Given a spinning hab, you couldn't bury it.Perhaps some radiation shielding could be enjoyed by having it spin within Stickney crater (this gives shielding from Phobos as well as Mars). Perhaps regolith or water could be exported from Phobos to the spin hab to use for radiation protection.
Quote from: Hop_David on 08/06/2010 07:35 pmGiven a spinning hab, you couldn't bury it.Perhaps some radiation shielding could be enjoyed by having it spin within Stickney crater (this gives shielding from Phobos as well as Mars). Perhaps regolith or water could be exported from Phobos to the spin hab to use for radiation protection.Some research on Earth indicates many humans can handle 4rpm. Then a 25 m radius gives a = .4^2 x 25 = 4m/s, or Mars surface.There's no reason why a 50m wide torus couldn't be inflated under the Phobos regolith (assuming very low tensile strength).
Quote from: alexterrell on 08/07/2010 07:01 amQuote from: Hop_David on 08/06/2010 07:35 pmGiven a spinning hab, you couldn't bury it.Perhaps some radiation shielding could be enjoyed by having it spin within Stickney crater (this gives shielding from Phobos as well as Mars). Perhaps regolith or water could be exported from Phobos to the spin hab to use for radiation protection.Some research on Earth indicates many humans can handle 4rpm. Then a 25 m radius gives a = .4^2 x 25 = 4m/s, or Mars surface.There's no reason why a 50m wide torus couldn't be inflated under the Phobos regolith (assuming very low tensile strength).I like the idea of putting the base within Stickney and burying almost everything under the regolith of Phobos. However, instead of a spinning hab, I'd think that an extremely lightweight electric train running around inside a torus would work. A train can be engineered to be simple and reliable and fixable. The train's length can extend all the way around the torus, thus it wouldn't have a front or tail. Centrifugal force is what you want. How to get centrifugal force in a lightweight and reliable format is one of the interesting questions for a Phobos base and spaceships. I have looked at some pretty lightweight and simple trains and roller coasters... I don't see any advantages to giving angular momentum to the structure that has to deal with the centripetal force. Thus the structure that resists the centrifugal force should not rotate. Let the Phobos centrifugal force train roll on and on in an endless circle. Stops are scheduled every hour on the hour. Maintenance checks are done continuously and automatically. Cheers!Edited.
A rat wheel would do the job, but am trying to imagine how the rat wheel and torus balloon would fit inside plausible fairings. If put inside plausible fairings, seems to me a lot of assembly would be required.
The rat wheel consists of several thousand 8m rigid "planks". These are held parallel to the main axis. They are all connected by thin sheets of Spectra, as well as Spectra cables running through them. All the planks are pushed into the core for transit. Once the rat wheel starts to rotate, the planks extend to make floors. The effect on each of the several floors is like walking on a rope bridge, about 8m in diameter, suspended by flexible sheet walls, with cables running through the planks.All the room walls are also present, as thin flexible sheets.The "bridge", spread over seven floors is 650m long. If each plank is 2cm thick, that needs 13m2 of the payload fairing cross section. I.e, wrapped around the core, they're only occupying a ring 9m in diameter and 1/2m wide. So plenty of room for "rigging" and sheets.So actually packing is easy. Testing the rat wheel before departure will be impossible so hope the CAD models are correct!
An origami rat wheel? Intriguing idea. If the idea's viable, I believe it could be tested in LEO.
If we can assume loose regolith, then it still makes more sense to do a spinning space station. This would be a "dumb-bell" style station where loose regolith is packed into empty fuel tanks and/or external balloon bags for long term cosmic ray shielding and countermass.The "dumb-bell" could be a 120m long beam between a lightweight crew module and a heavier service/supply module. At 2rpm, this provides Mars gravity on the crew side and Lunar gravity on the heavier side. (It can start off life in LEO as a spin gravity research station--one ATV derived MSS module on one side and two MSS modules on the other side.)I'm wary of spin rates greater than 2rpm, so an 80m radius may be the minimum practical for Mars level gravity.
