The attitude and orbit control subsystem (AOCS) provides attitude information communications service equipment, and scientific instruments. Control is. An operating communications satellite system consists of Physical Structure. Attitude and Orbit Control System. (AOCS). Power System. Thermal Control. oriented framework for Attitude and Orbit Control System or AOCS of satellites. Understanding the case study requires some familiarity with the AOCS domain.

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AOC subsystem is helpful in order to make the antennas, which are of narrow beam socs points towards earth. Comnunication communications satellite derive their electrical power from solar cells. However, should any serious anomaly occur, such as a prolonged loss of contact, XMM-Newton will automatically enter a survival mode and wait for direct control to be re-established from Earth.

Communication subsystem is placed on top of the drum. You can also try this books 1.

ESA Science & Technology: Engineering

The pointing accuracy of the 10 m long XMM-Newton is 0. So, the second gas jet will stop the motion of satellite in that axis direction. Learn all you need in order to create a. The satellites, which perform this kind of operation are called as de-spin. Let X, Y and Z are another set of Cartesian axes. Two types of transponder in use: These forces change cyclically over a hour period, since the satellite moves around the earth. This site was designed with the. Orbit control subsystem is useful in order to bring the satellite into its correct orbit, whenever the satellite gets deviated from its orbit.

The telemetry system sends data derived from many sensors on the satellite, which monitor the satellites health, via telemetry link to the controlling earth station. In this way, the AOC subsystem takes care of the satellite position in the right orbit and at right altitude during entire life span of the satellite in space. Before delivery for integration into the spacecraft, the AOCS system underwent several weeks of intensive testing, and subsequent System Validation Tests on the assembled satellite have confirmed its perfect operation.


For redundancy XMM-Newton carries a second star-tracker telescope. By continuing to use the site you are agreeing to our use of cookies.

Satellite Communication AOC Subsystem

During launching phase, the satellite spins when the small radial gas jets are operated. The TTCM subsystem present at earth station monitors the position of satellite. They will provide the rotation in both directions of the three axes.

The receiver-transmitter units are known as transponders. Create your website today.

A vital requirement of the XMM-Newton mission is that its delicate science detectors must not be damaged by luminous sources in the sky. Satellites are of this type are called as spinners. Spinner contains a drum, which is of cylindrical shape.

The orientation of a satellite in space is crucial, whether it be for telecommunications or Earth observation craft, or for astronomy missions like XMM-Newton. Due to this, the spin axis gets stabilized and the satellite will point in the same direction.

Given XMM-Newton’s very specific orbit highly elliptical, irregular eclipse seasons, Sun avoidancethis required satellute complex hardwired logic within the unit. The maximum rotation speed of the reaction wheels is rpm.

The AOCS has also been designed to enable the satellite to operate in kn autonomous mode for 36 hours, and during eclipses. These systems are partly on the satellite and partly at the controlling earth station. The fully redundant AOCS represents some kg of electronics: Following are the two methods to make the satellite that is present in an orbit as stable.

Altitude and Orbit Control AOC subsystem consists of rocket motors, which are capable of placing the satellite into the right orbit, whenever it is deviated from the respective orbit. Then, it will resolve that issue by bringing the satellite into the correct orbit.

Note that this acs not a bright source avoidance cone, but driven by requirements on the spacecraft’s alignment with respect to the Sun to ensure sufficient energy supply and thermal stability. In this method, each axis contains two gas jets. It is responsible for the detection of anomalies of whatever origin and their correction. The letter use communication housekeeping, since these subsystems serve to support the communications system. The direction of this motor will be opposite to the rotation of satellite body, so that the antennas point towards earth.


Based on telemetry data received from the satellite and orbital data obtained from the tracking system, the control system is used to correct the position and attitude of the satellite. In this method, the body of the satellite rotates around its spin axis.

Satellite Communication – AOC Subsystem

From then on, the X-ray observatory’s life in space, for more than ten years, has been beating to the rhythm of its “electronic heart”. ESA’s X-ray space observatory targets distant X-ray sources for long periods often exceeding ten hours and one of the key requirements of the satellite is its very high pointing accuracy and stability. In general, it can be rotated at communicatin to rpm in order to produce a force, which is of gyroscopic type.

The tracking system is located at this earth station and provides information on the range and the elevation and azimuth angles of the satellite. This set of three axis provides the information about orientation of the satellite with respect to reference axes.

It is usually composed of one or more antennas, which receive and transmit over wide bandwidths at microwave frequencies, and a set of receivers and transmitters that amplify and retransmit the incoming signals.

After this, the de-spin system operates in order to make the TTCM subsystem antennas point towards earth station.