Engineering
Data Processing
Data Handling and Telecommunications
This sub-system had the following tasks:
- Interim storage data from the experiment
- Transmission of experiment, attitude measurement system and satellite status to Earth
- Transmission of ground commands to the sub-systems concerned
- Support for satellite orbit tracking
The total buffer to store data was 8 kilobits. The data was then transmitted to Earth at a bit rate of 160 bits per second. A clock was also placed on board to create a time stamp on each dataset being transmitted. The antennas for transmission and reception were composed of four rods at a length of 54.3 cm each.
Electrical Power
Power Supply
Power Supply was provided by 9480 silicon solar cells, which occupied almost the entire outer surface of the satellite cylinder. This gave it an output of around 60 W. In order to increase the longevity of the solar cells, they were constructed to last longer than the initial lifetime of the mission. A backup battery was also installed to allow for the satellite to operate, while in the Earth's shadow.
Guidance and Navigation
Attitude Measurement and Control
The attitude control system had the job of keeping the satellite's revolutions and the attitude of its axis constant, and pointing the satellite to the different objects to be observed. It works with the aid of liquid nitrogen, which is ejected as required through two pairs of nozzles, imparting a rotary motion to the satellite through the recoil effect.
Thermal Control
The Thermal Control was constructed to ensure that the overall satellite's temperature remains between -10 °C (while the spacecraft was the Earth shadow for about two hours) and +30 °C (while in the Sun). The concept used superinsulation foils, radiation plates and coatings.