Washington, Feb 11 (IANS): Unfavourable weather again led private US spaceflight company SpaceX to put off a rocket launch that would have led to an experiment to test the possibility of reusable rockets.

With just 12 minutes remaining in the countdown at the Cape Canaveral space station in Florida Tuesday night, wind gusts of 185 kmph caused a safety concern, the Guardian reported.

Consequently, the launch of the Falcon 9 rocket, carrying a deep-space observatory was put off. The launch must go forward by Wednesday, or face delays until next week, the report said.

It was SpaceX's second attempt this week to launch the Deep Space Climate Observatory (DSCOVR) after an earlier attempt Sunday was cancelled on account of inclement weather.

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

More importantly, perhaps, it was 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.

A similar attempt in January ended in a spectacular explosion, which the company's chief executive, Elon Musk, euphemistically dubbed a "rapid unscheduled disassembly".

The $340 million DSCOVR project began as a pet project of the then US vice-president Al Gore, but was put on hold in the early 2000s as a result of setbacks at the National Aeronautics and Space Administration (NASA) under then US President George W. Bush.

When launched, the satellite will take photos and monitor the amount of energy radiating from the Earth's surface -- a sign of whether carbon emissions trap energy.

The Falcon 9 rocket taking DSCOVR into deep space, about four times farther from the Earth than the moon, is integral to the company's aims. After releasing the satellite into space, the rocket will return to Earth several hours later.

Ahead of Tuesday's cancelled attempt, Musk tweeted 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".

The reusable rocket technology is important for its potential effect on the costs of spaceflight and for improving technology necessary to land on other planets.

"The reason that there's low demand for spaceflight is that it's ridiculously expensive," Musk told a 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 Tuesday for the company to use Cape Canaveral as a landing site for returning Falcon rockets.

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