Rendezvous pitch maneuver

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The discovery at the very first RPM during mission STS-114
Video of the discovery performing the RPM during STS-119

The Rendezvous Pitch Maneuver ( RPM ) is a flight maneuver practiced by the US space shuttle since STS-114 in July 2005 to check the heat shield for possible damage. This maneuver has since been performed on every shuttle mission to the International Space Station prior to docking with the station.

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The RPM is a maneuver in which the underside of the space shuttle is rotated in the direction of the ISS so that the crew there can photograph the heat shield with high-quality digital cameras in order to avoid any damage that was overlooked during the preliminary investigation with the Orbiter Boom Sensor System discover.

The prerequisite for this maneuver is a precise approach from below to the ISS so that the sunlight can illuminate the underside of the orbiter when it is directed towards the station. The maneuver must be carried out close to the station so that the cameras on board the station can guarantee the necessary recording precision. This requires special flying skills on the part of the pilot of this maneuver. For this reason, most RPMs have so far been flown by the shuttle commander instead of the pilot, because the latter has the greater flight experience in space.

The flight maneuver describes a 360 ° rotation of the orbiter and is similar to a "roll backwards", which is why the maneuver often bears this name. It is usually carried out about 180 meters away from the station. This maneuver must be flown very slowly so that the space station crew has the necessary time to photograph the underside of the shuttle. This also makes the maneuver so difficult because it takes a lot of time due to the slow turn and the pilot cannot see the space station while the underside of the shuttle is pointing towards the ISS. So he does not know whether the shuttle is approaching the station in a critical way or whether it is so far away that the cameras in the station can no longer achieve the required recording precision. He must therefore be able to accurately estimate the position and movement of the shuttle before the actual maneuver.

The first mission to perform the rendezvous pitch maneuver was STS-114, the first shuttle mission since the Columbia disaster . The maneuver was first carried out by shuttle commander Eileen Collins with the space shuttle Discovery . It has been carried out on every mission to the ISS since then.

This maneuver was invented by NASA engineers Steve Walker, Mark Schrock and Jessica LoPresti. This procedure became necessary because parts of the foam insulation of the external tank repeatedly fell off during take-offs and hit the shuttle's heat shield with great force. The impact of such a piece of foam material is so great that it can cause serious damage to the heat shield, as was the case with the Columbia disaster in February 2003.

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