Mars and nuclear power

[scottb50]

And was it worth it? One mistake could end it all, and they didn't worry about that then anyway. <div class="Discussion_UserSignature"> </div>

 

[skyone]

Does anyone have the numbers? Might help to frame the discussion.

 

[scottb50]

Vegas could probably come up with one. Might be a good money maker now that I think about it, forget I said anything, just send your checks to..... <div class="Discussion_UserSignature"> </div>

 

[ve7rkt]

<font color="yellow">please name one western space use of radioactive material that has resulted in any release of radioactivity on earth.</font><br /><br />Well, let's see here... Transit 5-BN-3, with the SNAP-9A RTG aboard. "The RTG burned up on reentry as designed with the plutonium dispersed in the upper atmosphere." (here). NASA's Cassini documentation (here) estimates that SNAP 9A accounts for almost twice as much Plutonium-238 in the wild as all the atmospheric atomic bomb tests combined.<br /><br />I'm in favour of nuclear power on the ground. I'm in favour of nuclear power out beyond LEO. I have big problems with the systens for moving nuclear power sources in between. Maybe there's a uranium-rich asteroid out there somewhere...

 

[peterweg]

Why do the Nazi's assume that the being left wing is always anti-nuclear? The dangers of radiation are a scientific fact and not affected by political leaning. Liberal or Nazi, radiation can be a health hazard. Nuclear fusion has advantages and benefits that make it worthwhile.

 

[mattblack]

Believe me: I WANT 'them' to pour more money into fusion research!!<br /><br />Also: Modern left-wing is not your Grandpa's left wing liberal. The liberals of the fifties and sixties have got NOTHING on today's, nor do SOME of the conservatives of yesteryear have anything on todays 'neocons'. <div class="Discussion_UserSignature"> <p> </p><p>One Percent of Federal Funding For Space: America <strong><em><u>CAN</u></em></strong> Afford it!!  LEO is a <strong><em>Prison</em></strong> -- It's time for a <em><strong>JAILBREAK</strong></em>!!</p> </div>

 

[mlorrey]

from the page ve7rkt quoted: "The RTG design was changed shortly after that to accommodate intact reentry. The next accident was with the Nimbus-B-1 that was aborted shortly after launch by a range safety destruct. The RTG was recovered, with no release of plutonium, and the heat sources were reused in later missions. The Apollo 13 spacecraft carried an RTG to be used on the moon to power a seismic station. The Apollo 13 mission was aborted and the spacecraft returned to Earth. The RTG was attached to the lunar module that broke up on reentry. The RTG heat source reentered the Earth atmosphere intact, with no release of plutonium, and currently is located deep in the Tonga trench in the Pacific Ocean. Extensive testing of RTGs in sea water has been conducted, and there will be no release of plutonium over time from this unit. "

 

[j05h]

>Does anyone have the numbers? Might help to frame the discussion.<br /><br />I don't have numbers handy, but a couple of stop-smoking billboards would counteract the worst-case scenario for RTG release. Worst-case being to take the plutonium, physically grind it and force people to directly inhale it. Scott50's suggestion of the number coming up (statistical catastrophe) has already happened, as mentioned. No one died, the RTGs were reused. The environment of an exploding rocket is simply not as intense as some suggest. RTGs and future nuclear fuel will be fully protected inside iridium-carbon casings. The amount of radioactive material, even for a manned nuclear rocket, is trivial compared to what got blown up in atmospheric test explosions, or the amount released yearly from coal-burning power plants. If you are truly concerned about added radioactivity in the environment/you, there are MUCH bigger emmiters, right next door to you. <br /><br />You have a lot more to worry about from the 18-wheeler hauling gasoline that you pass on the highway. Or the truely toxic fuels that some rockets use, etc. <br /><br />The only reason this is any kind of issue is that "nuclear" is involved. If we called it "refined daisy power" or similar, it might make it more acceptable. Do you stay up at night worrying about the powerplant down the street or the Americium in your smoke alarm?<br /><br />One actual tech/policy question, esp. for the anti-spacenuke crowd: Would encapsulated fuel, as in a pebble-bed reactor, make you more comfortable for launching space reactors? The fuel would be sealed in graphite spheres, then inside a roughly typical RTG casing made of iridium and carbon fiber. There would be almost zero chance of radioactive release into Earth's environment. Would this be acceptable?<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[scottb50]

