Thermal regime
The system controlling the subsatellite's thermal regime (SOTR)
is designed to balance the thermal field of the subsatellite
elements in the range acceptable for all possible operation modes:
- for the mode of the subsatellite flight as a component of the
main spacecraft before separation;
- for the mode of subsatellite operation on the orbit of the
Earth's satellite;
- for the mode of passing through the Earth's shadow (the
maximum duration of the shadow passage is 5 hours for the S2-T).
The system controlling the subsatellite thermal regime includes
both the active and passive devices for thermal regulation. It is
based on the preflight data which determine the subsatellite design,
its orientation relative to the Sun in the main operation
modes (before and after separation from the main spacecraft and
during its pass through the Earth's shadow), and on the
requirements to the thermal regime of the subsatellite systems.
Among the passive means of the thermal control the following
are employed:
- Special covers for thermal regulation;
- Multi-layer metallized film insulation (MMLI);
- Calibrated thermal resistors;
- Heat pipes to balance the subsatellite thermal field.
The active devices for thermal balance include the electric
foil heaters of SOTR. Their principle objective is to provide
the needed thermal field up to the moment of the subsatellite
separation.
The part of the outer side of the subsatellite body has
the thermo-regulating covers. Besides
that the KDU is shielded by MMLI. To provide the thermal regime
of chemical batteries and the subsatellite body during 5 hours
of passing through the shadow the calibrated thermal resistors are
used.
To smooth the subsatellite thermal fields along the Z-axis
oriented toward the Sun, two heat pipes are installed. Each pipe
generates the thermal power of up to 35 Watts for the temperature
gradient between the zone of heating and zone of condensation with
the maximum value of 4deg.C.
Thermal Control system was designed and heat pipes were produced in Kiev Polytechnical Institute, Ukraine.
Testing of the system was made in Space Research Institute, Russia.
Calculations were made in Space Research Institute and in Scientific and Production Association named after S.A.Lavochkin , Russia.
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