Under the direction of Starliner flight director Chloe Mehring and with Boeing engineers on console monitoring, flight controllers commanded the sequential firing of 27 RCS thrusters.

"The integrated teams between Starliner and ISS worked extremely well together this week to finalize and safely execute the docked hotfire sequence," said Mehring, who will lead the Starliner flight control team in the upcoming undocking from the International Space Station.

"Both teams were very happy with the results."

The test involved one-pulse firings designed to verify the performance of each thruster. The aft-facing thrusters fired for 1.2 seconds, while the others fired for 0.4 seconds. Between each firing, the team reviewed real-time data and confirmed that all thrusters performed at peak thrust ratings, ranging from 97-102%. The helium system remained stable, and an RCS oxidizer isolation valve that had not been fully seated previously was cycled several times and is now operating normally.

This marks the second successful docked hot fire test for the spacecraft, an integrated operation that the station and Starliner teams will also conduct during future long-duration missions.

Flight test astronauts Butch Wilmore and Suni Williams were inside Starliner Calypso, providing real-time feedback to the ground team during the test. In preparation for the return home, Wilmore and Williams will participate in two undock to landing simulations next week.

A Flight Test Readiness Review is tentatively planned for late next week, with the new data gathered to be reviewed and included in the return flight rationale. While a landing date has not yet been set, opportunities are available throughout August.

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