and lightweight craft. For these purposes, I will borrow the title CEV. The CEV is a lifting body based on the X-33 configuration. As with the X-33, its main engines are the RS-2200 Linear Aerospikes (must be capable of restart) which are more lightweight and efficient giving them two vital advantages over traditional rocket engines. The CEV will use the Space Shuttle’s RCS thrusters. The OMS engines will be replaced, however, with an engine to be used for both a deorbit burn and a TEI burn – all to be fueled by internal fuel tanks. The Logistics/Cargo Bay will have dimensions of approximately 25x15 and include a docking module, solar wings and the ability to carry the Space Shuttle’s Robotic Arm.
This vehicle will allow the United States to maintain its leading role in space with a smaller gap. It will build on the best of the Space Shuttle and avoid a return to the past of capsules and splashdowns. It will reduce the throwaway of both Ares and, as currently proposed, SDLV. It will be a lasting tribute to the technological achievement of the Space Shuttle – allowing the Orbiters to retire with the honor they deserve. Finally, the CEV will resume exploration of the Moon and beyond.
The way I see it, you are taking far too much to the moon.Wings are only needed for re-entry. For the rest of the mission, they are just dead weight. And the further you take them, the more affect that extra weight has. Taking the ET to the moon? Again, unnecessary dead weight. the tank will be at most a quarter full, and the rest of the tankage is therefore unneeded.I agree, going back to a capsule from shuttle seems like negative progress, but shuttle is an LEO vehicle, as are all winged spaceships. A capsule landing with an ignominious thud or splash might not be as "beautiful" or "noble" as a winged spaceplane gliding back too earth, but beauty is not the motivation for the space program.NOTE: I don't disagree with you regarding the ares rockets, though.
The lifting body design of the X-33 does not use wings.
Quote from: Idol Revolver on 12/26/2009 07:31 pmThe way I see it, you are taking far too much to the moon.Wings are only needed for re-entry. For the rest of the mission, they are just dead weight. And the further you take them, the more affect that extra weight has. Taking the ET to the moon? Again, unnecessary dead weight. the tank will be at most a quarter full, and the rest of the tankage is therefore unneeded.I agree, going back to a capsule from shuttle seems like negative progress, but shuttle is an LEO vehicle, as are all winged spaceships. A capsule landing with an ignominious thud or splash might not be as "beautiful" or "noble" as a winged spaceplane gliding back too earth, but beauty is not the motivation for the space program.NOTE: I don't disagree with you regarding the ares rockets, though.Yes, I understand the deadweight argument. My concern is which is more costly carrying deadweight or throwing away so much of the rocket and spacecraft? Please note I am not suggesting the ET be carried to the Moon but rather just through TLI and then discarded like the S-IVB.The lifting body design of the X-33 does not use wings.
Would this smaller shuttle have the adequate shielding the present shuttle lacks to protect the crew from you know what? Would this change your smaller design? Just curious.
Jim, Are you opposed to the shuttle concept generally or just because it is not feasible beyond LEO?
Quote from: Mr. Justice on 12/26/2009 08:42 pmJim, Are you opposed to the shuttle concept generally or just because it is not feasible beyond LEO?The current flight rates don't support the need for one. Also, it is not feasible beyond LEO. RLV's need flight rates more than 3 per month.
I am not dead set against Orion. Orion is reusable
RLV's need flight rates more than 3 per month.
Quote from: Jim on 12/26/2009 09:04 pm RLV's need flight rates more than 3 per month.I'm curious Jim, what are your thoghts on the flight rate nescessary for just a reusable capsule as opposed to the whole launch vehicle?Would it be realistic to have a fully reusable capsule at current amounts of manned launches?
Quote from: Rabidpanda on 12/26/2009 10:27 pmQuote from: Jim on 12/26/2009 09:04 pm RLV's need flight rates more than 3 per month.I'm curious Jim, what are your thoghts on the flight rate nescessary for just a reusable capsule as opposed to the whole launch vehicle?Would it be realistic to have a fully reusable capsule at current amounts of manned launches?I don't understand why do you seek a justification for RLV. RLVs are not the goal. They are (one of possible) means to the real goal.Thus flight rate should NEVER be adapted to the "need" to have RLV.Instead, flight rate should be adapted to the real goal, and then, based on that rate, LVs / capsules / spaceplanes / whatever should be designed to achieve it economically.Only an organization with unlimited supply of taxpayer $$$ it did not earn can afford to put the horse before the cart.
the Saturn I's first stage was a bunch of existing RLV's mated together.
Quote from: Downix on 12/28/2009 02:26 amthe Saturn I's first stage was a bunch of existing RLV's mated together.No it wasn't. None of the components were re-usable. And it wasn't as simple as bunch of first stages mated together.It had tanks from a jupiter and a redstone with entirely new engines.
