SpaceX F9 : Crew Dragon In-Flight Abort Test : Jan. 19, 2020 : Discussion

[wannamoonbase]

I think it’s going to be a fantastic spectacle. 

I don’t see how the stage survives the abort test.  I expect a fireball and amazing press coverage.

Elon likes press coverage. 

[marsbase]

I don’t see how the stage survives the abort test.

If the booster is going down, that will set off the AFSS.  So it will be quite spectacular.

[russianhalo117]

I don’t see how the stage survives the abort test.

If the booster is going down, that will set off the AFSS.  So it will be quite spectacular.

Well the CRS-7 booster core did survive for several seconds until making contact with an object above it.

[ZachS09]

For some reason, I'm under the assumption that the F9 booster rocket is robust in design, so I'm predicting that it'll survive the abort test at Max-Q similar to what happened with New Shepard in October 2016.

[wannamoonbase]

I don’t see how the stage survives the abort test.

If the booster is going down, that will set off the AFSS.  So it will be quite spectacular.

Exactly.

Maybe they could come up with a plan for hardware and software to allow recovery. But how much time and money would that cost?  And it might now work.

Keep it simple, get it over with and move on.

[woods170]

The only real question is whether the stack will include a second stage so that the test may be more true to actual flight conditions.

The example of the Apollo in-flight abort test argues "no".  The 50+ years of increasingly cautious NASA since then argues "yes".

Experience = the painful memories of one's past mistakes.  NASA thought they knew about pain in 1965.  They know a lot more about it now.  Why Boeing gets a pass on this test is a nice question.

The answer to that is simple: because performing a in-flight abort test is NOT MANDATORY for CCP.
In fact, even a pad-abort test is not mandatory for CCP.

The original requirements set by NASA, for CCiCAP and CCtCAP, did not contain language for performing flight tests to validate the abort systems. NASA only required the CCP contractors to "prove" their abort-system designs via computer modeling and test-stand firing of the abort motors.

The pad-abort tests as performed by SpaceX, and yet to perform by Boeing, were contractor-proposed tests above and beyond what was required by NASA.
SpaceX went a step further than Boeing and proposed even an in-flight abort test.

But again: none of the abort-system flight tests are mandatory. Should SpaceX decide to NOT do the in-flight abort test after all, it will not affect certification of the abort system. It will just cost them a $30 million CCiCAP milestone payment.

[vanoord]

For some reason, I'm under the assumption that the F9 booster rocket is robust in design, so I'm predicting that it'll survive the abort test at Max-Q similar to what happened with New Shepard in October 2016.

It would *probably* be possible to sort the guidance software to save the core - assuming that the abort test isn't triggered by blowing the core apart.

However, why bother? If the core does survive, it's likely to have been stressed in strange ways and not be reusable.

Easier, surely, just to drag the capsule off the stage at Max-Q and then wait for the AFTS to finish it off - which would be a useful confirmation that AFTS does what it's meant to do.

[envy887]

With the uncrewed demo now NET "end of the year", the In-Flight Abort has to be NET 2019, probably late Q1.

Is there a reason the in-flight abort has to be after the uncrewed demo?

[Jarnis]

With the uncrewed demo now NET "end of the year", the In-Flight Abort has to be NET 2019, probably late Q1.

Is there a reason the in-flight abort has to be after the uncrewed demo?

Uses the same capsule.

[chrisking0997]

But again: none of the abort-system flight tests are mandatory. Should SpaceX decide to NOT do the in-flight abort test after all, it will not affect certification of the abort system. It will just cost them a $30 million CCiCAP milestone payment.

which IMO directly goes back to what hardware we are going to see in the abort test.  If SX is getting 30 million for the milestone, then I dont see how it will be anything other than a standard F9 launch with D2 on top.  They arent going to jury rig a brand new vehicle configuration and all the GSE changes associated with it for a one off test

[biosehnsucht]

It would *probably* be possible to sort the guidance software to save the core - assuming that the abort test isn't triggered by blowing the core apart.

However, why bother? If the core does survive, it's likely to have been stressed in strange ways and not be reusable.

There might be useful things to learn from a stage put through such stresses...

[oiorionsbelt]

The answer to that is simple: because performing a in-flight abort test is NOT MANDATORY for CCP.
In fact, even a pad-abort test is not mandatory for CCP.

And yet SpaceX and Boeing are doing one or both.
Kinda flies in the face of the "risk averse NASA" line, no?

[Proponent]

Just blow it all to heck at Max-Q and show that it works... period... 

If the IFA Test is to be a demonstration of D2 ability to prevent LOC at the conditions that would have the highest chance for a LOC event.  use a working S2  fill it with propellant and then use the S2 FTS to initiate a catastrophic event.   when Dragon and the simulated test humans inside are shown to have survived this worst case scenario so that there would be no LOC then you have set bar very high for safety and Risk reduction.

