"Used" Dragons

[wkann]

I was re-watching the CRS-3 webcast and saw this screen shot with 3 of the 4 flown Dragon Spacecraft. (I know the COTS-1 spacecraft is hanging in Hawthorne). I’m assuming this is at McGregor?

Since Dragon is considered to be a partially reusable spacecraft, does anyone know if these will fly again? Or if there “scrapped” of there electronics and propulsion systems and those parts are being reused?

Also, I know this is off topic, but since we know SpaceX is hanging on to their Dragons, what do the Russians do with the recovered Soyuz Descent Module? I’m guessing they are scrapped?

[Coastal Ron]

The current CRS contract with NASA requires new spacecraft for each delivery, so the only customer for a used Dragon would be for DragonLab.  As of today there are two DragonLab missions SpaceX shows on their manifest, with the earliest being the fourth payload listed in 2016.

I would imagine they will use a more recently flown Dragon for the DragonLab missions since those will have all the latest hardware and software updates, but overall SpaceX will have 12 slightly-used (or "fully tested") cargo versions of Dragon available by the end of the current CRS contract.

I would imagine that when SpaceX bids for the CRS-2 contract they might submit two bids, one with new-build Dragons, and one with reused ones.  For a number of reasons, I hope NASA selects the reused ones.

[QuantumG]

The current CRS contract with NASA requires new spacecraft for each delivery,

Where does it say that?

I think this forum has had this discussion about a dozen times.

[Chris Bergin]

The current CRS contract with NASA requires new spacecraft for each delivery,

Where does it say that?

I think this forum has had this discussion about a dozen times.

I've certainly heard that started several times. Currently, for some reason, CRS Dragons have to be new. Not sure why.

[bilbo]

The current CRS contract with NASA requires new spacecraft for each delivery, so the only customer for a used Dragon would be for DragonLab.  As of today there are two DragonLab missions SpaceX shows on their manifest, with the earliest being the fourth payload listed in 2016.

I would imagine they will use a more recently flown Dragon for the DragonLab missions since those will have all the latest hardware and software updates, but overall SpaceX will have 12 slightly-used (or "fully tested") cargo versions of Dragon available by the end of the current CRS contract.

I would imagine that when SpaceX bids for the CRS-2 contract they might submit two bids, one with new-build Dragons, and one with reused ones.  For a number of reasons, I hope NASA selects the reused ones.

I'm curious as well, I'm guessing they obviously study the heat shield for analysis. Other then that though im not really sure what they do. They could possibly be studying some small parts of them like the thrusters.

I think if Coastal is correct, then NASA requires new capsules, they really don't have to re-use them. I think NASA is just trying to get SpaceX to Build up their fleet.

Another idea is that Space X is planning on reusing Dragon Mk2, since they can use it for both a human flight, and cargo landing/crew on Mars perhaps.

[Joffan]

The current CRS contract with NASA requires new spacecraft for each delivery, ...

I think not. The CRS contract is priced for a new spacecraft for each delivery, and certainly that path is one that requires least additional justification, but as far as I know (from many discussions here on NSF) there is no absolute requirement for it.

...so the only customer for a used Dragon would be for DragonLab.  As of today there are two DragonLab missions SpaceX shows on their manifest, with the earliest being the fourth payload listed in 2016.

I could imagine a Bigelow station needs supplies - I know this is speculative but it's another possible use, and no doubt someone more imaginative than me could think of more uses and customers.

I would imagine they will use a more recently flown Dragon for the DragonLab missions since those will have all the latest hardware and software updates, but overall SpaceX will have 12 slightly-used (or "fully tested") cargo versions of Dragon available by the end of the current CRS contract.

I would imagine that when SpaceX bids for the CRS-2 contract they might submit two bids, one with new-build Dragons, and one with reused ones.  For a number of reasons, I hope NASA selects the reused ones.

I'm with you on this, although there still might be some new Dragons required if there is some upgraded capability required on certain missions. And SpaceX might want to retire them after a certain number of missions anyway, so mix in a trickle of new Dragons into that contract submission .

[Avron]

The current CRS contract with NASA requires new spacecraft for each delivery,

Where does it say that?

I think this forum has had this discussion about a dozen times.

I've certainly heard that started several times. Currently, for some reason, CRS Dragons have to be new. Not sure why.

Could be in the baseline requirement  i.e open for review via acceptance criteria .. TBD.. i.e not open at this time

[Jim]

All NASA said to Spacex was to bid the costs of new vehicles since refurb costs were unknown at the time.  And since they did, NASA gets a new Dragon each mission.

[QuantumG]

The contract is public information right? I remember reading it. Pretty sure I got a copy from this forum.

[clongton]

All NASA said to Spacex was to bid the costs of new vehicles since refurb costs were unknown at the time.  And since they did, NASA gets a new Dragon each mission.

That is correct.The contract did not specify "only" a new Dragon could be flown, but SpaceX was instructed to price each spacecraft at the "new" price because the cost to refurbish and re-certify a flown Dragon was unknown. It is to SpaceX's advantage therefore to supply a new Dragon for each CRS mission and keep the already flown (and paid for) reusable spacecraft for their own developing in-house spaceflight program. Whether new or used, SpaceX retains ownership of the spacecraft itself. It is an interesting opportunity for SpaceX to build up its own in-house fleet of successfully flown reusable spacecraft on NASA's dime. SpaceX will only need to fund the refurbishment and re-certification costs.

[Rocket Science]

My understanding was that NASA gets a new spacecraft and Elon gets a free spacecraft as a result which he will refurbish/refit for future flights including tourism. This is made possible since Dragon was designed to be human rated from the beginning...

Hah, what Chuck said above...

[Coastal Ron]

The contract did not specify "only" a new Dragon could be flown, but SpaceX was instructed to price each spacecraft at the "new" price because the cost to refurbish and re-certify a flown Dragon was unknown.

Thanks to all for the clarifications and corrections to what I originally said.

And the bottom line for SpaceX is a good one - a fleet of already proven spacecraft that should cost far less to re-fly for cargo missions than building new.  And if they fly them on top of a F9R, that could really be a paradigm changer...

[TrevorMonty]

Long term Dragon 2 will replace Dragon1 which may make these used Dragons obsolete. One possible use is expendable missions eg supplying an L2 station, or for deep space experiments.

[yg1968]

The contract is public information right? I remember reading it. Pretty sure I got a copy from this forum.

Yes, see this link:
http://www.nasa.gov/centers/johnson/news/contracts/NNJ09GA04B/NNJ09GA04B_prt.htm

[QuantumG]

It is to SpaceX's advantage therefore to supply a new Dragon for each CRS mission and keep the already flown (and paid for) reusable spacecraft for their own developing in-house spaceflight program.