Quote from: Idol Revolver on 12/28/2009 08:00 amQuote from: Downix on 12/28/2009 02:26 amthe Saturn I's first stage was a bunch of existing RLV's mated together.No it wasn't. None of the components were re-usable. And it wasn't as simple as bunch of first stages mated together.It had tanks from a jupiter and a redstone with entirely new engines.ELV's, finger flipped while typing.But my idle thought has merit, yes?
Quote from: Downix on 12/29/2009 09:06 amQuote from: Idol Revolver on 12/28/2009 08:00 amQuote from: Downix on 12/28/2009 02:26 amthe Saturn I's first stage was a bunch of existing RLV's mated together.No it wasn't. None of the components were re-usable. And it wasn't as simple as bunch of first stages mated together.It had tanks from a jupiter and a redstone with entirely new engines.ELV's, finger flipped while typing.But my idle thought has merit, yes?Yes, it would work better than the Saturn I, because it would be much bigger (26.81 MN vs 6.7 MN) and the mass-production of cores would lower costs, and the cost of an Atlas V would decrease as well. However, Russian engines would be a problem.EDIT:Also, it is in no way shuttle-derived, which is mandated by congress.
"Cheaper, faster, stronger" and all that.
On another topic: given the delta-v required for TLI, taking any un-needed mass into the TLI burn is almost certainly a mistake. I'm still amazed the current Constellation architecture, which burns propellant from the EDS tankage on the way to LEO, became the plan of record.
Quote from: sdsds on 12/26/2009 09:01 pmOn another topic: given the delta-v required for TLI, taking any un-needed mass into the TLI burn is almost certainly a mistake. I'm still amazed the current Constellation architecture, which burns propellant from the EDS tankage on the way to LEO, became the plan of record.For a two-stage SDLV, you get higher performance if the EDS burns during ascent, since you deliver far more payload (inc prop) than you waste in extra mass pushed through TLI.Saturn V was three-stage, and also burned it's EDS during ascent. Although this had a kerolox first stage, I understand the same would apply for an Ares-type first stage.cheers, Martin
LEO and Deep Space are two (2) different environments and the ships that traverse them should be designed for their respective environments.RLV's will ultimately be necessary if launch costs are ever to become reasonable, but I don't foresee them becoming practical for a while. A good interim step would be a reusable spacecraft launched on an expendable rocket. But that's where it gets complicated because it will cost a lot of money to develop two (2) different types of reusable spacecraft; one for LEO and one for deep space. Personally, I'd prefer to see runway landings for the LEO spacecraft, but I do not want to see wings; they are just too much wasted mass that needs to be orbited. A lifting body of some type would likely fit the bill. For deep space operations something along the lines of LANTR would be good. But again, where are we going to get that kind of money?In the mean time, I think we are going to be stuck with the single-use capsule launched on an expendable rocket. For the foreseeable future, I don't see sufficient flight rates of either type of spacecraft to justify going the route I suggested.
Perhaps, in the future a spaceship will be constructed in LEO. The spaceship could be constructed and serviced by a X-33 type craft. Astronauts would board the spaceship and head out for their mission. Upon their return to LEO they would slow and dock with the X-33 and land.This would require regular launches to service the spaceship helping reduce launch cost. While more fuel would be required for the spaceship to decelerate to enter LEO. The cost of fuel seems like it may be a bargain compared every mission throwing away so much hardware.
Quote from: Mr. Justice on 12/31/2009 07:09 pmPerhaps, in the future a spaceship will be constructed in LEO. The spaceship could be constructed and serviced by a X-33 type craft. Astronauts would board the spaceship and head out for their mission. Upon their return to LEO they would slow and dock with the X-33 and land.This would require regular launches to service the spaceship helping reduce launch cost. While more fuel would be required for the spaceship to decelerate to enter LEO. The cost of fuel seems like it may be a bargain compared every mission throwing away so much hardware. The problem being, you double the delta-v, so either beyond-LEO fuel depots, NEP, or SEP.
I have no objections to nuclear power. However, we can't even build a nuclear power plant because of fear. Of course, New Horizons and Cassini both drew to protest because of their RTGs. Politically it seems NEP is a nonstarter. Fuel depots are great. The best near term solution maybe methane fueled rockets.
build an earth-to-LEO crew transport [that] serves one job, and one job well, getting the crew to the space ship, and returning them to earth afterwards.
Quote from: Downix on 01/04/2010 01:56 pmbuild an earth-to-LEO crew transport [that] serves one job, and one job well, getting the crew to the space ship, and returning them to earth afterwards. This assumes the space ship can return to LEO, which is technically challenging.