SpaceX has called off its planned launch of a deep-space observatory that would have been its latest attempt to land a reusable rocket booster on a barge in the Atlantic Ocean.

With just 12 minutes remaining in the countdown at Cape Canaveral in Florida on Tuesday night, wind gusts of 115mph caused a safety concern, officials said. It was SpaceX’s second attempt this week to launch the Deep Space Climate Observatory (DSCOVR) after an earlier attempt on Sunday was cancelled due to weather. The launch must go forward by Wednesday, or face delays until next week.

Extreme wind shear over Cape Canaveral. Feels like a sledgehammer when supersonic in the vertical. Hoping it changes … — Elon Musk (@elonmusk) February 10, 2015

The company is hoping to launch its DSCOVR satellite, which is designed to monitor weather in space, including solar storms whose explosive bursts of solar particles can cause blackouts and disrupt communications on Earth.



It is the company’s second attempt this year to test reusable rockets. Ten minutes after the launch, the booster is scheduled to land on an unanchored barge in the Atlantic Ocean, from which it will be recovered and used again.

An earlier attempt in January ended in a spectacular explosion which the company’s chief executive, Elon Musk, euphemistically dubbed a “rapid unscheduled disassembly”.

A ‘rapid unscheduled disassembly’ occurs. Guardian

The $340m DSCOVR project began as a pet of the then vice-president Al Gore, was put on hold in the early 2000s due to setbacks at Nasa under President George W Bush, and then refurbished over the course of the next decade for launch on Sunday – until weather and a radar glitch forced another short delay until Monday and then Tuesday night.



When launched, the satellite will also take photos and watch Earth, monitoring how much energy radiates from the surface – a sign of whether carbon emissions trap energy.

The rocket taking DSCOVR into deep space, about four times farther from Earth than the moon, is integral to the company’s aims. SpaceX will make its second attempt to land reusable rocket technology, what Musk conceives of as the next generation of spacecraft.

The ill-fated rocket, which uses repeated thruster bursts to slow its incredibly fast descent back towards Earth, used up too much of its hydraulic fluid, Musk said, and then lost control just before hitting the ship’s deck.

Ahead of Tuesday’s cancelled attempt, Musk said on Twitter that given the distance of the mission, “rocket re-entry will be much tougher this time around” because of almost twice the amount of force and four times the heat involved in re-entry. The company described the challenge of landing the rocket, which stands about 14 storeys tall, as akin to “trying to balance a rubber broomstick on your hand in the middle of a wind storm”. After releasing the satellite into space the rocket will return to Earth several hours later.

The reusable rocket technology is important to SpaceX for its potential effect on the costs of spaceflight and for improving thruster technology necessary to land on other planets. “The reason that there’s low demand for spaceflight is that it’s ridiculously expensive,” Musk told an MIT symposium in October. “These spaceships are expensive and they’re hard to build,” he said. “You can’t just leave them there.”

SpaceX and the US air force announced an agreement on Tuesday for the company to use Cape Canaveral as a landing site for returning Falcon rockets. “The way we see it, this is a classic combination of a highly successful launch past morphing into an equally promising future,” Brigadier General Nina Armagno said in a statement.

Also on Tuesday, an unmanned SpaceX Dragon spaceship splashed back to Earth after a successful supply run to the International Space Station.

The Dragon parachuted into the Pacific west of Mexico’s Baja Peninsula at 4.45pm, according to SpaceX.

The capsule had flown 5,000lb (2,250kg) of groceries and belated Christmas presents to the space station in January. The station’s astronauts had been awaiting supplies since a ship from another company was destroyed in an October launch explosion.

Dragon returned with science samples and broken equipment, including bad spacesuit parts.

The landing came about 90 minutes after SpaceX scrubbed the planned launch of DSCOVR.