I think what is being dicussed is not RTG's. There is quite a bit of difference between RTG's and full scale reactors. I would think a container to provide the same level of safety would have to be pretty massive. <div class="Discussion_UserSignature"> </div>

 

[spacester]

Yes, the discussion shifted to RTGs, but what needs to be discussed is the deployment of Fission Reactors.<br /><br />I think it is very unfortunate that anyone here is called ‘anti-spacenuke.’ It appears to me that everyone here wants nuclear power in space and understands how important it is to the overall success of space development. Seeking a specific solution that is a political winner is not anti-nuke! In fact it’s arguably more pro-nuke than simply calling the opposition idiots and trying to ignore them.<br /><br />Not that I think there is the massive opposition to nuclear power in general that there once was. I think Americans in particular are starting to come to grips with the necessity of nuclear reactors.<br /><br />But launching a fully fueled nuclear reactor? Hey, that is not gonna be an easy thing to sell. Can you launch the reactor and its fuel on the same vehicle and achieve the same level of protection against release as with RTGs? That’s the question: do you need to launch only unfueled reactors?<br /><br />If the fuel needs to be launched separately, then I propose the lunar surface as the first fuel depot location. One launch could provide the fuel canisters for several reactors.<br /> <div class="Discussion_UserSignature"> </div>

 

[scottb50]

It appears to me that everyone here wants nuclear power in space.....<br /><br />I don't see the present need, especially considering the current state of both Nuclear and rocket technology. <br /><br />I do think current solar technology exists that can more than meet the needs, if nothing else for the initial phases. I seriously doubt a reactor could be designed, built and launched in quite some time, solar could start today.<br /><br />I would think assembling large scale solar arrays in orbit would be fairly straight forward and the weight to launch would be managable even by todays launchers, though it would not be cost effective without re-usable launchers. <div class="Discussion_UserSignature"> </div>

 

[krrr]

Myself I am not totally opposed to nuclear energy in space but I'm a fan of solar energy because of its sheer elegance.<br /><br />Let's look at some scenarios within the inner solar system:<br /><ul type="square"><li>In-space cargo transport: Solar. SEP tugs are the rational way of transporting cargo. NEP is inferior to SEP below ~1 Megawatt.<li>Human transport: Chemical propulsion plus solar power generation. Nuclear-thermal is woefully inefficient (yes, one could go to Mars in 4 to 5 months instead of 6 to 8, but 60% of a long time is still a long time).<li>Lunar flag & footprint mission: Solar; even batteries or fuel cells would be sufficient.<li>Small lunar outpost: Solar is OK, the long lunar nights would need buffering with fuel cells or similar. Or maybe place the outpost in the "eternal light" areas near the poles. <li>Lunar industrial outpost (with ISRU): Again, if the "eternal light" option proves feasible, no problem with solar. Otherwise, production would have to be shut down during lunar nights, or a string of solar power plants would have to be built around the Moon's circumference.<li>Martian outpost (excluding F&F here): The case for nuclear power. Solar would not be impossible, but very fragile in sight of dust storms.<br /></li></li></li></li></li></li></ul>

 

[scottb50]

If you use solar power exclusively to provide Hydrogen and Oxygen and supply system electrical power using fuel cells it becomes a matter of how much storage is required. Cryogenics would be needed on Mars and the moon, in LEO and open Space gasses would be used, simplifying operation considerably. <br /><br />Other than loses in the system the same water could be used over and over again eliminating large scale needs for replenishment. Using LH2/O2 as propellant would provide additional water when needed and using liquification equipment in orbit would allow refueling capabilities. <div class="Discussion_UserSignature"> </div>

 

[josh_simonson]

The big difference between plutonium RTGs and uranium reactors is that plutonium does not exist in nature in significant quantities, which makes any release of plutonium result in an incredible increase in plutonium abundance, which enviros can get in a huff about. Uranium however is pretty common, there's probably a gram of it in the granite countertop that a greenie cuts their tofu on. <br /><br />Being that uranium is common, it'd take a tremendous release of the stuff to measureably affect it's abundance as a 'pollutant'. Fuel grade uranium is also far more difficult to build a bomb from than plutonium, which is another huge boost in safety (from a security standpoint) over plutonium. Much of the rhetoric that affected cassini will be more difficult to argue with a uranium based reactor than the plutonium ones.

