SpaceX_landing_target

Space Exploration Technologies Corp., the start-up rocket-maker known as SpaceX and headed by billionaire Elon Musk, hasn’t yet received certification to launch U.S. military and spy satellites.

But that hasn’t stopped it from looking for ways to further drive down the launch costs by making rockets reusable.

The company, based outside Los Angeles, this weekend will for the first time attempt to land its Falcon 9 rocket on an unmanned ship in the Atlantic Ocean after launching from Cape Canaveral on a NASA mission to resupply the International Space Station.

Liftoff is scheduled 4:47 a.m. local time Saturday. The mission was previously scheduled for Tuesday, but called off after a computer detected an unrelated anomaly on the booster’s upper-stage actuator during countdown.

Musk put the odds of successfully landing the first-stage booster on the moving target aren’t that great — about 50–50. But the company has already come close to accomplishing the feat in August, when the section returned from space, entered the atmosphere and soft-landed in the water.

Stabilizing the 14-story rocket for reentry “is like trying to balance a rubber broomstick on your hand in the middle of a wind storm,” is how SpaceX describes it.

If successful, it’s hard to imagine what else the company would have to do to prove to the Air Force that it can launch national-security payloads. The service recently pushed back the date it expects to approve the company for such missions to mid-2015 — a six-month delay from its original date.

The reason for the longer time line wasn’t clear. As Andrea Shalal of Reuters reported:

“It said SpaceX had met 80 percent of the jointly agreed criteria for certification, and was demonstrating the ability to innovate and resolve outstanding issues.”

SpaceX, which is also working with NASA to develop a spacecraft capable of carrying astronauts, wants to compete against United Launch Alliance LLC, a joint venture of aerospace giants — Lockheed Martin Corp. and Boeing Co. — to launch military satellites as part of the Air Force’s Evolved Expendable Launch Vehicle, or EELV, program.

SpaceX will face added pressure to perform after an unmanned rocket made by Orbital Sciences Corp., another commercial space firm trying to compete for a bigger piece of the military market, exploded shortly after liftoff in Virginia. The Antares booster was using Soviet-era engines that had been refurbished.