Boeing's Starliner Crew Flight Test challenges: The full story from launch delays, extended mission and to uncrewed return decisionn

NASA astronauts Butch Wilmore (L) and Suni Williams (R) outside the Neil A. Armstrong Operations and Checkout Building at the agency’s Kennedy Space Center in Florida on June 1, 2024. Photo Credit: NASA/Joel Kowsky

The Boeing Crew Flight Test, featuring NASA astronauts Butch Wilmore and Suni Williams aboard the Starliner spacecraft, was originally set for May 6, 2024. However, the mission faced numerous delays and technical problems, including valve malfunctions and helium leaks, which affected the spacecraft’s performance.

Despite these issues, the spacecraft successfully launched on June 5, 2024, from Space Launch Complex-41 at Cape Canaveral Space Force Station and docked with the ISS on June 6. Although the mission was planned for one week, performance issues necessitated an extension.

Despite multiple attempts to return the astronauts and numerous assessments, NASA decided on August 24 to postpone their return. Instead, the agency chose to use a SpaceX spacecraft for their return, scheduled for February 2025. As a result, their stay on the ISS was extended from one week to eight months, with the Starliner set to return uncrewed.

This timeline details the Boeing Starliner Crew Flight Test, emphasizing the technical challenges, troubleshooting efforts, and adjustments made during the mission.

Here's a summary of the updates regarding Boeing's Starliner Crew Flight Test from April 2 to August 24, 2024:
April 2024: Preparations for the Boeing Starliner's first Crew Flight Test with NASA astronauts Butch Wilmore and Suni Williams began, with the initial launch set for May 6. Pre-flight quarantine and reviews took place in anticipation of the mission. However, the launch faced delays due to technical issues with the Atlas V rocket's oxygen systems - a faulty oxygen relief valve and helium leaks in the service module. Teams worked to resolve these issues, and this led to repeated launch delays, pushing the launch date from early May to June.

May 2024: Ongoing repairs and valve replacements, additional helium leaks and other technical assessments pushed the launch multiple times. The target launch date moved to May 21. Replacement work and further testing extended the launch to May 25, and ultimately to June 1 due to ongoing troubleshooting. After the launch was rescheduled several times, it was yet again pushed for a fresh launch on June 5, 2024.

June 2024: Ongoing tests of Starliner’s systems continued. After multiple delays, the launch finally took place on June 5. The spacecraft experienced helium leaks, and some thrusters failed as it was approaching the ISS, but adjustments allowed a successful docking with the ISS on June 6. Despite these issues, the docking went smoothly with the International Space Station on June 6. Post docking, the astronauts, Wilmore and Williams, carried out various mission objectives, such as haven checks, habitability studies, and spacecraft system tests.

Thruster and propulsion system assessments continued by ground teams to resolve them, with NASA targeting June 22 for Starliner’s return. A "fire test" was performed to evaluate thruster performance, with subsequent undocking rescheduled multiple times as teams analyzed data.

July 2024: The mission extended into July as astronauts completed their objectives on the ISS, with ongoing evaluations on Earth for a safe return. Ground testing and fire evaluations continued throughout the month as teams worked to ensure the spacecraft's propulsion system would perform correctly during undocking and re-entry. NASA and Boeing teams completed additional fire tests of the spacecraft's thrusters for its eventual return. The astronauts prepared for potential departure by performing systems checks and tests aboard Starliner.

August 2024: On August 1, 2024, NASA and Boeing were analyzing data from recent ground and spacecraft testing of the Starliner spacecraft. Teams were evaluating the spacecraft’s propulsion system and conducting docked hot-fire testing.

Efforts included finalizing flight rationale and confirming system reliability before Starliner’s return to Earth from the ISS. Astronauts Wilmore and Williams worked on lab upkeep: Wilmore inspected plumbing hardware and packed life support components; Williams set up video gear and inspected bar code reader and radio frequency hardware. Both astronauts organized cargo inside the Tranquility module and participated in a conference call with Boeing mission controllers.

On August 22, 2024, NASA and Boeing were analyzing data to determine the next steps for Starliner’s return from the ISS.
A decision on whether to return Starliner with astronauts aboard was expected on August 24. NASA's decision would follow an agency-level review. The review was to address any formal dissents and be followed by a televised news conference.

Teams were working on finalizing flight rationale, evaluating new thruster mechanics models, and preparing for the spacecraft's return, including risk assessments and community recommendations.

On August 24, 2024, NASA announced a delay in the return of astronauts Butch Wilmore and Suni Williams due to safety concerns with Boeing’s Starliner. It was announced that the spacecraft would return to Earth uncrewed, extending the astronauts’ stay on the ISS from a planned weeklong test flight to February 2025, an eight-month stay. The decision is due to ongoing safety and performance issues with the Starliner spacecraft.

Also Read: Why Sunita Williams will stay in space until 2025 and why the Starliner will return empty; NASA explains