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

[Orbiter]

From what I've read in the environmental impact report, they expect the first stage to start tumbling after engine shutdown, and the sidewards wind load then snapping the rocket apart. This may lead to propellants mixing and combusting, but could also just create a white vapor cloud and some debris.

Are you or they certain it will tumble and not just flip?

It will have a lot of remaining propellant onboard after 80 seconds so the CoG will not be severely skewed toward the engine section so it will definitely not be a dart-like situation trending toward engine first stable flight. Moreso with the fact the 2nd stage will still be fully loaded. I kinda expect the aeroloads to first rip off the 2nd stage off of the stack and then the 1st stage will tumble until it breaks up.

That would be a sight to see! Can a video camera get anywhere close to something like that? Edit: If so, SpaceX will probably do it

If Playalinda Beach is open I will be shooting with a pretty decent sized telescope the entire breakup sequence. If not, then somewhere near Max Brewer.

[wannamoonbase]

From what I've read in the environmental impact report, they expect the first stage to start tumbling after engine shutdown, and the sidewards wind load then snapping the rocket apart. This may lead to propellants mixing and combusting, but could also just create a white vapor cloud and some debris.

Are you or they certain it will tumble and not just flip?

It will have a lot of remaining propellant onboard after 80 seconds so the CoG will not be severely skewed toward the engine section so it will definitely not be a dart-like situation trending toward engine first stable flight. Moreso with the fact the 2nd stage will still be fully loaded. I kinda expect the aeroloads to first rip off the 2nd stage off of the stack and then the 1st stage will tumble until it breaks up.

I wouldn't be surprised if SpaceX tries to fly it after separation.

However, I'd expect the flight plan to contain an action to activate the FTS shortly after separation.

Edit: After years of waiting and seemingly endless delays we are 8 days from this test.  That's pretty exciting.

[oldAtlas_Eguy]

If I am not mistaken this is a first of it's kind test to do an abort at max Q.

I am sure that NASA will be very interested in all the data gathered from this test to do validation of all ot it's past and current models to see how close their predictions were to reality.

[hektor]

A-002 was such a test. It was not successful to reach that point exactly, but it was aiming at it.

[FutureSpaceTourist]

https://twitter.com/emrekelly/status/1213185567359410176

Launch hazard area issued for 1/11 #SpaceX Crew Dragon in-flight abort test. In effect from 0600 to 1230 ET (1100 to 1730 UTC). After abort, booster is expected to break apart over the Atlantic.

[Hankelow8]

I don't know if anybody has asked the question, but will they be doing at static fire ??

[Ken the Bin]

I don't know if anybody has asked the question, but will they be doing at static fire ??

Per this NASA Commercial Crew blog post: SpaceX In-Flight Abort Test Launch Date Update, yes.

The In-Flight Abort Test follows a series of static fire engine tests of the spacecraft conducted Nov. 13 near SpaceX’s Landing Zone 1 on Cape Canaveral Air Force Station in Florida. SpaceX will also conduct a static fire test of its Falcon 9 rocket ahead of the In-Flight Abort Test.

[ChrisC]

With the event getting closer, and all this rehashing of topics that have been discussed already, maybe it's time to split this thread into updates and discussion?

[russianhalo117]

With the event getting closer, and all this rehashing of topics that have been discussed already, maybe it's time to split this thread into updates and discussion?

I forwarded the request to the mods.

[SteveU]

From what I've read in the environmental impact report, they expect the first stage to start tumbling after engine shutdown, and the sidewards wind load then snapping the rocket apart. This may lead to propellants mixing and combusting, but could also just create a white vapor cloud and some debris.

Are you or they certain it will tumble and not just flip?

It will have a lot of remaining propellant onboard after 80 seconds so the CoG will not be severely skewed toward the engine section so it will definitely not be a dart-like situation trending toward engine first stable flight. Moreso with the fact the 2nd stage will still be fully loaded. I kinda expect the aeroloads to first rip off the 2nd stage off of the stack and then the 1st stage will tumble until it breaks up.

Question - won’t the AFSS automatically sense the departure of the capsule as a flight anomaly triggering a termination command?

[gongora]

Question - won’t the AFSS automatically sense the departure of the capsule as a flight anomaly triggering a termination command?