It's also to their advantage to refurbish a Dragon and fly it again, if it costs less than a new Dragon. Assuming mission success, they get paid the same either way. So why haven't they? Surely, making a bigger profit on a signed contract makes a lot more sense than building up a supply for some unspecified future business. Maybe they're not so certain of mission success with a refurbished Dragon?

[Lar]

It is to SpaceX's advantage therefore to supply a new Dragon for each CRS mission and keep the already flown (and paid for) reusable spacecraft for their own developing in-house spaceflight program.

It's also to their advantage to refurbish a Dragon and fly it again, if it costs less than a new Dragon. Assuming mission success, they get paid the same either way. So why haven't they? Surely, making a bigger profit on a signed contract makes a lot more sense than building up a supply for some unspecified future business. Maybe they're not so certain of mission success with a refurbished Dragon?

I agree. And I'd expect it tried sometime before CRS-12.

But maybe they want to build up the fleet a bit or the design hasn't stabilised yet? (why reuse one you know is wrong when a better one is in the wings). Or maybe they're just too busy right now and wil have time in a flight or 3... So ya, I think they will, just not next flight.

[RocketmanUS]

It is to SpaceX's advantage therefore to supply a new Dragon for each CRS mission and keep the already flown (and paid for) reusable spacecraft for their own developing in-house spaceflight program.

It's also to their advantage to refurbish a Dragon and fly it again, if it costs less than a new Dragon. Assuming mission success, they get paid the same either way. So why haven't they? Surely, making a bigger profit on a signed contract makes a lot more sense than building up a supply for some unspecified future business. Maybe they're not so certain of mission success with a refurbished Dragon?

I agree. And I'd expect it tried sometime before CRS-12.

But maybe they want to build up the fleet a bit or the design hasn't stabilised yet? (why reuse one you know is wrong when a better one is in the wings). Or maybe they're just too busy right now and wil have time in a flight or 3... So ya, I think they will, just not next flight.

A little bit of upgrades each flight as they learn more.
They will want them quick turn around and at as little cost as possible. That should be after the first land-landing.

They might reuse one for a Dragon Lab mission, less to risk and  no risk for CRS/ISS.

[Coastal Ron]

It is to SpaceX's advantage therefore to supply a new Dragon for each CRS mission and keep the already flown (and paid for) reusable spacecraft for their own developing in-house spaceflight program.

It's also to their advantage to refurbish a Dragon and fly it again, if it costs less than a new Dragon. Assuming mission success, they get paid the same either way. So why haven't they? Surely, making a bigger profit on a signed contract makes a lot more sense than building up a supply for some unspecified future business. Maybe they're not so certain of mission success with a refurbished Dragon?

Could be they haven't had enough employee "bandwidth" to work on reusability yet due to all the other activities they have going on (upgraded Dragon cargo, Dragon MK2, Grasshopper, F9 v1.1, F9R, etc.).  Maybe part of the bump in employment from 3,500 to 4,500 will provide that bandwidth for later flights.

Compared to all the other activities they have been working on, reusing cargo vehicles may have been near the bottom of their priority list, especially since their customer is happy with the existing contract.

[CuddlyRocket]

It is to SpaceX's advantage therefore to supply a new Dragon for each CRS mission and keep the already flown (and paid for) reusable spacecraft for their own developing in-house spaceflight program.

It's also to their advantage to refurbish a Dragon and fly it again, if it costs less than a new Dragon. Assuming mission success, they get paid the same either way. So why haven't they? Surely, making a bigger profit on a signed contract makes a lot more sense than building up a supply for some unspecified future business. Maybe they're not so certain of mission success with a refurbished Dragon?

Can you imagine the slating SpaceX would get if they used a refurbished Dragon on their taxpayer-funded NASA contract and it failed?! The political and PR risk is too great; especially as they're being paid for a new Dragon in any event.

Refurbished Dragons will first be used either on a SpaceX test flight (perhaps the FH) or where a customer has specifically contracted for a refurb accepting the risks for a cheaper price. There are no such customers at present.

[clongton]

It is to SpaceX's advantage therefore to supply a new Dragon for each CRS mission and keep the already flown (and paid for) reusable spacecraft for their own developing in-house spaceflight program.

It's also to their advantage to refurbish a Dragon and fly it again, if it costs less than a new Dragon. Assuming mission success, they get paid the same either way. So why haven't they?

Because if they refurbish a Dragon and fly it again for CRS, that's one new Dragon they don't get to have NASA pay for.
So while NASA is paying for new Dragons, build new Dragons. Every new one is an additional Dragon in the barn that they don't have to pay for themselves. It's pure economics - nothing more.

[dasmoth]

Because if they refurbish a Dragon and fly it again for CRS, that's one new Dragon they don't get to have NASA pay for.
So while NASA is paying for new Dragons, build new Dragons. Every new one is an additional Dragon in the barn that they don't have to pay for themselves. It's pure economics - nothing more.

It's a fixed price contract, right?  So a reused Dragon == spare cash for Raptor development or whatever.

So it comes down to whether or not they want that many dragons in the barn.  And/or how much it costs to refurbish one after salt water immersion.

[Rocket Science]

Because if they refurbish a Dragon and fly it again for CRS, that's one new Dragon they don't get to have NASA pay for.
So while NASA is paying for new Dragons, build new Dragons. Every new one is an additional Dragon in the barn that they don't have to pay for themselves. It's pure economics - nothing more.

It's a fixed price contract, right?  So a reused Dragon == spare cash for Raptor development or whatever.

So it comes down to whether or not they want that many dragons in the barn.  And/or how much it costs to refurbish one after salt water immersion.

A good metric may be when they begin to perform propulsive landings and avoiding any salt water immersion...

[aero]

Maybe SpaceX should start transporting cargo to the ISS using crew Dragons. That way they get to test fly the crew Dragons and end up with a more valuable/versatile Dragon when it is recovered, paid for by the current contract. Of course it would cost them money now based on the nature of the contract.

[meekGee]

All NASA said to Spacex was to bid the costs of new vehicles since refurb costs were unknown at the time.  And since they did, NASA gets a new Dragon each mission.

Interesting.  If that's ALL that NASA said, than I read it differently.

I read it that NASA told SpaceX to bid the *costs* of new vehicles, since given the financial unknowns, a bid that already takes capsule reuse into account my turn out to be such a losing proposition that SpaceX will not be able to uphold the contract.   Also maybe, cost-wise, NASA also wanted to compare apples to apples.

But if the contract doesn't specify new Dragons,  and SpaceX can perform the tasks using used Dragons, than I don't see why NASA would object.

[MP99]

It is to SpaceX's advantage therefore to supply a new Dragon for each CRS mission and keep the already flown (and paid for) reusable spacecraft for their own developing in-house spaceflight program.

It's also to their advantage to refurbish a Dragon and fly it again, if it costs less than a new Dragon. Assuming mission success, they get paid the same either way. So why haven't they? Surely, making a bigger profit on a signed contract makes a lot more sense than building up a supply for some unspecified future business. Maybe they're not so certain of mission success with a refurbished Dragon?

