGs are not dangerous (1)

tonigonenstein (912347) | more than 7 years ago | (#16243987)

An RTG-powered rover will work longer and better than a MER rover, assuming all other things are equal (not breakdowns elsewhere)
Except that power is not necessarily the limiting factor. Spirit lost one wheel and won't be able to move at all if it loses one more. So in this case an RTG won't make it work longer.

Riiiight, because they have such a good record (0)

Anonymous Coward | more than 7 years ago | (#16242865)

I'm sorry but the mission success rate is pretty damn low. I mean we have been doing very basic stuff and failing horribly. No way do I think the odds are very good for a successful nuclear powered mission. Most engineers suck and their project management sucks even more, it's as simple as that.

They'll be perfectly fine (1, Funny)

jlebrech (810586) | more than 7 years ago | (#16242867)

If you send the Fissible material on a seperate rocket. And the Material should rendevous, with the nuclear reactor rocket. then an active nuclear reaction would have no chance of starting in lift off.

The problem with a failed launch, might create the need for recovery, which may be a problem if reactive ingredients, were to land on hostile territory.

I think assembly in space is the safest bet tho.

Re:They'll be perfectly fine (5, Informative)

Detritus (11846) | more than 7 years ago | (#16242955)

Pu-238 is not fissile, and an RTG (radioisotope thermoelectric generator) is not a nuclear reactor, it uses the decay heat of the radioisotope to produce electricity.

WOW (-1, Troll)

Anonymous Coward | more than 7 years ago | (#16243019)

I'll bet that you are a WHOLE lot of fun at parties, aren't ya?

Re:They'll be perfectly fine (1)

chrismcdirty (677039) | more than 7 years ago | (#16243177)

Sounds about as fun as Alice Cooper in Wayne's World.
Does this guy know how to party, or what?

Re:They'll be perfectly fine (1)

locofungus (179280) | more than 7 years ago | (#16243179)

Pu-238 is not fissile

I don't know for certain but I'd be very surprised if it wouldn't undergo fast neutron fission.

I think what you mean is that Pu-238 can't support a self sustaining chain reaction. Again, I don't know this for certain but it sounds believable, at least in quantities of less than tonne lots.

Tim.

Re:They'll be perfectly fine (2, Interesting)

NekoXP (67564) | more than 7 years ago | (#16243283)

At least the amount of Pu-238 they use isn't big enough to support a self-sustaining chain reaction.

Basic effects;

* if the rocket explodes on launch, everyone within a 100 mile radius (mostly downwind) will get their recommended maximum radiation dose for the week.. on one day. But people living in houses with lots of Radon (which is something insane like 5% of the USA) get more than this anyway. It's not a disaster.

* if the probe his Mars like Beagle 2 did, the radioactive material hits Mars. Oh. Well, if you were searching for life (microbes), and it was out for a walk on the surface, you just pretty much killed it. However the solar radiation that hits Mars every damn day is much higher. If it was out on the surface it would no doubt be hardier than you could kill with a fine dusting of Pu-238.

So basically who gives a fuck? Only the BAN NUKLUAR POWAR idiots. Cheapest, cleanest, safest (in combination) form of energy and they want to ban it.

Re:They'll be perfectly fine (1)

MikeBabcock (65886) | more than 7 years ago | (#16244017)

As pointed out elsewhere ...

If the rocket explodes on launch, the container of fuel will most likely be undamaged.

If the probe smashes into Mars and makes a big hole, it will probably still have the container of fuel at the bottom of the hole.

This is a well proven technology.

Re:They'll be perfectly fine (2, Funny)

NekoXP (67564) | more than 7 years ago | (#16244169)

In response to that then, I'll change it:

* Someone in Florida will have a nasty headache when it hits them in the head
* Some microbe in Mars will be very, very squished

I think the consequences are equally serious and therefore equally irrelevant :D

Re:They'll be perfectly fine (1)

locofungus (179280) | more than 7 years ago | (#16243381)

I think what you mean is that Pu-238 can't support a self sustaining chain reaction

According to http://en.wikipedia.org/wiki/Radioisotope_thermoel ectric_generator [wikipedia.org] this is wrong. The problem with using Pu-238 in a bomb is that it's too hard to assemble a critical mass due to the chain reaction starting too early.

