SpaceX resupply launch scrubbed by helium leak
BY STEPHEN CLARK
Posted: April 14, 2014
The launch of a SpaceX's Dragon supply ship from Cape Canaveral was scrubbed Monday due to a helium leak in the Falcon 9 rocket's first stage. The next launch attempt will be no earlier than Friday.
"As folks heard on the anomaly net, we have encountered an issue that will result in a scrub of today's 4/14 launch attempt," Lim said. "The team here will start to safe the vehicle and offload propellants."
The 208-foot-tall launcher was on track for liftoff at 4:58 p.m. EDT (2058 GMT) on SpaceX's third operational resupply run to the International Space Station. A Dragon cargo ship is mounted atop the rocket packed with approximately 2.4 tons of supplies, including fresh experiments, food, spare parts and other gear.
SpaceX spokesperson Emily Shanklin said the problem was in the helium system on the Falcon 9's first stage. Helium is used to pressurize the rocket's propellant tanks and carries out several other functions during the terminal countdown and flight of the booster.
Shanklin said the issue will be fixed in time for Friday's launch opportunity, which comes at 3:25 p.m. EDT (1925 GMT), the moment the space station's orbital plane crosses over the launch pad at Cape Canaveral.
The weather outlook is iffy for Friday, with meteorologists calling for a 60 percent chance of violating the Falcon 9 rocket's weather rules.
The mission can only launch on certain days to ensure the Dragon spacecraft can expeditiously rendezvous with the space station with time-sensitive experimental cargo.
The Dragon spacecraft would complete an automated rendezvous with the space station early Sunday, with grapple by the lab's Canadian-built robotic arm expected around 7 a.m. EDT (1100 GMT).
SpaceX is one of two companies contracted by NASA to deliver cargo to the space station. NASA signed a $1.6 billion contract for 12 resupply flights by SpaceX, and Orbital Sciences Corp. has a $1.9 billion deal for eight missions through 2016.
NASA contracted with two commercial providers to ensure the station could receive cargo in the event one of the delivery vehicles was unable to fly.
The Dragon spaceship's internal cabin is filled with 1,576 pounds of science and research gear, 1,049 pounds of crew provisions, 449 pounds of vehicle hardware, and 271 pounds of spacewalk tools.
An unpressurized trunk section on the aft end of the Dragon spacecraft contains to NASA technology demonstration payloads: a high data-rate optical communications terminal named OPALS and a high-definition camera system to return videos of Earth.
Monday's scrubbed countdown comes after several delays in launching the SpaceX cargo flight.
Engineers discovered contamination on thermal blankets inside the Dragon's external cargo bay, prompting a delay from a planned March 16 launch date. SpaceX later determined the contamination would have no impact on the mission.
Another launch opportunity in late March was missed after a U.S. Air Force range radar was damaged by a short-circuit, delaying the Falcon 9 launch and the liftoff of a United Launch Alliance Atlas 5 rocket from Cape Canaveral.
After the Air Force activated a backup radar, the Atlas 5 mission launched successfully April 10 and the SpaceX mission was retargeted for liftoff Monday.
Follow Stephen Clark on Twitter: @StephenClark1.