SpaceX Launches Falcon 9 Countdown Cutoff Data Review

SpaceX is launching a data review today that is expected to clear the way for another attempt to test-fire its Falcon 9 first stage later this week or next week at Cape Canaveral Air Force Station.

Engineers gathered all data from a countdown Tuesday that was cut off two seconds before the rocket's nine Merlin 1C engines were to ignite in a 3.5-second test firing. The cutoff apparently occurred when an unspecified problem cropped up during the engine start-up sequence.

"Given that this was our first abort event on this pad, we decided to scrub for the day to get a good look at the rocket before trying again. Everything looks great at first glance," SpaceX spokeswoman Emily Shanklin said in a statement.

Shanklin noted that SpaceX completed all pad preps at Launch Complex 40 on time, and that the countdown included range safety hold-fire checks, S-band telemetry tests, C-band radar tests and simulated checks of the rocket's Flight Termination System.

The Flight Termination System includes small pyrotechnic devices that would be used to deliberately destroy the rocket if it careened out of control during launch and threatened populated areas surrounding Cape Canaveral Air Force Station.

The rocket's propellant tanks were filled with liquid oxygen and RP-1, a highly refined kerosene, and the tanks were pressurized with gaseous helium. All terminal countdown, flight software, ground software checks were completed down to the T-Minus two second mark when engineers encountered a problem during the engine start-up sequence and the countdown was cut off.

The abort involved closing valves to isolate the engines from propellant tanks and a purge of residual propellant. The flash of orange flames seen at the bottom of the rocket was created when the residual propellants burned off.

"The engines did not ignite and there was no engine fire," Shanklin said.

SpaceX engineers drained propellants and inspectors were to be sent out late Tuesday after the pad area was deemed safe. Tanker trucks with additional liquid oxygen, RP-1 and helium are expected to arrive today to replenish storage vessels at the pad in advance of another test-firing attempt later this week.

Shanklin said that attempt likely would be made in three or four days.