Quote from: Comga on 03/18/2015 10:45 pmQuote from: ChrisWilson68 on 03/18/2015 04:29 amIt looks to me like the Dream Chaser Cargo has a much higher development cost and schedule risk than any of the other known CRS2 proposals. Not only do they have to do a huge amount of development on Dream Chaser itself, but they also have to develop a service module. The service module probably won't be developed entirely from scratch since SNC has some experience in the area, but I think they're a lot farther away from a service module than LM is from Jupiter.The service module is also going to add to their per-mission costs. Being compatible with a variety of launch vehicles is definitely a step in the right direction on cost, but for CRS-2 they will have had to propose missions with a specific launch vehicle partner. Launching on Ariane isn't allowed by the CRS-2 rules, as I understand them, so unless SpaceX signed onto their bid (which I highly doubt for competive reasons), they're still stuck with Atlas V. With both LM and Boeing submitting competing CRS-2 bids, ULA probably didn't offer SNC a particularly special deal on Atlas V for DC for CRS-2.So I don't think they can compete with SpaceX on price for downmass. And OrbitalATK and LM proposals have much more cargo per trip, so I don't think they can compete with either of those bids.I think it's not impossible Dream Chaser could pick up something from CRS-2, but it's a long shot.I agree on the development costs and the long shot.The wing hinges fold so that the mechanisms have to hold them against the drag. Sounds difficult.The fairing simplifies the aerodynamics but adds cost and mass, which could mean extra solids on Atlas and even more cost.Does Cargo Dream Chaser still include the Dual Engine Centaur?(Does the LM's proposal use a single or dual engine Centaur?)Isn't that another element to be developed?The X-38 was to have folding wings so the idea is not "too off the wall"...
Quote from: ChrisWilson68 on 03/18/2015 04:29 amIt looks to me like the Dream Chaser Cargo has a much higher development cost and schedule risk than any of the other known CRS2 proposals. Not only do they have to do a huge amount of development on Dream Chaser itself, but they also have to develop a service module. The service module probably won't be developed entirely from scratch since SNC has some experience in the area, but I think they're a lot farther away from a service module than LM is from Jupiter.The service module is also going to add to their per-mission costs. Being compatible with a variety of launch vehicles is definitely a step in the right direction on cost, but for CRS-2 they will have had to propose missions with a specific launch vehicle partner. Launching on Ariane isn't allowed by the CRS-2 rules, as I understand them, so unless SpaceX signed onto their bid (which I highly doubt for competive reasons), they're still stuck with Atlas V. With both LM and Boeing submitting competing CRS-2 bids, ULA probably didn't offer SNC a particularly special deal on Atlas V for DC for CRS-2.So I don't think they can compete with SpaceX on price for downmass. And OrbitalATK and LM proposals have much more cargo per trip, so I don't think they can compete with either of those bids.I think it's not impossible Dream Chaser could pick up something from CRS-2, but it's a long shot.I agree on the development costs and the long shot.The wing hinges fold so that the mechanisms have to hold them against the drag. Sounds difficult.The fairing simplifies the aerodynamics but adds cost and mass, which could mean extra solids on Atlas and even more cost.Does Cargo Dream Chaser still include the Dual Engine Centaur?(Does the LM's proposal use a single or dual engine Centaur?)Isn't that another element to be developed?
It looks to me like the Dream Chaser Cargo has a much higher development cost and schedule risk than any of the other known CRS2 proposals. Not only do they have to do a huge amount of development on Dream Chaser itself, but they also have to develop a service module. The service module probably won't be developed entirely from scratch since SNC has some experience in the area, but I think they're a lot farther away from a service module than LM is from Jupiter.The service module is also going to add to their per-mission costs. Being compatible with a variety of launch vehicles is definitely a step in the right direction on cost, but for CRS-2 they will have had to propose missions with a specific launch vehicle partner. Launching on Ariane isn't allowed by the CRS-2 rules, as I understand them, so unless SpaceX signed onto their bid (which I highly doubt for competive reasons), they're still stuck with Atlas V. With both LM and Boeing submitting competing CRS-2 bids, ULA probably didn't offer SNC a particularly special deal on Atlas V for DC for CRS-2.So I don't think they can compete with SpaceX on price for downmass. And OrbitalATK and LM proposals have much more cargo per trip, so I don't think they can compete with either of those bids.I think it's not impossible Dream Chaser could pick up something from CRS-2, but it's a long shot.
I feel there is very little chance now especially that LM has thrown their hat into the ring. DCSS looks like it would take a lot of time & effort to get to where it needs to be & I just don't see that happening.
NASA has a tough choice ahead, but DCSS could squeak in.If SpaceX and Orbital get the primary CRS2 contracts as they did with CRS1, they'll again provide dissimilar services. SpaceX has its modest upmass thanks to the cramped capsule but also includes unpressurized upmass and extremely important return downmass capability. Orbital has much larger upmass due to the large volume of Cygnus and soon Enhanced Cygnus, and disposes of ISS's trash when it burns up after mission end.DCSS can backstop both craft: SpaceX's unpressurized upmass and return downmass, as well as Cygnus' large volume (with both DC's internal space and the pressurized external pod) and trash disposal (when the pod detaches and burns up during reentry). And if DCSS flies on Atlas V, then that's a third rocket providing services to the ISS, after SpaceX's Falcon 9 and Orbital's Antares (well, Antares II, I guess).With those three flying CRS2 missions, if any provider is forced to stand down launches, NASA won't lose any capability.