Here was me assuming Pu-238 would behave similarly to U-238 - a dangerous assumption :-)

Tim.

Re:They'll be perfectly fine (0)

Anonymous Coward | more than 7 years ago | (#16243395)

I work at a nuclear power plant. I can tell you that the technology being used here basically uses "irradiated" fuel and uses the decay heat from the fission products and uses it to generate relatively SMALL amounts of electricity. The heat that's produced from nuclear fission is so great because there is a conversion of mass to energy that takes place during the fission process. Decay heat is much lower and can be easily managed using a very simple light water pool and small heat exchangers. In the event of a failed launch, the fission products would almost certainly remain in containment. There is no real danger of the decay products reaching "critical mass".

Check the RTG packaging. (4, Interesting)

WindBourne (631190) | more than 7 years ago | (#16242871)

Even if the launch system fails, the question should be, what happens to the fissile material? And the answer? Absolutely nothing. It is in a container that is meant to withstand that. All in all, it would still be in one piece. The advantage of nukes is that a great deal more science can go on for a LONG time (and at a lighter weight). Considering that there is no real risk, we really should use them.

Re:Check the RTG packaging. (1)

Detritus (11846) | more than 7 years ago | (#16242927)

Pu-238 is not fissile.

Re:Check the RTG packaging. (1)

jlebrech (810586) | more than 7 years ago | (#16242963)

If its not fissible, why cant i have that in my car?

I dunno. Maybe... (1)

hummassa (157160) | more than 7 years ago | (#16243343)

Because it's radio-ACTIVE ??? It's not fissile means its nuclei would not break apart, but it does not mean that its nuclei would not decay (like emit _one_ neutron and some photons per nucleus in its lifetime). That is what a RTG taps into: get those photons (heat) and generate kinetic energy for some electrons (electricity). But now, you don't want some Joe Sixpack's pile of junk car leeking neutrons because they are NOT GOOD for your health.

Re:Check the RTG packaging. (0)

Anonymous Coward | more than 7 years ago | (#16243065)

The problem is that failed launches have led to vaporized Plutonium in the past. Vaporized Plutonium causes lung cancer and is believed to be a significant contributor in the rising lung cancer rate over the past 30-40 years. Will the package certainly stay in one piece? NASA makes mistakes.

Re:Check the RTG packaging. (1)

PeterBrett (780946) | more than 7 years ago | (#16243393)

The problem is that failed launches have led to vaporized Plutonium in the past. Vaporized Plutonium causes lung cancer and is believed to be a significant contributor in the rising lung cancer rate over the past 30-40 years. Will the package certainly stay in one piece? NASA makes mistakes.

Yes, the package most certainly will stay in one piece. The canisters are designed to withstand re-entry, to the extent that if the launch fails NASA can follow the ballistic trajectory, pick up the canister and put it in a new probe (well, I exaggerate, but only slightly).

Yes, dust containing plutonium is incredibly hazardous, to the extent that if you inhale a gramme of plutonium you've sentenced yourself to a painful death in about three weeks time. However, I would postulate that a much larger cause of lung cancer are the thousands of tonnes of carcinogenic metal oxide particulates output every year by the ever-growing population of motor vehicles around the world. Not to mention that up until about a decade ago (when they started fitting decent filters), burning fossil fuel in power stations dumped hundreds of tonnes of uranium oxides into the atmosphere every year. Once again, knee-jerk reactionism (oh noes, a kilogram of plutonium oxide!) defeats actual science in the battle of public opinion...

I'm much more worried about the millions of litres of very nasty insecticide and herbicide sprayed onto the food I eat and into the air I breathe, personally.

