Quote from: deruch on 05/07/2015 02:50 pmSpeaking of doing testing on actual (existing) flights, I wonder how hard it would be to begin using a model of Dragon 2 that is similar to the one just used in the pad abort test as the vehicle for later CRS missions. The thing already gets sent to LEO. It already undergoes an actual reentry. I realize some issues would be approaching ISS with that much hypergolic prop on board in a Dragon variant that has never been to ISS. Maybe the first of these would need to approach and berth with no prop for the SuperDracos. There is also the issue of getting approval of a landing site. Places that come to mind are Spaceport America, Mojave Desert around Edwards, maybe Kazakhstan, though were I Elon, I wouldn't want any chance of proprietary hardware falling into the wrong hands. Maybe even land the first ones on the ocean surface like Falcon stage 1 just to show it can be done.This is just off the top of the head thinking, I realize there would be substantial issues to deal with. OTOH, it would be somewhat like using existing launches to test stage 1 landings. Thoughts?
Quote from: guckyfan on 05/09/2015 09:13 pmThe trunk is used to provide stability during the boost phase, not or only secondary during the coast phase.I believe those things have not been discussed yet because the trunk with fins on abort was not known before.Wrong, it is there for the coast phase. It is not needed for the boost phase, the vehicle has active control. If it was not needed for the coast phase, it would not fly at all much less have fins.
The trunk is used to provide stability during the boost phase, not or only secondary during the coast phase.I believe those things have not been discussed yet because the trunk with fins on abort was not known before.
Somehow the lack of a CBM hatch on the Dragon 2 (aka Dragon V2, crewed Dragon, Dragonrider, etc) make it very unlikely.
Quote from: Zed_Noir on 05/10/2015 12:35 amSomehow the lack of a CBM hatch on the Dragon 2 (aka Dragon V2, crewed Dragon, Dragonrider, etc) make it very unlikely.Not to mention lack of a grapple fixture.
I wonder if they'll bother with tethered flight tests?I probably would.
Quote from: TomH on 05/10/2015 12:04 amQuote from: deruch on 05/07/2015 02:50 pmSpeaking of doing testing on actual (existing) flights, I wonder how hard it would be to begin using a model of Dragon 2 that is similar to the one just used in the pad abort test as the vehicle for later CRS missions. The thing already gets sent to LEO. It already undergoes an actual reentry. I realize some issues would be approaching ISS with that much hypergolic prop on board in a Dragon variant that has never been to ISS. Maybe the first of these would need to approach and berth with no prop for the SuperDracos. There is also the issue of getting approval of a landing site. Places that come to mind are Spaceport America, Mojave Desert around Edwards, maybe Kazakhstan, though were I Elon, I wouldn't want any chance of proprietary hardware falling into the wrong hands. Maybe even land the first ones on the ocean surface like Falcon stage 1 just to show it can be done.This is just off the top of the head thinking, I realize there would be substantial issues to deal with. OTOH, it would be somewhat like using existing launches to test stage 1 landings. Thoughts?Somehow the lack of a CBM hatch on the Dragon 2 (aka Dragon V2, crewed Dragon, Dragonrider, etc) make it very unlikely.
Quote from: Robotbeat on 05/09/2015 07:11 pmI wonder if they'll bother with tethered flight tests?I probably would.They probably won't.The drop tests should validate precision control. Take-offs from the pad for parachute-assisted landings will validate take-off control. Hopping should round out the envelope.Their testing boldness continues to increase as shown by just-completed pad abort where eight engine performance was demo'd 24 hrs before live launch from a pad they have fully booked.
Quote from: AncientU on 05/10/2015 12:28 pmQuote from: Robotbeat on 05/09/2015 07:11 pmI wonder if they'll bother with tethered flight tests?I probably would.They probably won't.The drop tests should validate precision control. Take-offs from the pad for parachute-assisted landings will validate take-off control. Hopping should round out the envelope.Their testing boldness continues to increase as shown by just-completed pad abort where eight engine performance was demo'd 24 hrs before live launch from a pad they have fully booked.I don't expect them to fly tethered tests. But I certainly would as that's a lot cheaper than building a new expensive spacecraft.
Quote from: Zed_Noir on 05/10/2015 12:35 amQuote from: TomH on 05/10/2015 12:04 amQuote from: deruch on 05/07/2015 02:50 pmSomehow the lack of a CBM hatch on the Dragon 2 (aka Dragon V2, crewed Dragon, Dragonrider, etc) make it very unlikely.CRS-2 actually allowed for IDA equipped vehicles. And I doubt that they'll will waste the uncrewed demonstration flight and thus it won't flight empty. I wouldn't be surprised if SpaceX actually wins a fat contract in CRS-2 (a likely outcome), they might offer an uncrewed Dragon v2 as a one-off mission. For CRS-2 it will offer cargo without the cost of crew time required for training and actual berthing operation, and it wouldn't conflict with any CBM CVV. It could also sand unpressurized cargo that's not well behaved in an abort situation. And it would allow to certify the propulsive (assited?) landing. Size limited unpressurized cargo might be manifested on a different flight.Now, how does this affects DragonFly? Well, I believe that the cheapest opportunity to certify the Crewed Dragon for propulsive landing would be the Uncrewed Flight. But it would seem like they won't go that route and DragonFly might actually happen after it. Besides, they must have a mountain of certificates in development for water landing and redoing it for propulsive landing will take a while. And SpaceX wants that flag!Thus, I would assume, that the next cheapest and safest way is to do the DragonFly program after Uncrewed Flight, and once all the kinks are out, they can negotiate a single Dragon v2 flight within their CRS-2 program, with the specific purpose of demonstrating the propulsive landing. It would also allow for a significant amount of downmass with a relatively gentle landing and could probably be in the hands of investigators at L+4hrs. Nothing that CST-100 Cargo wouldn't offer. But a nice thing to have if it doesn't cost anything.
Quote from: TomH on 05/10/2015 12:04 amQuote from: deruch on 05/07/2015 02:50 pmSomehow the lack of a CBM hatch on the Dragon 2 (aka Dragon V2, crewed Dragon, Dragonrider, etc) make it very unlikely.
Quote from: deruch on 05/07/2015 02:50 pm
What you suggest seems doable with a restricted cargo manifest. However don't think NASA will go for it.
They have to fly it unmanned to test it. It will go to ISS. Why send it empty when smaller cargo items that are able to fit through the hatch can be carried to the station? This would not be a regular resupply mission, but at the cost/Kg of cargo, sending it empty rather than with cramming it full of smaller cargo just doesn't make sense.
So Chris' latest article http://www.nasaspaceflight.com/2015/07/saving-spaceship-dragon-contingency-chute/ indicates that the first uncrewed Dragon2 will carry cargo, and that there may also be a second uncrewed Dragon2 which would also carry cargo. My question is this, being that the vehicle is uncrewed, how likely is it that the SuperDracos could be tested in a DragonFly landing scenario? Or would the first docking attempt of the spacecraft with ISS be too risky to carry the hypergolics aboard? What if the first flight is done successfully with no hypergolics, if there is a second uncrewed Dragon2, might they try a DragonFly landing on that flight? Or is DragonFly too far down the line to attempt it so early? After enough manned Dragon2 vehicles fly, I assume the first DragonFly landing will have to be an unmanned test. It just seems that the initial unmanned flight of Dragon2 to ISS would also be a good opportunity to test the powered landing ability of DragonFly.