SpaceX demo flights merged as launch date targeted
BY JUSTIN RAY
Posted: December 9, 2011
The next demonstration test-flight for the SpaceX Dragon cargo freighter will link up with the International Space Station, officials have decided, allowing the company to combine the two previously-planned flyby and capture missions into one, launching from Cape Canaveral on February 7.
The COTS 1 mission occurred a year ago Thursday when a Falcon 9 rocket sent the unmanned Dragon capsule on a two-orbit shakedown cruise before successfully reentering the atmosphere and splashing down into the Pacific Ocean for recovery.
The original plans called for the COTS 2 mission to approach the space station and test communications and rendezvous systems before retreating and returning to Earth. The COTS 3 flight would actually travel to the station and link up.
But SpaceX founder Elon Musk had pushed for merging COTS 2 and COTS 3 into one mission, and on Thursday NASA officials formally agreed to combining the flight goals into a single trek.
"Pending all of the final safety reviews and testing, SpaceX will send its Dragon spacecraft to rendezvous with the International Space Station in less than two months. So it's the opening of that new commercial cargo delivery era for ISS," NASA deputy administrator Lori Garver announced Friday.
Following blastoff from Complex 40 at Cape Canaveral Air Force Station, the two-stage liquid-fueled Falcon 9 rocket will insert the Dragon spacecraft into a preliminary Earth orbit begin its pursuit of the space station.
The COTS 2 demonstrations are planned for Feb. 9 as Dragon approaches the orbital laboratory from behind and below, eventually coming to 1.55 miles (2.5 km) beneath the station before breaking away to follow a racetrack pattern around the complex at a safe distance. Exercising the craft's safety abort system to halt the incoming Dragon is a key requirement in the testing, NASA officials said.
The capsule then prepares for a second rendezvous sequence on Feb. 11, coming back at the station from behind and below, then slowly approaching underneath the station to get itself within arm's reach for the Canadarm2 to grab the free-flying vehicle.
The astronauts grapple the payload in much the same fashion as Japan's HTV cargo ships, maneuvering the spacecraft on the arm and berthing it to the Earth-facing port of the Harmony connecting module.
"It's the same profile that the Japanese HTV uses, it flies in a holding pattern, about 30 feet away, 10 meters, and then we go in with the arm and snag it," said astronaut Don Pettit. He launches to the space station later this month and will help with the retrieval operations along with Expedition 30 commander Dan Burbank.
"Dan Burbank and I will be snaggin' the first Dragon, assuming everything goes as scheduled, and he'll be flying the arm," Pettit said.
Dragon will spend two weeks mounted to the station for the crew to unload the cargo before again using the arm to detach the spacecraft and cast it free to fly away from the outpost for reentry and splashdown off the coast of California.
"SpaceX has made incredible progress over the last several months preparing Dragon for its mission to the space station," said William Gerstenmaier, NASA's associate administrator for the Human Exploration and Operations Mission Directorate.
"There is still a significant amount of critical work to be completed before launch, but the teams have a sound plan to complete it and are prepared for unexpected challenges. As with all launches, we will adjust the launch date as needed to gain sufficient understanding of test and analysis results to ensure safety and mission success."
SpaceX stands to receive up to $396 million under the COTS program. NASA says the company has been paid $376 million for completing 36 out of 40 milestones to date.
After completing the upcoming demonstration flight, SpaceX will begin flying a dozen operational resupply missions to the space station under a separate deal worth $1.6 billion.
The other company NASA has been funding is Orbital Sciences Corp. and its Cygnus spacecraft to be launched aboard Taurus 2 rockets from Wallops Island, Virginia. The company hopes to test-fly its new rocket in early 2012, followed by a single COTS demonstration mission to the station later in the spring.
"Our partners in COTS -- SpaceX and Orbital Sciences -- are marking significant progress in demonstrating their systems. NASA has invested significant money -- $800 million -- in these efforts," Garver said.
Orbital's COTS deal is worth up to $288 million, of which the company has received $261.5 million for completing 23 out of 29 milestones so far. Its separate operational cargo deal covers 8 flights valued at $1.9 billion.