02-07-2018, 02:18 AM
|
|
Master Modeler
|
|
Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 6,507
|
|
Quote:
Originally Posted by Royatl
It didn't run out of fuel, but of the igniter fluid to relight the engines (on liftoff of F9, you see a green flash at ignition; that's the stuff -- hypergolic?). They only had enough to light one engine, and it hit at about 300kmh about 150m off the ship, but the resulting explosion damaged two of the drone ship's engines.
|
They use a mixture of TEA-TEB (triethylaluminum and triethylboron [also called triethylborane]), which ignites spontaneously on contact with the LOX. This is actually even better news, because (just as the inadequate hydraulic fluid supply for the grid fins was fixed by simply using a larger reservoir) they only need to use a larger TEA-TEB reservoir (and probably not much bigger) to fix the landing burn engine ignition problem. This is a fleabite of a problem compared to what had worried them--that the vehicle might buckle at Max Q or shake itself apart (they don't have the facilities to conduct a full-duration--with throttling--static firing at McGregor, Texas [plus imagine the cows' terror at *that*! :-) ], and Pad 39A doesn't have a big enough supply of sound-suppression water to protect itself and the vehicle for that long).
|