Wednesday, August 31, 2011
Destination: Moon or Asteroid?
Part I: Operational Considerations by Paul Spudis
excerpts
comment:
I do not favor a trip to an asteroid first. To the moon first, I say. Instead of flags and footprints, we should settle it. If this can't be done on the moon, where can it be done at all?
excerpts
- they do not have significant gravity fields of their own, so missions to them do not “land”
- Although there are several thousand NEOs, few of them are possible destinations for human missions.
- On a NEO mission, a broken system must be both fixable and fixed by the crew.
- Astronauts in low Earth orbit are largely protected from radiation because they orbit beneath the van Allen radiation belts, which protect life on the Earth. On the Moon, we can use regolith to shield crew but for now, such mass is not available to astronauts traveling in deep space.
- Is it worth it? [comment: asteroid trip] That will be the subject of my next post.
comment:
I do not favor a trip to an asteroid first. To the moon first, I say. Instead of flags and footprints, we should settle it. If this can't be done on the moon, where can it be done at all?
Thinking big
In previous posts, I discussed how to make a lunar colony self supporting. After all, it makes little sense to spend a lot of money just to subsidize an uneconomical activity. We do that pretty well already right here on the ground.
So, just exactly what can a lunar colony produce for the Earth?
It struck me that a big energy project could be built on the moon and beam the energy back to Earth. Yes, I've discussed this before. I ruled it out, now I am thinking it over again. It occurred to me that the basic infrastructure would enable additional infrastructure to be built, which could earn an income.
I think I ruled it out previously because energy is only worth about 40 bucks per megawatt hour, at wholesale rates. So, let's see. If a gigawatt plant running continuously, should be able to produce 40,000 dollars in income per hour. That's 350 million dollars of output per year. If it lasted 30 years, it would generate 10,512,000,000 ( 10.5 billion) in revenues. If one plant could be built thusly, it would need to be considerably less than this cost in order for it to be profitable.
A lunar water cracking facility was priced at 88 billion or so. It would not appear to be profitable, if the projects were comparable in complexity and cost. But, let me forge ahead anyway. Note: All of this is speculative, as I don't have the details of an actual design.
Could you build such a structure on the moon? It would be large, I would think. For such a project would require a large workforce and a considerable amount of material being put into position in order to bring this facility into being.
You would need to supply the fuel from the moon. You probably want to build it out of materials readily at hand on the lunar surface. This would require mining facilities. It would be a complex undertaking. Impossible? Perhaps.
Now, if you were to build some supporting infrastructure first, this may be a bit more feasible. I covered that in a previous post.
You do not need water for a LFTR. It is an inherently safe design and may not need much in the way of operational costs to run it.
How big would a LFTR design need to be? Hard to say. From the link above, it would take 1 ton of thorium per year to run it. That means 30 tons of thorium need to be mined and processed on the moon. Thirty tons sounds like a lot, but is only slightly less than twice what the lunar landers weighed on the launch pad during the Apollo era.
It would not require heavy shielding nor containment facilities, as it would not be under pressure. So, the construction should be simpler than with a uranium fueled reactor. If it would be possible to make it as simple as possible, it would help matters a lot. Don't know if it needs to be covered, because I don't know if the salts would evaporate in the lunar vacuum. If it does evaporate, then it will have to be fully enclosed. That would make it more complex.
It is an ambitious project, but if you are going to do something, why not think big and go all the way?
So, just exactly what can a lunar colony produce for the Earth?
It struck me that a big energy project could be built on the moon and beam the energy back to Earth. Yes, I've discussed this before. I ruled it out, now I am thinking it over again. It occurred to me that the basic infrastructure would enable additional infrastructure to be built, which could earn an income.
I think I ruled it out previously because energy is only worth about 40 bucks per megawatt hour, at wholesale rates. So, let's see. If a gigawatt plant running continuously, should be able to produce 40,000 dollars in income per hour. That's 350 million dollars of output per year. If it lasted 30 years, it would generate 10,512,000,000 ( 10.5 billion) in revenues. If one plant could be built thusly, it would need to be considerably less than this cost in order for it to be profitable.