Re:Check the RTG packaging. (1)

Like2Byte (542992) | more than 7 years ago | (#16243531)

I did a study of the Cassini mission's RTGs while I was in college. Even if the RTG's broke, the ceramic-like material they're made of is designed to "clump" which leads to easy collection and disposal or recycling. In the end, it was determined that there is more radiation from the Earth's natural background radiation than that from any incident that a catastrophic failure of the launch vehicle could cause.

The Bottom Line: The activists should have been out picketing their local cement supplier/home builder for not supplying more shielding to their basements walls.

Re:Check the RTG packaging. (1, Informative)

Ash Vince (602485) | more than 7 years ago | (#16244373)

Actually no, if the launch fails very late on after the container has left the atmosphere but before it escapes earths magnetic field then the container would have to withstand re-entry.

Anyone who has studied re-entry will tell you this is bad. The container could quite easily (no atmosphere to slow it down in space) attain speeds of the order of 1000+mph (http://www.physlink.com/Education/AskExperts/ae15 8.cfm). Something travveling at this speed hitting the atmosphere will get hot, very hot. I am sorry I cant be bothered to go into all the details now as I am on my lunch break at work at have no access to my old Physics with Space Technology Uni notes.

Basically, you would be hard pressed to design a container that can with stand anything more than a 5 degree angle re-entry. Something tumbling out of control will almost certainly come in much steeper, and it will burn up. This will disperse its contents over a wide area (half the globe).

Nuclear fissile material will not become magically inert in this process though. This is because even if it gets hot enough become a gas it is still too heavy to be captured by the earths magnetic field (normal radiation from the sun is trapped by earths field and enters at the poles producing the funny lights in the sky). Think Chernobyl, this caused radioactive material to rain (litterally in rain) down over a wide swaith of Europe and this was a near meltdown at ground level.

A nuclear meltdown in low earth orbit would be very bad. Not planet destroying, but still bad.

That said, I am still in favour of using nuclear power, it just has to be done very carefully in all circumstances.

Sorry this article is light on technical details, but I could write 30 page essays on this and still leave bits out. If anyone is that interesting try this wikipedia link for a start:

http://en.wikipedia.org/wiki/Atmospheric_reentry [wikipedia.org]

Re:Check the RTG packaging. (0)

Anonymous Coward | more than 7 years ago | (#16244561)

1) This is Nasa. They're at least passingly familiar with reentry. They say the capsule can handle reentry. In fact, two such capsules already have. So, as improbably as you think it is, it's already worked, two out of two times.
2) It's not "nuclear fissile material." RTGs work on decay, not fission.

As an apparent Wiki fan, did you think of checking the wiki entry on RTGs?

Russian Mars Train (5, Interesting)

Anonymous Coward | more than 7 years ago | (#16242877)

I think it's a great idea. The Russian space agency had plans for a nuclear power "Mars Train" in the 60s. It was manned as well. Mars train [russianspaceweb.com].

Make sense but the strategy could be wrong (3, Interesting)

99luftballon (838486) | more than 7 years ago | (#16242889)

In a cost/benefit analysis the nuke option makes sense. If you can get a larger rover that can move faster it opens up many new vista. I mean, I love the current Rovers for lasting so long but they move slowly and are too small to get past many geological barriers. A larger rover could carry more equipment and move farther and faster.

No-one likes the idea of the power source rupturing but on a planetwide basis it's not a major issue. Mars has probably received more radioactive material from comets et al than would be found in the battery and as we're not going to get there for another twenty years at best harm to humans isn't an issue. The worst result for us would be the plethora of B-movies about the radioactivity causing hyper-evolution that turns algae into ravening Martian monsters that look suspiciously CGIed.

But maybe the whole strategy is wrong. Instead of a few big rovers make lots of little ones. You get a better sampling of a variety of areas on the planet for your budget and it matters less if a few don't survive the trip.