 

[scottb50]

I think the improvements in power using Plutonium as well as breeder reactors makes more sense than the simplification Uranium offers. I really doubt material taken into Space would be diverted for bombs and strict controls could be put in place. For that matter you could ship Uranium concentrate into orbit and refine it there, centifuges and other equipment needed work just fine in Space.<br /><br />For the destinations we can reasonably consider for manned missions, until vast improvements in propullsion occur, solar would work just fine. <div class="Discussion_UserSignature"> </div>

 

[mlorrey]

As I recall, the risk in the event of a Cassini flyby failure resulting in RTG reentry in which the RTG was for some reason ruptured, against all design and real world experience, would have meant that 12 more people worldwide would have died of lung cancer, in total. Gimme a break, you can do more by convincing people to stop smoking.<br /><br />With respect to nuke reactor fuel, each fuel rod would have so little fuel in it that it would not pose a serious risk of contamination, and would be surrounded by graphite casing. That is in conventional reactor design. <br /><br />In the event of a plasma style reactor, the uranium plasma would be stored in impact resistant cylinders much like the RTG capsules.<br /><br />Generally the people most worried about space nuke reactors are the people who know the least about them.

 

[john_316]

I would also hope that some people who are against nuclear power take into account that cosmic and solar radiation are also as deadly if not more deadly than a shielded reactor for power. <br /><br />Even though NGP requires shielding on both the ship and the crew it would be more economical to build a gas core or solid core nuclear rocket for the Mars Transition Vehicle.<br /><br />It would provide a way less than a 120 day transit time to Mars and another 120 less in.<br /><br />Why are people so afraid of nuclear power. The US has 83 vessels at this very moment fueled with uranium nuclear reactors and so does Russia, China, United Kingdom, France, and anyone else who has a SSBN or SSN.<br /><br />We also have not had a major accident in the USA since 1981. Thats is due to the safety concerns we put into place with our reactors. When I referr to the lefties here I actually mean the anti-nuke crowd (though our mostly left leaning). Yes! I know there are plenty of Kerry-Gore supporters who would like to see space nuke power. <br /><br />I correct myself to say those who dont want to see space muddied with nuclear material are the people I am bashing, critizing, and smacking around. <br /><br />Ooooops.... I forgot space is just as deadly as working at TMI. I think TMI is alot safer today dont you think? Safer than space I would say.<br /><br />So why not build Nuclear Powered Space Craft for Travel and as temorary power facilities until solar power effeciency increases. <br /><br />Perhaps beaming power to Mars can be an idea. If your into beaming power and all....<br /><br /><img src="/images/icons/smile.gif" /><br /><br /><br />

 

[mlorrey]

Nobody ever died at or as a result of TMI.

 

[gunsandrockets]

<br />"I don't see the present need, especially considering the current state of both Nuclear and rocket technology."<br /><br />NASA has identified nuclear thermal propulsion and nuclear surface power as key technologies for manned exploration of Mars.<br /> <br /><br />"I do think current solar technology exists that can more than meet the needs, if nothing else for the initial phases. I seriously doubt a reactor could be designed, built and launched in quite some time, solar could start today."<br /><br />That ignores the fact the multiple nuclear power reactors have already been designed, built and successfully flown in the past.<br /><br /><br />"I would think assembling large scale solar arrays in orbit would be fairly straight forward and the weight to launch would be managable even by todays launchers, though it would not be cost effective without re-usable launchers."<br /><br />The nightmarish costs of assembling the ISS should give an indication of just how expensive solar power is when scaled up to ISS intended power levels of 100 kWe. <br /><br />

 

[scottb50]