Quote from: IsaacKuo on 08/07/2010 07:11 pmIf we can assume loose regolith, then it still makes more sense to do a spinning space station. This would be a "dumb-bell" style station where loose regolith is packed into empty fuel tanks and/or external balloon bags for long term cosmic ray shielding and countermass.The "dumb-bell" could be a 120m long beam between a lightweight crew module and a heavier service/supply module. At 2rpm, this provides Mars gravity on the crew side and Lunar gravity on the heavier side. (It can start off life in LEO as a spin gravity research station--one ATV derived MSS module on one side and two MSS modules on the other side.)Though "fixing" several thousand tons of regolith to the habitat modules, and accelerating this to 20m/s and supporting it under .38g will be problematic.Perhaps you could launch the modules with a void space ready for filling.
If we can assume loose regolith, then it still makes more sense to do a spinning space station. This would be a "dumb-bell" style station where loose regolith is packed into empty fuel tanks and/or external balloon bags for long term cosmic ray shielding and countermass.The "dumb-bell" could be a 120m long beam between a lightweight crew module and a heavier service/supply module. At 2rpm, this provides Mars gravity on the crew side and Lunar gravity on the heavier side. (It can start off life in LEO as a spin gravity research station--one ATV derived MSS module on one side and two MSS modules on the other side.)
I'd rather wait for some spin rate research, and if possible, ...
... inflate the whole thing on deimos or phobos and then cover in regolith (or inflate in deimos or phobos).
Quote from: MATTBLAK on 09/20/2009 01:39 amIn the next 7 years the best we could hope for would be visit to a NEO, L-2 or lunar orbit.Phobos round trip is easier than the vast majority of NEO round trips.
In the next 7 years the best we could hope for would be visit to a NEO, L-2 or lunar orbit.
DiZio's work on rotational adaptation has shown that 5RPM is feasible, possibly as high as 10RPM. If people get sick, don't send them. Skylab astros were happily running on the "race track" at rates greater than 5RPM. However, program managers really hate the idea of artificial gravity, so a short-arm centrifuge for exercise sessions is probably all that will be used.
The ring wouldn't need to be sealed at all (in fact, it would best not be sealed), and should be able to be spun-down at any time. Any structural considerations should be handled by the structure of the ring.Just an idea.EDIT: Part of the benefit of this idea is that the whole artficial gravity mechanical system would be inside a pressurized environment, and thus could be fixed mid-flight using conventional hand tools without a difficult and risky EVA.
Are there any possible ramifications of this research for the early manned and robotic missions to Phobos?Martian Moon Phobos May Have Been Formed by Catastrophic BlastAt: http://www.spaceref.com/news/viewpr.html?pid=31665Cheers!
Quote from: HappyMartian on 09/21/2010 02:05 pmAre there any possible ramifications of this research for the early manned and robotic missions to Phobos?Martian Moon Phobos May Have Been Formed by Catastrophic BlastAt: http://www.spaceref.com/news/viewpr.html?pid=31665Cheers!Kind of makes it halfway a Mars surface mission! At least, the remains of an older Mars. It makes it quite likely that fossilized life may be present, if there was such fossilized life on Mars in the distant past.Depending on when life arose and when the catastrophic collision happened, of course.It may mean there are fewer hydrocarbons there, though, which is too bad.
I wonder about that Robotbeat. Martian Moon Phobos May Have Been Formed by Catastrophic BlastAt: http://www.spaceref.com/news/viewpr.html?pid=31665The article notes, "High porosity is required in order to absorb the energy of the large impact that generated Stickney crater..."Other comments in the article also imply the possibility that Phobos could be good at catching comets and meteoroids. The interior of Phobos could be a treasure house of useful material, including hydrocarbons and H2O. Maybe we could envision Phobos as being somewhat like a large scale gel object. I seem to remember that gels have been used to catch micrometeroids...Anyway, this research may make a Phobos mission even more attractive for an early robotic explorer. Cheers!See: http://en.wikipedia.org/wiki/CometEdited.