Docking Clamps

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Lore & Background

Boeing and NASA agreed on this second uncrewed flight test to address the software problems that prevented rendezvous during OFT-1. The mission adhered to a fixed-price contract paid by Boeing, with an estimated out-of-pocket cost of US$410 million. Notably, the hardware originally intended for the crewed Crew Flight Test (CFT) was repurposed for this validation run. Following the 2019 failure, engineers modified the docking system design, adding a hinged re-entry cover below the expendable nosecone to protect against atmospheric heating, similar to SpaceX's Dragon 2. This flight also achieved a historic milestone: it was the first time a spacecraft utilizing NASA's standard docking system docked with the ISS, distinct from SpaceX's proprietary interface.

In Their Own Story

The path to launch was fraught with delays and technical hurdles. Initial targets in March 2021 were pushed back repeatedly due to software recertification needs and scheduling shifts into August and September. A major setback occurred on 29 July 2021, when the Atlas V rolled out only to be halted; a misfiring Nauka module thruster at the ISS made the station unable to receive visitors until corrected. Further complications arose in early August 2021 due to unexpected valve position indications in Starliner's propulsion system. Engineers decided on 13 August to remove the spacecraft for deep troubleshooting of thirteen valves, delaying the launch by a full year. Finally, on 19 May 2022 at 22:54 UTC, the Atlas V N22 (AV-082) lifted off. During orbital insertion, two OMAC thrusters failed out of twelve, but the flight control system seamlessly switched to backups, allowing Starliner to achieve a good orbit and complete soft capture just over 26 hours later.

Reader's Guide

Boeing modified the Starliner docking system after OFT-1 by adding a hinged re-entry cover for atmospheric protection. The mission utilized an Atlas V N22 with a dual-engine Centaur upper stage, which is mandatory to provide abort trajectories at any mission point. During launch on 19 May 2022, two of the service module's twelve OMAC thrusters failed immediately after ignition, yet the onboard system switched to backups to complete the burn successfully. Soft capture occurred 26 hours and 34 minutes into the flight, followed by hard capture 20 minutes later. A one-hour delay during docking was necessitated by the need to retract and re-extend the ring clamp on the NDS interface. The hatch opened on 21 May at 16:04 UTC for crew access simulation and closed on 24 May at 19:00 UTC. Undocking occurred on 25 May at 18:36 UTC, with a successful landing in White Sands, New Mexico, at 22:49 UTC.

Did You Know?

• The mission used Starliner Spacecraft 2, which was originally planned for the crewed Crew Flight Test.
• During orbital insertion, two of the twelve OMAC thrusters failed, but backup systems allowed the spacecraft to reach orbit successfully.
• This flight marked the first time a vehicle using NASA's standard docking system docked with the ISS.
• The launch was delayed for a full year starting in August 2021 due to valve issues in the propulsion system.
• Starliner carried a plush toy of Kerbal Space Program character Jebediah Kerman as a zero-G indicator.