Astronauts left behind by Starliner set for press conference from ISS: Timeline of space saga

NASA astronauts Butch Wilmore and Suni Williams are set to participate in a news conference aboard the International Space Station Friday afternoon, roughly a week after their original vessel − the Boeing Starliner − returned to Earth's surface without them.

The astronauts, who are set to address media questions at 2:15 p.m. ET Friday, launched aboard Boeing's Starliner spacecraft on June 5 for its first crewed flight, arriving at the space station on June 6. The two astronauts thought they might be home in time for the 4th of July, but turns out they won't even be back on Earth to ring in the New Year.

After a thorough analysis of the Starliner spacecraft upon landing on June 6, NASA officials deemed that the vehicle wasn't up to the task of reliably transporting Wilmore and Williams for the return trip, the space agency announced last month. That responsibility will now instead fall to Boeing's aerospace competitor, SpaceX.

The empty Starliner spacecraft returned to Earth earlier this month to free up a docking port for the delayed SpaceX Crew-9, which is scheduled to reach the space station Sept. 24 for a six-month rotation mission.

The Dragon capsule that Crew-9 will take to orbit is also now Williams and Wilmore's ride home. For that reason, Crew-9 will include just two members instead of four, NASA said. The Starliner crew will then hitch a ride Feb. 25, 2025 with Crew-9 on the Dragon after the SpaceX astronauts complete their six-month rotation at the station.

Here's a look at the major moments of the Boeing Starliner's inaugural crewed mission, including scrubs, launch and return delays.

May 6: Starliner launch called off hours of liftoff

Years in the making, the third and final orbital flight test for Starliner was scheduled for launch until it was called off within hours of liftoff when engineers detected an anomaly on the pressure regulation valve in the liquid oxygen tank of the rocket's upper stage, according to NASA. The United Launch Alliance later said in a statement that the cancellation was "out of an abundance of caution for the safety of the flight and pad crew."

June 1: Starliner prepares to launch again, scrubbed again

On June 1, the Starliner appeared poised to finally take off. NASA decides to continue with the launch without repairing the helium leak, as the chemical used in spacecraft thruster systems is not combustible or toxic. However, the launch was once again scrubbed, this time minutes before liftoff due to a computer issue, NASA said on X, formerly Twitter.

June 5: Starliner finally launches

On June 5, the Starliner launches. Boeing Space shared a post on X at 11:44 a.m. confirming Starliner had reached a stable orbit and had broken away from the Atlas V rocket. From there, the craft began firing its own engines as it powered onward to the space station, NASA said.

June 6: Starliner docks at ISS

The following day, the Starliner docks at 1:34 p.m. EDT on the forward-facing port of the space station's Harmony module. However, the night before, NASA shared an update unveiling that two more helium leaks had been discovered on the spacecraft occurring after Starliner arrived in orbit.

June 9: NASA announces astronauts will not return on date originally planned

Though Wilmore and Williams were only slated to spend a week on the space station, NASA announced on X that the Starliner and its two astronauts would likely land in the New Mexico desert no earlier than June 18. The space agency said the additional time at the space station was for the astronauts to assist with a spacewalk and to allow engineers more time to complete system checkouts of Starliner.

June 14: Astronauts return delayed again

The return is delayed a second time, with the astronauts now slated to undock from the space station no earlier than June 25, landing June 26 at the White Sands Space Harbor in New Mexico, Boeing said in an update.

June 21: And again

Boeing and NASA once again delayed the return of Williams and Wilmore until July at the earliest. This time the agencies cite "a series of planned International Space Station spacewalks while allowing mission teams time to review propulsion system data."

July 10: Astronauts aren't 'complaining' about being in space

Wilmore and Williams appear in a NASA telecast from the space station. During separate news conferences, Williams says, "I'm not complaining, Butch isn't complaining that we're here for a couple extra weeks." Meanwhile, scientists and engineers work through testing to better understand and resolve problems that occurred during Starliner's launch and flight, including some misfiring thrusters and helium leaks.

July 25: NASA, Boeing say there is still no return date

NASA and Boeing said in a press conference that the Starliner still does not yet have an official return date. However, NASA Commercial Crew Program Manager Steve Stich says, "We're making great progress."

August: Astronauts work at space station while planning to return home

Wilmore and Williams, both Navy test pilots before they joined NASA, were to spend their limited time at the space station testing the Starliner spacecraft and its subsystems. With their stay indefinitely extended, the astronauts, both of whom had ventured to space twice before, helped the space station crew with other operations.

August 24: Astronauts' return set for February 2025

NASA leaders announced Aug. 24 that Wilmore and Williams will have to wait it out at the ISS until February after a flight readiness review determined that it's too risky for them to return to Earth on the Boeing spacecraft. They are set to return aboard a SpaceX rocket that's scheduled to dock at the ISS in September.

Sept. 6-7: Empty Starliner undocks from ISS, returns to Earth

The ill-fated Starliner spacecraft undocked from the ISS without Wilmore and Williams aboard and made its way back to Earth just after midnight Saturday, September 7, landing in the New Mexico desert. Starliner landed under parachute and airbag at NASA's White Sands Space Harbor facility in New Mexico. Boeing teams began recovering the spacecraft, which was set to be shipped back to Kennedy Space Center for evaluation.

Eric Lagatta covers breaking and trending news for USA TODAY. Reach him at elagatta@gannett.com

Gabe Hauari is a national trending news reporter at USA TODAY. You can follow him on X @GabeHauari or email him at Gdhauari@gannett.com.