I agree. And I'd expect it tried sometime before CRS-12.

But maybe they want to build up the fleet a bit or the design hasn't stabilised yet? (why reuse one you know is wrong when a better one is in the wings). Or maybe they're just too busy right now and wil have time in a flight or 3... So ya, I think they will, just not next flight.

A little bit of upgrades each flight as they learn more.
They will want them quick turn around and at as little cost as possible. That should be after the first land-landing.

They might reuse one for a Dragon Lab mission, less to risk and  no risk for CRS/ISS.

Elon has said they didn't really know what they were doing when they designed Dragon, which they will fix with a later iteration. Not really sure if this is v2 or DragonRider, or in fact those will be much the same thing. [Edit: see below.]

We know there were mods to the CRS-3 dragon (increased freezer power, waterproofing, etc), which probably contributed to the delay of that flight.

I suspect they'll not want to re-fly their current stock, unless maybe for some form of DragonLab.

Edit:-

@elonmusk  Apr 29
Sounds like this might be a good time to unveil the new Dragon Mk 2 spaceship that @SpaceX has been working on with @NASA. No trampoline needed

‏@elonmusk
Cover drops on May 29. Actual flight design hardware of crew Dragon, not a mockup.

cheers, Martin

[meekGee]

I suspect they'll not want to re-fly their current stock, unless maybe for some form of DragonLab.

Very much so.
SpaceX doesn't cling.

[manboy]

Maybe SpaceX should start transporting cargo to the ISS using crew Dragons. That way they get to test fly the crew Dragons and end up with a more valuable/versatile Dragon when it is recovered, paid for by the current contract. Of course it would cost them money now based on the nature of the contract.

That wouldn't be possible until the first International Docking Adapter (IDA) gets launched, which is currently slated for April 2015 on SpX CRS-7. Also the NASA Docking Adapter has a smaller passthrough diameter than the Common Berthing Mechanism (which is what Cargp Dragon uses), which would limit the size of volumetrically larger payloads that could be delivered.

[clongton]

Maybe SpaceX should start transporting cargo to the ISS using crew Dragons. That way they get to test fly the crew Dragons and end up with a more valuable/versatile Dragon when it is recovered, paid for by the current contract. Of course it would cost them money now based on the nature of the contract.

There will be no differences between cargo Dragon and crew Dragon except that crew accommodations are removed to make room for cargo accommodations. I expect there to be a single manufacturing line for Dragon, with 2 final destination stations; 1 for crew and 1 for cargo for appropriate outfitting, which would include the appropriate docking or birthing mechanism. They are and will be the same basic vehicle. SpaceX will not be building or flying 2 different spacecraft.

[swervin]

WRT possible reuses of a Dragon spacecraft: how high of an orbit can a F9 get the spacecraft, in a 'mostly empty' state? Seems a possible useful test would be to test a very FAST re-entry (similar to what NASA is going to do, I think, with Orion) to gather more data on just how much the PICA-X heat shield can take?

I definitely agree with most postings above though, why not build new spacecraft for each mission. This builds up not only add'l capsules, but the processes and knowledge gained by producing more capsules can streamline said process in later iterations with lessons learned.

I think it will be some time until reuse occurs, however, as their manifest is way to packed to take on another 'experiment' right now, IMO -- regardless of how much I want to see it! :-) Possible contender for an early FH test launch, however... if they do not find a commercial company willing to be the first to ride along?

Cheers,
Splinter

[CraigLieb]

I want one!
 They should put one of these on a truck and tour every high school and college in the nation! Will cause a surge in science and math not to mention aerospace education desires in young people.

[Lars_J]

Maybe SpaceX should start transporting cargo to the ISS using crew Dragons. That way they get to test fly the crew Dragons and end up with a more valuable/versatile Dragon when it is recovered, paid for by the current contract. Of course it would cost them money now based on the nature of the contract.

There will be no differences between cargo Dragon and crew Dragon except that crew accommodations are removed to make room for cargo accommodations. I expect there to be a single manufacturing line for Dragon, with 2 final destination stations; 1 for crew and 1 for cargo for appropriate outfitting, which would include the appropriate docking or birthing mechanism. They are and will be the same basic vehicle. SpaceX will not be building or flying 2 different spacecraft.

No, the modifications on Crew Dragon appear to be incompatible with a CBM berthing port. The parachutes have been shifted around, and the drogues will now be situated around the docking ring. (No room for a CBM ring)

See image #1 - and compare with image #2, which shows the size of the CBM ring.

This assumes that the test article was using accurate drogue placement, but presumably it was, otherwise the test was not as representative as it could have been.

[docmordrid]

This cropped freeze frame from the 'chute test shows the early deployment.

[MickQ]

Prime candidates for Mars EDL test/Red dragon missions. IMHO.

Mick.

[clongton]

SpaceX is not going to build 2 different Dragons. That goes against the fundamental design concept of the vehicle. Musk has stated many times that there will be only 1 spacecraft, with appropriate mods for mission definition (cargo v.s. crew).

[swervin]

Slightly OT, but still on the same theme of re-usability. Are any parts reused between flights?

Specifically:
a) The grapple fixture
b) The CBM ring
c) Any internal fixtures, racks, ECS's, etc

Seems some of these parts would be easier reused and just make sense to do so. Is the CBM ring supplied by NASA?

Thanks,
Splinter

[Lars_J]

SpaceX is not going to build 2 different Dragons. That goes against the fundamental design concept of the vehicle. Musk has stated many times that there will be only 1 spacecraft, with appropriate mods for mission definition (cargo v.s. crew).

I'm glad you seem to know that with such "certainty". Because it goes against all evidence so far.

When has he stated that "there will only be 1 spacecraft"?

[Llian Rhydderch]

SpaceX is not going to build 2 different Dragons. That goes against the fundamental design concept of the vehicle. Musk has stated many times that there will be only 1 spacecraft, with appropriate mods for mission definition (cargo v.s. crew).

I'm glad you seem to know that with such "certainty". Because it goes against all evidence so far.

When has he stated that "there will only be 1 spacecraft"?

I took clongton's statement just a bit diffferently.  Not that there are not now, currently, two different models of Dragon.  There clearly are:  the cargo crew Dragon currently flying on CRS-3 (which is a "Dragon v2" with upgraded power and avionics), and perhaps with others in the production pipeline (as we've seen) for future CRS flights); and the new SuperDraco-included Dragons that will be unveiled late this month, and will participate in the ground-abort test and launch-abort test in the coming months.

I took his statement simply to mean that once the newer crew Dragons are development complete, and fully qualified, that SpaceX would likely have just a single Dragon production line, with a single base model Dragon, that could then be set up with or without seats, and with or without SuperDracos, depending on mission.