A lunar water cracking facility was priced at 88 billion or so. It would not appear to be profitable, if the projects were comparable in complexity and cost. But, let me forge ahead anyway. Note: All of this is speculative, as I don't have the details of an actual design.
Could you build such a structure on the moon? It would be large, I would think. For such a project would require a large workforce and a considerable amount of material being put into position in order to bring this facility into being.
You would need to supply the fuel from the moon. You probably want to build it out of materials readily at hand on the lunar surface. This would require mining facilities. It would be a complex undertaking. Impossible? Perhaps.
Now, if you were to build some supporting infrastructure first, this may be a bit more feasible. I covered that in a previous post.
You do not need water for a LFTR. It is an inherently safe design and may not need much in the way of operational costs to run it.
How big would a LFTR design need to be? Hard to say. From the link above, it would take 1 ton of thorium per year to run it. That means 30 tons of thorium need to be mined and processed on the moon. Thirty tons sounds like a lot, but is only slightly less than twice what the lunar landers weighed on the launch pad during the Apollo era.
It would not require heavy shielding nor containment facilities, as it would not be under pressure. So, the construction should be simpler than with a uranium fueled reactor. If it would be possible to make it as simple as possible, it would help matters a lot. Don't know if it needs to be covered, because I don't know if the salts would evaporate in the lunar vacuum. If it does evaporate, then it will have to be fully enclosed. That would make it more complex.
It is an ambitious project, but if you are going to do something, why not think big and go all the way?
Tuesday, August 30, 2011
ISS at risk?
To lose the ISS after spending all that money would be a colossal failure. It just goes to show that you can't trust the government to always get it right, regardless of how much some true believers want to believe in it.
Would this work on a flying rocket?
The article on NextBigFuture is about using these for windmills, but could there be another application for them? It is stronger than carbon fiber.
In a comparison of reinforcing materials, the researchers found carbon nanotubes are lighter per unit of volume than carbon fiber and aluminum and had more than 5 times the tensile strength of carbon fiber and more than 60 times that of aluminum.
Just when I thought that the flying rocket idea was impractical.
'Suitcase' Nuclear Reactors to Power Mars Colonies
Discovery News
- "The reactor itself may be about 1 feet wide by 2 feet high, about the size of a carry-on suitcase. There are no cooling towers. A fission power system is a compact, reliable, safe system that may be critical to the establishment of outposts or habitats on other planets. Fission power technology can be applied on Earth's Moon, on Mars, or wherever NASA sees the need for continuous power."
- First Mars Astronauts May Grow Their Own Food
- fission reactors would be desirable because they deliver more energy. And although solar arrays will undoubtedly have a role to play, fission reactors will be the premier energy source for the immediate future.
- A fission power system on the Moon could generate 40 kilowatts or more of electric power, approximately the same amount of energy needed to power eight houses on Earth."
- the biggest hurdle facing space fission power won't be the viability of its technology, but the bad press nuclear power receives, on Earth and in space.
Space Tethers and Space Elevators, Revisited
Let us now return to the book by van Pelt
. From page 171
The cable would be deployed from L1 until it reaches the surface. From there, it would be anchored down and further strengthened so that it can carry heavier payloads. With a lifting capacity of only 200 kg, this would indicate a need for heavier payloads. It may take multiple cables for that purpose, if that is the idea. It doesn't appear that passengers will be able to use the Moonstalks. They may be very useful in delivering cargo cheaply and efficiently, however.
A couple of Moonstalks, on each of L1 and L2 Lagrange points, would simplify transit between the surface and into space.
In order to colonize the moon, there will need to be some economic reason for its existence. In other words, how do you make money from this enterprise? If income isn't feasible, then how might you save money?
One thing is clear: getting stuff from the lunar surface and back into low Earth orbit should be cheaper than getting it from the ground into LEO. A Moonstalk would make it even more affordable.
