SpaceX Dragon CRS-7 cargo to ISS [vehicle failure analysis announcement]

[Dr Mordrid]

SpaceX Dragon CRS-7 cargo mission to ISS

Launch: June 28, 2015
Launch time: 1021 Eastern

Primary payload: IDA-1 docking adapter for Commercial Crew spacecraft

Stage landing: yes
Stage landing zone: ASDS Of Course I Still Love You (drone ship)

CRS-7 video streams

SpaceX YouTube channel (1001 Eastern)

https://www.youtube.com/user/spacexchannel

SpaceX webcast (1001 Eastern)

http://www.spacex.com/webcast/

SpaceX LiveStream (1001 Eastern)

http://livestream.com/spacex/events/4152712

NASA TV (0900 Eastern)

http://nasatv-lh.akamaihd.net/i/NASA_101@319270/master.m3u8

NASA TV on Ustream (0900 Eastern)

https://www.google.com/url?q=http://m.ustream.tv/channel/nasa-media-channel

Mission patch

[Evildead666]

Excellent!

I'm crap at this, but what would that make for GMT ? (UK is +1 atm and CET is +2, due to summertime rules)

-6 ?

[SitFlyer]

http://www.timeanddate.com/worldclock/converter.html

[Evildead666]

New York (U.S.A. - New York) Sunday, 28 June 2015, 11:00:00 EDT UTC-4 hours
Paris (France) Sunday, 28 June 2015, 17:00:00 CEST UTC+2 hours
Corresponding UTC (GMT) Sunday, 28 June 2015, 15:00:00

So 16h00 for the UK.

Looks right.

[Dr Mordrid]

The new, highly upgraded drone ship ASDS Of Course I Still Love You is on station, waiting for the CRS-7 first stage to attempt a landing.

Falcon 9 v1.1 now has a modded throttle valve system to prevent the stiction issue that caused the last stage to crash. Basically, the valve stuck for a moment on full throttle and the stage couldn't recover before arriving at the ASDS Just Read the Instructions.

This is the second to last Falcon 9 v1.1 core. The upgraded core, commonly called "v1.2" but as yet unnamed, will fly on the SES-9 commsat launch later this summer. F9 v1.2 will have about 33% higher performance, being capable of stage landings after a high mass GTO launch and up to 21+ tonnes to LEO as an expendable.

The upgraded core will also be used on Falcon Heavy, increasing its expected performance as well. Heavy just got seriously "Heavy-er." FH's maiden flight is still on for this year with the pacing largely determined by the construction on KSC LC-39A, which is in its final stages.

LC-39A's massive new hanger will be able to process 5 Falcon 9's, or 1 Falcon Heavy and 2 Falcon 9's, simultaneously in anticipation of Run 'n Gun launches (roll out, load propellants and launch in 60 minutes; rinse, wash, repeat.)

Image by OCISLY's resident DroneX Cam.

[cjolley]

Well heck.

[Umfriend]

So, Iain M. Banks, his books any good?

[cjolley]

Did he write a book about a second stage oxygen tank over-pressure?

PS Musk alluded cryptically to a "counter-intuitive" cause.

[Umfriend]

Oh, wait, I did not expect this....

Apparantly, the names of the landing crafts are from books of mr. Banks. Did not know that, found that out earlier today as I was wondering about the weird names.

[Dr Mordrid]

Here's what's known.

1) the first stage kept on plugging for almost 8 seconds after the upper stage failed and Dragon was ejected. That demonstrates a degree of toughness no one expected. Most rockets would have tumbled and disintegrated almost immediately.

2) the last few milliseconds of the upper stage telemetry has to be reconstructed in a hex editor. Something likely took out the telemetry and upper stage avionics hardware, which is at the top of the upper stage.

3) Dragon continued to send telemetry after it broke away from the booster. If it had been programmed to jettison its nose cone and deploy the chutes it may have been recoverable. A good sign for the crew version which also has escape engines.

4) there are a few theories about what caused the upper stage failure,

a. the IDA-1 docking adapter for ISS in the Trunk broke free and both took out the telemetry & avionics and caused the LOX tank overpressure, which caused it to burst.

b. the failure of a COPV (composite overwrapped pressure vessel) helium tank, which is inside the LOX tank.

c. the failure of the tank wall

d. the upper stage Merlin engine was chilling in to prepare for separation. A failure in the chill-in hardware could have over pressurized the LOX tank

or several other things.

[Dr Mordrid]

A supplier built 24" x 1" strut which supports a helium COPV let go at 20% of its design rating, COPV rattles around, helium line ruptures, helium leaks out in large volumes and bad things happened.

Those parts WILL NOT be used again, and each of the new parts will be proof tested.

The Dragon spacecraft would have survived if it had programmed to deploy its parachutes after the vehicle broke up, even without SuperDraco abort engines (!!), and from now on the software will support this safety mode.

Falcon Heavy delayed to next spring - dammit.

Return to flight no sooner than September.

Jeff Foust ‏@jeff_foust · 7s7 seconds ago
Musk: able to replicate by taking 1000s of these struts and testing; a few failed well below rated level.

Jeff Foust ‏@jeff_foust · 5s5 seconds ago
Musk: not going to move strut work in-house, but will move to a different design likely from a different supplier.

Parabolicarc.com ‏@spacecom · 9s9 seconds ago
Musk: same strut on upper and lower stages. Will be replacing them in both.

Jeff Foust ‏@jeff_foust · 38s38 seconds ago
Musk: this will not affect commercial crew timeline; this is not on the critical path.

Jeff Foust ‏@jeff_foust · 5s5 seconds ago
Musk: likely to change the bulk of the material in support struts to Inconel, but no final decision on that yet,

Jeff Foust ‏@jeff_foust · 15s15 seconds ago
Musk: examination of strut that failed in ground tests showed problems in the grain structure in the steel.

TWC Space Weather ‏@twcspacewx · 3m3 minutes ago
Musk: The first Dragon v2 flights will be without crew, so they will carry cargo

[Dr Mordrid]

Images of what we're discussing.

COPV = Composite Overwrapped Pressure Vessel

Basic struts


COPV installation in S2 LOX tank


A Falcon 9 upper stage COPV that survived reentry and fell in Brazil