On the Express-AM1 satellite operation

02.06 : 2010

As already reported on May 17, 2010, the Express-AM1orbit inclination cannot be kept from April 24, 2010 due to a failure on this spacecraft. In order to clear up the current situation, we inform that at present RSCC does not plan to put the satellite out of operation or to replace it into another orbital position and intends to continue its operation in the 40 East orbital position.

The preliminary data analysis results in terms of the Express-AM1  inclination variation show as follows:

- networks with auto tracking established via the Express-AM1 in C- and Ku-bands will be capable of operating without limitations till decision making about finishing its mission;

in Ku-band:

- with the satellite inclination by more than ± 0.1 degree, the E/S with minimum 4.8 m antennas without auto tracking will not be capable of securing round-the-clock operation of satellite communications systems. These systems will have after June 6, 2010 two periods of degraded operation quality up to the communications channel drop-up which will happen during passing the upper and lower points of the figure-of-eight of the satellite inclination trajectory;

- with the satellite inclination by more than ± 0.15 degree (after June 25,2010) the similar situation will take place with the E/S with 3.8 m antennas that do not have auto tracking;

- peripheral VSAT stations will have outages approximately from the following dates:

2,4 m antennas from July 13, 2010 (inclination more than  ± 0.20 degree),

1.8 m antennas from August 5, 2010 (inclination more than  ± 0.25 degree),

1.5 m antennas from August 30, 2010 (inclination more than  ± 0.30 degree),

1.2 m antennas from 28 September, 2010 (inclination more than  ± 0.35 degree).

In C-band the satellite station keeping degradation will, first of all, affect the communication networks established via E/S with large antennas without auto tracking. Depending on the receiving and transmitting antenna diameters without auto tracking, the satellite communication system outages will start approximately from the following dates:

12 m antennas from June 10, 2010 (inclination more than  ± 0.10 degree),

9.3 m and 7.6 m antennas from June 25, 2010 (inclination more than  ± 0.15 degree),

6.3 m and 7.3 m antennas from July 13, 2010 (inclination more than  ± 0.20 degree),

4.8 m antennas from August 5, 2010 (inclination more than  ± 0.25 degree).

3.8 m antennas from  September 28, 2010 (inclination more than  ± 0.35 degree).

- the digital TV receiving networks with 2.4 m antennas adjusted to the center of the figure-of-eight   will ensure a qualitative reception of digital TV&Radio programs  approximately till November 28, 2010 (inclination more than  ± 0.50 degree). With the satellite inclination growth up to ± 1.0 degree (approximately till May 2011) receiving digital TV&Radio programs will also be possible but the reliability will decrease with increasing the range of the round-the-clock drift in the period of passing the upper and lower points of the figure-of-eight.

Considering the above, herewith we inform that further communication services will be provided via the Express-AM1 satellite on the preemptible basis.

Diagram of the satellite inclination in the period from May 5, 2010 till November 1, 2010

Diagram of the satellite inclination in the period from October 1, 2010 till July 2, 2013