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Perigee Raise Burn sequencing

The crew was awakened to execute the PRB approximately 12 hours after the April 1st launch, adjusting Orion's orbital geometry to set up for the Trans-Lunar Injection burn scheduled on Flight Day 2.

TLI as trajectory commitment

The Trans-Lunar Injection burn serves as both the final major engine firing to reach the moon and the de-orbit burn, committing the spacecraft to a free-return trajectory around the lunar far side.

Lunar approach timeline

Following TLI, three smaller outbound trajectory correction burns will refine the path, culminating in the crew entering the moon's sphere of influence on Flight Day 5 and conducting the closest lunar flyby on Flight Day 6.

Environmental and operational adjustments

Mission specialist Christina Koch reported dangerously cold cabin temperatures, prompting Houston to modify radiator set points and consider shell heaters while the crew prepared for critical burns.

Science payload coordination

The crew collaborated with Huntsville's Payload Operations Integration Center to monitor Avatar, an organ-on-chip experiment studying radiation and microgravity effects to inform future astronaut medical countermeasures.

Communication protocols and traditions

The crew participated in pre-burn conferences with Capcom to verify procedure alignment, while wake-up music traditions dating to the Apollo era marked shift changes.

Precision targeting sequence

The Guidance, Navigation, and Control team commanded starfield maneuvers using Orion's star tracker cameras to determine spacecraft attitude before uploading final burn targeting parameters.

24/7 mission oversight

Three rotating flight controller shifts (Orbit 1, 2, and 3) monitor the spacecraft continuously from Houston, with Orbit 2 led by Flight Director Paul Ka managing the PRB preparation.

High Earth orbit positioning

Orion currently travels approximately 43,000 miles from Earth—over 165 times farther than the ISS—positioning it for the critical lunar injection maneuver.