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Space Forum / Shuttle / October 2005What would it take to convert ISS to an interplanetary mission?
I know, ISS is doomed to be ditched in less than ten years, but just as an intellectual excercise what would it take to make ISS into a Mars or Lunar-bound craft? My thoughts would be one or more ion thrusters powered with a nuclear source like the Topaz, lots of outside storage for breathing gases and food, etc. From a technical standpoint, what would it take? JazzMan  Signature********************************************************** Please reply to jsavage"at"airmail.net. Curse those darned bulk e-mailers! ********************************************************** "Rats and roaches live by competition under the laws of supply and demand. It is the privilege of human beings to live under the laws of justice and mercy." - Wendell Berry ********************************************************** > I know, ISS is doomed to be ditched in less than ten years, > but just as an intellectual excercise what would it take to [quoted text clipped - 4 lines] > breathing gases and food, etc. From a technical standpoint, > what would it take? It's been discussed in sci.space.station before (so tell me again why you posted this to s.s.shuttle...?), but here's the gist. If you go with ion thrusters, the station would spend a long time in the Van Allen belts and this will fry the electronics (and the crew) without extensive and expensive shielding. On the other hand, if you use a large enough engine to get through the Van Allen belts quickly to minimize the total radiation dose (as Apollo did), the station is too lightly built to handle the thrust loads unless you substantially beef up the structure. Once you are out of LEO you will have a very difficult time maintaining a good thermal balance on the station since the thermal control system was designed for the LEO environment, where the Earth fills up almost half the sky and there is plenty of eclipse time. The thermal control system would likely need substantial modifications. Once beyond LEO, you are also beyond resupply, at least with existing resupply vehicles (the Progress rendezvous ceiling is 410 km), so better develop some new resupply vehicles, or pack the station with supplies before leaving LEO. ISS' existing navigation systems, both US and Russian segment, also assume a LEO environment and would get very confused outside of LEO. On the US segment, the GPS wouldn't work well once the station is above the GPS constellation. On the Russian segment, the infrared horizon sensors will become progressively less precise as the Earth shrinks in the sky. So upgrades will be required there as well. Bottom line is that anything is possible if you don't care about money, but some ideas just aren't practical. It would be like me spending tens of thousands to convert my car into a fishing boat when I could have just gone out and bought a freaking boat. SignatureJRF Reply-to address spam-proofed - to reply by E-mail, check "Organization" (I am not assimilated) and think one step ahead of IBM. > > I know, ISS is doomed to be ditched in less than ten years, > > but just as an intellectual excercise what would it take to [quoted text clipped - 36 lines] > thousands to convert my car into a fishing boat when I could have just gone > out and bought a freaking boat. Thanks for the thoughts. I posted it here because I've never heard of sci.space.station before this very moment. I was thinking from the standpoint of the ISS being designed for long periods of time between resupply, so as an existing piece of hardware it would be more likely convertable for long-duration missions than something like the shuttle. How much water ice would it take to shield ISS through the van Allen belts? I could imagine large bags of water being shipped up and kept liquid while being applied to the hull of ISS in critical locations, then allowed to freeze to form. Also, if ISS was moved through the van Allen belts uninhabited then crewed once outside, that would reduce the biological side of the problem These are just random thoughts. I fully realize a purpose built craft could do it better, but I look around and see nothing realistic on the horizon. It would be like converting an old Chevy truck into a boat to get across from Cuba to Florida, why? Because there wasn't a boat available at any price, from anyone. If you have the truck, and the ability, what would it take to make it work? JazzMan Signature********************************************************** Please reply to jsavage"at"airmail.net. Curse those darned bulk e-mailers! ********************************************************** "Rats and roaches live by competition under the laws of supply and demand. It is the privilege of human beings to live under the laws of justice and mercy." - Wendell Berry ********************************************************** > These are just random thoughts. I fully realize a purpose built > craft could