To remove a spacecraft from orbit, using its retrorockets for re-entry into the atmosphere. On the space shuttle, the pilot and commander check computers 20 minutes before firing the retrorockets, to verify that the deorbit and landing software programs are working. The firing of the retrorockets is known as the deorbit burn.

Mission control alerts the pilot and commander that the vehicle is ‘go for deorbit burn.’ They rotate the shuttle to fly backwards in its deorbit-burn attitude. The commander then activates the proper command in the computers and, about an hour before touchdown, the engines fire for three minutes to achieve deorbit. They then point the vehicle forward for landing.