^{Edited:  changed "crew" to "cargo"; right thought in my head, didn't make it to phosphor.   Now fixed!   Thanks LarsJ!}

 

[Lars_J]

What? CRS-3 is not a crew dragon. The dragon that will be unveiled later this month is crew dragon - aka "dragon 2".

[InfraNut2]

I took clongton's statement just a bit diffferently.  Not that there are not now, currently, two different models of Dragon.  There clearly are:  the crew Dragon currently flying on CRS-3 (which is a "Dragon v2" with upgraded power and avionics), and perhaps with others in the production pipeline (as we've seen) for future CRS flights); and the new SuperDraco-included Dragons that will be unveiled late this month, and will participate in the ground-abort test and launch-abort test in the coming months.

Dragon V2 is the docking and land-landing capable dragon initially intended for crew transport. CRS-3 dragon is upgraded but not a new main version. It have been called Dragon v1.5 on one occasion, but that seems a bit high a version number, since the only confirmed changes are improved power system that can provide much more power to payloads and more waterproof solutions for electronics boxes in the unpressurized but internal part of dragon. Perhaps the upgrades are much more extensive than what is confirmed -- It would probably be smart to "backport" much of the minor v1.x compatible changes intended for V2 back into v1.x cargo dragons to get them tested early, spread out the risks on more than one flight and avoid unnecessary parallel versions of subsystems.

edit: typos etc.

[yg1968]

SpaceX is not going to build 2 different Dragons. That goes against the fundamental design concept of the vehicle. Musk has stated many times that there will be only 1 spacecraft, with appropriate mods for mission definition (cargo v.s. crew).

I'm glad you seem to know that with such "certainty". Because it goes against all evidence so far.

When has he stated that "there will only be 1 spacecraft"?

It has been stated that Cargo Dragon will eventually have propulsive landing.

[yg1968]

I took clongton's statement just a bit diffferently.  Not that there are not now, currently, two different models of Dragon.  There clearly are:  the crew Dragon currently flying on CRS-3 (which is a "Dragon v2" with upgraded power and avionics), and perhaps with others in the production pipeline (as we've seen) for future CRS flights); and the new SuperDraco-included Dragons that will be unveiled late this month, and will participate in the ground-abort test and launch-abort test in the coming months.

Dragon V2 is the docking and land-landing capable dragon initially intended for crew transport. CRS-3 dragon is upgraded but not a new main version. It have been called Dragon v1.5 on one occasion, but that seems a bit high a version number, since the only confirmed changes are improved power system that can provide much more power to payloads and more waterproof solutions for electronics boxes in the unpressurized but internal part of dragon. Perhaps the upgrades are much more extensive than what is confirmed -- It would probably be smart to "backport" much of the minor v1.x compatible changes intended for V2 back into v1.x cargo dragons to get them tested early, spread out the risks on more than one flight and avoid unnecessary parallel versions of subsystems.

edit: typos etc.

The 1.5 Dragon would be a cargo Dragon that lands on land with parachutes.

[docmordrid]

Let's not forget they're on the record for 2 types of propulsive landing; under 'chutes with a braking burn similar to Soyuz (but according to the conops video, a bit higher), and fully propulsive.

[InfraNut2]

SpaceX is not going to build 2 different Dragons. That goes against the fundamental design concept of the vehicle. Musk has stated many times that there will be only 1 spacecraft, with appropriate mods for mission definition (cargo v.s. crew).

I'm glad you seem to know that with such "certainty". Because it goes against all evidence so far.

When has he stated that "there will only be 1 spacecraft"?

It has been stated that Cargo Dragon will eventually have propulsive landing.

I think it obvious that Cargo Dragon will eventually have propulsive landing, (even if I am not certain whether I have heard it confirmed). It improves reusability and along with any other commonality, it reduces the overhead of producing/supporting different versions of things.

However, that does not mean that there necessarily will be a single version of dragon v2 (except for the interior). It is not obvious to me whether SpaceX will prefer keeping a berthing version for cargo to preserve the advantages of that or leave berthing to the competitors to reap the benefits of a single version.

In any case I fully expect anything not directly berthing or docking-mandated to be made identical eventually, even if they keep a berthing version.

[clongton]

SpaceX is not going to build 2 different Dragons. That goes against the fundamental design concept of the vehicle. Musk has stated many times that there will be only 1 spacecraft, with appropriate mods for mission definition (cargo v.s. crew).

I'm glad you seem to know that with such "certainty". Because it goes against all evidence so far.

When has he stated that "there will only be 1 spacecraft"?

It has been stated that Cargo Dragon will eventually have propulsive landing.

That is correct. As Dragon 2 crew comes on line, the cargo Dragons will already be transitioning to the same base spacecraft.

Like I said - there will eventually be a single base spacecraft which will take 2 different tracks at the end of assembly to become mission specific - either crew or cargo. All Dragons - crew and cargo - will default to propulsive landing. Sea-parachute landings will not be nominal for either spacecraft. They are the future backup recovery mode for both crew and cargo. I believe the transition has either already begun or will begin soon. It is paced to bring Dragon 2 crew on line first. Dragons 1/1.5 that are in the assembly pipeline will be completed to their original design specs but no new ones of that generation will be started once the transition is underway. At some point the first full Dragon 2 cargo spacecraft will start construction, and it will share the assembly process with its identical twin - Dragon 2 crew.

For those that keep asking me for source, I will only say that I can't begin to count the number of times Elon has stated that there is/will be no difference in the base spacecraft between cargo and crew. He has repeatedly said that Crew Dragon IS Cargo dragon, modified at the end of assembly for crew. Dragon was designed from the beginning for crew. Cargo Dragon is Crew Dragon minus crew equipment. That is a fundamental design intent of Dragon.

[A12]

CRS-3 splashdown successful. Another piece to be added to the inventory :-)

[guckyfan]

I took clongton's statement just a bit diffferently.  Not that there are not now, currently, two different models of Dragon.  There clearly are:  the crew Dragon currently flying on CRS-3 (which is a "Dragon v2" with upgraded power and avionics), and perhaps with others in the production pipeline (as we've seen) for future CRS flights); and the new SuperDraco-included Dragons that will be unveiled late this month, and will participate in the ground-abort test and launch-abort test in the coming months.

Dragon V2 is the docking and land-landing capable dragon initially intended for crew transport. CRS-3 dragon is upgraded but not a new main version. It have been called Dragon v1.5 on one occasion, but that seems a bit high a version number, since the only confirmed changes are improved power system that can provide much more power to payloads and more waterproof solutions for electronics boxes in the unpressurized but internal part of dragon. Perhaps the upgrades are much more extensive than what is confirmed -- It would probably be smart to "backport" much of the minor v1.x compatible changes intended for V2 back into v1.x cargo dragons to get them tested early, spread out the risks on more than one flight and avoid unnecessary parallel versions of subsystems.

edit: typos etc.

