Engineers are designing the thermal control system for a small research satellite…
PHYSICS · Multi-part · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
Engineers are designing the thermal control system for a small research satellite that will experience repeated transitions between full sunlight and Earth’s shadow every 90 minutes. Two types of panels must be selected:
• Sun-side insulation panels that limit the rate at which the interior heats during sunlight exposure.
• Shadow-side radiator panels that absorb excess interior energy during sunlight and then release it to space during shadow.
Candidate materials and their properties are listed below.
Material
Thermal Conductivity k (W m−1 K−1)
Specific Heat c (J kg−1 K−1)
Density ρ (kg m−3)
Aerogel
0.018
1000
120
Aluminum honeycomb
5.5
880
540
Carbon-fiber composite
9.0
710
1600
Bulk copper
390
385
8900
All panels must have the same surface area and nominal thickness of 1.0cm. Assume that other forms of heat transfer (radiation, convection) are handled separately and do not influence the ranking arguments requested here.
(a) Which listed material is most suitable for the sun-side insulation panels? Justify your choice using relevant thermal properties and explain why the other materials are less appropriate for this function.
(b) The radiator panels must (i) rapidly absorb interior thermal energy without undergoing a large temperature rise and (ii) conduct that energy efficiently to their exterior surface for emission. Identify the material that best satisfies both requirements and provide a reasoned argument that considers numerical property values as well as the satellite’s mass budget constraints.
(c) Suppose mission planners impose a strict upper limit on panel mass. Discuss how this constraint could alter the material choice made in part (b), and propose a plausible alternative material from the table if necessary. Support your proposal with quantitative or qualitative comparisons.