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SpaceX puts the odds of successful Falcon landing at 75-80 percent

Irene Klotz, Spaceflight Correspondent
Apr 13, 2015, 8:52 UTC

Sen—SpaceX will make a second attempt to land a Falcon 9 rocket on an ocean platform following launch Monday to send a cargo ship on its way to the International Space Station.

Liftoff is scheduled for 4:33 p.m. EDT (2033 UTC) from Cape Canaveral Air Force Station in Florida, the company’s third mission this year and the 16th launch of a Falcon 9 rocket since flights began almost five years ago.

During the last cargo run for NASA in January, SpaceX attempted to land the rocket’s discarded first stage on a customized barge, located about 200 miles northeast of the launch site.

The booster ran out of hydraulic fluid to maneuver its steering fins so its descent onto the platform ended in a fireball. SpaceX wanted to try the test again in February when it flew the U.S. government’s Deep Space Climate Observatory (DSCOVR) space weather satellite, but seas were too rough. The rocket did however hover vertically above the ocean before crashing.

Though the rockets were destroyed, both tests provided valuable engineering information for modifications to the first-stage and the drone ship, boosting SpaceX’s confidence of success.

“I would up my probability to 75 percent at this point in time, maybe 80,” Hans Koenigsmann, SpaceX vice president in charge of mission assurance, told reporters at a prelaunch press conference Sunday.

Previously, the company figured its chance of success was 50-50.

Conditions at sea are expected to be suitable for Monday’s landing attempt, with 4- to 6-foot waves, but launch weather is a little iffy. Air Force meteorologists on Sunday predicted a 40 percent of a delay due to rain, thick clouds and/or nearby lightning.

SpaceX has to launch exactly at 4:33 p.m. on Monday to properly position the Dragon cargo ship for a rendezvous with the space station on Wednesday. If weather or a technical problem delays liftoff, the company will have another opportunity at 4:10 p.m. EDT (2010 GMT) Tuesday.

The Dragon capsule is loaded with more than 4,300 pounds (1,950 kg) of food, clothing, equipment and research experiments, including a habitat of rodents that will be subjects for muscle-wasting and bone-loss studies, sponsored by Novartis, a Swiss pharmaceutical company.

If launch occurs on Monday, the spacecraft should reach the orbital outpost on Wednesday morning. It is slated to remain berthed for 35 days—a record for a Dragon cargo ship—then splash down in the Pacific Ocean with more than 3,000 pounds (1,360 kg) of returning cargo.