The 1.5 Dragon would be a cargo Dragon that lands on land with parachutes.

But it won't be different hardware. Just an intermediate step for safety. And I am quite sure that purely parachute landing on land would be very harsh. There will be a propulsive braking for the last few meters to soften touchdown. Purely parachute will be survivable but not desirable and not done intentionally.

[docmordrid]

SpaceX Dragon CCiCAP landings: 'chutes & rockets:

[Lars_J]

SpaceX is not going to build 2 different Dragons. That goes against the fundamental design concept of the vehicle. Musk has stated many times that there will be only 1 spacecraft, with appropriate mods for mission definition (cargo v.s. crew).

I'm glad you seem to know that with such "certainty". Because it goes against all evidence so far.

When has he stated that "there will only be 1 spacecraft"?

It has been stated that Cargo Dragon will eventually have propulsive landing.

If it has been stated, then you wouldn't mind posting a source, right?

This forum can be a cesspool of speculation that after being repeated a few times turn into "facts". So source it, please.

[Lars_J]

SpaceX is not going to build 2 different Dragons. That goes against the fundamental design concept of the vehicle. Musk has stated many times that there will be only 1 spacecraft, with appropriate mods for mission definition (cargo v.s. crew).

I'm glad you seem to know that with such "certainty". Because it goes against all evidence so far.

When has he stated that "there will only be 1 spacecraft"?

It has been stated that Cargo Dragon will eventually have propulsive landing.

That is correct. As Dragon 2 crew comes on line, the cargo Dragons will already be transitioning to the same base spacecraft.

Like I said - there will eventually be a single base spacecraft which will take 2 different tracks at the end of assembly to become mission specific - either crew or cargo. All Dragons - crew and cargo - will default to propulsive landing. Sea-parachute landings will not be nominal for either spacecraft. They are the future backup recovery mode for both crew and cargo. I believe the transition has either already begun or will begin soon. It is paced to bring Dragon 2 crew on line first. Dragons 1/1.5 that are in the assembly pipeline will be completed to their original design specs but no new ones of that generation will be started once the transition is underway. At some point the first full Dragon 2 cargo spacecraft will start construction, and it will share the assembly process with its identical twin - Dragon 2 crew.

For those that keep asking me for source, I will only say that I can't begin to count the number of times Elon has stated that there is/will be no difference in the base spacecraft between cargo and crew. He has repeatedly said that Crew Dragon IS Cargo dragon, modified at the end of assembly for crew. Dragon was designed from the beginning for crew. Cargo Dragon is Crew Dragon minus crew equipment. That is a fundamental design intent of Dragon.

Chuck, what is the point of attempting to argue things with you when you ignore evidence that contradicts your assumption?

Don't you have ANY comment about my reply to you that illustrated how the Dragon 2 drogue placement is incompatible with a CBM ring? Or are you going to ignore this as well?

[Llian Rhydderch]

I took clongton's statement just a bit diffferently.  Not that there are not now, currently, two different models of Dragon.  There clearly are:  the crew Dragon currently flying on CRS-3 (which is a "Dragon v2" with upgraded power and avionics), and perhaps with others in the production pipeline (as we've seen) for future CRS flights); and the new SuperDraco-included Dragons that will be unveiled late this month, and will participate in the ground-abort test and launch-abort test in the coming months.

Dragon V2 is the docking and land-landing capable dragon initially intended for crew transport. CRS-3 dragon is upgraded but not a new main version. It have been called Dragon v1.5 on one occasion, but that seems a bit high a version number, since the only confirmed changes are improved power system that can provide much more power to payloads and more waterproof solutions for electronics boxes in the unpressurized but internal part of dragon. Perhaps the upgrades are much more extensive than what is confirmed -- It would probably be smart to "backport" much of the minor v1.x compatible changes intended for V2 back into v1.x cargo dragons to get them tested early, spread out the risks on more than one flight and avoid unnecessary parallel versions of subsystems.

edit: typos etc.

I do understand the major distinction between the cargo Dragon and the new, soon-to-be-unveiled, crew Dragon.  I thought that Shotwell referred to the upgraded Dragon (new avionics and additional power for the NASA cargos) as "v2".  I could quite easily be wrong.  I know I was surprised to hear her say that as I had been aware of the major upgrades for crew that had been planned for a long time.

What is SpaceX formally referring to the particular model of cargo Dragon that just flew on CRS-3?

[Garrett]

It has been stated that Cargo Dragon will eventually have propulsive landing.

If it has been stated, then you wouldn't mind posting a source, right?
This forum can be a cesspool of speculation that after being repeated a few times turn into "facts". So source it, please.

Sometimes, things are stated many times on this forum because they are facts. At some point, it gets ridiculous to ask for sources for every bit of information.
Some users are more reliable than others. yg1968 is one of the more reliable posters.

But for the record, here is possibly the most well-known source: a quote from Shotwell transcripted by manboy from here: http://archive.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 :

"When will the cargo version of Dragon begin making propulsive landings?" "So the current version of Dragon lands in water on parachute descent, we are looking at landing it on land under parachute. As for propulsive landing that is for our new version, we call it V2 for Dragon and that's the primary vehicle, that's the vehicle for crew, and we will retrofit that for cargo."

[Lars_J]

Thanks, Garret, I appreciate you digging up the quote.

The "retrofit" wording does indicate that the Cargo Dragon will remain a separate line, though. (even though many or most components are shared)

[baldusi]

There's the issue of approx ops. The sensors are arranged differently, and the Docking port is not a bolt on kit on the CBM. My guess is that they have been designing the Crew considering a cargo version, and they'll try to maximize commonality, but they will have some differences. In particular, the top will be different.
But, if they get to reasonable reusability, it won't matter that much. But this 1.0 Dragons will find some other use, because they will have too expensive ops in comparison to 2.0.

[clongton]

Chuck, what is the point of attempting to argue things with you when you ignore evidence that contradicts your assumption?

It is not an assumption.
From Garrett:

But for the record, here is possibly the most well-known source: a quote from Shotwell transcripted by manboy from here: http://archive.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 :

"When will the cargo version of Dragon begin making propulsive landings?" "So the current version of Dragon lands in water on parachute descent, we are looking at landing it on land under parachute. As for propulsive landing that is for our new version, we call it V2 for Dragon and that's the primary vehicle, that's the vehicle for crew, and we will retrofit that for cargo."

The direct quote from Shotwell trumps your "evidence".
 
There will be one "base" Dragon design for both Crew and Cargo, Dragon v2. First use will be crew. Then Cargo will be backfitted to conform to v2. Between Dragon-Crew v2 and Dragon-Cargo v2 will be the time of transitioning Dragon-Cargo v1.5 to Dragon-Cargo v2, just like she said. In the end there will be only one Dragon design, Dragon v2. They will be completely identical until final outfitting. They will be final outfitted to be mission specific; crew or cargo.

