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NASA Revives Plan to Put Nuclear Reactors on Mars

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Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#101

Post by Retric »

SEJeff wrote: post #95
Cumulonimbus wrote: post #85

Before we can consider seeding terrestrial stations on Mars, we should consider seeding a communications net around Mars. Once we have a half dozen satellites circling Mars, we can start stable comms from the surface to orbit to Earth. It may take 10-20 minutes (for a signal to be received), but the communication is the essential piece here. I'd also consider putting satellites in Earth and Mars lagrange L3, L4, and…

Pretty sure this reason in specific is why SpaceX accepted the 1 billion USD investment from Google Ventures for their satellite internet constellation project in Seattle. If Musk's endgame plan is a serious Mars colony, there needs to be both location and communication over the entire planet (of mars). There also needs to be bidirectional communication with Earth. An orbiting constellation makes sense to do this. ht…

The important part of mars colonization is being able to produce 100% of all needed goods (from food to CPU's) on the surface of mars, not covering the planet with people. Really 2-3 redundant geosynchronous satellites on mars should be plenty for a very long time.

Musk wants satellite internet as it lets Space X lower cost per launch by launching a lot of satellites.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#102

Post by rocky1138 »

legulere wrote: post #14

How will they convert heat into electricity? On earth you have plenty of water as a good medium for the heat and a thick atmosphere that serves as the heatsink. On mars you have neither.

https://en.m.wikipedia.org/wiki/Thermophotovoltaic

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#103

Post by Finnucane »

Will no one think of the children?! I mean, specifically, NASA's hostage martian slave children. Will the reactors be made half-scale, so they can be operated by the children's tiny hands? Will the children be forced to labor in the plutonium mines, far from OSHA oversight?

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#104

Post by baybal2 »

xorfish wrote: post #45
baybal2 wrote: post #37

Earlier quoted context omitted.

>Enriched uranium has a very high energy density. 20% enriched Uranium would countain 16TJ/kg. I did not count in burnup ratio. A simple thermal neutron reactor can only use <1% of fission energy in its fuel.

I'm pretty sure that conventional reactor split around as much fuel as the U-235 content. For conventional reactors it is around 3% and you are left with around 3% fission products. Natural uranium has around 0.7% U-235. But I0m pretty sure that you would enrich the uranium befor you send it to mars. The 16TJ/kg is for enriched uranium with 20% U-235 content. Anyway, energy density of nuclear fuel is extremly high. E…

Yes, it will be higher by few times for highly enriched uranium (90%+) or plutonium 239 (because of higher cross-section)

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#105

Post by Robotbeat »

Cumulonimbus wrote: post #85

Before we can consider seeding terrestrial stations on Mars, we should consider seeding a communications net around Mars. Once we have a half dozen satellites circling Mars, we can start stable comms from the surface to orbit to Earth. It may take 10-20 minutes (for a signal to be received), but the communication is the essential piece here. I'd also consider putting satellites in Earth and Mars lagrange L3, L4, and…

> Before we can consider seeding terrestrial stations on Mars, we should consider seeding a communications net around Mars.

We already do.

> Once we have a half dozen satellites circling Mars...

We already have half a dozen active satellites circling Mars:

https://en.wikipedia.org/wiki/2001_Mars_Odyssey

https://en.wikipedia.org/wiki/Mars_Express

https://en.wikipedia.org/wiki/Mars_Reconnaissance_Orbiter

https://en.wikipedia.org/wiki/Mars_Orbiter_Mission

https://en.wikipedia.org/wiki/MAVEN

https://en.wikipedia.org/wiki/ExoMars_Trace_Gas_Orbiter

All of these (including the European satellites) except the Indian MOM orbiter contain a communications relay radio (for relaying from Mars surface to Earth) provided by NASA: https://en.wikipedia.org/wiki/Electra_(radio)

We actually have quite a bit of infrastructure built up around Mars already. All these spacecraft are referred to as the "Mars fleet" (which is frakking awesome...).

