Author Topic: SpaceX Dragon V2 Updates and Discussion  (Read 444329 times)

Offline Garrett

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #20 on: 08/25/2014 01:38 PM »
I'd have been a lot happier if SpaceX had gone ahead with a crewed Dragon v.1. This second model strikes me as a time- and money-eater.

I'll probably get flames for this but one part of me wonders if Musk has already been warned he won't get commercial crew funding, so he's offering a high-spec final model to interest other potential customers that he'll work towards on SpaceX's own dime and schedule rather than a simpler and quicker-to-deploy model to fit into NASA's budget and schedule.
The v.1 didn't have a LAS (required by NASA, and sensible folks alike)
Installing a life support system to a cargo ship is not analogous to the assembly of LEGO elements, i.e. a lot of redesign was likely necessary.

I can understand an argument that v2 may be overkill, but a crewed v1 makes no sense to me.
« Last Edit: 08/25/2014 01:39 PM by Garrett »
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Offline Ben the Space Brit

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #21 on: 08/25/2014 01:50 PM »
Well, I suppose it would have really been 'v.1.5' as it would have had the LAS motor pods and an ECLSS added as originally intended. My speculation is that the list of things to do to get v.1 crew-ready was getting longer and, combined with negative rumbles about getting the CCrew contract, Elon decided it would be more cost-efficient to build an optimised crew variant rather than a modified cargo version used for crew.
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Offline llanitedave

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #22 on: 08/25/2014 02:12 PM »
I think you're confusing your imagination with reality.  What "rumbles"?
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Offline su27k

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #23 on: 08/25/2014 02:51 PM »
I'd have been a lot happier if SpaceX had gone ahead with a crewed Dragon v.1. This second model strikes me as a time- and money-eater.

Yeah the COTS-D Dragon would probably be quicker to build, if they go down that route they could be ready to fly humans by now. It would be interesting to know why they changed direction.

Quote
I'll probably get flames for this but one part of me wonders if Musk has already been warned he won't get commercial crew funding, so he's offering a high-spec final model to interest other potential customers that he'll work towards on SpaceX's own dime and schedule rather than a simpler and quicker-to-deploy model to fit into NASA's budget and schedule.

This makes no sense, if EM knew years in advance that they won't get the contract  (which is impossible), they would make the model simpler and cheaper so that it can be finished with CCiCAP funding alone.

Offline Garrett

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #24 on: 08/25/2014 03:00 PM »
...combined with negative rumbles about getting the CCrew contract,<snip>
I too am curious. What "rumbles". If anything, there was a feeling that SpaceX were hot favourites.

There are many good reasons for redesigning Dragon, not least because adding a pusher LAS meant adding SuperDracos, which with a bit of extra effort can be used for propulsive landing.
Also Elon was quoted saying something along the lines of SpaceX not really knowing what they were doing when designing Dragon V1. One can only presume they were all very eager to have a second, more experienced, go at designing a spacecraft.
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Offline butters

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #25 on: 08/25/2014 03:16 PM »
Who says that V1 is "simpler" than V2? As Elon has stated, V1 was their first stab at a spacecraft, and minimizing risk was more important than the simplicity and manufacturability of the design. V1 is a battleship. The V2 design is a substantial refinement incorporating numerous lessons learned. A more refined design may be more advanced yet also simpler, with lower part counts and easier assembly processes.

Offline Ben the Space Brit

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #26 on: 08/25/2014 03:18 PM »
...combined with negative rumbles about getting the CCrew contract,<snip>

I too am curious. What "rumbles". If anything, there was a feeling that SpaceX were hot favourites.

If you check back on my original post on this discussion, you will see that I was speculating that one possible motive for v.2 was SpaceX not getting commercial crew, thus removing a major time constraint on developing crewed Dragon.

Who says that V1 is "simpler" than V2? As Elon has stated, V1 was their first stab at a spacecraft, and minimizing risk was more important than the simplicity and manufacturability of the design. V1 is a battleship. The V2 design is a substantial refinement incorporating numerous lessons learned. A more refined design may be more advanced yet also simpler, with lower part counts and easier assembly processes.

But will it be quicker to reach flying status? I've a feeling that schedule will be a hard constraint on commercial crew.
« Last Edit: 08/25/2014 03:19 PM by Ben the Space Brit »
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Offline rpapo

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #27 on: 08/25/2014 03:33 PM »
But will it be quicker to reach flying status? I've a feeling that schedule will be a hard constraint on commercial crew.
And you think CST-100, DreamChaser or Blue Origin will get there quicker?
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Offline dglow

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #28 on: 08/25/2014 03:51 PM »
Do we think Dragon v2's first flight will be 'full-up' with propulsive landing?
Or will the SuperDracos be only for abort at first, with landing integrated later as Dragonfly testing progresses?

Offline rcoppola

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #29 on: 08/25/2014 03:54 PM »
D-V2 can't be viewed in isolation but as part of a larger, more integrated and well thought out plan.

