Entry operations begin long before the actual landing day. Deorbit Opportunities are generated throughout the mission, with orbit adjust maneuvers sometimes planned in conjunction with the Orbit FDO teams in order to shape the trajectory to define landing times and groundtracks that are within Flight Rule limits.On the day prior to landing, the Entry FDO officially takes over from the corresponding (usually Orbit 1) FDO and plans any final deorbit and entry trajectory items. Detailed weather forecasts as well as preliminary crew communications about the actual landing data are reviewed.
On landing day, the Entry FDO and the entire entry MCC team come onto console 5-6 hours before the deorbit burn time. After another final review of the landing weather forecasts, the official deorbit burn targets are generated and uplinked to the Orbiter.
Once the Payload Bay Doors are closed and the Orbiter is positioned in the proper tail-first attitude, the two Orbital Maneuvering System (OMS) engines are fired in a precise, closed-loop guidance burn that results in a re-entrant trajectory that takes the Shuttle from 17,500 MPH to wheels-stopped in approximately one hour!The Entry FDO monitors the trajectory of the Orbiter against the ground predictions all the way down. Several detailed calls at precise times are made from the Entry FDO to the crew (via CAPCOM, of course!) to let the crew know the status of their entry profile.
If anything off-nominal were to have happened (and this occurred ALL THE TIME in simulations!), the Entry FDO could recommend actions for the crew to take, up to and including a Ground Controlled Approach (GCA), where the Entry FDO would essentially “fly the Orbiter” via trajectory headings from the MCC to get the crew within sight of the landing runway.
Orbit FDOs, as part of their extended training, would be certified as Entry Trajectory (TRAJ) Officers, so that they would have basic knowledge and capability to provide support during an off-nominal, unplanned, or emergency deorbit scenario. While this never happened during any actual missions, it always made for fun simulations for those of us on console! 🙂
Make sure to view the rest of the Entry FDO displays!