The existence of a cargo version of "Dragon 2" is just speculation
We know from imagery of the recent parachute drop test that Dragon 2 has a captive nosecone which presumably opens (somehow) to expose the docking/berthing interface on-orbit and closes for reentry, with a parachute system (for aborts only?) that deploys through a small opening in the tip of the closed nosecone.
But the cargo craft really has no need for any type of LAS support or ECLSS or internal view ports (windows or portals), so there is a huge opportunity for cost savings vs the crewed version.
Currently, NASA has stipulated that each Cargo Dragon be new so although they have not actually signed a contract with any potential provider for crew services yet, I suspect they will require a new Dragon for each crewed mission. But that certainly does not preclude SpaceX from re-using a crewed Dragon for another customer besides NASA.
Quote from: Elmar Moelzer on 01/08/2014 04:07 pmBut then, I am pretty sure that SpaceX wants to land ALL of their Dragons on land to allow reuse. That would require the cargo Dragons to be Dragon 2s as well.You can be pretty sure all you want, but I don't expect to see it during this CRS contract.
But then, I am pretty sure that SpaceX wants to land ALL of their Dragons on land to allow reuse. That would require the cargo Dragons to be Dragon 2s as well.
Quote from: Lars_J on 01/08/2014 03:53 pmThe existence of a cargo version of "Dragon 2" is just speculationQuantumG is claiming otherwise.Quote from: butters on 01/08/2014 04:07 pmWe know from imagery of the recent parachute drop test that Dragon 2 has a captive nosecone which presumably opens (somehow) to expose the docking/berthing interface on-orbit and closes for reentry, with a parachute system (for aborts only?) that deploys through a small opening in the tip of the closed nosecone.Dragon already has a nosecone, it's jettisoned during launch. The parachutes are on the side of Dragon not underneath the nosecone.Quote from: Lurker Steve on 01/08/2014 04:04 pmBut the cargo craft really has no need for any type of LAS support or ECLSS or internal view ports (windows or portals), so there is a huge opportunity for cost savings vs the crewed version. It does if they want to do terra firma landings.Quote from: rcoppola on 01/09/2014 01:07 amCurrently, NASA has stipulated that each Cargo Dragon be new so although they have not actually signed a contract with any potential provider for crew services yet, I suspect they will require a new Dragon for each crewed mission. But that certainly does not preclude SpaceX from re-using a crewed Dragon for another customer besides NASA.http://forum.nasaspaceflight.com/index.php?topic=28486.msg909803#msg909803
Quote from: manboy on 01/09/2014 01:17 amQuote from: Lars_J on 01/08/2014 03:53 pmThe existence of a cargo version of "Dragon 2" is just speculationQuantumG is claiming otherwise.Quote from: butters on 01/08/2014 04:07 pmWe know from imagery of the recent parachute drop test that Dragon 2 has a captive nosecone which presumably opens (somehow) to expose the docking/berthing interface on-orbit and closes for reentry, with a parachute system (for aborts only?) that deploys through a small opening in the tip of the closed nosecone.Dragon already has a nosecone, it's jettisoned during launch. The parachutes are on the side of Dragon not underneath the nosecone.Quote from: Lurker Steve on 01/08/2014 04:04 pmBut the cargo craft really has no need for any type of LAS support or ECLSS or internal view ports (windows or portals), so there is a huge opportunity for cost savings vs the crewed version. It does if they want to do terra firma landings.Quote from: rcoppola on 01/09/2014 01:07 amCurrently, NASA has stipulated that each Cargo Dragon be new so although they have not actually signed a contract with any potential provider for crew services yet, I suspect they will require a new Dragon for each crewed mission. But that certainly does not preclude SpaceX from re-using a crewed Dragon for another customer besides NASA.http://forum.nasaspaceflight.com/index.php?topic=28486.msg909803#msg909803As I already said, NASA wanted new Dragons for each cargo mission
Quote from: Lars_J on 01/08/2014 03:53 pmThe existence of a cargo version of "Dragon 2" is just speculationQuantumG is claiming otherwise.
Quote from: rcoppola on 01/09/2014 01:29 amQuote from: manboy on 01/09/2014 01:17 amhttp://forum.nasaspaceflight.com/index.php?topic=28486.msg909803#msg909803As I already said, NASA wanted new Dragons for each cargo missionThat does not appear to be entirely true (i.e. there isn't a requirement for them to be new Dragons). Read the comments in the thread attached above.
