The second commercial flight of Space Exploration Technologies’ (SpaceX) Dragon cargo vessel to the International Space Station (ISS) has been pushed back from January until no earlier than March 1, 2013. The delay, announced by NASA managers, will allow more time for investigation of the Falcon 9 engine malfunction, which occurred during the launch of the first commercial Dragon mission on Oct. 7.
Hawthorne, Calif.-based SpaceX is tasked with supplying Dragon spacecraft and the two-stage Falcon 9 launch vehicles to NASA under the Commercial Resupply Services (CRS) contract. The speed in which SpaceX has reached this historic milestone has been nothing short of a whirlwind.
Things, however, did not go off without a hitch during SpaceX’s last flight.
About one minute 19 seconds into the CRS-1 flight to the ISS, one of the Falcon’s nine first-stage Merlin engines encountered an anomaly, the exact cause of which has yet to be determined. Observers on the ground at first thought there had been an explosion, as debris was seen falling from the rocket.
However, early analysis by the post-flight investigation board showed that while the fuel dome of Engine One, above the nozzle, apparently ruptured it did not explode. Burning fuel that escaped while the engine was still running then caused the fairing to rupture, as evidenced by the flight video recordings.
Upon Engine One losing pressure, it was immediately shut-down. At the same time, panels designed to relieve pressure within the engine bay were ejected to protect the stage and other engines. Almost instantaneously the onboard flight computer calculated a new ascent profile in real time, based on the remaining eight engines, to ensure that Dragon would still reach its correct orbit for rendezvousing and docking with the ISS.
The Falcon’s secondary payload, Orbcomm’s prototype OG2 communications satellite, didn’t fare quite as well and had to be dropped into a lower-than-planned orbit. However, the rocket did what it was designed to do, which is recover from an engine-out situation and complete its primary mission. The Saturn V also had this ability and boasted a 100 percent launch success rate despite engine loss on two flights. No other rocket currently flying can handle engine-outs and still complete its mission.
Video courtesy of SpaceX
The CRS-1 post-flight investigation board will continue to look at the flight data in an effort to understand what happened to Engine One. While responsibility for resolving the issue rests firmly with SpaceX, as the launch provider, the company is able to draw upon NASA’s vast experience in failure analysis in order to understand the sequence of events that led up to the failure and avoid a similar incident on future flights.
When CRS-2 does eventually depart from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida, it will be the fourth flight of a Dragon spacecraft and the fifth for the Falcon 9 rocket. It will also mark the first excursion of the Dragon detachable trunk section, which allows the transport of unpressurized cargo to the ISS. Meanwhile, NASA officials have confirmed that the space station is well stocked with supplies and its operations will not be affected by Dragon’s delay.