The United States on Wednesday delayed a planned launch of a commercial spacecraft carrying two astronauts because of bad weather conditions, with the next attempt planned for Saturday afternoon.
The decision was made about 17 minutes ahead of what would have been the first flight into orbit of NASA astronauts from American soil since the final Space Shuttle mission in 2011.
The Crew Dragon space capsule, developed by U.S. aerospace manufacturer SpaceX, was scheduled to lift off on a Falcon 9 rocket at 4:33 p.m. from NASA's Kennedy Space Center in Florida for a 19-hour trip to the International Space Station. Now the launch is expected at 3:22 p.m. Saturday.
"Due to orbital mechanics, we need to make sure that at the time we launch, we are able to reach the Space Station on time and accurately. Because of this, we could not wait for clear weather today," the U.S. National Aeronautics and Space Administration said on Twitter.
Weather conditions had been a concern throughout the day, with the U.S. Air Force saying there was only a 50 percent chance of favorable weather for the launch and warning of potential risks such as flying through precipitation.
In March of last year, the Crew Dragon succeeded in its first demonstration mission, an unmanned trip to and from the ISS. Saturday's second demonstration mission will be SpaceX's final test flight to validate its crew transportation system, including the Crew Dragon, Falcon 9 and launch pad.
If the mission turns out to be a success, the crew for the next flight, possibly in late August, will include Japanese astronaut Soichi Noguchi, 55.
The development comes as the administration of President Donald Trump seeks to reassert U.S. leadership in space and refocus America's space program on human exploration, setting a goal of putting astronauts on the Moon again and sending humans to Mars.
Since the costly Space Shuttle program ended 30 years of service in 2011, the United States has relied on Russian Soyuz spacecraft for flying its astronauts to the ISS.
In 2014, NASA selected SpaceX, officially known as Space Exploration Technologies Corp., and Boeing Co. to transport crew to the ISS from the United States, awarding contracts worth $3.1 billion and $4.8 billion, respectively, under its Commercial Crew Program.
Meanwhile, the coronavirus pandemic has made preparations even more challenging, with extra precautions taken to protect the astronauts -- Douglas Hurley, 53, and Robert Behnken, 49 -- from infection risks such as by putting them in a three-week quarantine and only allowing individuals who have been tested for the disease to interact with them, officials said.
Following the liftoff, the Crew Dragon will separate from the Falcon 9 rocket's first and second stage boosters in about 12 minutes, entering into orbit as it begins its navigation toward the ISS.
The Crew Dragon will then perform a series of phasing maneuvers to position itself for rendezvous and docking with the ISS. The ship is designed to do them autonomously, but the astronauts aboard will be ready to take control of the spacecraft if necessary, according to the U.S. National Aeronautics and Space Administration and SpaceX.
Upon arriving at the ISS, Hurley and Behnken will conduct research and other tasks with the ISS crew, while running tests to ensure the Crew Dragon will be able to remain connected to the ISS for up to 210 days on future missions.
The specific duration of the mission will be determined once the astronauts have reached the ISS.
In concluding the mission, the Crew Dragon, with the two astronauts on board, will depart the ISS and re-enter the Earth's atmosphere. It will splash down off the Atlantic coast of Florida, with the crew expected to be picked up at sea by SpaceX's recovery vessel.
