Boeing Starliner ISS docks after delay

NASA flight controllers have called off a previously planned approach to fix problems with Starliner's propulsion system. Starliner has 28 jets, known as the RCS (Reaction Control System) engines, that help the spacecraft make small movements in orbit.

Wilmore and Williams were told by NASA Capsule Communicator, or CAPCOM, Neal Nagata that the 12:15 docking attempt had to be aborted due to the ISS' zero fault tolerance for a spacecraft control problem.

The agency and Boeing had to troubleshoot five of the RCS jets that were inactive. Four of the defective Starliner jets were recovered after NASA astronauts Butch Wilmore and Suni Williams worked with flight controllers to test the thrusters.

CAPCOM Nagata had the astronauts keep the spacecraft outside the “keep out sphere,” an invisible boundary around the ISS that serves as a safety measure, while they diagnosed the problematic thrusters.