NASA has identified nuclear thermal propulsion and nuclear surface power as key technologies for manned exploration of Mars.....<br /><br />Your right, why question that? What was I thinking!<br /><br />That ignores the fact the multiple nuclear power reactors have already been designed, built and successfully flown in the past....<br /><br />I don't care, they could be as safe as could be, they just don't meet the need. Luckily none of those flown have had serious problems, at least that we know about.<br /><br />The nightmarish costs of assembling the ISS should give an indication of just how expensive solar power is when scaled up to ISS intended power levels of 100 kWe.....<br /><br />I don't remember serious problems adding Modules or external fixtures to ISS. When were there serious problems with solar power?<br /> <div class="Discussion_UserSignature"> </div>

 

[gunsandrockets]

NASA has identified nuclear thermal propulsion and nuclear surface power as key technologies for manned exploration of Mars.<br /><br />"Myself I am not totally opposed to nuclear energy in space but I'm a fan of solar energy because of its sheer elegance."<br /><br />The small SEP unmanned space probes are the wave of the future, and a perfect application for solar electric power. The solar powered CEV is another sensible application of solar power. <br /><br />"Let's look at some scenarios within the inner solar system:" <br /><br />"* In-space cargo transport: Solar. SEP tugs are the rational way of transporting cargo. NEP is inferior to SEP below ~1 Megawatt."<br /><br />?One mWe? Supporting data with links please. The information I have found contradicts the claim of solar-electric-power superiority. I refer you to some of the links I provided at the very beginning of this thread about solar and nuclear power. In particular the information about the HOMER-15 small nuclear power reactor, which for a total mass of 212 kg (including Brayton power generator) provides 3 kWe. When the scale of energy starts to climb into the tens of kilowatts range nuclear just completly runs away from solar-power in the ratio of power/mass. The 100 kWe power SAFE-400 reactor masses less than one tonne.<br /><br /><br /> <br />"* Human transport: Chemical propulsion plus solar power generation. Nuclear-thermal is woefully inefficient (yes, one could go to Mars in 4 to 5 months instead of 6 to 8, but 60% of a long time is still a long time)."<br /><br />Woefully inefficient? How do you get that?<br /><br />For typical trip times of 6 months, the only way chemical propulsion can match the lower mass requirements of NTR is a Zubrin style Mars Direct architecture and the manufacture of chemical propellent on Mars for the trip home. And even that chemical architecture requires nuclear power on the surface of Mars to manufacture the propellent.<br /> <br />"* Lunar flag & footprint mission: So

 

[gunsandrockets]

<br />[The nightmarish costs of assembling the ISS should give an indication of just how expensive solar power is when scaled up to ISS intended power levels of 100 kWe.....] <br /><br />"I don't remember serious problems adding Modules or external fixtures to ISS. When were there serious problems with solar power?"<br /><br />Do you see what a non-sequitor your response is? How you ignore my statement about the high cost of solar? As in money costs? You aren't listening, and I have no desire to degenerate into a flame war. <br /><br />Fine. I get that you oppose nuclear power for space applications. I have heard your rhetoric and your claims. <br /><br />Now then do you have any evidence to support your rhetoric? With links? I have provided plenty of linked evidence to support the superiority of nuclear power.

 

[scottb50]

I don't ignore your statements about high costs of solar, I just wonder why we have to supply a power source when we have a free one. A reactor provides the energy and you convert it to electricity, the sun provides the energy and you capture it, which requires the least hardware? Why do I need links? It seems pretty simple to me. <div class="Discussion_UserSignature"> </div>

 

[lampblack]

Seems that one key question regarding solar cells vs. nuclear power on Mars would relate to the use of batteries.<br /><br />Solar cells (of course) require batteries -- to tide folks through the dark Martian night. And of course, a reactor would be on all the time, day or night.<br /><br />One wonders how much it would cost in terms of tonnage to haul the appropriate batteries all the way to Mars -- and how long they'd be expected to last.<br /><br />I am far from expert on these matters. But it did strike me as surprising that batteries haven't been mentioned before now.<br /> <div class="Discussion_UserSignature"> <font color="#0000ff"><strong>Just tell the truth and let the chips fall...</strong></font> </div>

 

[najab]

<blockquote><font class="small">In reply to:</font><hr /><p>A reactor provides the energy and you convert it to electricity, the sun provides the energy and you capture it, which requires the least hardware?<p><hr /></p></p></blockquote>Nuclear, actually, once you require more than a few kilowatts.