Kaputnik - 7/9/2007 3:15 AMThere's no need for 400mt+ boosters. It would be much better to develop a smaller booster suitable for lunar missions which can then fly three to five times to build up a Mars mission.Your IMLEO estimates are far too high, IMHO. A Mars mission can be done for under 500t total.
Kaputnik - 7/9/2007 7:15 PMThere's no need for 400mt+ boosters. It would be much better to develop a smaller booster suitable for lunar missions which can then fly three to five times to build up a Mars mission.Your IMLEO estimates are far too high, IMHO. A Mars mission can be done for under 500t total.
kkattula - 7/9/2007 11:10 AMQuoteKaputnik - 7/9/2007 7:15 PMThere's no need for 400mt+ boosters. It would be much better to develop a smaller booster suitable for lunar missions which can then fly three to five times to build up a Mars mission.Your IMLEO estimates are far too high, IMHO. A Mars mission can be done for under 500t total.Ask Richard P. Speck of Micro-Space. He thinks he can put 1 man (or 2 petite women) on Mars using one Falcon 9. Not a heavy either, just a regular.
How?
tnphysics - 7/9/2007 3:53 PMHow?
Sorry.
You must surround the entire living quarters with shielding that has the same effectiveness as five feet of water in a tank. This requirement should be used for all mass calculations for extremely long duration missions. Lighter elements are more effective per unit mass, so using liquid hydrogen gives the lightest shield. A thin layer of boron-10 would be needed as a neutron absorber. It is not possible to get away with less shielding, owing to the fact that the incoming cosmic rays have enough energy to create electron-positron pairs. These pairs are called secondary radiation, and they, too, must be stopped. However, these, in turn, create more electron-positron pairs until their energy drops below 1.1 MeV (the minimum energy needed to create an electron-positron pair) (At some point, each positron will annihilate an electron, producing two gamma rays). Because, for a given total energy of ionizing radiation, alpha radiation is more damaging than beta radiation which is more damaging than gamma rays, and lower frequency (longer wavelength) gammas are more damaging than shorter wavelength gammas, a thinner shield would actually be counterproductive, so far as cosmic rays are concerned.
tnphysics - 9/9/2007 1:34 AMSorry. You must surround the entire living quarters with shielding that has the same effectiveness as five feet of water in a tank. This requirement should be used for all mass calculations for extremely long duration missions. Lighter elements are more effective per unit mass, so using liquid hydrogen gives the lightest shield. A thin layer of boron-10 would be needed as a neutron absorber. It is not possible to get away with less shielding, owing to the fact that the incoming cosmic rays have enough energy to create electron-positron pairs. These pairs are called secondary radiation, and they, too, must be stopped. However, these, in turn, create more electron-positron pairs until their energy drops below 1.1 MeV (the minimum energy needed to create an electron-positron pair) (At some point, each positron will annihilate an electron, producing two gamma rays). Because, for a given total energy of ionizing radiation, alpha radiation is more damaging than beta radiation which is more damaging than gamma rays, and lower frequency (longer wavelength) gammas are more damaging than shorter wavelength gammas, a thinner shield would actually be counterproductive, so far as cosmic rays are concerned.
Kaputnik - 8/9/2007 11:23 AMI'm not an expert on this, but what's the difference in radiation exposure between LEO and the Earth-Mars interplanetary space?
Christine - 10/9/2007 7:50 AMThe best way to shield from solar protons during a flare in my mind would be to put a giant water filled polyethylene tank on the sun-facing side of your habitat.
tnphysics - 11/9/2007 9:58 PMIn principle, why couldn't you make the spacecraft able to withstand launch loads without a fairing?