MOSCOW. Nov 18 (Interfax-AVN) - The International Space Station (ISS) has failed to reach the altitude specified, the Ballistic Service of Rusisan Mission Control told Interfax-Military News Agency on Thursday.
"The ISS orbit altitude was expected to have reached 359.9 km as a result of starting up the Progress-M50 spacecraft engines yesterday. However, according to telemetry data, the average altitude totals 358.2 km," an official said.
According to him, experts will discuss the problem on Thursday and arrive at a decision on further activities.
Russian Mission Control spokesman Valery Lyndin earlier told Interfax-AVN that there was nothing extraordinary in the situation.
"The Progress engines did start and work for the required time. But the impulse turned out lesser than it was expected for some reason," he said.
"The ISS has a large amount of fuel, which will allow it to carry out any orbit adjustment," he said.
It is too early to speak about postponing the launch of a Progress-M51 cargo spaceship, which is scheduled for December, he said.
"It does not make sense to speak about it now. And setting the date for the ship's launch is a matter for the council of the senior designers," Lyndin said.
The ISS orbit was expected to have been raised by 4.4 km on Wednesday with the help of the power plant of the Russian Progress-M50 cargo spacecraft. The orbit was corrected for ISS to make rendezvous with another cargo spacecraft to be launched from Baikonur on December 23.
The ISS orbit is maintained at an altitude of about 400 km from the Earth. The daily average altitude loss amounts to 100-150 m. ISS started descending at a greater rate after magnetic storms of November 9-12, when it started losing its altitude at a rate of 300 m per day. The ISS orbit descended by seven kilometers from the moment of its latest correction in September.
Mission Control said that in the next half a year experts would carry out a whole range of small orbit corrections in order to facilitate rendezvous of both Russian spacecraft with ISS, and U.S. shuttles, which are expected to resume flights to ISS in May 2005.
The orbit is corrected several times a year. It is necessary to facilitate ISS rendezvous with another spacecraft, either manned or unmanned. The ISS orbit is also corrected for it not to collide with space waste such as small meteorites, and debris of old satellites and spacecraft.