Control Térmico de Naves Espaciales: 7.Calentadores

sábado, 22 de octubre de 2011

Control Térmico de Naves Espaciales: 7.Calentadores

The Goals of Spacecraft Thermal Control:

1. To maintain equipment temperature in specified ranges (usually room temperature) during all mission life.

2. To guarantee optimum performances when equipment is operating

3. To avoid damage when equipment is not operating

4. To keep the specified temperature stability for delicate electronics, or stable optical components.

5. To minimise temperature gradients as specified between units, or along structural elements.

6. To maintain boundary temperatures at interface between subsystems, to ease interface management

7. Guarantee the correct operation of thermal control subsystem by means of design, analysis and test

8. Determine the most influencing factors, and manage them within the satellite resources and Space environment constraints.

So, when developing spacecraft systems we need to:

1. Maintain the temperatures and minimise temperature gradients in structures to help keep alignment.

2. Minimise temperature fluctuations and thermal cycling of components to limit ageing.

3. Keep optical components in specified ranges to guarantee their relative position, their minimum deformation / index variation of optics and the proper detector temperature.
Example temperature ranges in flight:
Electronics equipment:
Classical electronics equipment [-10°C ; +40°C]
Telecommunication receptor [+10°C ; +40°C]
Travel wave tube [-10°C ; +70°C]
Battery [0°C ; +20°C]
Unified propulsion system [+10°C ; +50°C]
Solar array [-190°C ; +120°C]

Cryogenics: Earth observation IR Detectors in the range 50 to 100K, Down to 0.1K for bolometers for scientific missions.

High Temperatures: 400°C to 1600°C for thermal protection (shuttle tiles) 1200°C inside ovens for metallurgy in micro-gravity.

http://mechanical-engineering.esa.int/thermal/aboutthermal.html