CAPE CANAVERAL, Fla. — Space Exploration Technologies () was cleared for a second supply run to the international space station, with launch of the company’s Falcon 9 rocket and Dragon capsule slated for 10:10 a.m. EST on Friday (March 1).
The capsule carries more than 1,000 kilograms of science equipment, spare parts, food and supplies for the six-member station crew. Meteorologists forecast an 80 percent chance of acceptable weather for launch on Friday from Cape Canaveral Air Force Station in Florida.
If all goes as planned, the Dragon capsule should reach the station about 20 hours later. It is slated to return to Earth on March 25 carrying about 1,400 kilograms of equipment no longer needed on the station, completed science experiments and samples for analysis in ground-based labs.
Preparations for SpaceX’s second Commercial Resupply Services (CRS) mission included extensive troubleshooting, analysis and testing to determine why a Falcon engine shut down early during launch of CRS-1 in October.
“There was a material flaw that went undetected in the jacket of the Merlin engine, resulting in a breach … causing depressurization of the combustion chamber,” SpaceX President Gwynne Shotwell told reporters during a prelaunch press conference Thursday (Feb. 28).
“The flight computer recognized that depressurization and then it commanded shutdown,” Shotwell said.
The Falcon’s eight other engines compensated for the loss of power and the Dragon capsule successfully reached the station. The situation, however, triggered a contract stipulation with NASA that barred SpaceX from restarting the engine, leaving an experimental Orbcomm satellite flying as a secondary payload in a lower-than-intended orbit.
“This vehicle has been designed to accommodate an engine-out. Though you never necessarily want to see it happen, it’s nice that we demonstrated the vehicle as it was designed,” Shotwell said.
She declined to provide details about the material flaw, citing an ongoing U.S. State Department review of SpaceX’s report for potential International Traffic in Arms Regulations (ITAR) violations.
“I don’t look good in horizontal stripes,” Shotwell quipped.
“The conclusions they came to, we agree with,” added NASA space station program manager Mike Suffredini.
“Our role as NASA is to sit next to them and work with them and understand the anomaly so that we’re comfortable. We have two options as the customer: We can either put our hardware on that vehicle or not.”