— DanSpace77 (@DanSpace77) June 28, 2015
Some notes from the NASA press conference covering the loss of Falcon 9 and the Dragon resupply ship on Sunday morning.
Cause of the Accident & Investigation
The cause is as yet undetermined. SpaceX CEO Elon Musk, who was not at the press conference, Tweeted that there was an overpressure event in the second stage liquid oxygen (LOX) tank prior to the launch vehicle breaking up. “Data suggests counterintuitive cause,” he wrote. Video of the accident appears to show the breakup of the vehicle beginning there.
During the press conference, SpaceX President Gwynne Shotwell said she could not provide any additional details about the overpressure event. She said the first stage performed nominally for the first 2 minutes and 19 seconds of the flight, leading engineers to believe the problem occurred in the second stage.
Shotwell said she did not believe the range safety officer transmitted a destruct command to the rocket.
The Dragon spacecraft continued to transmit data to controllers for a period of time after the launch vehicle exploded, she added. Video appears to show that it was thrown free of the rocket.
SpaceX engineers are looking at data from 3,000 telemetry channels. The company also has deploys assets in the ocean to search for debris, Shotwell added. The investigation could take several months.
The FAA’s Pam Underwood said the investigation will be lead by SpaceX with oversight by the FAA.
What Was Lost
The Dragon cargo ship was carrying more than 4,000 pounds of supplies, payloads and experiments to astronauts aboard the International Space Station. NASA said the space agency had sent up some important pieces of hardware:
- the first of two International Docking Adapters to prepare for commercial crew vehicles being built by Boeing and SpaceX;
- a new spacesuit to replace an aging one on the station; and,
- water filtration beds used to filter out impurities to replace ones that are beginning to get full.
NASA officials said they would need to watch the situation with water filtration. This is the second set of filtration beds NASA has lost in launch accidents; the first set was destroyed when Orbital’s Antares rocket blew up eight months ago.
They also said the station’s water supply would be replenished by Russian and Japanese supply ships scheduled for launch later this summer.
Supply Status on ISS
NASA officials said they could go until October without any other supply ships visiting the space station. A Russian Progress cargo ship is due to launch on July 3, with a Japanese HTV freighter scheduled for August.
Orbital ATK will launch a Cygnus resupply ship in December aboard an United Launch Alliance Atlas V rocket. Officials said it might be possible to move that launch up to an earlier month.
They also said they did not anticipate a delay in the July 23 launch of a new three-person crew to the station aboard a Russian Soyuz spacecraft.