US space firm SpaceX resumed its resupply mission to the International Space Station (ISS) on Friday, carrying aboard an experimental inflatable space habitat that might be crucial for future deep space explorations.
The California-based company also made history by landing the first stage of its Falcon 9 rocket on a droneship in the Atlantic Ocean, after it launched the Dragon spacecraft at 4:43 p.m. (2043 GMT) from Cape Canaveral Air Force Station in Florida, Xinhua reported.
This was SpaceX's eighth cargo mission to the ISS. It also marked the first flight of Dragon to the ISS since June, when the Falcon 9 rocket exploded about two minutes after liftoff.
As usual, SpaceX attempted to land the Falcon 9's first stage on the "Of Course I Still Love You" droneship, which was stationed in the Atlantic Ocean off the Florida coast.
Minutes later, the company posted a photo via Twitter in which the first stage was clearly seen standing on the deck of the ship.
It is the first time SpaceX has been able to stick a landing on a droneship after four previous such attempts ended in failure. It also achieved one successful soft landing on a land-based pad at Cape Canaveral in December last year.
What is different this time was "the rocket landed instead of putting a hole in the ship or tipping over. So we are really excited about that," said SpaceX founder Elon Musk at a press conference after the landing.
NASA offered a congratulation via Twitter to SpaceX for the successful landing and sending the unmanned Dragon to the orbiting laboratory.
Among the almost 7,000 pounds (3,200 kilograms) of items inside the Dragon spacecraft is the 3,100-pound (1,400-kilogram) Bigelow Expandable Activity Module (BEAM), a $17.8-million project that will be attached to the ISS to test the use of an inflatable space habitat in microgravity.
"It is the future," said Kirk Shireman, manager of NASA's ISS programme.
"Humans will be using these kinds of modules as we move further and further off the planet and actually as we inhabit low Earth orbit."
According to NASA, inflatable habitats greatly decrease the amount of transport volume at launch for future space missions and take up less room on a rocket, but once set up, provide additional volume for living and working.
Shireman said the company that developed BEAM, Bigelow Aerospace, launched two inflatable modules about 10 years ago using Russian rockets but this will be the first time humans will interact with such a module.
After being attached to the ISS, BEAM will be filled with air to expand it for a two-year test period in which ISS astronauts will conduct a series of tests to validate overall performance and capability of expandable habitats.
BEAM is 5.7 feet (1.7 meters) long and 7.75 feet (2.4 meters) in diameter when packed; 12 feet (3.7 meters) long and 10.5 feet (3.2 meters) in diameter when expanded, with 565 cubic feet (16 cubic meters) of interior volume.
Bigelow Aerospace is also developing a new inflatable module called B330, which is 20 times larger than BEAM, and hopes to put two B330s together in orbit into a private space station in 2020, Robert Bigelow, the company's president, told reporters.
"We are in the early phase of a new kind of spacecraft that offers a lot of promise," Bigelow said.
The cargo also included new experiments that will help investigators study muscle atrophy and bone loss in space, seek insight into the interactions of particle flows at the nanoscale level and use protein crystal growth in microgravity to help design new drugs.
SpaceX is one of two US companies that provide ISS cargo services for NASA. The other company is Orbital ATK, whose Cygnus capsule was launched to the ISS on March 22.
It is the first time that both companies' cargo ships will be docked at the orbiting lab simultaneously.