Quote from: manboy on 01/09/2014 01:17 amhttp://forum.nasaspaceflight.com/index.php?topic=28486.msg909803#msg909803As I already said, NASA wanted new Dragons for each cargo mission
http://forum.nasaspaceflight.com/index.php?topic=28486.msg909803#msg909803
Both Falcon 9 and Dragon are designed for reusability, but the costs as proposed assume no reusability economics. Until a given launch system has flown several times and all costs are understood, it is very risky to make reusability cost assumptions. However, SpaceX intends to work hard to make the reusability economics positive and has started that learning curve. with the Falcon 1 first stage. If such economics work out, there is the potential for substantial savings in cost per flight.
Quote from: manboy on 01/09/2014 01:39 amQuote from: rcoppola on 01/09/2014 01:29 amQuote from: manboy on 01/09/2014 01:17 amhttp://forum.nasaspaceflight.com/index.php?topic=28486.msg909803#msg909803As I already said, NASA wanted new Dragons for each cargo missionThat does not appear to be entirely true (i.e. there isn't a requirement for them to be new Dragons). Read the comments in the thread attached above.What manboy said. We've been through this discussion several times...CRS solicitation did not require new. CRS contract does not require new. NASA's requirement for the CRS contract was (per FAR) firm fixed price (FFP) not to exceed (NTE). Without knowing the economics of reuse, the CRS contract was necessarily bid on the assumption of no reuse, not due to any inherent NASA requirement. As SpaceX stated in their COTS proposal:QuoteBoth Falcon 9 and Dragon are designed for reusability, but the costs as proposed assume no reusability economics. Until a given launch system has flown several times and all costs are understood, it is very risky to make reusability cost assumptions. However, SpaceX intends to work hard to make the reusability economics positive and has started that learning curve. with the Falcon 1 first stage. If such economics work out, there is the potential for substantial savings in cost per flight.While that precedes CRS, I think we can safely say the "learning curve" and making "reusability economics positive" is still a work in progress.Moreover, SpaceX is already reusing Dragon components for CRS flights (IIRC that from a NAC presentation some time ago). It's not a matter of whether reuse is allowed, but what and when.
Regarding differences between the eventual crew and cargo Dragon, I have to wonder if it would be possible to build a single base vehicle with plug in modules to make it crewed? Docking adapter could be bolted into the CBM (just like how the station does it) as long as it is low profile enough to fit under the nose cone. Seats, displays, and life support systems could bolt into attachments inside the Dragon. This way you have a single production line for the spacecraft that only requires some post production installation to go from cargo to crew. This would seem to fit with how SpaceX looks towards efficiency.
If you look at the interior pictures of the crewed Dragon, parts of the seats already appear to be easily removable, so this may already be part of the design. You won't always be sending a full crew compliment, so sending additional cargo would make sense.
This may be a stupid question, but ill ask anyway. Will the CRS-3 Falcon have legs? They said that they would attempt recovery of the first stage, and I have herd that the legs will stop the spinning, so aren't they necessary? Thank You
We have two geostationary flights: SES and Thaicom and then we have got the orbital resupply mission for NASA, the CRS flight and it's on that CRS flight that we are going to try to bring the first stage back. We are hoping to put the landing legs on that stage. It's still debatable whether at that stage, we will land with landing legs in the ocean or land with landing legs on land. Either way, we do want it to have the landing legs on.
We are not going hold up that flight for landing legs. So if landing legs end up being delayed for any reason then we won't hold up the flight for that. But the full plan is to have landing legs on that mission. The schedule for that mission is mostly governed by upgrades to the Dragon spacecraft.
Wouldn't that be cheaper and more efficient to have only one version of Dragon, and only the embarked systems (batteries, panels, life support, etc...) would change between the cargo and human transport versions ?
Quote from: luinil on 01/10/2014 01:10 amWouldn't that be cheaper and more efficient to have only one version of Dragon, and only the embarked systems (batteries, panels, life support, etc...) would change between the cargo and human transport versions ?Yes but there may be some mass and volume issues; and there's a lot of stuff we don't know. Such as Falcon 9R's payload to LEO, Dragon's max payload mass (which would tell us how much margin they're working with) and what the mass of a CBM to NDS adapter would be. Also a CBM to NDS adapter may be too long to fit within the nose cap.
I think a good reason to use Dragon2 for cargo as well is to gain experience with landing on land and give the spacecraft more flight history prior to launching humans on it.
This plus land landing will facilitate reuse and has advantages in handling sensitive cargo. I also don't see NASA object to it in the present contract. They can find downmass they can risk losing for one flight once the present backlog of freezers is reduced.
You never see freighter versions of commercial aircraft used for passenger transport with palletised seating (unless you are military) because it is not efficient to use an aircraft optimised for cargo for passengers, I believe the same will be true of spacecraft.