NASA and Boeing have decided to extend the stay of the CST-100 Starliner spacecraft at the International Space Station (ISS) for at least four more days. The decision comes in order to conduct additional testing of the commercial crew vehicle, further ensuring its capabilities before it returns to Earth. Previously scheduled to undock on June 18, the spacecraft will now depart no earlier than June 22 with NASA astronauts Butch Wilmore and Suni Williams aboard.

During the extended stay, NASA and Boeing will utilize the extra time to finalize departure planning and operations, as well as conduct some unplanned tests on the Starliner. Mark Nappi, Boeing Vice President and Commercial Crew Program Manager, emphasized the unique opportunity to gather invaluable data during the extended mission, providing valuable insights for all partners involved.

One of the additional tests planned for the Starliner is a brief test of the aft-facing thrusters. This test, which involves firing seven of the eight thrusters in two pulses lasting one second in total, will assess how the spacecraft will perform when docked to the ISS for future missions lasting up to six months. Notably, the thrusters posed difficulties during the Starliner's approach to the station on June 6, with five of them being temporarily disabled due to abnormal readings.

The extended stay will also involve making cabin air temperature measurements to compare with the spacecraft's life support system readings, performing additional tests on the spacecraft hatch and forward window, and conducting a "safe haven" test to evaluate how well the spacecraft can accommodate four people in the event of an emergency on the ISS.

Steve Stich, NASA Commercial Crew Program Manager, highlighted the importance of understanding the capabilities of the Starliner as the long-term goal is to have it perform docked missions at the ISS lasting up to six months.

However, there was no update provided regarding helium leaks in Starliner's propulsion system. NASA had previously confirmed the detection of a fifth leak after the spacecraft docked with the ISS. The helium manifolds in the propulsion system remain closed during docking, and it was confirmed that there is still enough helium to support undocking and deorbit maneuvers.

Originally planned for an eight-day stay at the ISS, the departure of the Starliner was postponed to June 18 to avoid having major events, such as a spacewalk and spacecraft undocking, occur on consecutive days. Unfortunately, the scheduled spacewalk on June 13 was canceled due to a "suit discomfort issue" that arose shortly before its commencement. The tasks planned for this spacewalk will now be carried out on a previously scheduled spacewalk on June 24.

The extension of the CST-100 Starliner's stay at the ISS highlights the commitment of NASA and Boeing to ensuring the spacecraft's readiness for future missions. As testing and preparations continue, space enthusiasts eagerly anticipate the safe return of the crew and the wealth of knowledge gained from this mission.