SpaceX Dragon 2 Updates and Discussion - Thread 3

[Vettedrmr]

Even assuming a 100% LAS success rate, over 6/7ths of the 1:276 risks would have to come during ascent to achieve his estimate.

If the LAS was 100% successful, then by definition *all* of the 1:276 risks would come outside of ascent.

You'd still have parachute/recovery risks unless you're counting that as part of the LAS.

No, that would be the same risks as during the EDL.  So, ascent terminates when the LAS transitions to the recovery modes (wherever on the profile the abort occurs).

[kdhilliard]

IIRC the LOC risk is a cumulative number, ...

IIRC the greatest LOC risk - that both CC providers had trouble with - was MMOD risk while on orbit.

Right.  I wasn't trying to suggest that nearly all of the risk was in the ascent, just that Koenigsmann's statement implied that, and thus the statement didn't make sense.  I'm guessing that he was speaking off the cuff when mentioning the added safety of the LAS and didn't think beyond the ascent phase when he said "1 zu mehreren Tausend".

[gongora]

Let's discuss something a little more useful than dubious claims about risk probabilities...

https://twitter.com/nextspaceflight/status/1268316718750814209

SpaceX has been given NASA approval to fly flight-proven Falcon 9 and Crew Dragon vehicles during Commercial Crew flights starting with Post-Certification Mission 2, per a modification to SpaceX's contract with NASA.

https://beta.sam.gov/awards/90121604%2BIDV

[snotis]

For people who can't access twitter and/or can't see the picture in the tweet:

MOD 78: THE PURPOSE OF THIS BILATERAL MODIFICATION IS TO EXTEND THE DEMO-2 FLIGHT TEST FROM TWO WEEKS TO UP TO 119 DAYS AND ADD THE REQUIREMENT FOR 45TH OPERATIONS GROUP DETACHMENT 3 (DET-3) JOINT TEST TRAINING FOR PCM-1 THROUGH PCM-6 IN EXCHANGE FOR ALLOWING REUSE OF THE FALCON 9 LAUNCH VEHICLE AND CREW DRAGON SPACECRAFT BEGINNING WITH PCM-2.

[salpun]

So will C206 be reused or not. I think it will.

[cppetrie]

Let's discuss something a little more useful than dubious claims about risk probabilities...

https://twitter.com/nextspaceflight/status/1268316718750814209

SpaceX has been given NASA approval to fly flight-proven Falcon 9 and Crew Dragon vehicles during Commercial Crew flights starting with Post-Certification Mission 2, per a modification to SpaceX's contract with NASA.

https://beta.sam.gov/awards/90121604%2BIDV

That is one heck of an endorsement of reuse given these are carrying crew. Wow. Very awesome to see.

[Vettedrmr]

Let's discuss something a little more useful than dubious claims about risk probabilities...

Is this as big a deal as I think it is??

[salpun]

Let's discuss something a little more useful than dubious claims about risk probabilities...

Is this as big a deal as I think it is??

yes

[Kansan52]

Why was Det-3 added? Does it replace some other group?

[salpun]

Why was Det-3 added? Does it replace some other group?

There might not have been a formal arrangement for them to be on the recovery ships during training. Now it allowed in writing.

[yg1968]

Good negotiating by SpaceX.

[sevaithan]

My read of this is NASA is pretty unconcerned about reuse, given what they know about SpaceX's process etc. but obviously you can't look like you're giving something for nothing in these things so they proposed a "trade off" that SpaceX would readily accept. Seems like a very strong endorsement of reuse from NASA, I wonder if Gerst's approval and oversight had anything to do with it.

[TrevorMonty]

Let's discuss something a little more useful than dubious claims about risk probabilities...

https://twitter.com/nextspaceflight/status/1268316718750814209

SpaceX has been given NASA approval to fly flight-proven Falcon 9 and Crew Dragon vehicles during Commercial Crew flights starting with Post-Certification Mission 2, per a modification to SpaceX's contract with NASA.

https://beta.sam.gov/awards/90121604%2BIDV

That is one heck of an endorsement of reuse given these are carrying crew. Wow. Very awesome to see.

Surprised on reuse of Dragon so soon, maybe after few have been reflown on cargo missions. They have been reflying v1 cargo version for while.

Good news for commercial flights as they can sell them lot cheaper.

[DistantTemple]

Good negotiating by SpaceX.

They could easily lay on extra training "voyages" with the recovery fleet, since it has inactive periods. I suspect the outlay for SX will be low, and SX will also benefit by having better relationships with Det-3, and a higher chance of better outcomes in the event of an abort or unusual landing.

SX gets the better deal by absolute miles! -
Of course NASA WANTS SpaceX to be successful. Part of the CC is to nurture the development of commercial spaceflight. This is a way of handing SX a bonus for knuckling down and delivering. Since SX will use any extra profit for further developments, NASA will benefit more from granting this.

[Tulse]

The timing of the Dragon reuse announcement doesn't make much sense to me, as SpaceX hasn't even returned a single crewed Dragon yet, much less demonstrated their reusability. Why now? Obviously NASA wanted to extend the DM-2 mission, but surely they could have bargained something else with SpaceX.

 (Allowing previously-flown Falcon 9s makes sense, as their reliability is well-demonstrated.)

[clongton]

The timing of the Dragon reuse announcement doesn't make much sense to me, as SpaceX hasn't even returned a single crewed Dragon yet, much less demonstrated their reusability. Why now? Obviously NASA wanted to extend the DM-2 mission, but surely they could have bargained something else with SpaceX.

 (Allowing previously-flown Falcon 9s makes sense, as their reliability is well-demonstrated.)

Everything doesn't have to have a reason. Stuff happens whenever stuff happens.

[Tulse]

Everything doesn't have to have a reason. Stuff happens whenever stuff happens.

Sure, but NASA has in the past been somewhat leery of re-use, and with actual crewed flight, it seems weird to approve Crew Dragon for reuse when it hasn't demonstrated one full crewed use yet, much less how it will work refurbished after being in salt water. Cargo Dragon has worked fine, but Crew Dragon is very different and more complex vehicle. I would have thought that NASA would have required at least one successful reuse of a Crew Dragon for cargo before they agreed to put people back into a previously-flown vehicle.

[salpun]

Crew Dragon is a different build. Crew will not be converted to cargo.

[Tulse]

Crew Dragon is a different build. Crew will not be converted to cargo.

The SpaceX plan was/is to reuse Crew Dragons for cargo, in part because NASA wouldn't allow their reuse for NASA crew.

[salpun]

Crew Dragon is a different build. Crew will not be converted to cargo.

The SpaceX plan was/is to reuse Crew Dragons for cargo, in part because NASA wouldn't allow their reuse for NASA crew.

Now they can so that is restriction is gone.