Quote from: Rocket Science on 03/18/2015 10:57 pmQuote from: Comga on 03/18/2015 10:45 pmThe wing hinges fold so that the mechanisms have to hold them against the drag. Sounds difficult.The fairing simplifies the aerodynamics but adds cost and mass, which could mean extra solids on Atlas and even more cost.The X-38 was to have folding wings so the idea is not "too off the wall"...Aircraft carrier fighter airplanes have been using them for decades. It ain't rocket science.
Quote from: Comga on 03/18/2015 10:45 pmThe wing hinges fold so that the mechanisms have to hold them against the drag. Sounds difficult.The fairing simplifies the aerodynamics but adds cost and mass, which could mean extra solids on Atlas and even more cost.The X-38 was to have folding wings so the idea is not "too off the wall"...
The wing hinges fold so that the mechanisms have to hold them against the drag. Sounds difficult.The fairing simplifies the aerodynamics but adds cost and mass, which could mean extra solids on Atlas and even more cost.
Quote from: Star One on 03/18/2015 07:27 pmI feel there is very little chance now especially that LM has thrown their hat into the ring. DCSS looks like it would take a lot of time & effort to get to where it needs to be & I just don't see that happening.And Jupiter/ExoLiner won't take a lot of time and effort?
A full, autonomous space tug versus a pressurized tin can with a docking adapter on the end?
A cargo version of Dream Chaser is likely simpler and easier than a crewed version -- what with not having to ensure astronaut safety and all, so no abort engines, no ECLSS -- and the crew version was only a couple of years from flying.
Folding wings and a fairing simplifies things, and folding wings have been used for decades on military aircraft pulling higher Gs than DC will returning from orbit.
Quote from: TrevorMonty on 03/18/2015 11:35 pmQuote from: Rocket Science on 03/18/2015 10:57 pmQuote from: Comga on 03/18/2015 10:45 pmThe wing hinges fold so that the mechanisms have to hold them against the drag. Sounds difficult.The fairing simplifies the aerodynamics but adds cost and mass, which could mean extra solids on Atlas and even more cost.The X-38 was to have folding wings so the idea is not "too off the wall"...Aircraft carrier fighter airplanes have been using them for decades. It ain't rocket science.Yeah, but the carrier airplane wings are folded by ground crews. They don't have to be folded autonomously in space.Nobody is arguing that it's impossible, just that it adds mass and complexity and cost. None of those things helps Dream Chaser cargo compete against the other proposals, none of which have to deal with folding wings.
Quote from: ChrisWilson68 on 03/19/2015 05:21 amQuote from: TrevorMonty on 03/18/2015 11:35 pmQuote from: Rocket Science on 03/18/2015 10:57 pmQuote from: Comga on 03/18/2015 10:45 pmThe wing hinges fold so that the mechanisms have to hold them against the drag. Sounds difficult.The fairing simplifies the aerodynamics but adds cost and mass, which could mean extra solids on Atlas and even more cost.The X-38 was to have folding wings so the idea is not "too off the wall"...Aircraft carrier fighter airplanes have been using them for decades. It ain't rocket science.Yeah, but the carrier airplane wings are folded by ground crews. They don't have to be folded autonomously in space.Nobody is arguing that it's impossible, just that it adds mass and complexity and cost. None of those things helps Dream Chaser cargo compete against the other proposals, none of which have to deal with folding wings.What makes you think the wings on carrier aircraft are folded by ground crew? Not that this small point makes any difference to the bigger argument, but there's no harm in being factually correct.
Quote from: adrianwyard on 03/19/2015 06:04 amQuote from: ChrisWilson68 on 03/19/2015 05:21 amQuote from: TrevorMonty on 03/18/2015 11:35 pmQuote from: Rocket Science on 03/18/2015 10:57 pmQuote from: Comga on 03/18/2015 10:45 pmThe wing hinges fold so that the mechanisms have to hold them against the drag. Sounds difficult.The fairing simplifies the aerodynamics but adds cost and mass, which could mean extra solids on Atlas and even more cost.The X-38 was to have folding wings so the idea is not "too off the wall"...Aircraft carrier fighter airplanes have been using them for decades. It ain't rocket science.Yeah, but the carrier airplane wings are folded by ground crews. They don't have to be folded autonomously in space.Nobody is arguing that it's impossible, just that it adds mass and complexity and cost. None of those things helps Dream Chaser cargo compete against the other proposals, none of which have to deal with folding wings.What makes you think the wings on carrier aircraft are folded by ground crew? Not that this small point makes any difference to the bigger argument, but there's no harm in being factually correct.I can't see why they would build a carrier aircraft with wings that can be folded by the pilot from the cockpit. It would be like designing a car that lets you remove the wheels from the driver's seat. It seems obvious to me it's better to require someone to physically go up to the wheel with a lug wrench and unbolt the wheel, both because it prevents accidental, catastrophic removal of the wheel while driving and because it would be a bunch of extra complexity that's not needed because there's no reason to remove the wheel except when the vehicle is stopped and you can physically access it.
We don't need suppositions when we have facts. Ladies and gentlemen, the E-2C, the EA-6B, the V-22, and the F/A-18. The last one is now the base platform for the vast majority of USAF carrier aircraft.
Quote from: Burninate on 03/19/2015 06:44 amWe don't need suppositions when we have facts. Ladies and gentlemen, the E-2C, the EA-6B, the V-22, and the F/A-18. The last one is now the base platform for the vast majority of USAF carrier aircraft.Not relevant. None of those perform reentry, have TPS on them or deal with high velocity hot gas.
I must have missed it but why would the cargo Dream Chaser need to be inside a fairing?