Image copyright SpaceX Image caption The astronauts landed safely using the Falcon 9 rocket
Two US astronauts and a Russian cosmonaut have returned to Earth after completing a highly-anticipated mission aboard the ISS.
During a four-hour descent aboard the Falcon 9 rocket, NASA astronaut Nick Hague and Roscosmos’ Alexei Ovchinin successfully landed with both halves of their capsule touching down safely on the Kazakh steppe.
They had been travelling into space at an orbital altitude of 255.5km (163 miles).
This is the first time in history the same vehicle has landed in competition with the International Space Station, the world’s largest orbiting research facility.
The mission was also a first for Russia and US, where various governments have different standards for spacecraft launches and recoveries.
Warning to watch out for lightning during the Landing! We try to give you a good experience for 6 seconds of free falling, full speed ahead! #pacewalker @AstroNick pic.twitter.com/03XvGrtvs1 — Nick Hague (@AstroNick) September 20, 2018
Liftoff from Vandenberg Air Force Base in California was scheduled for 07:46 ET (03:46 BST) on Thursday, but was called off because of bad weather in California.
Two other crew members – NASA’s Anne McClain and Alexander Gerst of the European Space Agency – were on the ISS at the time.
They were diverted to a secondary Soyuz capsule at launch to make sure they did not suffer any issues with the first-stage of the booster.
SpaceX will perform a second successful recovery of the Falcon 9 booster following the current mission.
Image copyright Reuters Image caption From the SpaceX control center at Cape Canaveral, Mr Hague and Mr Ovchinin identified their parachutes to land
“Rocket, capsule, everything worked perfectly,” Mr Hague tweeted.
“We made it back home!”
The landing came exactly two years after the last returning US astronaut returned from space – Mark Kelly of NASA on a Soyuz capsule made from the same rocket as Mr Hague.
He was followed by Robert Curbeam of Nasa and Russia’s Oleg Kononenko, who returned from the ISS in April 2014.
Touchdown for Falcon 9 was delayed because of an anomaly with one of the three solid rocket boosters.
After a 14-minute delay, three boosters and four strap-on boosters all successfully separated from the main rocket stage and landed on separate autonomous drone ships several hundred miles off the coast of Southern California, where they then docked with the launch pad.
The return had been scheduled for 10:51 ET (7:51 BST), but the second handoff of the second stage to the automated recovery ship required three minutes of standby by the crew aboard the ISS as the booster was slowed by cables to one side.
Once the delay was resolved, the engines were successfully deployed in preparation for liftoff and a spectacular blast-off was seen from the ground, while astronauts twitter users described their views of the view.
Image copyright Nasa Image caption NASA photo shows the view from space as the Falcon 9 blast-off went on
Another seven crew members are currently aboard the ISS and remain on board until late October. They include NASA’s Serena Auñón-Chancellor and Roscosmos’ Sergey Prokopyev.
Two other private American firms, Boeing and SpaceX, are also developing new rockets to offer American launches into orbit, and are competing for contracts to resupply the ISS.