NASA and Boeing have decided to extend the review period for the Starliner spacecraft before allowing its return to Earth, officials announced on Tuesday. The additional four-day delay will provide the team with more time to thoroughly analyze the data and ensure a safe journey home.

According to the new schedule, pending final review meetings later this week, Starliner will undock from the International Space Station at 10:10 pm ET on Tuesday, June 25th, setting up a landing at 4:51 ET on June 26th at the White Sands Test Facility in New Mexico.

The decision to delay the spacecraft's return is due to two major hardware issues that occurred during its recent flight to the International Space Station. One issue involves five separate leaks in the helium system responsible for pressurizing Starliner's propulsion system. The other issue is the failure of five out of the vehicle's 28 reaction-control system thrusters as it approached the station.

Engineers from both NASA and Boeing have been diligently studying these problems since their occurrence. In a significant step toward better understanding the issues, a thruster test was conducted on Saturday, June 15th, during which engineers discovered lower helium leak rates inside Starliner's Service Module compared to previous power-ups. While the exact cause of the leak remains unknown, the reduced leak rate has given engineers confidence in managing the helium loss. It is worth noting that even before the decrease in the leak rate, Starliner had substantial reserves of helium.

The test of the reaction control system thrusters also yielded positive results, with four out of five thrusters operating normally. These thrusters, which are primarily used for small maneuvers, will be crucial for the undocking and the de-orbit burn required for Starliner's return to Earth. Although the number of thrusters that can be safely lost was not specified, they are expected to be available for use later this month.

Due to the significance of being the first crewed flight of the Starliner, NASA is exercising caution in its approach. The space agency funded the development of the vehicle to provide transportation services to the International Space Station, with the goal of regularly shuttling four astronauts for six-month rotations. This maiden test flight, carrying NASA astronauts Butch Wilmore and Suni Williams, aims to gather data necessary to certify the vehicle for operational missions.

While the first operational mission was initially slated for early 2025, there is a possibility that it may be delayed depending on the outcome of the current test flight. NASA will need to assess whether to award the slot to Starliner or SpaceX's Dragon vehicle for the Crew-10 mission, NASA's 10th operational flight on Dragon. The technical challenges encountered during the test flight suggest that Starliner's operational mission may be postponed to a later slot, potentially in August or September of 2025. However, NASA will review the results of the test flight before making any decisions.

Steve Stich, the program manager for NASA's Commercial Crew Program, emphasized that despite the ongoing challenges, the process has been characterized as a learning experience rather than a source of frustration. The focus now remains on addressing the helium leaks and understanding the impact of the rendezvous profile on the thruster performance.

In conclusion, the extended delay of Starliner's return will allow NASA and Boeing teams to thoroughly review and analyze the data to ensure a safe return to Earth. The space agency remains committed to advancing crewed missions and will use the valuable information gathered during this test flight to refine and enhance the Starliner's capabilities for future operational missions.