Weather Scrubs SpaceX Launch, Booster Recovery Attempt

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COLORADO SPRINGS, Colo. — An incoming storm forced SpaceX to postpone the launch of a Falcon 9 rocket April 13 carrying a Dragon cargo spacecraft to the International Space Station, a mission that also features another landing attempt of the rocket’s first stage.

Controllers halted the countdown for the launch a little more than three minutes before the scheduled 4:33 pm EDT launch time at Cape Canaveral, Florida, when approaching storm clouds violated range safety requirements. With an instantaneous launch window, the hold in the countdown scrubbed the launch for the day.

The next launch attempt is currently scheduled for April 14 at 4:10 pm EDT. Weather forecasts call for a 50-percent chance of acceptable weather at launch. Earlier forecasts projected a 60-percent chance of good weather for the initial launch attempt.

NASA and SpaceX have not announced when the next launch opportunity would be should the launch not take place April 14. Dan Hartman, NASA deputy ISS program manager, said at a pre-launch press conference April 12 that a new launch date would depend on availability of the launch range, the status of the launch vehicle and spacecraft, and any requirements by scientists to change out experiments inside the Dragon.

The Dragon spacecraft is carrying 2,015 kilograms of cargo for the ISS, including experiments, crew supplies, and other equipment, on SpaceX’s sixth mission under its Commercial Resupply Services contract with NASA. Dragon will return about five weeks after berthing, returning 1,370 kilograms of science investigations and other items.

Much of the attention about the launch is focused on SpaceX’s plans to attempt to land the first stage on the company’s “autonomous spaceport drone ship” in the Atlantic Ocean. SpaceX attempted a landing on a January launch of another Dragon spacecraft, crashing the stage on the deck of the ship.

SpaceX planned to make a second landing attempt on the February launch of the Deep Space Climate Observatory spacecraft, but rough seas forced SpaceX to withdraw the ship. SpaceX later said the stage touched down on the ocean at the planned target site. “If the drone ship would have been there, it would have been a good landing,” SpaceX vice president Hans Koenigsmann said at the April 12 press conference.

That test made Koenigsmann more confident that SpaceX can land the Falcon 9 stage on the ship during this launch. “I would up my probability to 75 percent at this point in time,” he said. “Maybe 80.”

However, SpaceX chief executive Elon Musk was not as optimistic. “Odds of rocket landing successfully today are still less than 50%,” Musk tweeted April 13, prior to the scrubbed launch. “The 80% figure by end of year is only [because of] many launches ahead.”

Koenigsmann said that if SpaceX is able to land the stage on its ship, it would be transported back to port in Jacksonville, Florida, then transferred by truck to the company’s test site in McGregor, Texas. Depending on the condition of the stage, it could perform additional tests flights there, similar to those flown by SpaceX’s earlier Grasshopper and F9R-Dev technology demonstrators.

Something else, though, would come before the stage is sent to Texas for tests, Koenigsmann said at the pre-launch press conference. “First, there would be an epic landing party, I guess.”