[guckyfan]

"When will the cargo version of Dragon begin making propulsive landings?" "So the current version of Dragon lands in water on parachute descent, we are looking at landing it on land under parachute. As for propulsive landing that is for our new version, we call it V2 for Dragon and that's the primary vehicle, that's the vehicle for crew, and we will retrofit that for cargo."

I interpreted that as "we will retrofit V2 for cargo. But english is not my native language so I may be wrong.

How they would deal with the drogue chutes I don't know.

[clongton]

How they would deal with the drogue chutes I don't know.

I don't know the answer to that either, because the current arrangement would be difficult, as Lars has correctly pointed out. I am assuming that the drogue and parachute locations will need to be adjusted. There is much about Dragon v2 that we just don't know yet.

[swervin]

Does anyone know if the trunk is large enough to house a VF-200 VASIMR rocket, or a modified one? Besides the ridiculously high price of building one of those (I assume) -- perhaps a used Dragon would be a great test platform, should using the ISS as a test platform not work out.

If a Dragon can theoretically stay up for an extended period of time (i.e., DragonLab), then placing a right-sized VASIMR engine in the trunk may be useful. Obviously, the main problem would be the lack of enough solar power to power such a system, and I recognize that. Perhaps, modify to have larger solar panels? Pack the internal volume with a crap-ton of batteries?

But hey, here's to theorizing and not arguing about quotes and sources... . If theorizing re-uses of Dragon is not appropriate in this thread, then I won't be offended if this post disappears.

Cheers,
Splinter

[Dudely]

Read a quote from Elon saying Dragon 2 will be not have solar panels at all. Can't find it now.

[VulcanCafe]

I remember reading about no solar on Dragon v2 as well... I suspect the trunk will feature 'mission modules' including solar as needed. Just wild speculation on my part.

[Elmar Moelzer]

Read a quote from Elon saying Dragon 2 will be not have solar panels at all. Can't find it now.

I remember something about the crewed Dragon not having solar panels. If there is a cargo version of Dragon2 (which I personally find plausible), then it might still have solar panels.

[clongton]

Read a quote from Elon saying Dragon 2 will be not have solar panels at all. Can't find it now.

I remember something about the crewed Dragon not having solar panels. If there is a cargo version of Dragon2 (which I personally find plausible), then it might still have solar panels.

Unlikely. See above:

But for the record, here is possibly the most well-known source: a quote from Shotwell transcripted by manboy from here: http://archive.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 :

"When will the cargo version of Dragon begin making propulsive landings?" "So the current version of Dragon lands in water on parachute descent, we are looking at landing it on land under parachute. As for propulsive landing that is for our new version, we call it V2 for Dragon and that's the primary vehicle, that's the vehicle for crew, and we will retrofit that for cargo."

Per Shotwell, Cargo Dragon will be backfitted from Crew Dragon.

[Elmar Moelzer]

But for the record, here is possibly the most well-known source: a quote from Shotwell transcripted by manboy from here: http://archive.thespaceshow.com/shows/2212-BWB-2014-03-21.mp3 :

"When will the cargo version of Dragon begin making propulsive landings?" "So the current version of Dragon lands in water on parachute descent, we are looking at landing it on land under parachute. As for propulsive landing that is for our new version, we call it V2 for Dragon and that's the primary vehicle, that's the vehicle for crew, and we will retrofit that for cargo."

Per Shotwell, Cargo Dragon will be backfitted from Crew Dragon.

And that contradicts what I said exactly how? You think that a crew Dragon that has been retrofitted for cargo cant have trunk with solar panels? I am confused.

[llanitedave]

I think the Dragon and the trunk should be considered two separate entities.

[baldusi]

Does anyone know if the trunk is large enough to house a VF-200 VASIMR rocket, or a modified one?

Current Dragon supplies about 3kW of power to payload. VF-200 requires 200kW.

[swervin]

Does anyone know if the trunk is large enough to house a VF-200 VASIMR rocket, or a modified one?

Current Dragon supplies about 3kW of power to payload. VF-200 requires 200kW.

For sure! ...and thanks for following up with me. My understanding was that the possible test when/if flown to the ISS would utilize battery packs to provide power during tests vs only relying on the solar panels.

Not sure how large a battery pack that may be, if that method is to be used, but perhaps the internal volume of Dragon could be packed with batteries?

Also, would VASIMR physically FIT in the trunk?

All questions we may not know, but I'm a fan of finding different uses and re-uses of existing hardware to advance technology!

Cheers,
Splinter

[Jim]

I think the Dragon and the trunk should be considered two separate entities.

No, it shouldn't.  Dragon has limited capabilities (mission life) once it sheds the trunk.

[Lar]

Does anyone know if the trunk is large enough to house a VF-200 VASIMR rocket, or a modified one?

Current Dragon supplies about 3kW of power to payload. VF-200 requires 200kW.

For sure! ...and thanks for following up with me. My understanding was that the possible test when/if flown to the ISS would utilize battery packs to provide power during tests vs only relying on the solar panels.

Not sure how large a battery pack that may be, if that method is to be used, but perhaps the internal volume of Dragon could be packed with batteries?

I'm not clear on how batteries can take you from 3 Kw to 200 Kw. You might want to try running some numbers but my gut tells me that would be much of the usable mass of the vehicle.

[kirghizstan]

Does anyone know if the trunk is large enough to house a VF-200 VASIMR rocket, or a modified one?

Current Dragon supplies about 3kW of power to payload. VF-200 requires 200kW.

For sure! ...and thanks for following up with me. My understanding was that the possible test when/if flown to the ISS would utilize battery packs to provide power during tests vs only relying on the solar panels.

Not sure how large a battery pack that may be, if that method is to be used, but perhaps the internal volume of Dragon could be packed with batteries?

Also, would VASIMR physically FIT in the trunk?

All questions we may not know, but I'm a fan of finding different uses and re-uses of existing hardware to advance technology!

Cheers,
Splinter

i'm not clear on if you are asking if it would fit in the trunk but do the testing with power form ISS or if you are suggesting using Dragon's power?

i'm also not clear on how this relates to used Dragons

[Avron]

I think the Dragon and the trunk should be considered two separate entities.

No, it shouldn't.  Dragon has limited capabilities (mission life) once it sheds the trunk.

Why.. if they go to batteries, the trunk is just a trunk, ?

[docmordrid]

IIRC  crew Dragon gets extra batteries, which are in the trunk. Jettison the trunk and you lose that reserve.

[ey]

It might still be feasible. A Tesla Model S uses a 310 kW motor and has a 60 kWh battery. At 200 kW that should last for the 15 minute burst planned for the ISS test. Though that's ~1000 pounds of batteries in addition to the mass of the VF-200 which is 620 kg (1300 pounds).