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#106

Post by tajen »

Cumulonimbus wrote: post #85

Before we can consider seeding terrestrial stations on Mars, we should consider seeding a communications net around Mars. Once we have a half dozen satellites circling Mars, we can start stable comms from the surface to orbit to Earth. It may take 10-20 minutes (for a signal to be received), but the communication is the essential piece here. I'd also consider putting satellites in Earth and Mars lagrange L3, L4, and…

> I'd also consider satellutes in Earth/Mars lagrange L3, L4 and L5 (...) solar internet.

If there isn't already a patent on space strategies, it may be a good idea to create a patent agency. The first intergalactic agency.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#107

Post by tajen »

MichaelMoser123 wrote: post #90
sp0ck wrote: post #2

It's about time. Engineering decisions shouldn't be made based of irrational fears of general population. If nuclear power plant is best option for space mission we should use it.

Irrational fears? What are the chances of the rocket launcher blowing up with the reactor? How would we compute the fallout range as a function of altitude of the blast?

Please at least tape it! A nuclear reactor mounted on a gigantic explosive sounds like a stupid idea once you count this risk, but even if we did it, would it be among the most stupid things we did?

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#108

Post by striking »

thehardsphere wrote: post #87
mikejb wrote: post #58

Earlier quoted context omitted.

I fully agree that newer designs are safer, but ignoring the human factor in the equation is IMO not very reasonable. Without the human factor, driving a car is very safe. That argument is valid, but it doesn't reflect reality.

There are some "human factor" problems that engineers cannot and should not be expected to resolve. I mean, how can someone design a communist-proof nuclear reactor?

Make them pay to get in?

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#109

Post by monocasa »

Retric wrote: post #101
SEJeff wrote: post #95

Earlier quoted context omitted.

Pretty sure this reason in specific is why SpaceX accepted the 1 billion USD investment from Google Ventures for their satellite internet constellation project in Seattle. If Musk's endgame plan is a serious Mars colony, there needs to be both location and communication over the entire planet (of mars). There also needs to be bidirectional communication with Earth. An orbiting constellation makes sense to do this. ht…

The important part of mars colonization is being able to produce 100% of all needed goods (from food to CPU's) on the surface of mars, not covering the planet with people. Really 2-3 redundant geosynchronous satellites on mars should be plenty for a very long time. Musk wants satellite internet as it lets Space X lower cost per launch by launching a lot of satellites.

> on the surface of mars

Why? Wouldn't it be easier to bootstrap by mining asteroids, and manufacturing in micro gravity, then dropping nearly finished goods onto the planet? That'd also allow you to use the same bootstrapping infrastructure for several surface sites.

Re: NASA Revives Plan to Put Nuclear Reactors on Mars

#110

Post by Retric »

monocasa wrote: post #109
Retric wrote: post #101

Earlier quoted context omitted.

The important part of mars colonization is being able to produce 100% of all needed goods (from food to CPU's) on the surface of mars, not covering the planet with people. Really 2-3 redundant geosynchronous satellites on mars should be plenty for a very long time. Musk wants satellite internet as it lets Space X lower cost per launch by launching a lot of satellites.

> on the surface of mars Why? Wouldn't it be easier to bootstrap by mining asteroids, and manufacturing in micro gravity, then dropping nearly finished goods onto the planet? That'd also allow you to use the same bootstrapping infrastructure for several surface sites.

Mining asteroids has a ton of issues even beyond the obvious cost and R&D problems. They are generally far from the sun so solar power is significantly less useful. You need to move a lot of bulk material which means heavy Delta V problems. Micro gravity means you can't have humans in the area for long without giant structures. Finally, economically resources are just not that scarce.

The delta V issues are more reasonable when you want stuff to end up in space. But, that's not an issue for a Mars colony. As to mining Mars's moon's they don't really have a lot of useful material that is not on Mars in the first place.

PS: Space X's slightly lower the cost to orbit actually makes Asteroid mining even less viable.

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