do it better, but I look around and see nothing realistic > on the horizon. It would be like converting an old Chevy truck into > a boat to get across from Cuba to Florida, why? Because there wasn't > a boat available at any price, from anyone. If you have the truck, > and the ability, what would it take to make it work? It would be far cheaper to build new modules on the ground. Astronaut time (in orbit) costs an extreme amount of money when you add in launch and support costs. You've got far less overhead costs on an aerospace factory floor than you do in LEO. Jeff SignatureRemove icky phrase from email address to get a valid address. > Bottom line is that anything is possible if you don't care about money, but > some ideas just aren't practical. It would be like me spending tens of > thousands to convert my car into a fishing boat when I could have just gone > out and bought a freaking boat. Ever watch the Red Green Show? Imagine what Red could do with ISS and a few thousand rolls of duct tape. :-) Jeff SignatureRemove icky phrase from email address to get a valid address. "Jorge R. Frank" <jrfrank@ibm-pc.borg> wrote: >Bottom line is that anything is possible if you don't care about money, but >some ideas just aren't practical. Your post is an excellent analysis that ought to kill the ISS-as-vehicle idea stone dead, but of course it won't... because what really drives that and a bunch of similar notions is not the superficial motive (can we re-purpose existing hardware?) but a bone-deep conviction that space should be all about *going places*, by any means necessary, at any cost. A *projected* reusable orbital transport and a *projected* space station were on the Oberth-von Braun agenda for decades -- but the real ones, well... "All we've done since 1973 is go round in circles in LEO!" A *projected* moon landing (and then a base, and exploration in depth) were on the agenda for decades -- but for a sizeable fraction of the community, the half-begun real thing doesn't stir the blood: "Been there, done that -- on to Mars!" I value your rationality about costs, means and ends. But it can't compete with that. > Your post is an excellent analysis that ought to kill the > ISS-as-vehicle idea stone dead, but of course it won't... While the ISS currently isn't suited for intertplatetary mission, consider how much of it is suited. It is a given that a expedition ship to mars would be built "new". It would have appropriate shielding. But consider how much of the ISS systems can be re-used (in terms of designs). The big question is whether CBM assemblies are strong enough and if not, if they can be beefed up. Jorge Frank pointed out that cooling would no longer work as predicted. But that is an issue that will have to be looked at no matter what shape of ship goes to mars. An umbrella would shield the station from the heat of the sun, but it would also put shadown on the solar arrays. And solar arrays might have to be designed to be extended along the axis of travel so that any acceleration won't bend them. But the technology use by ISS might be reusable. Consider all the R&D money spent on the ISS to develop all sorts of systems and designs. A lot of that can be reused. JazzMan, ISS could be moved safely (though taking some radiation damage) into the ME-L1 station-keeping orbit, as a somewhat of an interactive halo-orbit that roughly 60,000 ~ 64,000 km from the moon. There is NOT an insurmountable problem with viable thrust options. The very same re-orbit thrust if sustained would do just fine and dandy. The further away from Earth the more thrust energy could be safely applied. >Once you are out of LEO you will have a very difficult time maintaining a >good thermal balance on the station since the thermal control system was >designed for the LEO environment, where the Earth fills up almost half the >sky and there is plenty of eclipse time. The thermal control system would >likely need substantial modifications. Station cooling as stated above, as is this would be a real bitch, as would have been 10 fold the case for those supposed NASA/Apollo EVAs that seem to require evidence exclusions and conditional laws of physics in order to accept as is. Although ISS cooling could be modified and/or having an artificial solar shade as taken along for the mostly robotic ride should do quite nicely. In fact, the auxiliary solar shade could be a massive array of PV cells, if need be large enough to shade the entire ISS. ~ Kurt Vonnegut would have to agree; WAR is WAR, thus "in war there are no rules" - In fact, war has been the very reason of having to deal with the likes of others that haven't been playing by whatever rules, such as GW Bush. Life upon Venus, a township w/Bridge & ET/UFO Park-n-Ride Tarmac: http://guthvenus.tripod.com/gv-town.htm The Russian/China LSE-CM/ISS (Lunar Space Elevator) http://guthvenus.tripod.com/lunar-space-elevator.htm Venus ETs, plus the updated sub-topics; Brad Guth / GASA-IEIS http://guthvenus.tripod.com/gv-topics.htm scrap the modules as