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SUMMARY CHARACTERISTICS OF

THE SESAT SATELLITE

This document contains information on the mission, communications features, coverages, frequency plans and

implementation of the SESAT satellite.



The SESAT Satellite

TABLE OF CONTENTS

THE SESAT SATELLITE ............................................................ ........................................................... ...............3

INTRODUCTION ......................................................................................................................................................3COMMUNICATIONS FEATURES ...............................................................................................................................3

BEACONS ...............................................................................................................................................................4

SATELLITE IMPLEMENTATION ................................................................................................................................5



The SESAT Satellite

THE SESAT SATELLITE

Introduction

In mid-1995, EUTELSAT decided to order a satellite from NPO-PM to satisfy the telecommunications needs in

central and eastern Europe.

The satellite, called SESAT (Siberia Europe Satellite), is designed to provide 18 channels for a minimum

operational lifetime of 10 years. The main characteristics of this satellite are given below.

SESAT was launched in April 2000 and is operated at 35.9° East within a window of +/- 0.1°E/W and +/- 0.1°

N/S.

SESAT enables the provision of a wide range of telecommunications services over a very large geographical area,

as well as other regions within the visibility of the satellite, from the Atlantic Ocean to eastern Russia, including a

large part of Siberia.

SESAT helps in the development of international, regional and domestic services such as long distance trunk

telephony, thin route telephony services, corporate and specialised data services, as well as other services as the

need may arise.

In terms of commercial objectives, SESAT ensures that capacity is available to provide continuity to the current

telecommunications business in western and central Europe and to allow the development of new markets in the

East and Far-East for all types of telecommunication and business services.

Communications Features

The SESAT satellite is designed to provide 18 transponders, each of 72 MHz usable bandwidth, for a minimum

satellite lifetime of 10 years, in the geostationary orbit.

The frequency plan given in Figure 1 shows the uplink and downlink frequency bands



The SESAT Satellite

In addition to this fixed beam, 6 channels on the uplink and 6 channels on the downlink are independently

switchable to a steerable beam (see Figure 1), channel-by-channel. Hence, in addition to communications within

the fixed coverage, communications between the fixed beam and the steerable coverage, or communications

within the steerable beam, can be established through certain channels. This feature makes SESAT particularly

attractive for communications with a single satellite hop between Europe and the geographical regions covered by

the steerable coverage. Figures 4 and 5 show the uplink and downlink coverages of the steerable beam pointed to

India.

Beacons

SESAT carries two tracking beacons, designated B1 and B2. B1 uses the telemetry and ranging carrier while B2

is independent. In addition, a third tracking beacon, B3, is provided for the steerable antenna. All beacons operate

in X polarization. The following table lists the beacon frequencies:

Frequency (MHz)

Beacon B1/(TM+RG)*

11 450.350 or 11 451.091

Beacon B2 12 501.000

Beacon B3 11 199.500

*Frequency selectable by ground command.



The SESAT Satellite

Satellite Implementation

The industrial organisation for the SESAT programme is led by NPO-PM of Russia as the prime contractor and

Alcatel Space of France as the main subcontractor. NPO-PM is reponsible for all relations with EUTELSAT, the

platform production, satellite integration, launch services and the LEOP phase. Alcatel Espace is responsible for

the payload development, production and integration. The EUTELSAT satellite control centre performs the on-

station operations.

The SESAT satellite was delivered in orbit to EUTELSAT in April 2000 and was placed directly into

geostationary orbit by PROTON.

The 3-axis stabilized SESAT satellite is shown in its in-orbit configuration with solar panels and communications

antennas deployed in Figure 6. The satellite is shown with solar panels stowed around the satellite body and

communications antennas non-deployed in Figure 7.

Adapted from GALS and EXPRESS satellites, the SESAT satellite platform is designed around a pressurised

container which houses most of the platform equipment (Figure 8). As may be noted, a lower tubular truss

connects the pressurised container to the Proton through a launch adapter and an upper truss supports the payload

module.

The payload equipment, including repeater and antennas, is integrated on a separate Earth facing honeycomb

baseplate, as shown in Figure 9.

The two dual-gridded, shaped reflectors are located on the sides of the payload module and the dual reflector

steerable antenna is located in the centre of the module. The repeater units are mounted on both sides of the

payload module structure. Thermal control is supplied by a fluid loop emanating from the pressurised container.

