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Old January 15th 20, 01:39 PM posted to sci.space.policy
Jeff Findley[_6_]
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Default SpaceX Dragon 2 In Flight Abort Test

In article ,
says...

On 2020-01-14 07:04, Jeff Findley wrote:
I'm sure this will be
live-streamed by people like @EverydayAstronaut


Wouldn't SpaceX live stream it? I would expect nothing less than views
from many on-board cameras. A good disaster movie :-)

I take it the ejection will happen at MaxQ? At that altitude, can
aircraft assets film the event?


I understand that the abort will actually happen at the time of maximum
drag, which isn't exactly maximum aerodynamic pressure. But, the two
are "close enough" that people just keep saying MaxQ.

Will Stage1 come back to land?


Absolutely not. It will be destroyed by the test. The first stage has
no grid fins or landing legs.

The Falcon 9 first stage will be simulating an abort, which means that
its engines will all shut down. So it will have little control
authority when Dragon 2 aborts. This will expose the (blunt) top of the
2nd stage directly to airflow, including exhaust from the Super Dracos.
This will no doubt cause the booster to tumble. It will therefore break
up quite quickly due to aerodynamic forces because launch vehicles that
are very tall and thin (fineness ratio) are simply not designed to fly
sideways through the air near the portion of the flight where it
experiences maximum aerodynamic pressure.

What is the impact on Stage1 upon Dragon2 popping out? Is it a
survivable event where Stage1 could cut off engines, start falling and
then aim for the drone ship?


See above. Or if you like here's a cite:

SpaceX test-fires rocket ahead of Crew Dragon in-flight abort test
January 11, 2020 Stephen Clark
https://spaceflightnow.com/2020/01/1...cket-ahead-of-
crew-dragon-in-flight-abort-test/

Or does separation happening in "thick" atmosphere result in Stage1
hitting atmosphere in the wrong angle and causing breakup and fireworks?


Again, the top of the 2nd stage will be directly exposed to airflow. It
is simply not designed for this.

Or are they actually going to detonate Stage1 prior to the abort and
also test the software/sensors that will automatically trigger the
Dragon abort?


I don't believe they're going to "detonate" stage 1 because it won't
have a chance to do so. On a crewed flight, the detonation would not be
commanded until after the Dragon 2 has time enough to escape. Falcon
will quite likely be torn apart by aerodynamic forces long before it has
a chance to self destruct.

Falcon 9 does have destruct devices. It also has an automated destruct
system that has been used on uncrewd flights. This article describes
that system:

https://www.floridatoday.com/story/t.../03/11/spacex-
autonomous-flight-safety-system-afss-kennedy-space-center-florida-
falcon9-rocket-air-force-military/98539952/

At the time this article was written, NASA had not yet decided if it
would use the aforementioned automated system on crewed flights. From
the article above:

NASA's Commercial Crew Program is reviewing the system and has
not yet accepted it.

"If done correctly, an automated system is actually safer,
more reliable than having a human in the loop," said Kennedy
Space Center Director Bob Cabana. "We've still got some work
to do before Commercial Crew is going to certify that this
is the way to go, but this is the future."

Cabana, a four-time shuttle astronaut, remembered how
shuttle crews before launches would meet with the Range
safety personnel who could decide their fate.

"We used to go visit the guys that sat on console that
would push the button and show them pictures of our kids
and get to know them," he said.

So, it's not clear to me whether or not crewed Dragon 2 flights will use
the automated system, or whether an actual range safety officer will
have to "push the button".

Jeff
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