https://cna-sg-res.cloudinary.com/image/upload/q_auto,f_auto/image/12776714/16x9/991/557/1414bca94e69255d9861c1ddd2cc69da/su/crews-work-on-the-spacex-crew-dragon--attached-to-a-falcon-9-booster-rocket--as-it-sits-horizontal-on-pad39a-6.jpg
Crews work on the SpaceX Crew Dragon, attached to a Falcon 9 booster rocket, as it sits horizontal on Pad39A at the Kennedy Space Center in Cape Canaveral, Florida, U.S. May 26, 2020. REUTERS/Steve Nesius

'We are go for launch': NASA due to resume human spaceflight with SpaceX takeoff

CAPE CANAVERAL, Fla.: SpaceX, billionaire entrepreneur Elon Musk's private rocket company, made final preparations to launch two Americans into orbit on Wednesday from Florida on a mission that would mark the first spaceflight of NASA astronauts from U.S. soil in nine years.

A SpaceX Falcon 9 rocket was due to lift off from the Kennedy Space Center at 4:33 p.m. EDT (2033 GMT), launching astronauts Doug Hurley and Bob Behnken on a 19-hour ride aboard the company's newly designed Crew Dragon capsule to the International Space Station.

"We are go for launch!" NASA Administrator Jim Bridenstine wrote on Twitter, although looming storm clouds off Florida's coast potentially could force a postponement of the mission until Saturday.

SpaceX and NASA "will continue monitoring liftoff and downrange weather as we step into the countdown," Bridenstine added.

The two astronauts continued their preparations for the planned launch. Hurley even posted a picture of his breakfast of steak and eggs before suiting up in SpaceX's white flight suits at the Kennedy Space Center's operations and checkout building.

Musk and Bridenstine, wearing protective face masks due to the coronavirus pandemic, were present at the building to join the two astronauts, who did not wear face masks. The astronauts then emerged from the building, waved to family members and onlookers including Vice President Mike Pence and hopped into a Tesla vehicle to drive to the launch pad.

Prospects for an on-time liftoff hinged on the weather, with U.S. Air Force forecasters on Wednesday morning citing a 50per cent chance that thick clouds over eastern Florida could force a postponement. If that happens, the next launch window would be on Saturday afternoon.

The astronauts are scheduled to blast off from the same launch pad used in 2011 by NASA's final space shuttle flight, piloted by Hurley. President Donald Trump was scheduled to visit Florida's Cape Canaveral to view the launch.

A successful mission would achieve NASA's top priority, as articulated by Bridenstine, of resuming launches of "American astronauts on American rockets from American soil." Over the past nine years, NASA astronauts have had to hitch rides into orbit aboard Russia's Soyuz spacecraft.

For Musk, Wednesday's launch represents another milestone for the reusable rockets his company pioneered to make spaceflight less costly and frequent. It would also mark the first time that commercially developed space vehicles - owned and operated by a private entity rather than the U.S. space agency - have carried Americans into orbit.

The last time NASA launched astronauts into space aboard a brand new vehicle was four decades ago at the start of the shuttle program.

Musk, the South African-born high-tech entrepreneur who made his fortune in Silicon Valley, is also CEO of electric carmaker and battery manufacturer Tesla Inc.

Hurley, 53, and Behnken, 49, are NASA employees under contract to fly with SpaceX. They are expected to remain at the space station for several weeks, assisting a short-handed crew aboard the orbital laboratory.

Hawthorne, California-based SpaceX, founded by Musk in 2002 and formerly known as Space Exploration Technologies, has never previously flown humans into orbit, only cargo.

SpaceX successfully tested Crew Dragon without astronauts last year in its first orbital mission to the space station. That vehicle was destroyed the following month during a ground test when a valve for its in-flight abort system failed, causing an explosion.

(Reporting by Joey Roulette in Cape Canaveral, Fla.; Writing by Steve Gorman; Editing by Will Dunham)