Russia Mission Control adjusts ISS orbit by almost 2 km
The MCC told Itar-Tass that the "orbit correction passed nominally." The manoeuvre was performed in automatic mode with the help of two powerful vernier engines of the Zvezda service module. For the first time accelerometers (meters of linear acceleration) installed on the American segment of the station were used in the operation, the MCC said.
The engines ignited at 03:11, Moscow time and worked for 63 seconds. During this time, the average altitude of the ISS orbit, according to expert estimates, has increased by about 1.8 kilometres and reached some 392.2 kilometres. The average altitude is a virtual value used by ballisticians. It is an imaginary circular orbit with the period of revolution around the Earth equal to the station's real elliptical orbital period.
The MCC said that now, after US space shuttle flight program's termination, the ISS orbit can be raised to nearly 400 kilometres (earlier, its height at the request of the US side was maintained at a level no higher than 360 kilometres) that gives considerable fuel saving.
The ISS Expedition 30 crew of three people, who since November 16 are on the orbital mission at the station, had been warned in advance of the manoeuvre conducted on command from the Earth. As astronauts' participation in orbit correction operations is not required, they were sleeping at the time (they were to rise at 10 a.m. Thursday).
The ISS orbit adjustment manoeuvres are usually carried out in order to bring the station to the desired orbit for docking with cargo or manned spacecraft, to create conditions for a successful landing, as well as to avoid collision with space debris - small meteorites, fragments of old satellites and ships. For example, it so happened less than two months ago, on September 29, when the station had to be quickly moved from the dangerous proximity to a fragment of a carrier rocket.
The Thursday orbit adjustment is the second of three planned manoeuvres aimed at creating the conditions for the landing of the ISS crew in a favourable area, as well as to prepare the station for docking with the next Soyuz craft that in late December will take into orbit a new ISS expedition. The first operation to raise the orbit was held on November 18, before landing of the Soyuz TMA-02M spaceship, which returned to Earth three astronauts from the ISS Expedition 28/29 crew. Another similar manoeuvre is scheduled for December 7; Kazinform cites Itar-Tass.
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