Date: Sun, 10 Sep 1989 00:32-EDT From: space-tech-request@cs.cmu.edu To: "~/st/lists/stdigest" Subject: Space-tech Digest #31 Contents: Marc Ringuette New Space-tech topics Al Viall Mars Mission ship design Marc Ringuette Mars Mission ship design Paul Dietz Mars Mission ship design Henry Spencer Mars Mission ship design ------------------------------------------------------------ Date: Fri, 8 Sep 1989 17:46-EDT From: Marc.Ringuette@DAISY.LEARNING.CS.CMU.EDU To: space-tech@cs.cmu.edu Subject: New space-tech topics Hi, techies! How's it going? I think it's about time to revive space-tech. I grabbed the next message from sci.space - sounds like it's down our alley. I'll make sure the author sees the results of our discussion. I'd also like to collect topics for discussion, so we can cycle through a few this fall. Please send me mail with any topics that currently sound good to you (mail to space-tech-request@cs.cmu.edu). ---------------------------------------------------------------------------- | Marc Ringuette | mnr@cs.cmu.edu | Never lick a gift | | Carnegie Mellon Comp. Sci. | 412-268-3728(w) | horse in the mouth. | | Pittsburgh, PA 15213 | 412-681-5408(h) | | ---------------------------------------------------------------------------- ------------------------------ From: al@questar.QUESTAR.MN.ORG (Al Viall) Subject: Mars Mission ship design Keywords: mars shipdesign Date: 8 Sep 89 02:39:38 GMT Setting aside long discussions on logistics of a Mission to Mars (cross your fingers NOW), I would really like varied input on what you might think the ship for a Mars Mission would look like and how it would operate.(you may now uncross your fingers)<---heh!! Let's us possibly assume that the world powers could get together long enough for such an undertaking, since we all know that such a project will take much more than just one entity to do this. Such a ship would most likely be designed to incorporate some sort of artificial gravity for the two-year journey there and two-years back. But details, lets hear details.......... ------------------------------------------------------------------------ | Albert Viall | EMAIL:al@questar.QUESTAR.MN.ORG | | ARPA: al@questar.QUESTAR.MN.ORG | FIDONET: 1:242/2 | | "Uhh, Excuse me while I take a moment to adjust my tribble." | ------------------------------------------------------------------------ ------------------------------ Date: Fri, 8 Sep 1989 15:55-EDT From: Marc.Ringuette@DAISY.LEARNING.CS.CMU.EDU To: questar.QUESTAR.MN.ORG!al@uunet.uu.net,space-tech@cs.cmu.edu Subject: Re: Mars Mission ship design There are a couple of very obvious features in my opinion. Certainly you should have two capsules on a cable 100m to 1000m in length, spinning to provide between .1 and 1 G. My guess is, say, a 500m cable providing 1G might be most practical. That's no sweat. Probably one capsule will contain the people and life support, and the other one will contain random stuff to balance the weight (although exact balance doesn't matter). As much as possible can be left in at the center axis to reduce load on the cable. The astronauts would probably have a small electrical cable-climbing winch to transport one of them up the cable to the center, to get more supplies or do maintenance. [ Aside: ring-shaped structures are unnecessary and not as flexible as just two masses on a cable, spun up to speed after the mission starts. ] [ Aside #2: why waste all that microgravity time? Set up some tended experiments at the hub, and possibly have workspace for 1/3 of the crew so you can work there in shifts. ] Ion propulsion is a likely engine setup. Its practicality might depend on the power requirements once the mission has reached Mars. The bigger the power requirements at the destination, the more power-generating capability you're going to bring along, which would be available to fire reaction mass out the back end of the vehicle in transit. I'm very fond of ion propulsion and would try to design the mission using it. If that's done, then the ion propulsion unit and solar collectors would sit at the center axis, in the null gravity region. I don't have figures on the quantity of supplies you'd need, but probably some effort to recycle air and water would be made, and perhaps growing plants would be brought along. Let me know what you hear from others. I'd be interested to hear ideas on what kind of landers might be effective. -- Marc ------------------------------ Date: Fri, 8 Sep 89 21:46:54 EDT From: dietz@cs.rochester.edu To: Marc.Ringuette@DAISY.LEARNING.CS.CMU.EDU Cc: space-tech@cs.cmu.edu Subject: Mars Mission ship design Marc Ringuette wrote: > Certainly you should have two capsules on a cable 100m to 1000m in > length, spinning to provide between .1 and 1 G. My guess is, say, a > 500m cable providing 1G might be most practical. I wonder if it would be possible to ameliorate the bad effects of microgravity by *sleeping* in one gee. I imagine a small radius centrifuge with ordinary beds. Perhaps if properly strapped in (so the head cannot move) Coriolis forces would not be important. Perhaps the same centrifuge could be used for exercise, if the crew are careful not to turn their heads. The downside would be that the crew would have to move between one and zero gee every day. They would have to be selected for resistance to space sickness. > [ Aside #2: why waste all that microgravity time? Set up some tended > experiments at the hub, and possibly have workspace for 1/3 of the > crew so you can work there in shifts. ] This has been proposed (1986 Mars Conference). You can actually get much better microgravity in interplanetary space than in LEO, because of the gravity gradient in LEO. > Ion propulsion is a likely engine setup. Paper studies I've seen point towards MPD rather than ion engines. Also, in a large vessel a nuclear reactor is better than solar arrays, I think, if only because the solar arrays would be severely degraded spiralling up through Earth's radiation belts. My personal opinion is that while it will be possible to visit Mars, and perhaps even set up a base, using chemical or fission-electric propulsion, real exploration and colonization will require high power fusion rockets. An analogy is Antarctic exploration: although it was possible to partially explore the continent with sailing ships and dogsleds, really opening the continent required aircraft. Paul F. Dietz dietz@cs.rochester.edu ------------------------------ From: henry@utzoo.uucp To: cs.cmu.edu!space-tech@cs.toronto.edu Cc: uunet!cs.rochester.edu!dietz@cs.toronto.edu Subject: Re: Mars Mission ship design Date: Sat, 9 Sep 89 19:51:37 EDT > I wonder if it would be possible to ameliorate the bad effects of > microgravity by *sleeping* in one gee... This has been suggested, and there are people working on the idea. As far as I know, nobody's yet sure it will work. > The downside would be that the crew would have to move between > one and zero gee every day. They would have to be selected for > resistance to space sickness. The change from high rotation to no rotation and back might also be serious; the people who've worked on space-colony design say that if you're going back and forth between a rotating environment and the outside frequently, something like 1 RPM should be tops for the general population. You might have to select for tolerance to this. (Actually, personally I suspect that most people would build up a tolerance for it after a while -- humans are very adaptable given time -- but a lot of individual variation seems likely.) > ...You can actually get > much better microgravity in interplanetary space than in LEO, because > of the gravity gradient in LEO. If you can haul considerable masses to LEO, there are other ways of dealing with this -- you can cancel the gravity gradient with proper placement of nearby masses. > Also, in a large vessel a nuclear reactor is better than solar arrays, > I think, if only because the solar arrays would be severely degraded > spiralling up through Earth's radiation belts. So would any crew aboard! The obvious solution is either a quicker transit of the Van Allen belts [we must not forget to give these deadly hazards to spaceflight their proper, and very appropriate, name!] or else a slow transit for the main vehicle followed by a quick transit for the crew and crucial equipment. In the latter case, you can replace the arrays afterward. Henry Spencer at U of Toronto Zoology uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ End of Space-tech Digest #31 *******************