NASA will return Boeing's faulty Starliner capsule to Earth without astronauts Butch Wilmore and Suni Williams, who will return to Earth on a SpaceX vehicle early next year, NASA chief Bill Nelson said on Saturday.

Starliner launched its first two astronauts, both former military test pilots, into space on June 5 as a crucial test before it can receive NASA approval for routine flights. But what was supposed to be an eight-day mission docked to the ISS has been drawn out by months after the capsule sprang leaks and some of its thrusters failed.

Here's a rundown of key events in Starliner's journey to space over the past few years:

Sept. 4, 2015 - Boeing takes the wraps off an assembly plant for its first line of commercial spaceships, which NASA plans to use to fly crews to the ISS.

Nov. 4, 2019 - Boeing says one of three parachutes failed to open during a crucial unmanned test of the Starliner.

Dec. 20, 2019 - Boeing successfully launches its new astronaut capsule on an uncrewed debut journey to the ISS.

Dec. 22, 2019 - The spacecraft makes a "bullseye" landing in the New Mexico desert.

Jan. 7, 2020 - NASA and Boeing investigate a software glitch that prevented the unmanned capsule from reaching the ISS in its Dec. 2019 flight.

Feb. 6, 2020 - The NASA review panel says Boeing narrowly missed a "catastrophic failure" during its December flight test.

Aug. 25, 2020 - The first Starliner crewed mission is tentatively slated for 2021, with Boeing aiming to complete software and test hardware production development.

Oct. 7, 2020 - The chief astronaut for Starliner's crewed flight to the ISS, Chris Ferguson, steps down from the job, citing family priorities. He is replaced by Wilmore.

July 29, 2021 - A space station mishap prompts NASA to postpone the launch of the Starliner.

Aug. 3, 2021 - Boeing postpones Starliner launch after new glitch.

Aug. 13, 2021 - Boeing returns the spacecraft to the factory to resolve a valve issue, delaying the launch date until at least mid-October if not later.

May 19, 2022 - The Starliner capsule launches on a do-over uncrewed test flight bound for the ISS.

May 20, 2022 - The Starliner capsule, without astronauts onboard, docked for the first time with the ISS.

Aug 25, 2022 - Boeing announces it is targeting early 2023 for the first Starliner mission carrying astronauts.

June 1, 2023 - Boeing says it is standing down from late preparations for its first crewed Starliner test flight to space, which was planned for July 2023, after it discovered two safety-critical issues with the spacecraft.

May 3, 2024 - Boeing poised to send the first Starliner space capsule with a crew of humans into orbit the following week, after a year's delay.

May 6, 2024 - The first crewed test flight of the new Starliner space capsule was postponed after the planned May 6 launch countdown was halted over a fault with the Atlas V rocket.

May 7, 2024 - NASA says new targeted launch date for the mission was set to May 17 at the earliest.

May 14, 2024 - Boeing says the Starliner mission had been delayed again - until at least May 21 - over an issue with the spacecraft's propulsion system.

May 17, 2024 - NASA and Boeing delayed the launch of the Starliner crew capsule again to check helium leak, targeting May 25.

May 21, 2024 - NASA again delayed the debut crew flight to spend more time evaluating the helium leak in the spacecraft's propulsion system.

May 22, 2024 - NASA and Boeing target June 1 for the launch.

June 1, 2024 - A second attempt at launching the Starliner with astronauts on board was automatically halted with minutes to go before liftoff by a computer-abort system.

June 2, 2024 - Boeing and NASA target June 5 for the launch.

June 5, 2024 - The Starliner astronaut capsule was successfully launched from Florida with two astronauts aboard, with docking with the ISS scheduled for June 6.

June 6, 2024 - The Starliner capsule and an inaugural two-member NASA crew safely docked with the International Space Station.

June 11, 2024 - NASA and Boeing say they expect the Starliner capsule to return as soon as June 18, later than a previously scheduled return, citing fixes to faulty components on the capsule, and weather conditions among others.

June 21, 2024 - NASA further postponed the Starliner's return to Earth, to allow more time for review of technical issues encountered.

June 27, 2024 - NASA says it would continue to evaluate Starliner's propulsion system performance along with Boeing.

Aug 7, 2024 - NASA says the two astronauts could return on SpaceX's Crew Dragon in February 2025 if Starliner is still deemed unsafe to return to Earth.

Aug 24, 2024 - The Starliner capsule is returning to Earth without astronauts Butch Wilmore and Suni Williams aboard, after NASA chief Bill Nelson said the duo will need to return on a SpaceX vehicle early next year.