QuoteSpaceX traced the root cause of the cracks, located in the aft end of the nozzle, to a GN2 vent line that “caused flutter of the thinnest portion of the nozzle extension, creating the cracks,” the company said in a statement.
SpaceX traced the root cause of the cracks, located in the aft end of the nozzle, to a GN2 vent line that “caused flutter of the thinnest portion of the nozzle extension, creating the cracks,” the company said in a statement.
Just to close this one out, it was not a "process failure," unless your definition of "process failure" is so broad as to be "anything that causes failure that could have been prevented,"QuoteSpaceX traced the root cause of the cracks, located in the aft end of the nozzle, to a GN2 vent line that “caused flutter of the thinnest portion of the nozzle extension, creating the cracks,” the company said in a statement.Engineers cut off the bottom 4 ft. of the nozzle extension and corrected the root cause by diffusing the vent. “The extension increases the efficiency of the Merlin engine in vacuum and is installed by default on all upper-stage Merlin engines, but that efficiency increase is not required for this mission,” company spokeswoman Kirstin Brost said in a statement.http://www.space.com/missionlaunches/spacex-dragon-spacecraft-successful-test-flight-101208.html
SpaceX traced the root cause of the cracks, located in the aft end of the nozzle, to a GN2 vent line that “caused flutter of the thinnest portion of the nozzle extension, creating the cracks,” the company said in a statement.Engineers cut off the bottom 4 ft. of the nozzle extension and corrected the root cause by diffusing the vent. “The extension increases the efficiency of the Merlin engine in vacuum and is installed by default on all upper-stage Merlin engines, but that efficiency increase is not required for this mission,” company spokeswoman Kirstin Brost said in a statement.
Quote from: cuddihy on 12/09/2010 04:03 pmSpaceX traced the root cause of the cracks, located in the aft end of the nozzle, to a GN2 vent line that “caused flutter of the thinnest portion of the nozzle extension, creating the cracks,” the company said in a statement.If the nozzle is fragile enough to be damaged by a GN2 vent line, is it likely that it would also have failed under operation? I presume the stresses are substantial, even at the open end of the nozzle.cheers, Martin
... and most crucially, 3. the opportunity to review COTS-2 prox-ops and rendezvous data outside of the time-pressure of a flight environment.
Quote from: cuddihy on 12/09/2010 04:03 pmQuoteSpaceX traced the root cause of the cracks, located in the aft end of the nozzle, to a GN2 vent line that “caused flutter of the thinnest portion of the nozzle extension, creating the cracks,” the company said in a statement.If the nozzle is fragile enough to be damaged by a GN2 vent line, is it likely that it would also have failed under operation? I presume the stresses are substantial, even at the open end of the nozzle.cheers, Martin
Yes, it was process failure. A similar issue happened with a vent on the first launch and it disabled the roll control nozzle. The proper process would been to look at all vents to prevent similar problems.
Wasn't the vent that caused this issue re-located as well after the first F9 flight? (e.g. the fix for F9 F1 is part of the root cause for the nozzle problem on F9 F2).
The secret payload was a wheel of cheese. They posted photos on their facebook page.
Quote from: mnagy on 12/09/2010 06:27 pmThe secret payload was a wheel of cheese. They posted photos on their facebook page.This gives new meaning to the book "Who Moved my Cheese?"
Quote from: Jim on 12/09/2010 04:38 pmYes, it was process failure. A similar issue happened with a vent on the first launch and it disabled the roll control nozzle. The proper process would been to look at all vents to prevent similar problems.sigh...First I've heard of that. (thought SpaceX initially said it was a thermal issue on the 2nd stage roll control nozzle)...Still not convinced this is a process issue either way.
Yes, IIRC up to 2 years in flight for Dragon Lab. Mind you, checked their datasheet and it doesn't specify.So far as lifeboat goes, I'd expect it wouldn't be more than 12 months.
One crucial thing that has not been mentioned in this discussion is whether Dragon has enough consumables on board to do the fly-around check outs that ATV and HTV did on their first flights. It could be impossible to combine the remaining Demo missions due to that limitation.
