Four astronauts launched on Friday en route to the International Space Station.
A SpaceX Falcon 9 rocket lifted off at 7:03 p.m. Eastern time from NASA’s Kennedy Space Center in Florida.
This is a routine rotation of crew on the space station, but it is garnering extra attention because it will allow the return to Earth of Suni Williams and Butch Wilmore, two NASA astronauts whose brief scheduled visit to the space station last June was unexpectedly stretched to more than nine months.
The stay of Ms. Williams and Mr. Wilmore in orbit was extended at least two more days when the first attempt at launching this mission on Wednesday was called off with less than 45 minutes left in the countdown. Mission controllers were unable to solve a hydraulic issue with a clamp arm that holds onto the rocket until a few minutes before launch.
On Friday, the countdown proceeded smoothly with the rocket lifting off on time into the mostly clear skies. As typical, the booster of the Falcon 9 dropped off and landed on a pad near the launch site while the second stage continued to orbit.
A few minutes after the second stage completed its engine burn, the Crew Dragon spacecraft with the astronauts separated.
“Thank you to all of the teams from across the world who contributed to the launch today,” Anne McClain, the NASA astronaut who serves as the commander of the mission, known as Crew-10. “Spaceflight is tough. Humans are tougher.”
The Crew Dragon will catch up to the space station late Saturday.
Who is going to space on Crew-10?
In addition to Ms. McClain, Nichole Ayers of NASA is the pilot, and the other two crew members are Takuya Onishi of JAXA, the Japanese space agency, and Kirill Peskov of Roscosmos, the Russian space agency.
The astronauts selected a crocheted origami crane as their mission’s mascot. As she described it, Ms. McClain highlighted the international diversity of her crew, and she said they were united in sharing optimism.
“Crew-10 chooses to go together in peace because you cannot be great without the greatness of others,” she said.
This will be the first spaceflight for Ms. Ayers and Mr. Peskov and the second spaceflight for Ms. McClain and Mr. Onishi.
Will Suni Williams and Butch Wilmore be rescued after getting stranded in orbit?
Sort of.
Not really.
The spacecraft that will bring back Suni Williams and Butch Wilmore has been docked at the space station since late September and could have returned to Earth at any time.
Ms. Williams and Mr. Wilmore launched to the space station in June last year for a test flight of Starliner, an astronaut capsule built under a NASA contract by Boeing. Because of propulsion problems, NASA officials decided that Ms. Williams and Mr. Wilmore would not return to Earth in Starliner. In early September, the spacecraft undocked from the space station, re-entered the atmosphere and landed in New Mexico without any problems.
Just as when an airline scrambles to rebook passengers after a flight is canceled, NASA had to find seats on a ride home for Ms. Williams and Mr. Wilmore.
The next spaceflight was Crew-9, which lifted off a couple of weeks after Starliner left the space station without anyone aboard. Two astronauts assigned to the flight were bumped off, leaving two seats in the SpaceX Crew Dragon capsule for Ms. Williams and Mr. Wilmore on the return trip.
Thus, the Crew-9 capsule could have brought back the two astronauts any time after that, but that would have left the space station understaffed, affecting scientific experiments, operations and maintenance.
NASA and SpaceX could have rushed the Crew-10 mission to launch earlier, but NASA officials decided it was best for Ms. Williams and Mr. Wilmore to join the space station crew and keep the planned schedule for Crew-10.
When will Williams and Wilmore return to Earth?
Crew-10 will arrive at space station 11:30 p.m. on Saturday.
The astronauts of Crew-9 and Crew-10 will overlap for a few days at the space station. About four days after Crew-10 launches, Ms. Williams and Mr. Wilmore — along with Nick Hague of NASA and Alexander Gorbunov, the two astronauts who arrived with Crew-9 — will climb aboard their spacecraft and head home, perhaps as soon as March 19.
Their stay could be extended again if there is bad weather at the possible splashdown sites off the coast of Florida.
What have the astronauts said about their extended stay?
In an interview last month published on Friday, Michael Barbaro, the host of “The Daily,” asked the astronauts, “So, if not stuck, exactly how do you describe this scenario you find yourselves in?”
“That’s a great question,” Mr. Wilmore said. “I would say it’s work. It’s wonderful enjoyment. It’s been fun. It’s been trying at times, no doubt. But stranded? No. Stuck? No. Abandoned? No.”
This was the third trip to space for both Ms. Williams, 59, and Mr. Wilmore, 62, and they realize it might be their last one. “We’re heading home,” Ms. Williams said. “And it makes you really want to enjoy every bit of your time that you have up here.”
Michael Barbaro contributed reporting.