This link may help get an idea about the size of the VF-200: http://www.adastrarocket.com/aarc/VF-200

[swervin]

i'm also not clear on how this relates to used Dragons

That's valid, however, what do any of us really know about what 'relates' to used Dragons? So far as I can tell the known thing about them, is that they exist. I assume we all wonder if/when they will be reused at some point, and in what manner. I'm simply exploring one idea/possibility, not asserting I understand how or if they will be re-used.

It might still be feasible. A Tesla Model S uses a 310 kW motor and has a 60 kWh battery. At 200 kW that should last for the 15 minute burst planned for the ISS test. Though that's ~1000 pounds of batteries in addition to the mass of the VF-200 which is 620 kg (1300 pounds).

This link may help get an idea about the size of the VF-200: http://www.adastrarocket.com/aarc/VF-200

Interesting! I didn't realize that info about the Tesla Model S! Thanks for the link!

I think you understand what I'm getting at though. Basically, place batteries inside Dragon to power a notional VASIMR engine for short duration bursts, much as is planned on the ISS. Given the drastic difference in mass between the ISS and a Dragon, any idea how much those bursts could accelerate a Dragon? (I'm not qualified to run those numbers any longer... orbital mechanics classes were too long ago for me to remember...)   

Even at let's say 1500lbs for batteries + 1500lbs for a VF-200 sized engine, that is still within the F9 v1.1's up-mass capes, right? Didn't it just take up more than that to the ISS on the last mission?

If you all want this theoretical discussion to end, no harm no foul, but it seems the topic is worthy of a thought, to me. .... those Dragons should be re-used for something which might further spaceflight!

Splinter

[Jim]

The trunk also supplies more than just power, it has radiators.

[TrevorMonty]

The plan is to fit VASIMR engines to ISS and power them from a 50kwhr battery to enable 15 min bursts at full thrust.

Using Dragon as free flying test platform with a 60kwhr battery should be able to achieve same result. Allow 24 HR between tests for batteries to recharge. They could even send it around the moon.

[swervin]

The plan is to fit VASIMR engines to ISS and power them from a 50kwhr battery to enable 15 min bursts at full thrust.

Using Dragon as free flying test platform with a 60kwhr battery should be able to achieve same result. Allow 24 HR between tests for batteries to recharge. They could even send it around the moon.

I was thinking precisely that, Trevor. Sounds like a great technology demonstration platform to me. Would daily 15min firings (or maybe twice daily if you had enough room/capacity for two battery buses) provide much increase in thrust or would such short VF-200 firings be similar to an ion engine running continuously? (big picture?)

Why stop at the moon?

Splinter

[dror]

The plan is to fit VASIMR engines to ISS and power them from a 50kwhr battery to enable 15 min bursts at full thrust.

Using Dragon as free flying test platform with a 60kwhr battery should be able to achieve same result. Allow 24 HR between tests for batteries to recharge. They could even send it around the moon.

Why is that any better than using a light weight 3kw constant acceleration engine?

[Llian Rhydderch]

The plan is to fit VASIMR engines to ISS and power them from a 50kwhr battery to enable 15 min bursts at full thrust.

Using Dragon as free flying test platform with a 60kwhr battery should be able to achieve same result. Allow 24 HR between tests for batteries to recharge. They could even send it around the moon.

I was thinking precisely that, Trevor. Sounds like a great technology demonstration platform to me. Would daily 15min firings (or maybe twice daily if you had enough room/capacity for two battery buses) provide much increase in thrust or would such short VF-200 firings be similar to an ion engine running continuously? (big picture?)

Why stop at the moon?

Splinter

I would suspect that the main factor here is who is paying for the demonstration mission?

My guess is that NASA is paying for lofting the VASIMR VF-200 to space, and possibly for the twin 100 kW engines to be built in the first place.  In other words, Ad Astra is likely getting this flight test for a very low pecuniary price.

On the other hand, flying to space to do the demo with a "used Dragon" plus trunk plus VF-200 plus Tesla-sized large battery pack would need to be funded by someone.  If it were a commercial transaction, the ordinary way would be for the company developing the technology (Ad Astra) to pay the cargo transport and mission hardware supplier (SpaceX) for the launch and the satellite.  Even at SpaceX everyday low prices, with a used-price Dragon, this is an $80 or $100 million dollar mission. 

Thus, I think we won't see a VF-200 tested on a Used Dragon anytime real soon, but for economic reasons.

Now, if a philanthropic gabillionaire wanted to put a VASIMR-based moon cycler in LEO, and fly out to the moon or asteroids with a DragonLab space probe, cool.  Bring it on.   

[swervin]

The plan is to fit VASIMR engines to ISS and power them from a 50kwhr battery to enable 15 min bursts at full thrust.

Using Dragon as free flying test platform with a 60kwhr battery should be able to achieve same result. Allow 24 HR between tests for batteries to recharge. They could even send it around the moon.

Why is that any better than using a light weight 3kw constant acceleration engine?

Dror, I don't think anyone is arguing it is better. The idea of a VASIMR engine in a trunk was a way to put to use, or more like re-use, a Dragon spacecraft. The thought when I asked the question was, and still remains, reusing a  Dragon as a platform to further an unproven (in space) technology.

As stated above, unlikely to happen for understandable reasons. We may have beaten the idea to death... :-)

Splinter

[guckyfan]

The plan is to fit VASIMR engines to ISS and power them from a 50kwhr battery to enable 15 min bursts at full thrust.

Using Dragon as free flying test platform with a 60kwhr battery should be able to achieve same result. Allow 24 HR between tests for batteries to recharge. They could even send it around the moon.

Why is that any better than using a light weight 3kw constant acceleration engine?

Because the purpose would be testing VASIMR, not accelerating Dragon.

[fatjohn1408]

It's funny how, when SpaceX opts for mass production instead of reusability, a lot of people start to tout the benefits of mass production. Streamlining the process, enhancing the design iteratively, etc... 

[baldusi]

The plan is to fit VASIMR engines to ISS and power them from a 50kwhr battery to enable 15 min bursts at full thrust.

Using Dragon as free flying test platform with a 60kwhr battery should be able to achieve same result. Allow 24 HR between tests for batteries to recharge. They could even send it around the moon.

Assuming 5N of thrust and a 10tonne total weight, that would get 0.45m/s of delta-v per firing. Assuming 3kWh power budget, it would take 20hrs of sunlight between charges. You would have to launch either into an SSO orbit or polar to get constant power for a while. Else, you might not even get enough solar illumination for one firing per day. And it would take seven months to get 100m/s of delta-v. The whole point of testing a VASIMR in space is to validate a long firing, like you'd do on a missions where you might get 5,000m/s.

[Mader Levap]

About original topic of this thread: I don't think these dragons will be ever reused.

