An inflatable human habitat is scheduled for launch to the International Space Station for a two-year test to see how the lightweight, fabric module compares with traditional orbiting enclosures made from metal.
The prototype habitat, built by Nevada-based Bigelow Aerospace, was packed inside a capsule slated for liftoff aboard a SpaceX Falcon 9 rocket at 4.43pm on Friday (0643 AEST Saturday) from Cape Canaveral Air Force Station in Florida.
The scheduled launch marks the fourth mission for high-tech entrepreneur Elon Musk's privately owned Space Exploration Technologies since a rocket failure last June destroyed a cargo ship being carried on a resupply mission bound for the space station.
It also will serve as the latest bid by the California-based company to safely return the launch vehicle's main-stage rocket booster to a landing platform in the ocean where it can be retrieved for future flights.
Four previous ocean landing attempts have failed, though a Falcon 9 did make a successful landing on the ground in December, a key milestone in SpaceX's quest to develop a cheap, reusable rocket.
About a week after the delivery vehicle, or Dragon, reaches the space station, ground controllers will use a robot arm to pull the 1400kg Bigelow Expandable Activity Module, or BEAM, from the capsule's trunk and attach it to a berthing port.
Roughly a month later, astronauts aboard the orbiting laboratory 400km above Earth will inflate BEAM with pressurised air, increasing its volume to about the size of a small bedroom.
Bigelow Aerospace, owned and operated by real estate billionaire Robert Bigelow, plans to follow BEAM with modules 20 times larger to serve as free-flying orbital outposts leased to companies and research groups.
NASA is interested in expandable habitats to serve as crew living quarters during three-year trips to and from Mars.
BEAM's test run is intended to determine how well it withstands the temperature swings and high-radiation environment of space. BEAM, made of layers of fabrics and covered in a flexible, Kevlar-like material, also will be outfitted with sensors to monitor orbital debris and micrometeoroid impacts.
Friday's launch will be SpaceX's first cargo run for NASA since its launch accident in June 2015, though Musk's company has since flown three times successfully for other customers.
For this flight, SpaceX modified the capsule's software so that in case of an accident during liftoff, the Dragon can parachute to a splashdown in the ocean, potentially saving its cargo.