Result of accident? (3, Interesting)

Bl4d3 (697638) | more than 7 years ago | (#16242891)

Would it result in more radiation than an "open air" nuclear explosion test? What does it compare to?

Re:Result of accident? (1)

bcmm (768152) | more than 7 years ago | (#16242959)

A dirty bomb. Dunno how big. It's not a nuclear explosion, it's a lot of rocket fuel + some radioactive stuff.

Re:Result of accident? (1)

fotbr (855184) | more than 7 years ago | (#16244033)

Except the radioactive material is encased in a manner designed to survive such events.

It happened, and it worked. Go look up the the Nimbus mission that was destroyed by a range-safety-officer.

Re:Result of accident? (4, Informative)

Ironsides (739422) | more than 7 years ago | (#16243003)

Would it result in more radiation than an "open air" nuclear explosion test? What does it compare to?

A Radioisotope Thermal Generator (RTG) basically using nonfisile radioactive material as a heat source to create electricity. This is what has powered the two Voyager probes for the past 30 years. The amount of readiation released is effectively zero. An open air nuclear explosion releases several kilograms worth of fisile material into the atmosphere.

Oh, and as to the dangers of RTGs in case of a launch accident. We've actually launched radioactive material on a rocket where the rocket exploded partway into the flight. The nuclear material was recovered inside it's intact casing and reused on a later mission.

There is zero danger involved here.

Re:Result of accident? (1)

Bl4d3 (697638) | more than 7 years ago | (#16243017)

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?

Re:Result of accident? (2, Insightful)

Shakrai (717556) | more than 7 years ago | (#16243037)

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:Result of accident? (1)

M1FCJ (586251) | more than 7 years ago | (#16243163)

Hear hear!
What we need is not plain old nuclear energy but proper fast-breeder-based nuclear energy - if we choose the normal enriched uranium route, the total amount of fuel won't last 150 years and we're back to the original problem - how to we sort out the energy requirement cheaply.

I count myself as a green and I believe all renewable sources are needed - you can't solve the problem with only solar energy or only wind power and we need fast-breeders right away. The only commercial ones in Japan and France are in financial and technical difficulties, leave alone political flak from complete morons.

Re:Result of accident? (0)

Anonymous Coward | more than 7 years ago | (#16244355)

Pressure for cuting energy losses is IMHO A Good Thing, even though it is bashed here as "treehug-ism". If we were to get an abundant power source now, we would yet again face the problem of global warming, this time not by greenhouse effect alone, but thru thermal pollution. Abundance of cheap energy would prevent care about efficiency of its spending. Using renewable energy sources (...except geothermal, which is net gain of heat in atmosphere, all others are neutral in that respect as energy extracted from environment would dissipate into heat anyway) as much as possible helps on that account too - something that nuclear fission, nuclear fusion or any subsequent now unforseeable energy source (hadron fission, quark fusion?) cannot. Each megawathour we "make" is a megawathour of additional atmospheric heat. We need to adapt to reality, not the other way around. Look back in the history: we had coal as energy source for centuries, but it made a difference in everydays' lives of people only when more efficent (James Watt's) steam engine was invented. Analoguous to that, great advances will happen not when we apply more energy to our old, "leaky", conversion and processing equipment, but when we start relentlessly fixing that "leaks" with new solutions to problems. Consequently, small-power renewable energy sources (who knows, perhaps even our own muscular strength again, thus both solving most of our energy needs and saving our sedentiary-lifestyle-endangered health at the same time) will gain signifficance.

Re:Result of accident? (4, Informative)

Ironsides (739422) | more than 7 years ago | (#16243101)

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?

As the other guy said, an irrational fear of nuclear. I remember hearing that during one of the nuclear launches in the 70's, there were people protesting saying that NASA was going to kill them all by launching a nuclear powered Satelite/Probe (I can't remeber which). They protested at the launch holding up there babies holding signs "You're going to kill me." Launch went off without a hitch.