[Lar]

It's funny how, when SpaceX opts for mass production instead of reusability, a lot of people start to tout the benefits of mass production. Streamlining the process, enhancing the design iteratively, etc... 

We're not in "mass" production but we are in serial production. As of now each unit seems to be different than the last, and that's true for Dragons, first stages, and maybe even second stages. So far.

About original topic of this thread: I don't think these dragons will be ever reused.

Yes. These are too early. Once things settle down and there isn't variance from one to the next, that's when reuse is more likely, to my way of thinking.

[Coastal Ron]

It's funny how, when SpaceX opts for mass production instead of reusability, a lot of people start to tout the benefits of mass production. Streamlining the process, enhancing the design iteratively, etc... 

Serial production of low-cost designs can lower overall costs, but reusability is still the ultimate solution.

And it's not unusual for 1st generation systems to not have all the features needed to fully realize the potential of a design.  In that light, think of the current Dragon as capable of reusability, but not optimal for a number of reasons.  And certainly they are proving out all their manufacturing processes on the 1st generation systems too, which benefits later versions.

And likely because SpaceX has continued to participate in the Commercial Crew program, they have not needed to pursue reusability for the 1st generation Dragons, and instead have focused all their internal resources on their 2nd generation Dragon.

Note:  I was typing this before dinner then finished afterwards, and I see Lar has covered the same topic, but I'll post what I wrote anyways.

[llanitedave]

I think the Dragon and the trunk should be considered two separate entities.

No, it shouldn't.  Dragon has limited capabilities (mission life) once it sheds the trunk.

You're going to reuse the capsule.  Unless they extensively redesign the trunk, it's always going to be expended.

[Llian Rhydderch]

I took clongton's statement just a bit diffferently.  Not that there are not now, currently, two different models of Dragon.  There clearly are:  the crew Dragon currently flying on CRS-3 (which is a "Dragon v2 v1.1" with upgraded power and avionics), and perhaps with others in the production pipeline (as we've seen) for future CRS flights); and the new SuperDraco-included Dragons that will be unveiled late this month, and will participate in the ground-abort test and launch-abort test in the coming months.

Dragon V2 is the docking and land-landing capable dragon initially intended for crew transport. CRS-3 dragon is upgraded but not a new main version. It have been called Dragon v1.5 on one occasion, but that seems a bit high a version number, since the only confirmed changes are improved power system that can provide much more power to payloads and more waterproof solutions for electronics boxes in the unpressurized but internal part of dragon. Perhaps the upgrades are much more extensive than what is confirmed -- It would probably be smart to "backport" much of the minor v1.x compatible changes intended for V2 back into v1.x cargo dragons to get them tested early, spread out the risks on more than one flight and avoid unnecessary parallel versions of subsystems.

edit: typos etc.

I do understand the major distinction between the cargo Dragon and the new, soon-to-be-unveiled, crew Dragon. I thought that Shotwell referred to the upgraded Dragon (new avionics and additional power for the NASA cargos) as "v2".  I could quite easily be wrong. (I was wrong, it is v1.1 I know I was surprised to hear her say that as I had been aware of the major upgrades for crew that had been planned for a long time.

What is SpaceX formally referring to the particular model of cargo Dragon that just flew on CRS-3?

I think we have the answer now, direct from Elon.

Elon just tweeted this to our very own QuantumG:

Elon Musk ‏@elonmusk 2h

@QuantumG Dragon V1.1 doesn't have a launch escape system. Probably comparable reliability to Shuttle, but we need to do better.

(emphasis added).

I think we can safely say that the descriptor for the Dragon model first flown on CRS-3, the one with upgraded avionics and a lot more power available for powered payloads, is Dragon v1.1.

The reveal on March 29th will be of the crew Dragon, aka DragonRider, aka Dragon Mk II, and on this forum often as Dragon v2.

Cheers,
  Llian

[Andy Smith]

Given the signed off capability of the dragon for proximity operations around the ISS, I would suggest that a "used" v1.1 dragon is used to berth an empty F9 second stage to the ISS. I.e. the second stage is not separated from the dragon.

From www.spacelaunchreport.com/falcon9v1-1.html the empty mass of the second stage is approx 6 tonnes, which should be within the capability of the dragon control system (www.spacex.com/dragon).

The extended length and different mass distribution would obviously need some consideration.

Once berthed, the ISS now has a fuel depot capability able to hold over 40 tonnes each of RP1 and LOX. Power to the second stage (for valve control and stage health monitoring) can be supplied via an umbilical from ISS to what would have been the standard pad umbilical connectors, likewise pump connections for loading fuel or taking it off could be done via it's existing pad connectors.

Subsequent missions to ISS which have spare mass available could carry fuel or oxidiser in standalone tanks in the trunk. The arm could then be used to move and connect them to the fuel depot for offloading.

Potentially if suitable relocation takes place, the Merlin could also provide ISS reboost and debris avoidance capability (given the 40% throttle capability), though whether a standard second stage / trunk / dragon configuration is structurally robust enough to handle that I don't know.

[docmordrid]

How do you stop the RP-1 from gelling or stratifying? May be better off developing a disposable  Draco/SuperDraco (hypergolic) propulsion module with a PCBM.

[Andy Smith]

Thank you for your response. I can see that being a more efficient development if starting from scratch.

If it was actually possible to use the dragon / second stage this way then stratification and gelling could be avoided by pumping the RP1 between two identical second stage depots on a periodic basis.

I realise RP1 is not an ideal depot fuel, but perhaps stratification management is an acceptable trade-off for being able to deliver a capability based on existing infrastructure.

Regards

[Jim]

1.  From www.spacelaunchreport.com/falcon9v1-1.html the empty mass of the second stage is approx 6 tonnes, which should be within the capability of the dragon control system (www.spacex.com/dragon).


2.  Once berthed, the ISS now has a fuel depot capability able to hold over 40 tonnes each of RP1 and LOX. Power to the second stage (for valve control and stage health monitoring) can be supplied via an umbilical from ISS to what would have been the standard pad umbilical connectors, likewise pump connections for loading fuel or taking it off could be done via it's existing pad connectors.


3.  Potentially if suitable relocation takes place, the Merlin could also provide ISS reboost and debris avoidance capability (given the 40% throttle capability), though whether a standard second stage / trunk / dragon configuration is structurally robust enough to handle that I don't know.

1.  Why would you think it can?  The CG issue makes it a non starter.  Pure translations on various axis would be next to impossible.

2.  The stage systems were designed for loading in a one g environment.  There is nothing to keep LOX from coming out the vents.  Also, high pressure helium is needed for the stage and then there is the orbital debris issue and the tanks  Also, just plugging into the umbilicals doesn't mean the stage can be controlled.  Software would have to be rewritten if possible to control the stage.


3.  Still too much thrust

[TrevorMonty]

One possible use is as environmental test lab attached to ISS. Could be configured for different pressures, gas mixtures, temperatures and humidity.