

SpaceX – Pad abort test successful - outworlder
http://livestream.com/spacex/events/4027110?origin=stream_live&mixpanel_id=a3817fd678e79-0f41afd19-43681f0a-2ee000-a3817fd679f25&acc_id=6329104&medium=email

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JanSolo
From the video, it looked good. Great takeoff, boost, coast and landing.
Really well done!

[https://www.youtube.com/watch?v=5bhW2h08zhY](https://www.youtube.com/watch?v=5bhW2h08zhY)

Couple of points of interest: There were a couple of puffs of smoke from the
engines that might be a sign of premature shutdown. Having one engine out
would cause uneven thrust which will cause the vehicle to rotate or tumble.
The test continued successfully, so if an engine did indeed die, we can assume
that another was also intentionally shutdown to balance the thrust. The
remaining engines would have fired for a little longer to make up for the lost
ones.

The engine chambers are the first entirely 3d printed production rocket motors
in the world. They're printed in inconel using Direct Metal Laser Sintering.
This is the first time that so many of them have been fired in an actual
mission scenario. The tech is so new and untested that special shields were
built round the motors to isolate the rest of the vehicle in case of an
explosion. I'm very interested to see how they held up.

There was some pretty severe tumbling during the drogue and main chute
deploys. While easily survivable, this would have been quite uncomfortable for
any passengers inside. I wouldn't be surprised if SpaceX tweaked the
deployment sequence a little to help reduce this.

Good job, SpaceX... I can't wait for the In-Flight abort test later this year!

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cartoonfoxes
> they're printed in inconel using Direct Metal Laser Sintering.

As someone who works with people who occasionally have to machine this stuff,
that's seriously impressive.

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sounds
What are the comparative advantages of Direct Metal Laser Sintering vs the
more traditional CNC Milling?

CNC Milling

\- Broader base of manufacturers who can meet specs

\- Lower cost?

\- Higher strength?

\- Faster essential steps (prototyping can be done more rapidly)

3D Printing

\- More optimal alloy distribution since the part is built up instead of
milled down

\- Less raw materials used / lower waste

fixermark suggests: - Can machine shapes that are impossible to machine via
reductive process.

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fixermark
I don't know for certain if it mattered in this specific case, but the 3D
Printing list should include

\- Can machine shapes that are impossible to machine via reductive process.

... (sort of, if you turn your head and squint. "Without seams" ;) ).

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digerata
What blows me away is comparing the acceleration of a fully loaded Falcon 9
and today's test. Obviously, the two are different and you know the
acceleration will be different to escape a failure of the rocket.

But to see something so small with relatively little fuel on board, take off
so fast is really incredible.

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jamesmoss
Another great step for SpaceX. At the moment it feels like they're making
progress every other week.

What sort of G loads do the astronauts in that capsule experience in an abort
scenario? It shoots up much faster than a typical launch. The separation from
the trunk looks fairly violent too.

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trose
> At the moment it feels like they're making progress every other week.

And they intend to accelerate their schedule as they go! This is so exciting!

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stevep98
Anybody know why they don't leave the trunk behind in the first place? It
seems like a waste of fuel.

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JanSolo
The trunks mass moves the COG rearwards and when combined with the fins, it
provides passive stability that keeps the nose pointing in the direction of
travel.

Notice that when the trunk detaches, the craft immediately starts pitching
over.

