Boeing Starliner launch delayed again after being scrubbed 2 hours before liftoff

Boeing and NASA teams were working toward sending a new spacecraft with two astronauts to the International Space Station on Monday. However, that launch will be delayed yet again after being scrubbed two hours before liftoff. 

Following years of delays and additional testing, Boeing's CFT-100 Starliner spacecraft was scheduled to launch NASA astronauts Suni Williams, 58, and Butch Wilmore, 61, to the space station on what is known as the Crew Flight Test (CFT) for Starliner.

Liftoff was scheduled for 10:34 p.m. ET on Monday from Space Launch Complex 41 at Cape Canaveral Space Force Station in Florida. The Starliner is mounted on United Launch Alliance's Atlas V rocket, and engineers canceled Monday night's launch due to concerns over an oxygen relief valve on the Centaur upper stage. 

During a news conference, it was announced that the rocket must be rolled off the launch pad and back to the Vertical Integration Facility (VIF) for a complete assessment and repair.

NASA’s Boeing Crew Flight Test is now targeting no earlier than 6:16 p.m. EDT Friday, May 17, to send the Starliner spacecraft to the International Space Station if the technical issue that prevented the launch attempt on Monday is fixed. 

Should the launch occur in the coming days, it will mark the 100th mission for ULA's workhorse rocket and the rocket's first mission supporting human spaceflight.

The final Starliner test comes after more than 10 years of testing and development. In 2014, NASA awarded contracts to Boeing and SpaceX to fly astronauts to the ISS with commercial spacecraft. A crew-less Starliner launched to the ISS two years ago and returned to Earth during an orbital flight test (OFT). 

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Starliner was set to launch Williams and Wilmore last summer, but Boeing managers revealed new issues with the spacecraft after further examining data from Starliner's OFT orbital flight test in May 2022. Boeing launched an orbital test flight without astronauts twice because of a botched first attempt in 2019 that failed to reach the ISS.

Both astronauts are retired Navy captains going to space for the third time. As the CFT crew, the astronauts will test out Starliner's capability to certify the spacecraft for future astronaut missions. As former Navy test pilots, both astronauts say it is an honor.

"I sort of have to pinch myself a little bit to understand we're actually going," Williams told reporters this week.

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CAPE CANAVERAL, FL - MAY 18: In this handout photo provided by NASA, NASA astronauts (L-R) Suni Williams, Barry "Butch" Wilmore, and Mike Fincke watch as a United Launch Alliance Atlas V rocket with Boeings CST-100 Starliner spacecraft aboard is roll

Meet the crew

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NASA, Boeing Crew Flight Test Crew Butch Wilmore (left), and Suni Williams (right) arrive in Florida on Thursday, April 25, 2024. (NASA) ( )

Sunita "Suni" Williams

Williams spent 322 days on the International Space Station. 

She was a Navy test pilot and graduated from the U.S. Naval Academy and Florida Tech. 

Barry "Butch" Wilmore

Wilmore piloted space shuttle mission STS-129 and commanded Expedition 42 on the International Space Station. 

He was a Navy officer and pilot and graduated from Tennessee Tech and the University of Tennessee. 

Click here to learn more about the crew. 

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CAPE CANAVERAL, FLORIDA - APRIL 25: NASA’s Boeing Pilot Suni Williams (C) and Crew Flight Test Commander Butch Wilmore (R) address the media after arriving at the Kennedy Space Center on April 25, 2024 in Cape Canaveral, Florida. They arrived for a m

What's the purpose of the mission?

According to Boeing, this launch will demonstrate the Starliner's launch-to-landing capabilities and will "prove the team’s readiness to achieve NASA certification and fly long-duration missions for the agency." 

"The Starliner spacecraft, named Calypso, can fly autonomously or be steered manually and is expected to rendezvous and dock with the space station on Wednesday, May 8," NASA said. "Wilmore and Williams will spend about a week at the orbiting laboratory before the crew capsule makes a parachute and airbag-assisted landing in the southwestern United States."

About the patch for the mission

According to Boeing, the Crew Flight Test patch represents "the ambition of the flight test mission, the importance of partnership, and the adventurous spirit of Starliner's first crew who will wear the patch during (Crew Flight Test)."

Click here to learn more about the mission. 

FOX Weather's Emilee Speck contributed to this report.