Starliner set to return to flight on OFT-2

Starliner sits atop an Atlas V N22 rocket ahead of launch of OFT-2. Credit: Derek Newsome / Space Scout

Orbital Flight Test-2, the second uncrewed test flight of the CST-100 Starliner, is set to lift off tomorrow, May 19, at 6:54 p.m. Eastern onboard ULA’s Atlas V rocket. A critical milestone for Boeing, the mission will test the full capabilities of the capsule, most importantly proving its ability to rendezvous with and dock at the ISS. Orbital Flight Test-2 (OFT-2) will provide valuable data toward certifying the Starliner as a viable crew transportation system for NASA’s Commercial Crew Program and will complete the test objectives that the incomplete OFT-1 mission in 2019 failed to achieve.

OFT-2 information sheet. Credit: Space Scout

This is the second attempt at the OFT-2 mission, which has so far cost Boeing $595 million in cost overruns. The first attempt in August 2021 experienced a series of valve problems just hours before launch, leading to the launch to be entirely called off. Thirteen oxidizer valves in Starliner’s service module experienced damage from moisture intrusion, leading to the valves seizing while Starliner was on the launchpad. Starliner was de-stacked from the Atlas V launch vehicle and sent back to Boeing’s facilities for analysis and inspection with the assistance of NASA’s Marshall Spaceflight Center. The afflicted service module, SM2, was replaced with new service module SM4.

The investigation, which concluded earlier this year, found that moisture intruding into the valve body reacted with the aluminum body and nitrogen tetroxide, the oxidizer, to form reaction products that seized the valve in place. In a press briefing on May 3, Boeing’s Vice President of Space and Launch, Dr. Michelle Parker, explained that mitigations applied to Starliner include frequent cycling of the valves, later oxidizer loading, a nitrogen purge of valve compartments, and sealing electrical connections where moisture could have leaked into the valve. On May 11, after this attempt’s Flight Readiness Review, Boeing program manager Mark Nappi said that a redesign of the valves is “definitely on the table,” with Boeing studying options for long-term mitigation of the issue. 

Click to expand – OFT-2 Pre-launch and Ascent Timeline

Now, the yet-to-be-named Starliner Spacecraft 2 stands ready for launch under 24 hours from now onboard a United Launch Alliance Atlas V N22. Rocket-grade kerosene began loading into the Atlas V shortly after the rocket rolled out to Space Launch Complex-41 at Cape Canaveral Space Force Station earlier today. Starliner’s ascent will take just under 32 minutes, starting with liftoff at 6:54:47 p.m. EDT. The Atlas V launch vehicle will intentionally launch Starliner into an orbit dipping into the atmosphere—approximately 73 by 181 kilometers—in order to allow for a safe abort trajectory and for disposal of the Centaur upper stage. After separation at 14 minutes, 55 seconds into flight, Starliner will coast for sixteen minutes before conducting a 40-second orbital insertion burn with its own thrusters. The spacecraft is expected to dock with ISS module Harmony’s forward docking port at 7:10 p.m. Eastern, or 24 hours, 15 minutes into flight.

Along the way, Starliner will conduct a series of demonstrations to prove certain aspects of the capsule. At two hours into flight, Starliner will conduct an abort demonstration burn, followed by a demonstration of the spacecraft’s reaction control system. Two space-to-space command demonstrations are planned, one at 20 hours, 45 minutes and the other, a hold commanded from the ISS, during the docking sequence at 22 hours, 51 minutes. Also planned throughout the rendezvous are also four demonstrations of Starliner’s vision based guidance system, known as VESTA.

Click to expand – OFT-2 Rendezvous timeline

For OFT-2, Starliner will spend five to eight days in space, but possibly more depending on return weather. The capsule is outfitted with 800 pounds of cargo, including about 500 pounds for NASA, such as food and items requested by the current Expedition 67 crew, as well as some small EVA supplies. Starliner will also carry 300 pounds of commemorative cargo for Boeing, including founder Bill Boeing’s ID card, pennants and flags from 14 historically Black colleges and universities, Silver Snoopy pins, American flags and mission patches for the Starliner team, and a flag to be left on the ISS until the Starliner Crew Flight Test’s crew retrieves it. After completing its stay at the ISS, Starliner will return to Earth with 550 pounds of NASA cargo, including life support resource tanks to be recharged on Earth. 

While Starliner will not have a human crew for Orbital Flight Test-2, Rosie the Rocketeer, Boeing’s instrumented mannequin, will occupy the commander’s seat. Rosie will be outfitted with 15 data sensors to collect information about future astronauts’ experiences.The Expedition 67 crew onboard the ISS will also board Starliner in order to test its communications subsystems, retrieve and load cargo, and test other aspects of the capsule in space.

If OFT-2 completes all of the required objectives during this test, NASA and Boeing will begin preparations for the capsule’s Crew Flight Test, or CFT. Onboard CFT will be at least two astronauts, with the crew currently expected to be NASA astronauts Barry “Butch” Wilmore and Mike Fincke. However, NASA officials stayed today, May 18, that selection will only be finalized after the OFT-2 mission. CFT is expected to launch as soon as December 2022, though NASA officials stated that the date is subject to change. Once the test missions are complete, Starliner will move on to its six currently contracted post-certification missions. Future missions beyond PCM-6 will require Starliner to move from the winding-down Atlas V to a new launch vehicle. 

Starliner and Atlas V at SLC-41, just after rollout. Credit: An Tran / Space Scout

OFT-2 is scheduled to lift off at 6:54:47 p.m. EDT, May 19, 2022, with everything currently go for launch.

Go Starliner, Go Atlas, Go OFT-2!

To keep up with the OFT-2 mission, follow Space Scout’s ongoing coverage of the mission at our twitter, @WeAreSpaceScout, as well as Boeing’s Starliner Updates, ULA’s Mission Blog, and NASA’s OFT-2 blog.

Written by Lavie Ohana and Andrea Lloyd.

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