Starliner is Safely Back on Earth

The long and troubled journey of the Starliner Calypso capsule has finally come to an end. On Saturday, Sept. 7, at 04.01 UTC the uncrewed spacecraft safely touched down in the New Mexico desert. Previously, on Sept. 6, at 22.04 UTC, Calypso undocked from the ISS Harmony module.

Touchdown, #Starliner! The uncrewed spacecraft landed at New Mexico's White Sands Space Harbor at 12:01 am ET (0401 UTC) on Saturday, Sept. 7. pic.twitter.com/Q5lITEzATn
— NASA (@NASA) September 7, 2024

Starliner has returned to Earth three months after liftoff, but without the two astronauts, Suni Williams and Butch Wilmore, whom it had carried to the International Space Station on June 6. Suni and Butch will have to extend their mission by several more months, as they wait to return home aboard a SpaceX’s Crew Dragon.

Various issues with the capsule’s reaction control system (RCS) thrusters led NASA to consistently postpone Starliner’s return and eventually opt for a change in the return vehicle.

A troubled mission

As we previously reported, the Starliner Crew Flight Test (CFT) encountered several issues from the start. Specifically, five RCS thrusters temporarily failed during the docking maneuvers with the space station. From that moment, a complex situation arose, driven by the agency’s concerns about the safety of the mission’s return, which was originally scheduled to take place just a week later.

Liftoff of Boeing's Starliner Crew Flight Test. Credits: United Launch Alliance — *Liftoff of Boeing’s Starliner Crew Flight Test. Credits: United Launch Alliance*

Various discussions and analyses between Boeing and NASA gradually postponed Starliner’s return date. Extensive tests conducted at NASA’s White Sand Test Facility, allowed the teams to identify the cause of the thruster malfunction. The expansion of a Teflon seal affected the oxidizer flow.

However, not enough data have been collected to enable engineers to precisely understand what happened. Consequently, on August 24, NASA officials announced that the CST-100 Starliner would have returned to Earth uncrewed.

Double Dragons together ahead of Polaris Dawn and Cre-9 missions. Credits: SpaceX — *Double Dragons together ahead of Polaris Dawn and Crew-9 missions. Credits: SpaceX*

The decision was not a total surprise, as rumors and behind-the-scenes reports had been circulating for weeks about the agency’s request for SpaceX to make a Crew Dragon avaible to bring Suni and Butch back to Earth.

As a consequence, later in September, SpaceX’s Crew-9 mission will launch with only two astronauts aboard, the commander Nick Hague from NASA and the mission specialist Aleksandr Gorbunov of Roscosmos. Thus, upon its return in 2025, the Freedom capsule will also bring back the two astronauts from the Starliner mission.

A tough obstacle for Starliner

The CFT mission aimed to certify CST-100 Starliner for crewed flight and allow Boeing to begin conducting official missions contracted under NASA’s Commercial Crew Program (CCP). Given the issue encountered, it’s now difficult to determine the next steps and the impact on Boeing’s schedule.

*Boeing’s Starliner pictured docked to the Harmony module’s forward port. Credits: NASA Johnson*

It will be crucial to understand whether significant tests and improvements on the spacecraft’s thrusters will be sufficient to obtain NASA certification. It is likely that Starliner-1, scheduled for late 2025, will be postponed.

It’s important to note that, due to many development delays, Boeing is already way over the original roadmap. To date, SpaceX has already conducted nine crewed missions to the ISS, in addition to several private launches for Axiom and others.