SpaceX launch week begins with static fire Monday
BY STEPHEN CLARK
Posted: February 21, 2013
SpaceX engineers will spend the next week testing its next Falcon 9 rocket and packing its privately-built Dragon spaceship with supplies and experiments before the next commercial resupply flight to the International Space Station blasts off March 1.
The static fire, scheduled for Monday afternoon at SpaceX's launch pad at Cape Canaveral, will occur at the end of a practice countdown. The launch team stationed about 10 miles from the rocket will load kerosene and liquid oxygen propellants into the booster and oversee a computer-controlled countdown sequence leading to ignition of the Falcon 9's first stage engines.
The rocket's nine Merlin 1C engines will fire at full power for about two seconds, reaching more than 800,000 pounds of thrust while the vehicle remains firmly attached to the launch pad at Complex 40.
After a successful static fire, engineers will remove the two-stage rocket from the launch pad. Workers will connect the launcher's ordnance and pack the final items inside the Dragon spacecraft for shipment to the space station.
NASA has identified more than 1,200 pounds of pressurized cargo to launch on the Dragon mission, which is the second of at least 12 flights contracted to SpaceX under a $1.6 billion agreement signed in 2008.
Among Dragon's cargo: Clothing and food for the station astronauts, exercise equipment, crucial parts for the lab's carbon dioxide scrubber, refrigerated experiments, and computer gear.
The mission is also the first Dragon to haul equipment in its exposed trunk section. SpaceX designed the capsule to carry unpressurized cargo in a small payload bay at the aft end of the spacecraft, and the upcoming mission is slated to deliver two grapple bars for the space station's cooling system. The grapple bars could be used if astronauts ever need to replace one of the lab's external radiators.
Liftoff of the Dragon and its Falcon 9 launcher is set for March 1 at 10:10 a.m. EST (1510 GMT), beginning an abbreviated 20-hour rendezvous with the space station. After deployment from the Falcon 9's upper stage less than 10 minutes after launch, the Dragon capsule will unfurl solar arrays, open its navigation bay door, and begin approaching the outpost aided by GPS and laser navigation.
Astronauts Kevin Ford and Tom Marshburn will monitor Dragon's rendezvous. Using a joystick controller, Ford will grapple the robotic spacecraft as it floats about 30 feet from the space station at approximately 6:30 a.m. EST (1130 GMT) on March 2.
The crew will open the hatch to Dragon once the craft is bolted to the space station's Harmony module.
Astronauts will fill Dragon's pressurized cargo module with more than 2,600 pounds of equipment for return to Earth at the end of the flight.
Since the retirement of the space shuttle, the Dragon spacecraft is the only space station servicing vehicle capable of both delivering and returning large qauntities of cargo. SpaceX completed a successful test flight to the complex in May 2012, followed in October the first operational resupply sortie.
On the way back to Earth, Dragon will ferry valuable experiment samples, old spacesuit components, and a slew of equipment to be analyzed and potentially repaired and relaunched.
Departure of Dragon is scheduled for March 25. The spacecraft will fall back into the atmosphere and descend to a parachute-assisted splashdown in the Pacific Ocean, where a recovery team will pull the capsule from the ocean and sail it back to port in California.
Two reviews, one chaired by NASA and another by SpaceX, last week formally cleared the March 1 flight to proceed. SpaceX will convene a launch readiness review next week to discuss final launch preps before the countdown.
NASA agreed with the conclusions of a SpaceX-led investigation into an engine mishap during the last mission's launch, a SpaceX official told Spaceflight Now.
One of the Falcon 9 rocket's first stage Merlin engines shut down 79 seconds after the Oct. 7 launch, responding to a computer-detected anomaly inside the kerosene-fueled engine.
Investigators from SpaceX and NASA, relying on telemetry data and no physical evidence, found the engine suffered a breach and a sudden loss of pressure, said Michael Suffredini, NASA's space station program manager, in a January press conference.
"It was hard to find a specific smoking gun to point to, but a number of things were believed to be contributors," Suffredini said, adding the engines to be used on the March 1 launch were closely examined to verify their health.
"A contributing factor was perhaps the amount of testing this engine saw before it flew," Suffredini said.
SpaceX put the engines on the March 1 launch through standard acceptance testing, but the company otherwise limited the engines' run time to avoid any complications caused by additional tests, according to Suffredini.
SpaceX also beefed up shielding around an electrical box on the Dragon spacecraft to reduce the chances of water intrusion after the capsule splashes down in the Pacific Ocean.
During the October mission, the Dragon's experiment freezer lost power when sea water inundated the unit's power source. None of the freezer's biological samples were compromised by the snafu, but scientists worry similar occurrences on future missions could ruin research.
SpaceX is working on a new electrical system for experiment freezers, and Suffredini said the permanent upgrades are due to debut on SpaceX's third cargo flight later this year.