Telemetry, Command and Ranging (TCR) is in Ku-band and the equipment is mounted on the payload module. A

C-band TCR communicating with the Russian ground network is used for transfer orbit operations and for

emergency.

The control of the satellite is made in Ku-band by Eutelsat through the earth station in Dubna (near Moscow).



The SESAT Satellite

SESAT_(iss3.1_Jul01).doc - 6 -

B5

B6 G4 / D4G2 / D2

G1 / D1 G3 / D3

H4 / D4 H6 / D6

H3 / D3 H5 / D5

F2 / G2

F1 / G1

UPLINK

DOWNLINK

11.20 GHz 11.45 GHz 11.70 GHz10.95 GHz 12.50 GHz 12.75 GHz

Pol. X

Pol. Y

B1 B3

B2 B4

H1 / F1 H3 / F3 H5 / F5

H2 / F2 H4 / F4 H6 / F6G6 / D6

G5 / D5

1 0 9 9 1 . 6 7

1 1 0 7 5 . 0 0

1 1 1 5 8 . 3 3

1 1 4 9 1 . 6 7

1 1 5 7 5 . 0 0

1 1 6 5 8 . 3 3

1 2 5 4 1 . 6 7

1 2 6 2 5 . 0 0

1 2 7 0 8 . 3 3

1 0 9 9 1 . 6 7

1 1 0 7 5 . 0 0

1 1 1 5 8 . 3 3

1 1 4 9 1 . 6 7

1 1 5 7 5 . 0 0

1 1 6 5 8 . 3 3

1 2 5 4 1 . 6 7

1 2 6 2 5 . 0 0

1 2 7 0 8 . 3 3

Pol. X

Pol. Y

14.00 GHz 14.25 GHz 14.50 GHz13.75 GHz

H2 / D2

H1 / D1

F4 / G4 F6 / G6

F3 / G3 F5 / G5

B2 B4 B6

B1 B3 B5

1 4 2 9 1 . 6 7

1 4 3 7 5 . 0 0

1 4 4 5 8 . 3 3

1 4 2 9 1 . 6 7

1 4 3 7 5 . 0 0

1 4 4 5 8 . 3 3

1 3 7 9 1 . 6 7

1 3 8 7 5 . 0 0

1 3 9 5 8 . 3 3

1 3 7 9 1 . 6 7

1 3 8 7 5 . 0 0

1 3 9 5 8 . 3 3

1 4 0 4 1 . 6 7

1 4 1 2 5 . 0 0

1 4 2 0 8 . 3 3

1 4 0 4 1 . 6 7

1 4 1 2 5 . 0 0

1 4 2 0 8 . 3 3

Switchable to Steerable Coverage

72 72 72 72 72 72 72 72 72

72 72 72 72 72 72 72 72 72

72 72 72 72 72 72 72 72 72

72 72 72 72 72 72 72 72 72

Figure 1: SESAT Frequency Plan



The SESAT Satellite


+ 5 dB/K

+ 4 dB/K

+ 4 dB/K

+ 4 dB/K

+ 2 dB/K0 dB/K

- 3 dB/K

- 5 dB/K

Figure 2: Fixed Uplink Coverage of SESAT at 36° East



The SESAT Satellite


48 dBW

47 dBW

47 dBW

45 dBW

43 dBW

40 dBW

38 dBW

Figure 3: Fixed Downlink Coverage of SESAT at 36° East



The SESAT Satellite


- 5 dB/K- 3 dB/K

- 1 dB/K

+ 1 dB/K

+ 3 dB/K

+ 4 dB/K

+ 5 dB/K

+ 6 dB/K

Figure 4: Steerable Uplink Coverage of SESAT at 36° East



The SESAT Satellite


36 dBW

38 dBW

40 dBW

43 dBW

45 dBW

47 dBW

48 dBW

49 dBW

Figure 5: Steerable Downlink Coverage of SESAT at 36° East



The SESAT Satellite


Figure 6: The SESAT Satellite In Orbit



The SESAT Satellite



The SESAT Satellite

Pressure scaledcontainer

Upper truss



The SESAT Satellite


Figure 9: The SESAT Payload Module

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