SpaceX calls off rocket launch at last minute

James Dean | Florida Today

CAPE CANAVERAL, Fla. — SpaceX hopes to try again Friday to launch a cargo shipment to the International Space Station, after a technical problem scrubbed the mission's first launch attempt early Tuesday.

A Friday blastoff by a Falcon 9 rocket and Dragon spacecraft would be at 5:09 a.m., during another instantaneous window at Cape Canaveral Air Force Station's Launch Complex 40.

The latest forecast shows an 80 percent chance of favorable weather Friday.

Tuesday, the Cape's first launch countdown of the year proceeded uneventfully until suddenly being halted with less than 90 seconds until a planned 6:20 a.m. liftoff.

"Hold! Hold! Hold!" a member of the launch team called.

NASA and SpaceX cited a problem with the system that controls steering of the Falcon 9 rocket's upper stage engine.

SpaceX has several days to resolve the actuator issue since Friday is the next time the space station's orbit lines up properly for the resupply mission, which is the company's fifth of a dozen planned under a $1.6 billion NASA contract.

The unmanned Dragon capsule is packed with about 5,100 pounds of food, supplies and science experiments bound for the station and its six-person crew, which flew 250 miles over Cape Canaveral about an hour prior to the scrub.

After the launch, SpaceX plans to attempt a landing of the Falcon 9 booster on an ocean-going platform that the company calls its "autonomous spaceport drone ship," stationed a couple of hundred miles offshore.

The experimental landing is a step in the company's efforts to develop rockets that can be recovered and flown again, potentially lowering launch costs.

SpaceX and the Air Force are negotiating a deal for SpaceX to use Launch Complex 13, a former Atlas launch pad near where John Glenn blasted off, as a future landing site for returning boosters.

"We expect to have a final decision on such agreement no later than Jan. 31," said Chris Calkins, a spokesman for the Air Force's 45th Space Wing.

Now, liquid-fueled orbital rockets are called "expendable," and are discarded after one use.

Traveling above the atmosphere and at hypersonic speed, the booster was to begin an automated series of three engine firings aiming for the platform a couple hundred miles offshore.

New on Tuesday's flight is a set of "X-wing" fins designed to improve the booster's control during descent, which would culminate in touchdown on four landing legs just nine minutes after liftoff, if all goes right.

SpaceX CEO Elon Musk gave 50-50 odds of success.

"There's a certain likelihood that this will not work outright, that something will go wrong," said Hans Koenigsmann, SpaceX vice president for mission assurance, during a news conference Monday at Kennedy Space Center. "Nobody has ever tried that, to our knowledge."

SpaceX twice has landed boosters softly in the Atlantic Ocean, where they tipped over and broke apart in the waves.