In reply to Wesley Bruce's message of Sun, 06 Nov 2005 22:36:36 +1100: Hi, [snip] >>>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? >> >That is the time if you accelerated for half the time and decel for half >the time. no coasting.
Then why would you need "a hell of a bumper bar"? [snip] >>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] >> >> >You don't need to resupply and crew swap a Mars net robot sat. That's not really what I was referring to anyway. >The russian are concidering a base on phobos. Then they apparently see some value in the notion. >The delta t equations make >phobos easyer than the moon. You dont have to land you just dock woth >the big rock. That said the Japs are trying to dick a rover/hopper with >an asteroid and it's prooving tricky. May not be so difficult for a manned craft. No time lag in decision making. [snip] >It's a back up option. It means that if all but one breaks down then >you've still got comms. Ah, next time it comes around! :) >>Not so critical. Inertial navigation is currently pretty advanced, >>so there is no real need for anyone to get lost. >> >> >True for a rover but a good system for a man on foot with limited life >support is required. Anyone that walks so far that he is no longer in sight of his rover on another planet deserves whatever he gets. Mars is not like Earth, where one can be stopped by something as simple as a river. Rovers should be able to go anywhere a person can. The exception is climbing up mountains, or down into gorges, but a human in a space suit shouldn't be doing that either. That's what shuttles are for. IOW you fly there, you don't climb. Climbing on Mars will prove nearly always fatal. One rip in your suit, and you're a goner. [snip] >I'll have two please but the odds of finding Ice and a lava cave in the >same place is low. The jackpot would be ice in a lava cave. Judging by previous indications of water ice, it seems to be pretty wide spread in the polar region(s). The chances of finding a cave there as well, may be better than you think. A week spent in orbit first, would give plenty of opportunity to more closely examine previously identified potential sites, and make a final choice. Previously you mentioned a pebble bed reactor. What are you going to do about neutron shielding? (water?) If you used an ion drive, then human waste could be ionized and fed to the drive as reaction mass. That would mean that no separate reaction mass need be taken along, and the weight saved could be used for extra food and water for the crew. It would also mean that waste need not be recycled, which I'm sure the crew would prefer. Or don't the numbers add up? Regards, Robin van Spaandonk http://users.bigpond.net.au/rvanspaa/ Competition provides the motivation, Cooperation provides the means.