designed, with a heavy lifter large ones launched full up.... basically ISS is a first model of station. number 2 if it ever gets built will be very different just as a shuttle 2 would be different..... of course it wouldnt get built in my lifetime, and probably not yours, even if you are 10 Bob Haller; >scrap the modules as designed, with a heavy lifter large ones launched >full up.... >basically ISS is a first model of station. I agree that ISS is basically a minimal effort that absolutely requires shelter from the solar and cosmic storm that's rather nicely provided by way of the Van Allen zone of death, as well as otherwise it needs mother Earth for cooling itself off 50% of the time. However, with only a few billion worth of improvements including a very large area PV array that can act as an artificial and interactive solar tracking shade might be just the ticket. Then giving their re-orbit engines the extra fuel capacity for migrating ISS at a moderate velocity through the Van Allen badlands. Once establishing the halo like station-keeping mode that's somewhat of an interactive situation, and subsequently cutting the time of crew rotation down to 30 days might keep their need of banked bone marrow down to a dull roar. >number 2 if it ever gets built will be very different I totally agree. That's why I've suggested my LSE-CM-ISS that'll provide a good 50t/m2 worth of a basalt and perhaps the likes of JB-WELD as a tough composite level of protection surrounding a 1e9 m3 ISS abode within. That's roughly a 1.28 km diameter and perhaps looking somewhat as a borg-like sphere that gets tethered to the moon. Of course, in order to start the LSE phase we'll need something (damn near anything) situated at the one and only ME-L1/EM-L2 sweet spot, so that a small initial tether can get deployed and anchored into the moon. This need not even be manned, since robotics and a 100% terrestrial based ground control can more than accommodate the task at hand. >just as a shuttle 2 would be different..... of course it wouldnt get >built in my lifetime, and probably not yours, even if you are 10 Again, I couldn't agree more, nor could many others that have been suggesting upon all sorts of nifty and doable alternatives, including one of mine as having those LRn-->ion thrusters instead of the SSMEs, although we'll likely still need a couple of those massive SRBs, except as constructed of a basalt composite at roughly half the inert mass. I'm going for 100+t as delivered to 400+km or perhaps 50+t as going all the way to/from the ME-L1/EM-L2 zone that's supposedly situated at roughly 84% the distance towards the moon (mostly a shuttle/spaceplane situation of efficiently coasting to/from that mutual gravity-well/nullification), then possibly using the moon as a get home acceleration method of orbiting the spaceplane down to within as little as 10 km off the lunar deck before giving that final return-to-home-world thrust. Otherwise, just a slight thrust away from ME-L1 towards mother Earth and eventually you'd be arriving back home no matters what (dead or alive). ~ Kurt Vonnegut would have to agree; WAR is WAR, thus "in war there are no rules" - In fact, war has been the very reason of having to deal with the likes of others that haven't been playing by whatever rules, such as GW Bush. Life upon Venus, a township w/Bridge & ET/UFO Park-n-Ride Tarmac: http://guthvenus.tripod.com/gv-town.htm The Russian/China LSE-CM/ISS (Lunar Space Elevator) http://guthvenus.tripod.com/lunar-space-elevator.htm Venus ETs, plus the updated sub-topics; Brad Guth / GASA-IEIS http://guthvenus.tripod.com/gv-topics.htm We could replace their ISS re-orbit rocket engine with an array of LRn222-->ION thrusters that can be 100% adjusted in order to suit whatever amount of thrust. We could also deliver the Radon breeder reactor, that being Ra226-->Rn222-->LRn as for providing a 1600 year half life worth of supplying a continous supply of Radon as ION fuel. The exit velocity of the RN222 ions can be as great as 150,000 km/s. So, go right ahead and put that into your KE=.5MV2 formula and see what you get. Check out "How Rockets Differ From Jets", and certainly not for anything regarding "jets" but otherwise for all of the other nifty contributions by "tomcat" and myself; http://groups.google.com/group/sci.space.shuttle/browse_frm/thread/368ff2e3b379f 686/cf03bae1d059c3d8?lnk=st&q=brad+guth&rnum=3&hl=en#cf03bae1d059c3d8 ~ Kurt Vonnegut would have to agree; WAR is WAR, thus "in war there are no rules" - In fact, war has been the very reason of having to deal with the likes of others that haven't been playing by whatever rules, such as GW Bush. Life upon Venus, a township w/Bridge & ET/UFO Park-n-Ride Tarmac: http://guthvenus.tripod.com/gv-town.htm The Russian/China LSE-CM/ISS (Lunar Space Elevator) http://guthvenus.tripod.com/lunar-space-elevator.htm Venus ETs, plus the updated sub-topics; Brad Guth / GASA-IEIS http://guthvenus.tripod.com/gv-topics.htm |
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