Boeing’s first Starliner mission carrying astronauts into space has been delayed again — until at least May 21 — due to an issue with the spacecraft’s propulsion system, the company announced on Tuesday.

The Starliner mission, carrying two NASA astronauts, had been scheduled for liftoff from Florida last week. However, a technical issue with its Atlas 5 rocket initially prompted a delay to Friday, May 17. This marks the latest postponement for a program that is years behind schedule and over $1.5 billion above budget.

A new technical issue, now concerning the Starliner itself, has prompted another delay to at least next Tuesday. “Starliner teams are working to resolve a small helium leak detected in the spacecraft’s service module,” Boeing said. Engineers traced the leak to a component on one of the propulsion system’s 28 control thrusters used for maneuvering in Earth’s orbit.

Background on Starliner Development

Boeing has been developing the Starliner for over a decade to provide NASA with a second U.S. spacecraft capable of ferrying astronauts to and from the International Space Station (ISS). SpaceX’s Crew Dragon capsule, built under the same NASA program, first launched astronauts to space in 2020. The Starliner program has faced numerous delays and cost overruns, with the total cost now exceeding $1.5 billion above the initial budget.

Previous Technical Issues

The latest mission for Starliner, called the Crewed Flight Test, is set to be the final test before the spacecraft is certified by NASA to fly routine astronaut missions to the ISS. Boeing completed an uncrewed Starliner trip to the ISS in 2022 following years of technical and management issues. These included problems with software that caused a failed uncrewed test flight in 2019, necessitating a second uncrewed test flight.

Current Technical Issue

NASA officials and Boeing engineers will run tests and try to fix the helium leak before the next possible launch window on May 21 at 4:43 p.m. ET. Helium is used on the Starliner to pressurize the fuel that powers the spacecraft’s thrusters for orbital maneuvering. The precise nature of the leak has been traced to a component within the service module’s propulsion system, specifically a thruster control mechanism, which is critical for the spacecraft’s maneuvering once in orbit.

Atlas 5 Rocket

The Atlas 5 rocket that launches Starliner into space is built by the Boeing and Lockheed Martin joint venture United Launch Alliance (ULA). Before attempting to launch Starliner last week, ULA discovered a faulty valve on the Atlas 5 and rolled the rocket off the launchpad to replace the valve. This additional complication added to the timeline, delaying the launch further.

Safety Measures

Sensors on Starliner first detected suspicious traces of helium inside the propulsion system while the spacecraft was on the launchpad last week. However, these detections did not initially raise alarms among engineers, according to a person briefed on the mission operations. While ULA was replacing the faulty valve on Atlas 5, Boeing engineers investigated the helium detections and determined that more testing and scrutiny were needed to meet the mission’s strict launch safety criteria.

The process of verifying and ensuring the integrity of the spacecraft’s systems involves extensive diagnostics and potentially replacing the affected component. This meticulous process is crucial to prevent any in-flight malfunctions that could jeopardize the mission.

Importance of the Mission

Boeing's ongoing efforts to resolve these technical issues are critical, as the successful deployment of Starliner is essential for providing NASA with a dependable spacecraft for astronaut transport. As NASA aims to maintain a continuous U.S. presence on the ISS, having a second provider alongside SpaceX for crewed missions is strategically significant.

Industry and Public Reaction

This further delay underscores the persistent challenges Boeing faces in ensuring the reliability and safety of the Starliner spacecraft. The industry watches closely, hoping for a successful resolution that will advance human space exploration. Public interest remains high, as the success of the Starliner program is seen as a critical step in the United States’ broader ambitions for space exploration, including missions to the Moon and Mars.

Future Implications

Looking ahead, the successful certification and deployment of Starliner could pave the way for more frequent and reliable access to the ISS. It could also provide NASA with greater flexibility in scheduling and conducting missions, as well as foster a competitive environment that drives innovation and cost-efficiency in the aerospace sector.

Boeing’s commitment to resolving these issues and delivering a safe, operational spacecraft will not only bolster its reputation but also contribute significantly to the future of manned space exploration. As the aerospace giant continues to address these challenges, the industry watches closely, hoping for a successful resolution that will advance human space exploration. The next few days will be critical as engineers work tirelessly to rectify the issues and prepare for the new launch date.