Are Nuclear Powered Mars Rovers a Good Idea? 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?"
Yes (Score:5, Funny)
For now.
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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?
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Good old moon base alpha.
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http://www.geocentricity.com/geocentricity/index.
The earth is the center of the universe!!!!
Unnecessary (Score:5, Funny)
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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 (Score:4, Funny)
Sell them to terrorists, of course. "Nobody move, he has a Sony battery! Now calm down, son..."
Re:Unnecessary (Score:4, Funny)
Dump them into the ocean. It's pretty big.
Besides, out of sight, out of mind.
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We should use them in a reconstituted Orion project, where instead of lobbing a nuke out the back, let a battery off against the presser plate!
Hm, maybe that's why they kept the name!
(BTW, I hope no one thinks I'm being serious. If you do, you got problems...)
Cheap Return Mission (for NASA) (Score:2)
Yes, of course (Score:5, Insightful)
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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.
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RTGs are not dangerous (Score:5, Insightful)
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
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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
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[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
Re:RTGs are not dangerous (Score:5, Informative)
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.
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EXT. VILLA PATIO
The beam strikes the president like the finger of god. He vaporizes. The waiter turns back with the asked-for sugar to find a smoking hole where the President once stood.
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It was an old spy satellite. Those things were/are in highly ellipical polar orbits which took them relatively close to the ground so solar panels to drive the sensing gear were out of the question due to being in the upper atmosphere at high velocity at times.
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Meanwhile, deep in the ocean, a subacquean race of sentient beings is slowly unravelling the mysteries of nuclear power. In a few centuries they will emerge from the waters in their might! Beweaponed with terrifying RTG powered... mmm... cuttlefish?
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I'm hoping the Kosmos satellites used something a bit different in scale because the Canadians were paticularly pissed off about relatively large chunks of radioactive material spread around a lake and an expensive cleanup. The story in the Reader's Digest written about a year afterwards implied that some material was found using aircraft with detection gear - which would mean a pretty hot radioacti
Not in my back yard! (Score:3, Interesting)
Frankly it is a few nut jobs that make good news stories. There are severa
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Except that we're talking about a newer, bigger rover. So it's not in this case, it's in some other case that you aren't thinking or talking about - because all other things are not equal
Check the RTG packaging. (Score:5, Interesting)
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The Bottom Line: The activists should have been out picketing their local cement supplier/home buil
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http://www.teachersdomain.org/6-8/sci/phys/energy
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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
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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 i
Russian Mars Train (Score:5, Interesting)
Make sense but the strategy could be wrong (Score:4, Interesting)
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? (Score:3, Interesting)
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It happened, and it worked. Go look up the the Nimbus mission that was destroyed by a range-safety-officer.
Re:Result of accident? (Score:5, Informative)
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.
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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.
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Depends on how fast the heat was dissipated out into space. If it dissipated fast enough, there would be little net gain. Isn't it CO2 (among others) that holds in the heat? Reduce the insulation and more heat goes out into space resulting in a cooler climate.
Re:Result of accident? (Score:5, Informative)
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.
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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.
New meme? (Score:2, Interesting)
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We all know nuclear powered furbies are a good idea.
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So it's a good idea, right?
wrong question (Score:3, Insightful)
Re:wrong question (Score:4, Informative)
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
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Hit the weight room solar power.
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Eventually, even if nothing else on the Mars Rovers failed, the solar panels would no longer produce enough energy to make the robots move...and that would be the end of the exploration part of the mission.
Scale of the Rover (Score:2)
'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 (Score:2)
It's the
More power might be able to mean more spare parts, though..
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Whose backyard? (Score:3, Insightful)
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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 "boom
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As far as the rest of your post, you hit the nail on the head. Well said.
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(Sorry - couldn't resist.)
--
I know what you're thinking, but I am not a nut-bag. -- Millroy the Magician
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Incorrect. Routine [airborne] carriage of nuclear weapons ceased in the 1960's after the Thule and Palomares accidents.
These RTGs have STEROIDS in them!!!!!!!11 (Score:2)
Why launch it from Florida? (Score:2)
And cheaper too.
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They're Not a Good Idea (Score:3, Insightful)
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.
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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
RTGs are proven safe. (Score:3, Informative)
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? (Score:2)
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...
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An RTG enclosure is designed to survive a launch vehicle failure (read: *KA-BOOM*) with no release of radioactive material.
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Why does "designed to survive" mean it absolutely will? You have to look at possible failures throughout the design, not just in the launch vehicle. So why not consider what happens if it explodes and showers particles over a city?
When it comes down to it, though, this isn't an H-bomb exploding over Orlando, it's a single release of radioactive material that some here are equating with the radon that 6% of amer
How could it be dangerous? (Score:2)
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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.
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Are they are good idea?! (Score:2)
Just don't use the Earth for a gravity assist (Score:2)
Where do I get a house on Mars? (Score:2)
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!?
Simple answer: yes (Score:2)
-1, Bloody Obvious?
I want nuke powered cars! (Score:2)
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 woul
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But on the other hand, the idea that a collision between two nuclear-powered cars equates to an implosion bomb would improve driver safety no end, so the road safety crowd will support it.
Use the bunny (Score:2)
The answer the "old" NASA would give.... (Score:3, Insightful)
If you long haired hippy freaks don't like it, tough.
Already There (Score:2)
http://marsrovers.jpl.nasa.gov/technology/is_sever e_environments.html [nasa.gov]
Uneducated nuts (Score:2)
Re:They'll be perfectly fine (Score:5, Funny)
Re:They'll be perfectly fine (Score:5, Informative)
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Does this guy know how to party, or what?
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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
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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.
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* 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
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Wikipedia says 1 in 15, I make that 6%. Close enough. Caveat lector
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Pu-238 is not usable in a chain reaction at all. Its major use is a heat source for RTG type generators. Pu239 is what you use in a nuclear reactor or a bomb. Pu-240 is ok for a reactor, but not ok for a bomb. Pu-240 emits neutrons spontanously, so in a bomb it will either slowly burn away the Pu-239 making it useless, or it will set off the bomb prematurely, but only with
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If it fell into the sun, it would be falling into what is effectively, a thurmonuclear reactor anyway - and we don't have the technology to withstand that!
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I said nothing about a bigger power source, duh! I simply corrected an obvious word error.
Stupid, stupid, stupid!
Or maybe you simply replied to the wrong post!
duh...
The anti-NIMBY (Score:4, Funny)
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Mars is being bombarded with far more radiation then what would be on a rover.