Nuclear power and weapons detonation has released far less radiation than Coal and Fossil fuels in the past 60 years (Coal contains small ammounts of Uranium). If anything, they should be protesting Coal, not nuclear.

Re:Result of accident? (1)

Scarblac (122480) | more than 7 years ago | (#16243323)

It's a clump of radioactive material, no chain reaction is taking place, so absolutely not comparable to a nuclear explosion. It's just that a RTF uses 3-4 kg of Plutonium, which is a highly radioactive and poisonous material. In case of an accident, if it were to spread around an area, that area would be contaminated.

However, they've always used extremely rugged containers, that can survive rocket explosions leaving the block of plutonium intact.

Loaded question (1)

GapingHeadwound (985265) | more than 7 years ago | (#16242917)

Are nuclear powered rovers a *bad* idea?

Some vocal opposition to this has been voiced in the past.

In the past? Is that like in the '60s?

What is the basis for the argument?

1:420? (1)

tecnopa (931480) | more than 7 years ago | (#16242929)

If the people coming up with these odds are the same ones flying the ship, I would be a little nervous... "DUDE Where's Our Rover?????"

New meme? (1, Interesting)

bcmm (768152) | more than 7 years ago | (#16242935)

We need more articles like this, e.g.:
Are nuclear powered [iPods|laptops|hackers|furbies] a good idea?
Seriously though, the answer is nearly always obvious: probably not, because it's not really very safe.

Re:New meme? (1)

Donniedarkness (895066) | more than 7 years ago | (#16242999)

That would be stupid.

We all know nuclear powered furbies are a good idea.

Re:New meme? (0)

Anonymous Coward | more than 7 years ago | (#16243465)

If it's good enough for Godzilla, it's good enough for me!

Re:New meme? (2, Informative)

Goaway (82658) | more than 7 years ago | (#16243317)

Except of course that they are, in fact, really very safe.

So it's a good idea, right?

Re:New meme? (0)

Anonymous Coward | more than 7 years ago | (#16243637)

Please stop using that damn word, you Web 2.0 wannabe.

Meme = idea

So just say idea. Freakin idiots.

The biggest meme recently is every idiot on the web using the word meme.

wrong question (2, Insightful)

192939495969798999 (58312) | more than 7 years ago | (#16242937)

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.

Re:wrong question (3, Informative)

Ironsides (739422) | more than 7 years ago | (#16242979)

'what's wrong with continuing to build solar rovers that we need a nuclear one?

Solar powered rovers can't
1) Operate in shadow for long
2) Supply enough power if you want more insturments
3) Work through the martian winter

Re:wrong question (1, Informative)

Anonymous Coward | more than 7 years ago | (#16243751)

Solar powered rovers can't
1) Operate in shadow for long
2) Supply enough power if you want more insturments
3) Work through the martian winter


All true - but you missed the most important one:

4) Work at northerly or southerly latitudes.

Current technology can only operate close to the Martian equator. It's like being able to search for life in the Sahara desert. I'm sure we'd want to look closer to the poles if we could.

Scale of the Rover (1)

neurostar (578917) | more than 7 years ago | (#16243667)

'what's wrong with continuing to build solar rovers that we need a nuclear one?

Well, for one, this new rover is going to be much larger than the previous ones. More equipment = more power, and I imagine a nuclear fuel source would have a much higher energy/weight ratio than solar panels.

Well, look at our current rovers (1)

Lord Bitman (95493) | more than 7 years ago | (#16242951)

Their power was expected to last 90 days, it's lasted over three years.
It's the /other/ parts that keep going bad.

More power might be able to mean more spare parts, though..

Re:Well, look at our current rovers (1)

hcdejong (561314) | more than 7 years ago | (#16243087)

That's been due to luck (wind cleaning the solar panels more than expected), and planning/keeping limitations in mind (not driving the rovers into dark/shadowy places). For some part of those 3 years, the rovers have been stationary, because they didn't have sufficient power to move/needed to preserve what little power they had to keep essential functions running.

