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All New For NASA
SpaceX will only use brand new Dragon V2 craft for NASA crew missions.
Both SpaceX and Boeing were offered the option of reflying capsules and Boeing plans to do so, landing on dry land on airbags and then reflying each of their capsules up to 10 times. SpaceX, however, has announced that they will only use new spacecraft for NASA crewed missions (and still compete on costs because Falcon 9 is so much cheaper than any ULA launcher). So what happens with all the 'gently used' capsules that will be stacking up at SpaceX? Apparently the plan is to switch them to cargo versions and use them to fly ISS resupply missions under the next NASA Commercial Cargo contract. This will let SpaceX do the cargo launches for less than half the price of any competitors. Some number of Crew Dragon could presumably also be used for non-NASA launches. -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
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All New For NASA
JF Mezei wrote on Wed, 29 Aug 2018
16:58:39 -0400: On 2018-08-29 13:27, Fred J. McCall wrote: SpaceX will only use brand new Dragon V2 craft for NASA crew missions. How much work is needed to refurb a Dragon V1,0 for reflight? Do they have to get it back to bare shell and re-insall all components? Or just pass it through a car wash to remove salt water on the outside and refly it? Closer to the latter. Given Dragon V1 experience, it will probably take several months to clean up and test. For crewed version, after splash down in salt water, will NASA insist on extracting crews from a floating capsule, or will they lift capsule onto deck of ship and then open hatch? (aka: salt water ingress). I think the plan is to pick up capsule, crew, and all and open it up on deck, but I don't find anything definitive. Another big variable is ship's "best before" date. A Dragon that has spent 6 months docked to ISS may require full tear down because many components are past their "best before" dates. And monkeys may fly out my butt. They'll need to replenish consumables plus do cleanup from salt water immersion. There is very little that rots after 6 months. It becomes simpler to refit the bare shell as cargo with fewer comonents that require less testing to recertifty for flight. That's not how it works. There is a lot of commonality between crewed and cargo versions. Also need to look at flight rate. With demand split between 2 suppliers, SpaceX may have plenty of time to build a new crewed Dragon for each flight, and if it needs more cargo flights, it makes sense to recycle the crewed capsule into cargo. Since their plan is to use a new Crew Dragon for each flight they'd BETTER have time to get a new one ready. -- "Some people get lost in thought because it's such unfamiliar territory." --G. Behn |
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All New For NASA
Jeff Findley wrote on Thu, 30 Aug 2018
07:06:45 -0400: In article , says... SpaceX will only use brand new Dragon V2 craft for NASA crew missions. Both SpaceX and Boeing were offered the option of reflying capsules and Boeing plans to do so, landing on dry land on airbags and then reflying each of their capsules up to 10 times. SpaceX, however, has announced that they will only use new spacecraft for NASA crewed missions (and still compete on costs because Falcon 9 is so much cheaper than any ULA launcher). So what happens with all the 'gently used' capsules that will be stacking up at SpaceX? Apparently the plan is to switch them to cargo versions and use them to fly ISS resupply missions under the next NASA Commercial Cargo contract. This will let SpaceX do the cargo launches for less than half the price of any competitors. Some number of Crew Dragon could presumably also be used for non-NASA launches. Actually their CRS2 contract is going to cost NASA more money than their CRS1 contract. Yes, I know. But after the price increase they're still estimated to be 50%-75% cheaper than the competition. I'm sure that if they simply let to the 'best value' bidder SpaceX would wind up with all the business. But they have 'no more single point failures' as part of their objective, so they're going to buy much more expensive launches to keep the competition in business. -- "Millions for defense, but not one cent for tribute." -- Charles Pinckney |
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All New For NASA
Jeff Findley wrote on Thu, 30 Aug 2018
07:10:56 -0400: In article , says... It becomes simpler to refit the bare shell as cargo with fewer comonents that require less testing to recertifty for flight. That's not how it works. There is a lot of commonality between crewed and cargo versions. That's my understanding. Conversion to cargo configuration will involve taking out the seats, crew consoles, life support, and etc. Essentially it means unbolting, unplugging, and removing components that simply aren't needed. That's essentially correct. There are also some additions (like addition of cargo racks, both pressurized and unpressurized). It apparently looks like this: https://www.teslarati.com/spacex-no-...modifications/ -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
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All New For NASA
JF Mezei wrote on Thu, 30 Aug 2018
11:24:52 -0400: On 2018-08-30 07:10, Jeff Findley wrote: That's my understanding. Conversion to cargo configuration will involve taking out the seats, crew consoles, life support, and etc. Essentially it means unbolting, unplugging, and removing components that simply aren't needed. And adding the structural supports for cargo. (aka glorified shelves/racks or whatever). However, if the insides of the Dragon are re-usable easily and not damaged by a flight/landing, why go through the trouble of changing in inside config from a crewed one proven to work to a cargo one ? Because there are a lot more cargo flights than crewed flights. It isn't just the "bolted on" consoles, but also all wiring harnesses. If the wiring is 'built in' and not just strung all over Hell's half acre you can just leave it in place after you unplug the consoles. I wonder if Musk/SpaceX will ever explain what arguments were used to decide that crewed shouldn't be re-usable as crewed. Because even flying new they're cheaper than Boeing because Boeing uses a ULA booster, so they can get NASA to pay to buy the Crew Dragon new, which subsidizes the cargo side of things. As far as the heat shield, does SpaceX just "spray" new ablative material over existing used heat shield to bring it back to proper thickeness, or does it strip the whole thing out and spray on a totally new heat shield? Does either change the level of trust in its ability to support crewed re-entry? (aka: heat shield with new top layer vs totally new heat shield). Neither one of those. The heat shield is thick enough to stand multiple LEO reentries (something like 10) without any maintenance. Some of it ablates away every flight, but not enough to require replacement. -- You have never lived until you have almost died. Life has a special meaning that the protected will never know. |
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All New For NASA
"JF Mezei" wrote in message ...
On 2018-08-30 07:10, Jeff Findley wrote: That's my understanding. Conversion to cargo configuration will involve taking out the seats, crew consoles, life support, and etc. Essentially it means unbolting, unplugging, and removing components that simply aren't needed. And adding the structural supports for cargo. (aka glorified shelves/racks or whatever). However, if the insides of the Dragon are re-usable easily and not damaged by a flight/landing, why go through the trouble of changing in inside config from a crewed one proven to work to a cargo one ? It isn't just the "bolted on" consoles, but also all wiring harnesses. I wonder if Musk/SpaceX will ever explain what arguments were used to decide that crewed shouldn't be re-usable as crewed. NASA is always conservative (other than crewed STS-1 :-) So my guess is it ultimately came down to: "because we said so" and everything else was justification for that. And my guess is after 3-4 flights, NASA will relent and go with a refurbished crew capsule. -- Greg D. Moore http://greenmountainsoftware.wordpress.com/ CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net IT Disaster Response - https://www.amazon.com/Disaster-Resp...dp/1484221834/ |
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