I doubt it's realistic to expect the escape system to save the capsule in the event of a no-notice upper-stage explosion.  Apollo's LES, for example, required 2-3 seconds' warning, depending on which stage was exploding.

[docmordrid]

>
I doubt it's realistic to expect the escape system to save the capsule in the event of a no-notice upper-stage explosion.  Apollo's LES, for example, required 2-3 seconds' warning, depending on which stage was exploding.

Except that CRS-7's Cargo Dragon survived the breakup of F9's upper stage without a LAS, surviving until it hit the drink. As a result, SpaceX changed their code to deploy the chutes in a similar incident.

The SuperDraco's achieve full thrust in about 100 milliseconds, and ISTR there are break wires on the stages to signal a breakup to the safety system.

[John Alan]

I'm not sure I understand how the AFTS system and it's bounding boxes are defined for each flight...
BUT... let's assume it's a series of points on the intended flight path with allowed distance of deviation from same.
And it's all on board and loaded preflight in table format of some sort...
My guess is it's usually it's just a copy of the flight plan and just uses a separate GPS to cross check all is well...

Ok... for this flight...
Calculate the point of Max-Q and put a hard dog leg in the predefined AFTS data set uploaded... 
The rocket fly's normally and suddenly the AFTS thinks it's flown off course and a threat to all...

AFTS does it's thing... rocket "disassembles" breaking trip wires... Dragon 2 does it's thing and flies out ahead of the carnage... parachutes softly into the ocean unharmed...

They just proved out practically every safety system on the rocket... at the worst time in flight... in one shot...

Job done... 

[guckyfan]

And it's all on board and loaded preflight in table format of some sort...
My guess is it's usually it's just a copy of the flight plan and just uses a separate GPS to cross check all is well...

I sincerely hope not. It reminds me of the Ariane flight that was off track because it was programmed wrong. I hope SpaceX and the Airforce went through the process with a fine comb to make sure the values are derived independently.

[OneSpeed]

... They just proved out practically every safety system on the rocket ...

Except the system that the test is designed to prove, the LAS.

Once the booster is terminated, it turns to vapour and confetti, and essentially stops in mid-air. The capsule keeps travelling ballistically, ahead of the carnage, whether the LAS fires or not. So, firing the LAS after termination would prove nothing about its ability to escape a fully functional and thrusting booster at Max-Q, which is the point of the test.

This is not Mythbusters, a bigger bang is not always the answer.

[woods170]

The answer to that is simple: because performing a in-flight abort test is NOT MANDATORY for CCP.
In fact, even a pad-abort test is not mandatory for CCP.

And yet SpaceX and Boeing are doing one or both.
Kinda flies in the face of the "risk averse NASA" line, no?

No, it doesn't. Proving the abort system via an abort test flight is actually easier than doing thru computer modeling alone.

Also: SpaceX needed (at least) the pad abort test to verify the critical performance of the SuperDracos in a flight environment.
Testimony to this is that the pad abort test of Crew Dragon proved that Super Draco wasn't up to spec yet. Both reliability and performance of Super Draco were improved based on lessons-learned from the pad abort flight test.

[AncientU]

The answer to that is simple: because performing a in-flight abort test is NOT MANDATORY for CCP.
In fact, even a pad-abort test is not mandatory for CCP.

And yet SpaceX and Boeing are doing one or both.
Kinda flies in the face of the "risk averse NASA" line, no?

No, it doesn't. Proving the abort system via an abort test flight is actually easier than doing thru computer modeling alone.

Also: SpaceX needed (at least) the pad abort test to verify the critical performance of the SuperDracos in a flight environment.
Testimony to this is that the pad abort test of Crew Dragon proved that Super Draco wasn't up to spec yet. Both reliability and performance of Super Draco were improved based on lessons-learned from the pad abort flight test.

If your interest is saving the crew, instead checking off a block on some bureaucrat's checklist, you want to do the test and learn what you need to learn.  Saving the crew is more likely after improving based on lessons learned.

[meberbs]

But again: none of the abort-system flight tests are mandatory. Should SpaceX decide to NOT do the in-flight abort test after all, it will not affect certification of the abort system. It will just cost them a $30 million CCiCAP milestone payment.

which IMO directly goes back to what hardware we are going to see in the abort test.  If SX is getting 30 million for the milestone, then I dont see how it will be anything other than a standard F9 launch with D2 on top.  They arent going to jury rig a brand new vehicle configuration and all the GSE changes associated with it for a one off test

Whitelancer64 mentioned this on the previous page, but it seems you missed it. The plan previously involved using a 3 engine test booster for this test.

https://www.nasaspaceflight.com/2015/04/spacex-tanking-tests-in-flight-abort-falcon-9/

SpaceX clearly did not plan on including an upper stage, and certainly had plans for a one-off configuration. No reason to think that reusing their plans from back then for things like S1 to Dragon interface (other than the 3 engine booster, since that one is too old to be used with current GSE) wouldn't be less expensive than expending an upper stage.