Re:Well, look at our current rovers (1, Interesting)

Anonymous Coward | more than 7 years ago | (#16243127)

One of the reasons other parts break down is due to thermal cycling. RTG's give off plenty of heat and help reduce the temperature range hence stress on the parts.

Whose backyard? (2, Insightful)

brunes69 (86786) | more than 7 years ago | (#16242969)

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.

Re:Whose backyard? (0)

Anonymous Coward | more than 7 years ago | (#16243079)

Fear of an accident with one doesn't mean you can't have fear of an accident with another. In fact, given that any time an in-service military aircraft crashes these days, it is always announced that it was mechanical failure and certainly not shot down by insurgents, it's a surprise that the nuke planes don't drop out of the sky on a regular basis.

Re:Whose backyard? (1)

Shakrai (717556) | more than 7 years ago | (#16243085)

You do know that SAC no longer exists, right? And even during the Cold War the days of 24 hour alerts and constantly having a portion of the fleet airborne stopped after the accident at Palomares Spain in 1966. After that SAC would send nuclear armed planes into the air only during alerts (i.e: Yom Kipper War).

In fact according to treaty and announcements by both sides the only forces that are currently deployed with nuclear weapons are SSBNs -- the Ohio Class SSBNs [wikipedia.org] and the various types of Russian "boomers". Granted, we also retain ICBMs, but I don't know if you call a fixed missile "deployed".

In any case we don't deploy bombers with nuclear weapons as a matter of course these days. And we haven't in awhile.

Re:Whose backyard? (1)

d3ac0n (715594) | more than 7 years ago | (#16243591)

Erm.. That would be the Yom Kippur war. Kippers are little fish (http://en.wikipedia.org/wiki/Kippers). Yom Kippur is a Jewish Holiday (http://en.wikipedia.org/wiki/Yom_Kippur).

/spelling nazi

As far as the rest of your post, you hit the nail on the head. Well said.

Re:Whose backyard? (1)

the_humeister (922869) | more than 7 years ago | (#16243735)

Humans are not very good at assessing risk. Most people will tell you that it's safer to drive than fly. However, statistically, you're more likely to die in a car accident than in an airplane.

Why launch it from Florida? (1)

Opportunist (166417) | more than 7 years ago | (#16242977)

I'm quite sure other launch facilities are quite as capable of getting the payload off the ground. I'm quite sure Russia wouldn't mind getting that baby into the air, without asking what's on board.

And cheaper too.

Re:Why launch it from Florida? (1)

steveo777 (183629) | more than 7 years ago | (#16243557)

IIRC, they are using the earth's rotation for momentum during the launch. The closer to the equator, the more momentum they've already got. It's a lot easier then launching something into orbit, then re-boosting it to Mars, or even to a simple geosyncronis orbit (or however you spell that). So, basically Florida is the best bet since Hawaii is so small and it would be more than impracticle to ship equipment there.

I'm not so sure about that. (1)

Slithe (894946) | more than 7 years ago | (#16243607)

The reason NASA launches rockets from Florida is because rockets launched near the equator travelling east gain an ENORMOUS speed boost from the Earth's rotation. Also, if the rocket breaks up, it will break up over water. The Soviet Union is a tad farther north than Florida, so the rocket would require more fuel. Rockets have traditionally been a very NIH enterprise, so countries are relunctant to depend on others for their orbital needs.

They're Not a Good Idea (2, Insightful)

turgid (580780) | more than 7 years ago | (#16243005)

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:They're Not a Good Idea (1)

gevmage (213603) | more than 7 years ago | (#16243249)

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'd guess (based on comments by the head of the current rover project and stuff I've read) that the current rovers are at the large end of the design envelope for solar powered rovers. Larger vehicle, larger panels and batteries...but that means heavier chassis, more weight to move, heavier motors to move it. Eventually you get to the point all the weight is spent supporting other weight. (Besides, on a vehicle like that, the critical parameter is area of solar arrays which drives continuous power budget; batteries let you get through the night, but they don't help with overall power budget.)

