Boeing’s Starliner Begins Critical Return from ISS After Months in Space Delays

Boeing’s Starliner spacecraft undocked from the ISS on September 6, beginning its journey back to Earth after months of delays caused by a thruster malfunction. The deorbit burn, scheduled for late evening, will determine the success of Starliner’s reentry.

Starliner Undocks from ISS, Prepares for Critical Deorbit Burn After Months of Space Delays

After spending months in space, Boeing's Starliner spacecraft successfully undocked from the International Space Station (ISS) at 6:04 p.m. Eastern Time on September 6. Starliner, launched in June, was initially intended to return to Earth within a few weeks. However, the ship's return was postponed due to a malfunctioning thruster during its rendezvous with the International Space Station (“ISS”).

According to Wccftech, this resulted in a months-long investigation by NASA and Boeing, culminating last month when the agency determined that a lack of consensus among subject matter experts violated its policies regarding astronaut safety during missions.

After undocking, Starliner will close its entry cover and conduct thruster checkouts before Earth teams determine whether to initiate a deorbit fire to initiate its entry into the Earth's atmosphere.

The teams on the ground will decide to initiate the deorbit explosion at 10:57 p.m. Eastern Time. The ship will activate its propulsion twenty minutes after deciding to proceed with the burn. The deorbit burn will be the most critical aspect of Starliner's return voyage. If the ship executes the mission as intended, it will arrive at the White Sands landing site in New Mexico shortly after midnight.

The exit from the approach ellipsoid around the ISS has been the primary milestone for Starliner thus far. This assures that the ship does not approach the station for 24 hours, even if it loses all of its thrusters, thereby increasing the station's margin of safety.

The deorbit burn will activate the ship's four orbital maneuvering and attitude control (OMAC) thrusters for a 59-second burn. This will slow the vessel down by 130 meters per second, enabling it to enter the Earth's atmosphere. If this burn is successful, the ship should be able to return to Earth without incident, as its thrusters will have successfully cleared a critical burn for the landing profile.

NASA, Boeing Prepare Starliner for Return with New Thruster Test Plans, Assure Astronaut Safety

NASA and Boeing conducted simulations for the undocking before the September 6 separation as part of their mission preparations. During a pre-departure news conference on September 4, Steve Stich, NASA's Commercial Crew manager, disclosed that Boeing may conduct thruster hot fires after the Starliner departs the approach ellipsoid as part of the lessons learned from the Boeing Crew Flight Test mission.

The undocking profile of Starliner during the current mission was distinct from its previous orbital flight test. This profile is intended to facilitate the rapid removal of the spacecraft from the International Space Station and is more straightforward than the other return profiles. Additionally, it alleviates the strain on the ship's thrusters, as Starliner's forward thrusters are the primary means of propelling it away from the station.

NASA astronauts Butch Wilmore and Suni Williams will utilize SpaceX's Crew-8 Dragon, which is presently docked to the International Space Station, as their emergency escape vessel while their ship is currently en route to Earth. According to Stich, the astronauts are not stranded or trapped on the station. The NASA official explained during the most recent conference that, as of now, "Crew-8 is their emergency return vehicle, and when Crew-9 gets there, that will be their vehicle, that will be their vehicle, that will be their return vehicle for nominal and any emergencies."