Mission Boe-CFT: the Boeing CST-100 Starliner Calypso spacecraft has reached the International Space Station

Views of the Starliner Calypso spacecraft approaching the International Space Station in its Boe-CFT mission (Image NASA TV)
Views of the Starliner Calypso spacecraft approaching the International Space Station in its Boe-CFT mission (Image NASA TV)

A few hours ago, Boeing’s CST-100 Starliner Calypso spacecraft docked with the International Space Station’s Harmony module, completing the first leg of its Boe-CFT (Boeing Crewed Flight Test) mission which began with the launch just over 24 hours earlier. After checking that the pressure was correctly balanced, the hatch was opened to allow Butch Wilmore and Suni Williams to enter the Station and begin their mission, which will last about a week.

The Starliner spacecraft is equipped with an automated docking system to the International Docking Adapter (IDA). Station safety is a top priority so every little step of the Starliner during its approach is checked. Only if everything goes well in the spacecraft’s position and speed they proceed to the next step and in case of problems, it can be aborted at every step.

The automated docking maneuver is supposed to be the only one used by all spacecraft, but throughout the International Space Station’s history, there have been cases where communication or other problems forced a spacecraft to be manually driven. When there’s a crew on board, that means that the pilot assumes command and that the first mission in which there are astronauts on board also includes tests of manual controls.

Among the latest concerns for the Boe-CFT mission was a leak of the helium used in the propulsion system. After yet another delay to examine this problem, the leak levels were considered non-hazardous, so it was decided to proceed with the launch. However, after the Calypso spacecraft reached orbit, two more leaks were identified. For now, it was decided to close two valves and the state of the Calypso has been defined as stable.

The most serious problems came from the malfunction of some of the thrusters due to causes that are still unclear. That problem is similar to the one encountered during the Boe-OFT 2 mission, the second uncrewed test. This time there was a risk of preventing the arrival at the International Space Station because 6 of the 28 propulsion systems weren’t working, leaving the Calypso spacecraft with maneuverability below safety requirements.

While the Calypso remained 200 meters from the International Station, Butch Wilmore and Suni Williams performed various operations to restart the blocked propulsion systems and 4 of them were restored. This led to the permission to resume the maneuvers that led to the docking of the Calypso more than an hour after the original schedule. After about two more hours, the two astronauts finally entered the Station.

The first leg of the Starliner Calypso spacecraft mission was completed despite the problems and is scheduled to be completed on June 14 with its return to Earth. Landing was the only phase that caused no problems in the uncrewed tests but it’s always a critical moment, especially if there are people on board. Now two American spacecraft are docked at the International Space Station and the presence of a Crew Dragon reminds us of Boeing’s delays compared to SpaceX.

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