In reply to Wesley Bruce's message of Fri, 04 Nov 2005 19:14:02 +1100: Hi, [snip] >About the same. The time frame is not acceleration limited. Its limited >by orbital windows. Some have proposed making a cycler using ISS >modules. The minimum fuel option is a cycler. A cycler is a craft that >orbits the sun in such a way that it takes a crew to Mars in three >months and then swings around the sun unmanned to pick up a new crew. A
Wouldn't this be going pretty fast as it passes the Earth, and would that make it hard to catch up with it? >second cycler going in the opposite direction would take three months to >drop someone home from mars and then spend a year going around the sun. > >Ion engines are too slow for manned flight we want to go faster than >three months for manned missions. That gives us three options. Avoiding >solar flares, we have more than three months warning but less than six I >believe. Some say we have more than a year but we've only looked at a >years data from the new sats in close to the sun. Ion engines are OK for >dead cargoes but solar sails can match ion engines and plasma sails beat >them. The best sail design is at: >http://www.ess.washington.edu/Space/propulsion.html >2nPa is good thrust, better than Ion and you are not burning fuel. Also >you can combine robotic craft with manned craft in a way they >accumulates momentum in six unmanned craft. And then bounce them off the >manned crafts fields. This takes a months acceleration from the solar >wind and packs it into a few minutes of field interaction. This is my >reusable reaction mass drive. Not yet published. > >If you could run a drive at one g continously Mars is 3 to 5 _days_ away >but you'd need a hell of a bumper bar. How long would it take if you accelerated then decelerated? Is there an online trip calculator? >Nuclear salt water rocket 0.1 g ~ 3 -5 weeks, a good plasma drive 0.01 >g ~4 to 7 weeks, The best sail 0.005 ~6 to 9 weeks. >Reactionless drives rule. Too bad about newtons laws. ;-) [snip] >Lab racks with power and cooling. Their not much use on mars because >there systems are optimized for zero g. >On mars you want your lab on the ground or better still in the rover. I should think that a space station orbiting Mars would be quite useful. It could function as a planetary observatory, and as a relay station for both information and supplies. A.o. it could provide regular weather updates for ground crews. The Mars mission, should not be seen as a "one shot", but rather as the beginning of an ongoing program. Viewed in that light, a space station in orbit makes a lot of sense. It could also function as a staging post. Multiple shuttle trips between Mars and the orbiting station could be then be made using fuel manufactured on the surface. [snip] >>What's the lifting capacity of the Russian's largest rocket? You missed this one. [snip] >>How many satellites are already in Mars orbit, and is there any [snip] >There's at least three and one on the way but there are >incompatibilities and other problems in the current constellation. Doesn't sound like a lot of forward thinking went into that little lot. >Mars >Net is store and forward email, much bigger data streams and the sats >can talk to each other in the same language so you can send 'live' >video. If you have a constant real time link, then you don't need store and forward capability, just a transfer capability. The storage capability can exist on the main orbital vessel. > Also their clocks are optimized for limited gps type navigation. Not so critical. Inertial navigation is currently pretty advanced, so there is no real need for anyone to get lost. [snip] >>BTW I don't think the Hafnium reactor is for real. >> >> >You think it was a misinformation program or some thing. No, but AFAIK the initial indications that it worked haven't been replicated. [snip] > The half life must >change as a consequence. I believe the idea was indeed to trigger the decays through x-ray stimulation. >A a two kg neutron gun fires into a cavity lined with isotopes normally >found in medium grade nuclear waste. They fission but they don't make >enough neutrons to chain react. It can be turned off quickly. I'll >check my source on that one the web page has moved on me. What's wrong with a simple reactor? [snip] >>Why not land the reactor portion of the main ship on Mars? Then >>you can use the power from the main reactor to create all the fuel >>you need in a short period of time. It would save the whole fuel >>plant trip. It could also make enough fuel for it's own launch for >>the return trip. The fuel plant could be taken along on the main >>ship. Might be better than landing only to discover that the >>previous fuel plant mission didn't quite work, and you now have no >>way of getting back. If the crew + fuel plant landing doesn't >>work, then the crew are probably dead, and not very interested in >>coming back anyway. >>[snip] >> >> >Yes thats been thought of but if we have a big reactor on Mars then we >can do anything. But would you go to mars with a reactor and fuel plant >not knowing it will absolutly work. Send a robot. Make fuel to come >home. check it worked and then go. Then you had better make sure that you have a video camera that can actually see the fuel in the tank (sensors can be fooled). You also need to know that the fuel is not contaminated. >That way you garantee you'll get >back. That said my moneys on cold fusion. But I would still make fuel >with a fusion powered robot factory while I watched from the safty of earth. You might also consider a nuclear rocket for Mars takeoff. It could initially use compressed CO2 for reaction mass, then operate as a ram jet as it gained velocity. That way you wouldn't have to make any fuel. > See: http://www.marssociety.org/ and http://www.marssociety.org.au/ >and http://www.marshome.org/ for all the details. > Actually, I think a large cave would probably make a much cheaper abode. You need then only seal off the entrance(s). There are bound to be a few lava tunnels somewhere. [snip] Regards, Robin van Spaandonk http://users.bigpond.net.au/rvanspaa/ Competition provides the motivation, Cooperation provides the means.