SpaceX has a primary goal of driving down costs through re-use. If that is a primary business driver that ultimately becomes a design driver, then I'm not sure what else anyone expected them to do with regards to D-V2.

Why wold anyone be surprised in the least by how far they advanced their Dragon design? Look at what they did from Falcon 9 to Falcon 9R. It's the same scale of changes from Dragon V1 to Dragon V2 (yes, perhaps more). All because of 2 primary drivers:

1. Cost efficiencies through re-use.
2. Lessons learned.
 
Put those 2 together and you get F9R and Dragon V2.

And the beauty of that plan, is then they move to one core Dragon V2 line that separates at the points of crew and cargo producing even more efficiencies and capabilities, especially with regards to CRS-2.

These guys are on a tear. Step back and think about this.

From 2010 to 2016, they will have gone from F9 to F9R, Dragon V1 (Cargo) to Dragon v2 (Crew), 2 pads to 4 pads (including the worlds first private launch site & the historic crew launch facilities of Pad 39A) and an operational Falcon Heavy. They may even be very close to D-V2 Cargo by EOY 2016 as well. You don't get this far, this fast without taking some design risks. Dragon V2 may fall into the risk category but I'd say it's worked damn well so far. 
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Online guckyfan

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #30 on: 08/25/2014 03:56 PM »
Do we think Dragon v2's first flight will be 'full-up' with propulsive landing?
Or will the SuperDracos be only for abort at first, with landing integrated later as Dragonfly testing progresses?

We can only guess. My guess would be the first flights will be water landing or maybe land landing under parachutes, assisted by a burn on the last few meters to soften impact. Parachute landing would be survivable without engine burn, if that fails.

Land landing under SuperDraco thrust will come only after the extensive Firefly tests are completed.

Offline king1999

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #31 on: 08/25/2014 03:59 PM »
...combined with negative rumbles about getting the CCrew contract,<snip>

I too am curious. What "rumbles". If anything, there was a feeling that SpaceX were hot favourites.

If you check back on my original post on this discussion, you will see that I was speculating that one possible motive for v.2 was SpaceX not getting commercial crew, thus removing a major time constraint on developing crewed Dragon.


That's nonsense speculation. They would not have known that so early in advance to change their direction.

And they are further in the game in preparing abort tests than other teams. The man-rated Atlas V is still a way to go.

And under current situations with Russia, I would think the USG can't afford to create a new dependency on Russia by skipping SpaceX. SpaceX has them cornered, for good or bad.

Edit: typos.
« Last Edit: 08/25/2014 04:03 PM by king1999 »

Offline Lars_J

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #32 on: 08/25/2014 04:01 PM »
I'd have been a lot happier if SpaceX had gone ahead with a crewed Dragon v.1. This second model strikes me as a time- and money-eater.

I'll probably get flames for this but one part of me wonders if Musk has already been warned he won't get commercial crew funding, so he's offering a high-spec final model to interest other potential customers that he'll work towards on SpaceX's own dime and schedule rather than a simpler and quicker-to-deploy model to fit into NASA's budget and schedule.

People seem to exaggerate the difference between Dragon v1 and v2. In reality there isn't a whole lot of difference. Take off SD engine pods, and change the docking adapter to a CBM berthing ring. What do you have? An evolved Dragon v1.

Any change to Dragon v1 to make it human rated would quickly turn it into something close to v2.

Is your main issue that LAS? Would you have preferred that SpaceX use a solid LAS, and to do that develop expertise in a field where they had none? (and no interest?) Do you really think that would have taken much less time?
« Last Edit: 08/25/2014 04:02 PM by Lars_J »

Online Robotbeat

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #33 on: 08/25/2014 04:07 PM »
Solid LAS is WAY more complicated than it seems.
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Offline rcoppola

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #34 on: 08/25/2014 04:12 PM »
Do we think Dragon v2's first flight will be 'full-up' with propulsive landing?
Or will the SuperDracos be only for abort at first, with landing integrated later as Dragonfly testing progresses?
We can look at a few timelines to tweak out the possibilities.

-DragonFly testing program for propulsive landing will possibly go through to 2016. Four testing profiles and over 30 actual tests within that time.

-Pad abort in Nov, In-flight Abort in Jan 2015.

-Orbital un-crewed test flight late 2015 (Possibly early 2016)

-By the end of 2015, they should have a huge amount of data on both the Hardware (SDs) and software, both abort and propulsive landing. Elon mentioned another 1 to 2 years before propulsive landing will be operationally ready.
That lines up with all their development and testing schedules.

