Even if you can't use it in orbit, I know scrap haulers in the outback who would be more than happy to get their hands on a few tons of expensive alloys. It seems a waste that large satellites are always deorbited into the ocean, where everything sinks.
1. I just think about how much more practical it could be (in many, but not all, cases) to fabricate what we need in orbit rather than have to have something made on earth and sent up to orbit for however many hundreds of dollars per pound,2. let alone being able to make rapid repairs in emergency situations.
Quote from: Patchouli on 09/18/2008 05:32 pmQuote from: Ronsmytheiii on 09/18/2008 03:33 pmOne Important thing to remember was that Skylab was much smaller in diameter than the Shuttle Tank, yet had a massive internal volume. Why not just convert a J-232 Upperstage into a lab module, ala Skylab/S-IVB, it still would be a massive station. Why not use just a converted H2 tank from a J120 core stage no foam etc and pre outfitted with airlocks,MMOD shielding and a basic RCS and have a truly huge station module.I say module as the days of single module stations was over since the 70s and all future stations have been multiple module affairs.Even the giant BA330 is just a part of a larger space station.It also should be noted we have much cheaper cargo options now then the Apollo CSM and Saturn IB of the 60s so a finding in the 60s is likely no longer valid.In my mind the idea wasn't to send up a huge module as a single station, but many, although significantly less than ISS, sent up to build a large multi-purpose station. I envisioned sending up a standardised module with a six-point docking module attached. Every subsequent module would have this same configuration and a space station could be assembled Tinkertoy style.
Quote from: Ronsmytheiii on 09/18/2008 03:33 pmOne Important thing to remember was that Skylab was much smaller in diameter than the Shuttle Tank, yet had a massive internal volume. Why not just convert a J-232 Upperstage into a lab module, ala Skylab/S-IVB, it still would be a massive station. Why not use just a converted H2 tank from a J120 core stage no foam etc and pre outfitted with airlocks,MMOD shielding and a basic RCS and have a truly huge station module.I say module as the days of single module stations was over since the 70s and all future stations have been multiple module affairs.Even the giant BA330 is just a part of a larger space station.It also should be noted we have much cheaper cargo options now then the Apollo CSM and Saturn IB of the 60s so a finding in the 60s is likely no longer valid.
One Important thing to remember was that Skylab was much smaller in diameter than the Shuttle Tank, yet had a massive internal volume. Why not just convert a J-232 Upperstage into a lab module, ala Skylab/S-IVB, it still would be a massive station.
Quote from: davamanra on 10/22/2008 04:34 am1. I just think about how much more practical it could be (in many, but not all, cases) to fabricate what we need in orbit rather than have to have something made on earth and sent up to orbit for however many hundreds of dollars per pound,2. let alone being able to make rapid repairs in emergency situations. 1. no, for the flight rates now days, it is still cheaper to do it on the ground. Just as Spacex doesn't built the falcon on Kwaj2. For what missions? Other than ISS, none.
I guess I was considering a strategy for the future, where we would be doing processing and construction in orbit. A new core stage could be designed with orbital construction in mind.
Quote from: davamanra on 10/23/2008 03:56 pm I guess I was considering a strategy for the future, where we would be doing processing and construction in orbit. A new core stage could be designed with orbital construction in mind. By that time, there will be RLV's and no expendable cores to use
Quote from: A_M_Swallow on 09/18/2008 07:35 pmQuote from: Jim on 09/18/2008 04:10 amET was better since it was just a tank, no engines, avionics, etc{snip}Avionics and engines are the expensive bits. Could the J-120 core be refuelled and used as an Earth Departure Stage?RS-68 isn't restartable
Quote from: Jim on 09/18/2008 04:10 amET was better since it was just a tank, no engines, avionics, etc{snip}Avionics and engines are the expensive bits. Could the J-120 core be refuelled and used as an Earth Departure Stage?
ET was better since it was just a tank, no engines, avionics, etc{snip}
Crazy thought here but I'm outside the box... can't even see it from here... What if you put a restartable J-2 in between the RS-68's and only ignited it on orbit. I wouldn't see any purpose in igniting it on the ground, as overexpansion would cause problems, as well as fuel consumption from the core and probably result in over-acceleration anyway. The problem with using a core for an EDS though is the lousy mass fraction carrying the dead weight of the RS-68's and thrust structure through TLI or TMI, which really kills you, and the size of the core is way overkill for what you'd be sending out anyway, most likely, especially with a single J-2 mounted in the middle. Maybe if the engines/thrust structure were 'stage and a half' type design to get rid of most of the dead weight you might have something, but that creates a whole other set of costs/problems. Also I'm thinking the construction of the core would be seriously overkill for an EDS type stage. Fuelling it would require a second launch of either another similar size vehicle or multiple smaller vehicles, in which case you're probably better off launching a dedicated more optimized EDS anyway.... Just thinking off the cuff but I see more problems with this idea than solutions... Oh well, back to the drawing board... LOL:) OL JR
Well, let's not go back the drawing board completely! You wouldn't necessarily have to get rid of the dead weight. It would be nice, but not compulsory and the hardware necessary to jettison this weight would add to the complexity as well as the weight of the vehicle. It may not be a great idea for sending a crew into TLI or TMI, but for sending cargo on ahead of the mission or resupply missions this might have some merit.Drew
Quote from: davamanra on 10/26/2008 08:06 am Well, let's not go back the drawing board completely! You wouldn't necessarily have to get rid of the dead weight. It would be nice, but not compulsory and the hardware necessary to jettison this weight would add to the complexity as well as the weight of the vehicle. It may not be a great idea for sending a crew into TLI or TMI, but for sending cargo on ahead of the mission or resupply missions this might have some merit.DrewDragging that much excess mass to the moon for any reason makes for an untennable design, even for cargo. The cost greatly outweighs any percieved benefit; if it would actually work at all.Paul
Well, it's just one possible use for the core. Since it would already be in orbit, it would be a way to deliver cargo instead of having to launch a special mission all the way from Earth's surface. Now THAT cost would outweigh any benefit.