The plutonium powered rover is probably taking the design in another direction. It gives a larger power budget with no solar panels, which means that useful percentage of the load is much higher. You can spend weight carrying instruments, instead of solar panels to power them.

RTGs are proven safe. (3, Informative)

AWeishaupt (917501) | more than 7 years ago | (#16243049)

Scores, if not hundreds, of RTGs have been used in space exploration, going back to the '60s. There have only ever been three - iirc - incidents where the RTG's have been breached, resulting in detectable radioactive release.

Despite always having been controversial, RTGs have been proven safe.

Even if you run the space probe from solar cells, you cannot have analytical instruments such as Alpha particle X-ray spectrometers and Mossbauer spectrometers without radioactive sources.

Are 1:420 odds of an accident that bad? (1)

fantomas (94850) | more than 7 years ago | (#16243091)

I guess it depends on whether you're going to launch 420 of them, and what an "accident" means :-)

A chunk of metal falling into the sea probably isn't too worrying, but a nuclear device exploding and showering particles over a city, mmm, slightly more problematic...

Actual level of danger is not relevant (0)

Anonymous Coward | more than 7 years ago | (#16243115)

Firstly, it's a matter of cost/benefit - will a nuclear power source on board the rovers be that much more effective? Would it add weight? Would the benefits of a higher speed (I assume) be worth the risk of hitting a rock and denting an axle? This is something for the scientists to state their opinion of, I suspect they do think it would be a large improvement or they wouldn't have asked for it

Secondly, and more importantly - that container need to withstand falling into the sun. Regardless of whether the dust from an explosion would be indistinguishable from background radiation and no more toxic than eating earth, you know conspiracy theorists would seize on it globally with calls of 'global radiation poisoning of Mother Earth' - and lots of people would listen with at least one ear. Times the next hundred years.

How could it be dangerous? (1)

Bromskloss (750445) | more than 7 years ago | (#16243159)

Suppose ordinary reactors are used (not these RTGs). What would be the problem? I guess they aren't active during launch or even transit, so what could happen is the breakdown on the surface of Mars. A small one at that. Isn't that enough safety distance? ;-) Even if we go there soon, does it really matter?

Re:How could it be dangerous? (1)

tenco (773732) | more than 7 years ago | (#16243303)

If the rocket had a malfunction within the earth's gravity field, this reactor will surely come back to earth, exploding above our heads on reentry. This would IMHO scatter the amount of radioactive material included in the rocket over a more or less huge area.

Re:How could it be dangerous? (1)

d3ac0n (715594) | more than 7 years ago | (#16243653)

If you read above, you would see that THIS HAS ALREADY HAPPENED. One of Nasa's rockets exploded mid-flight. The RTG survived the explosion, was recovered INTACT from the ocean floor and RE-USED due to being largely undamaged. This was a decade or two ago, when the designs weren't as good as they are today. The situation you described is so unlikely as to be laughable. Stop wallowing in ignorance, READ AND LEARN.

Re:How could it be dangerous? (1)

amliebsch (724858) | more than 7 years ago | (#16243457)

Suppose ordinary reactors are used (not these RTGs). What would be the problem?

I think the chief problem is that traditional steam reactors are much more complex and that nobody to my knowledge has ever designed a steam reactor that small. It also seems much more prone to failure. One tiny coolant leak, for example, or a steam loop leak, and you're screwed.