One possibility would be solar panels which could be assembled and put into GEO. Once there, it can generate electricity and beam it back toward the ground. The panels can be manufactured on the lunar surface and sent up piece by piece to a station at the L1 Lagrange point.
Or, power could be supplied to spacecraft traversing Cis Lunar space. This would defray expenses in traveling from the Earth and back.
If operating costs were to be diminished enough, small amounts of goods transported from the lunar surface could make the entire enterprise self sufficient.
What goods, though? Some have suggested using lunar water as a fuel supply. This could make a mission to Mars much cheaper. The fuel could be transported from the poles to the Moonstalk, and from there onward to the Lagrange point. It would fuel the spacecraft at that point for its journey to Mars.
Furthermore, lunar water could be useful in growing food. Not only food to sustain a crew on the moon, but food for Mars missions. A substantial portion of food supplies from the moon could save a lot of money for Mars missions.
A more ambitious possibility is manufacturing stuff for use in space. Let's say you could build rocket engines and launch them from the lunar surface. Or build them piece by piece, send them up the Moonstalk, and assemble them at a Lagrange point. Together with being supplied by lunar fuel, a lot of the cost of the Martian expedition could be taken care of by the lunar colony itself.
Update: 11/21/2011
In reference to the need for an anchor in space of over 6000 tons, the following source is cited.
. From page 171According to Pearson, an already existing fiber material called M5 would be sufficiently strong to build a lunar space elevator [ comment: Moonstalk]. His calculations show that a cable with a lifting capacity of 200 kg (440 lbs) would have a mass of only 6800 kg (15000 lbs).The spool of cable would be large, however. It could be a problem with its size- you have to fit it in a cargo area that would be compatible with an available launch configuration. Since you need 38,000 miles or so of cable, the spool will be large.
The cable would be deployed from L1 until it reaches the surface. From there, it would be anchored down and further strengthened so that it can carry heavier payloads. With a lifting capacity of only 200 kg, this would indicate a need for heavier payloads. It may take multiple cables for that purpose, if that is the idea. It doesn't appear that passengers will be able to use the Moonstalks. They may be very useful in delivering cargo cheaply and efficiently, however.
A couple of Moonstalks, on each of L1 and L2 Lagrange points, would simplify transit between the surface and into space.
In order to colonize the moon, there will need to be some economic reason for its existence. In other words, how do you make money from this enterprise? If income isn't feasible, then how might you save money?
One thing is clear: getting stuff from the lunar surface and back into low Earth orbit should be cheaper than getting it from the ground into LEO. A Moonstalk would make it even more affordable.
One possibility would be solar panels which could be assembled and put into GEO. Once there, it can generate electricity and beam it back toward the ground. The panels can be manufactured on the lunar surface and sent up piece by piece to a station at the L1 Lagrange point.
Or, power could be supplied to spacecraft traversing Cis Lunar space. This would defray expenses in traveling from the Earth and back.
If operating costs were to be diminished enough, small amounts of goods transported from the lunar surface could make the entire enterprise self sufficient.
What goods, though? Some have suggested using lunar water as a fuel supply. This could make a mission to Mars much cheaper. The fuel could be transported from the poles to the Moonstalk, and from there onward to the Lagrange point. It would fuel the spacecraft at that point for its journey to Mars.
Furthermore, lunar water could be useful in growing food. Not only food to sustain a crew on the moon, but food for Mars missions. A substantial portion of food supplies from the moon could save a lot of money for Mars missions.
A more ambitious possibility is manufacturing stuff for use in space. Let's say you could build rocket engines and launch them from the lunar surface. Or build them piece by piece, send them up the Moonstalk, and assemble them at a Lagrange point. Together with being supplied by lunar fuel, a lot of the cost of the Martian expedition could be taken care of by the lunar colony itself.
Update: 11/21/2011
In reference to the need for an anchor in space of over 6000 tons, the following source is cited.
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