Depending on how the development and testing goes over the next 1.5 to 2 years, I think they will begin their crewed campaign with land propulsive landings. Possibly with a parachute assist for the first few missions. Regardless, I think operationally, water landing from the beginning is reserved for aborts only. Land landing will be standard operations from the outset. Whether full propulsive or parachute assist from the beginning? I'm not sure we can know that yet.
« Last Edit: 08/25/2014 04:15 PM by rcoppola »
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Online meekGee

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #35 on: 08/25/2014 04:29 PM »
Well, I suppose it would have really been 'v.1.5' as it would have had the LAS motor pods and an ECLSS added as originally intended. My speculation is that the list of things to do to get v.1 crew-ready was getting longer and, combined with negative rumbles about getting the CCrew contract, Elon decided it would be more cost-efficient to build an optimised crew variant rather than a modified cargo version used for crew.

How do you know that the v2 isn't "really" a v1.5?

It has Super Dracos with fancy fairings (which are not part of the pressure vessel), life support, seating, flight controls, new hatch, docking adapter...

But all of these are on the minimal-change list from 1.0 to "1.5" anyway.

What pushes it over the edge to becoming "totally new"?

The only thing I can see that makes it a v2 is that they've decided to present it as such.

There was a long argument 1-2 years ago about what the crewed Dragon would look like, and this is pretty much along the mid-range of the opinions.  It does not have wings, it still has a drop-off trunk...

It's all a matter of perception.
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Offline AncientU

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #36 on: 08/25/2014 04:32 PM »

-DragonFly testing program for propulsive landing will possibly go through to 2016. Four testing profiles and over 30 actual tests within that time.



I think that's 30 test flights per year... for two years.

http://forum.nasaspaceflight.com/index.php?topic=34800.msg1245372#msg1245372

Edit: added quote
« Last Edit: 08/25/2014 04:36 PM by AncientU »
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Offline MP99

Re: SpaceX Dragon V2 Updates and Discussion
« Reply #37 on: 08/25/2014 04:42 PM »
I'd have been a lot happier if SpaceX had gone ahead with a crewed Dragon v.1. This second model strikes me as a time- and money-eater.

I'll probably get flames for this but one part of me wonders if Musk has already been warned he won't get commercial crew funding, so he's offering a high-spec final model to interest other potential customers that he'll work towards on SpaceX's own dime and schedule rather than a simpler and quicker-to-deploy model to fit into NASA's budget and schedule.

Musk said that they didn't know what they were doing when they designed v1. (V2 unveiling?)

Sometimes you put together the task list to get to where you need to end up, and a reboot is the best way forward. I see this as a real strength of their proposal, though it exposes them to greatest risk on their greatest weakness - delivering to a schedule.

NASA will have technical insight into the design as part of their CCtCap proposal. Maybe there were some things that they wouldn't have been too keen on?

Cheers, Martin

Offline rcoppola

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #38 on: 08/25/2014 04:48 PM »
I think that's 30 test flights per year... for two years.
http://forum.nasaspaceflight.com/index.php?topic=34800.msg1245372#msg1245372
Thanks for that, it's always good to refer back to a published data point.

I worded it the way I did for a few reasons.

-It's not an official testing schedule from SpaceX but rather a range of dates and tests for permit approvals.
-They word it as "up to". We don't know how big of a swing that is.Therefore it could be 30, or 45 or 60 tests, over 12 months, 18 months or 24 months.
-They list 2014 - 2015. But 2014 is more then half over and whether that means this will spill over to 2016 or not, we don't know.

Again though, thanks for the re-groundning.
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Offline rcoppola

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Re: SpaceX Dragon V2 Updates and Discussion
« Reply #39 on: 08/25/2014 05:03 PM »
Well, I suppose it would have really been 'v.1.5' as it would have had the LAS motor pods and an ECLSS added as originally intended. My speculation is that the list of things to do to get v.1 crew-ready was getting longer and, combined with negative rumbles about getting the CCrew contract, Elon decided it would be more cost-efficient to build an optimised crew variant rather than a modified cargo version used for crew.

How do you know that the v2 isn't "really" a v1.5?

It has Super Dracos with fancy fairings (which are not part of the pressure vessel), life support, seating, flight controls, new hatch, docking adapter...

But all of these are on the minimal-change list from 1.0 to "1.5" anyway.

What pushes it over the edge to becoming "totally new"?

The only thing I can see that makes it a v2 is that they've decided to present it as such.

There was a long argument 1-2 years ago about what the crewed Dragon would look like, and this is pretty much along the mid-range of the opinions.  It does not have wings, it still has a drop-off trunk...

It's all a matter of perception.
My only caution would be a few data points:

1. Garett said a few weeks ago that they hit a few snags along the way.
2. IIRC, they are still working towards their Primary Structures Qualification.

I'm only thinking that perhaps attaching the SDs to the primary structure and all the added stresses that implies, necessitated enough core design changes that the very underlying structures have been modified to a greater extent then we are aware of. Not counting how they redesigned the entire parachute system and placement, modified plumbing, wiring/electric, outer mold-lines , fuel storage, TPS/ landing legs and trunk.

Start adding all that up and it's like going from Gemini to  Apollo. (or not)
« Last Edit: 08/25/2014 05:05 PM by rcoppola »
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