Only if they defined such a rule for this mission.  The booster regularly shuts down its engines, separates from the upper stage, moves around, relights engines, etc.  AFTS fires if it strays outside of the defined flight corridor.  They are shutting down the booster engines first, which the capsule (or wherever the logic resides in avionics) should sense as abnormal at that point in the flight, register it as a launch vehicle failure, and trigger the capsule abort.

[atsf90east]

This was the static fire for the Super Draco motors on the escape system... I think the poster was referring to a static fire of the Falcon 9 booster before the upcoming launch.

I don't know if anybody has asked the question, but will they be doing at static fire ??

Per this NASA Commercial Crew blog post: SpaceX In-Flight Abort Test Launch Date Update, yes.

The In-Flight Abort Test follows a series of static fire engine tests of the spacecraft conducted Nov. 13 near SpaceX’s Landing Zone 1 on Cape Canaveral Air Force Station in Florida. SpaceX will also conduct a static fire test of its Falcon 9 rocket ahead of the In-Flight Abort Test.

[gongora]

This was the static fire for the Super Draco motors on the escape system... I think the poster was referring to a static fire of the Falcon 9 booster before the upcoming launch.

The quote mentions both.

[soltasto]

Question - won’t the AFSS automatically sense the departure of the capsule as a flight anomaly triggering a termination command?

Only if they defined such a rule for this mission.  The booster regularly shuts down its engines, separates from the upper stage, moves around, relights engines, etc.  AFTS fires if it strays outside of the defined flight corridor.  They are shutting down the booster engines first, which the capsule (or wherever the logic resides in avionics) should sense as abnormal at that point in the flight, register it as a launch vehicle failure, and trigger the capsule abort.

Now that you mention this, it got me thinking that the AFTS should eventually trigger depending on how the launch corridor is defined. If the corridor is a 2D map then it will most likely not detonate unless strong winds pull the Falcon outside, bit it most likely will if the corridor is defined a 3D thing, like a bent pipe. Anyone knows how it is defined for FTS purposes?

[gongora]

The environmental assessment made it sound like the AFTS wouldn't fire based on altitude for this mission, but things can always change.

[SteveU]

Question - won’t the AFSS automatically sense the departure of the capsule as a flight anomaly triggering a termination command?

Only if they defined such a rule for this mission.  The booster regularly shuts down its engines, separates from the upper stage, moves around, relights engines, etc.  AFTS fires if it strays outside of the defined flight corridor.  They are shutting down the booster engines first, which the capsule (or wherever the logic resides in avionics) should sense as abnormal at that point in the flight, register it as a launch vehicle failure, and trigger the capsule abort.

Thanks-

Is there any literature on just what SpaceX parameters are for an abort. The NASA spec for the AFSS is very vague on that..

[alang]

A-002 was such a test. It was not successful to reach that point exactly, but it was aiming at it.

The wiki article claims that "Although the planned test point was not achieved, the early pitch up caused a higher maximum dynamic pressure than the design value."

[CorvusCorax]

regarding "toppling" of the booster. Remember that the booster has a 2nd stage "mockup" on top which is fully fueled.

AFAIK a fully fueled 2nd stage is heavier than dragon, so at the point of dragon separation the F9 should still be aerodynamically stable up until the point where the 2nd stage loses structural integrity (if it does) and as a result it becomes "bottom heavy"

it might actually be pretty hard to *make* it topple in this configuration with its engines of. it might not achieve significant AoA's until/unless the 2nd stage breaks up, as only thrust vectoring might have sufficient control authority. Unless the booster somehow manages to extend its grid fins, which would probably rip it apart nicely

[Draggendrop]

I was under the impression that this would be a modified 2nd stage. This would imply that a proper flight launcher model for this test was not required. It would seem that a legless and grid finless stage would do. This last sentence is horrid and seems like the poor booster is wounded...

[Orbiter]

I was under the impression that this would be a modified 2nd stage. This would imply that a proper flight launcher model for this test was not required. It would seem that a legless and grid finless stage would do. This last sentence is horrid and seems like the poor booster is wounded...

The only modification to the second stage will be that it'll fly without a Merlin engine. The first stage (B1046) will fly without landing legs or grid fins.