Misunderstood (1)

Devern (969297) | more than 7 years ago | (#16243169)

*sigh* People misunderstand Nuclear devices... Nuclear Power Systems are 100% safe. Well, I guess maybe I should say that Canadian made CANDU Nuclear Reactors are 100% safe. See, uranium needs something to react in, a cooling substance if you will. In the CANDU rector H2O (except that it's an isotope of hydrogen), Heavy Water (Deuterium) is used. I know it seems a bit Star Trek, but that's what it's called. The Heavy Water has to be almost 100% pure for the reactor to function. If NASA uses CANDU technology, there will be no problems. If the reactor breaks, the Heavy Water will be contaminated and the reaction will cease. Another thing thing, reactors do not cause Nuclear Winters. A Nuclear Meltdown does NOT mean explosion. Nuclear Missiles are COMPLETELY different than Nuclear Reactors. GOOGLE IT! CANDU Reactor

Re:Misunderstood (1)

tsjaikdus (940791) | more than 7 years ago | (#16243555)

Article head: "Next Mars rover will carry plutonium" As anyone will readily understand it is the higly toxic and cancerous plutonium that's the problem. Exploding mini reactors in the sky are ofcourse of no concern at all as far as the mechanical impact is concerned.

Re:Misunderstood (1)

Lurker2288 (995635) | more than 7 years ago | (#16244243)

Plutonium isn't really that toxic. Carcinogenic, sure, but in the traditional sense of 'toxicity, plutonium isn't much worse than lead. I forget his name, but one of the chemist in the Manhattan project got sprayed in the mouth with plutonium oxide and swallowed some. A little mouth-rinsing and stomach pumping later and he was fine--he lived long enough to give an interview on the project in 1998. He said that for the next several years periodic checks of his urine were still finding trace amounts of plutonium.

Re:Misunderstood (1)

crerwin (971247) | more than 7 years ago | (#16243659)

Yes, but not even Canada would be able to fit a reactor on a mars probe. RTGs are not reactors.

Just don't use the Earth for a gravity assist (1)

amorsen (7485) | more than 7 years ago | (#16243261)

I have no problem with RTG's. It has been conclusively shown that RTG's are safe even when launch fails. What hasn't been shown is what happens when a RTG impacts Earth at 10km/s or more, as would be the case in a gravity assist gone wrong.

Where do I get a house on Mars? (1)

jimstapleton (999106) | more than 7 years ago | (#16243265)

I mean, according to the article, lots of other RTGs have been launched without complaint, so it's not the launch site that's the problem.

NIMBY must be protecting the people with houses on Mars, that's the only logical explination (`sarcasmd --on` and we know NIMBY is logical, `sarcasmd --off`).

So, where do I get my Martian house!?

Necessary (1)

dupper (470576) | more than 7 years ago | (#16243787)

A good idea? Are they even necessary?! As we've been so excitingly reminded, today, two solar-powered rovers are at almost %1000 of their predicted operational lifetime, an utter engineering miracle. But the fact that this is the most weight we can send up without blowing earths' budget, Contact-style, suggests that there's no way we can put enough machinery up there to require that kind of energy.

Re:Necessary (1)

dupper (470576) | more than 7 years ago | (#16243831)

The biggest limitation of our space program, and, with it, our species' current potenatial access to space, is not how we power disposable rovers on another planet: our biggest limitation is the incredible resource expense of having nothing better chemical rockets. Or maybe I've been reading too much Asimov.

I want nuke powered cars! (1)

kabocox (199019) | more than 7 years ago | (#16243975)

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.

You know I'm sick and tired of driving around in oil powered vehicles. We should have nuke powered vehicles that only need filling once when manufactured and they last for the life of the vehicle. We'll never get it though because the anti-nuke lobby would be absolutely horrified at the thought of any nuke powered vehicle accident. The oil energy companies really shouldn't have to worry because we still need vast quantities of oil for our industrial society. In some sense, we've been "wasting" oil by burning to get around. There are tons of products that we make out of oil and that's not going to change if we switch from an oil fueled vehicles.

It says both in the article (1)

zogger (617870) | more than 7 years ago | (#16244015)

Both is a possibility, solar and the RTG. That's the best idea, redundant power supplies, a hybrid system. Much better to have more than adequate power it seems. Both methods are continually undergoing improvements as well,and after all it was the space program that really pushed the development of solar PV and we have had significant breakthroughs there even since the mars rovers currently working were launched.
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