The primary objective of the mission, due for takeoff from Cape Canaveral Air Force Station in Florida at 10:21 a.m. ET, is to deliver a robotic Dragon capsule with more than two and a half tons of supplies, equipment and experiments — ranging from a new docking adapter for accommodating future U.S.-built spaceships to a virtual-reality headset for the space station’s crew.
This will be the first robotic cargo delivery since a Russian Progress capsule went awry in April, resulting in the loss of the craft’s 3-ton payload. The Dragon’s payload includes food, oxygen and other much-needed basics — and that’s putting extra pressure on SpaceX for a successful launch.
SpaceX’s vice president of mission assurance, Hans Koenigsmann, told reporters on Friday that his company was up to the job. “Dragon has been super-reliable,” he told reporters.
No technical problems with the two-stage Falcon 9 rocket were reported, and the chances of acceptable weather were set at 90 percent. You can watch launch coverage on webcasts that are being streamed by NASA and SpaceX.
The Dragon already has made six successful cargo runs under the terms of a $1.6 billion contract with NASA, plus an initial demonstration mission in 2012. But this time, SpaceX is hoping to pull off a trick that’s never been done before: the safe landing of the Falcon‘s first stage on a drone ship stationed hundreds of miles out in the Atlantic.
The first stage’s autonomous landing maneuver is due to unfold minutes after launch, while the second stage continues its rise to orbit with the Dragon capsule.
A completely successful landing at sea would mark a milestone in rocket reusability. SpaceX’s billionaire founder, Elon Musk, says the technology would dramatically drive down launch costs and potentially pave the way for affordable trips to Mars.
Two earlier landing attempts — in January and in April — almost succeeded: Each time, the rocket was able to relight its engines, slow down its supersonic descent and find its way to the ship. The first time, the Falcon’s hydraulic control system ran out of fluid just before landing. The second time, a throttle valve was slower to respond than it should have been. In both cases, the rocket slammed onto the deck and blew up.
SpaceX said engineers have made changes to address those issues for Sunday’s flight, but added a cautionary note: “Even given everything we’ve learned, the odds of succeeding on our third attempt to land on a drone ship … are uncertain,” the company said in its online launch preview.
Musk, who turns 44 on Sunday, passed along a picture of the drone ship as seen by a drone helicopter flying overhead:
This drone ship is a new one, christened “Of Course I Still Love You.” That name, and the one given to SpaceX’s other floating platform (“Just Read the Instructions”), were both inspired by the mirthful monikers given to sentient drone spaceships in Iain M. Banks’ science-fiction novels.
Whether or not the landing works, the mission will be judged a success if the Dragon successfully delivers its payload.
If Sunday’s launch comes off as scheduled, astronauts will use the space station’s robotic arm to grab onto the Dragon sometime around 7 a.m. ET Tuesday and bring it in for its hookup. But in order for that to happen, the liftoff has to be executed right to the second.
If technical troubles or weather woes get in the way, the next opportunity for launch would come at 9:58 a.m. ET Monday.