Abstract

Reusable spacecraft experience extreme aerodynamic heating while re-entering Earth's atmosphere at hypersonic speeds. Temperatures exceeding 1,500–2,000°C can damage structural components if adequate thermal protection systems (TPS) are not employed. This research evaluates different TPS materials using computational fluid dynamics and thermal simulations to identify efficient solutions for future reusable launch vehicles.

Objectives
Evaluate aerodynamic heating during atmospheric re-entry.
Compare different thermal protection materials.
Analyze heat transfer through spacecraft structures.
Estimate thermal stresses under hypersonic conditions.
Improve reusable spacecraft safety.
Background

During atmospheric re-entry, kinetic energy is converted into thermal energy due to air compression and friction. Spacecraft surfaces experience intense heat flux that can compromise structural integrity.

Modern TPS systems include:

Reinforced Carbon-Carbon (RCC)
Ceramic Matrix Composites
Silica Tiles
Ablative Heat Shields
Ultra High Temperature Ceramics (UHTCs)

Selecting the proper material is essential for ensuring spacecraft survivability.

Methodology

A spacecraft nose cone and wing leading edge model were developed using CATIA and imported into ANSYS Fluent.

Simulation conditions:

Mach Number: 8–20
Altitude: 30–80 km
Air Temperature: Variable atmospheric profile
Heat Transfer: Conjugate Heat Transfer
Turbulence Model: k-ω SST

Material properties for RCC, silica tiles, and ceramic composites were incorporated into transient thermal simulations.

Results

The simulations showed:

RCC maintained the lowest structural temperatures.
Ceramic composites exhibited superior thermal stability.
Silica tiles provided excellent insulation but required careful maintenance.
Peak heat flux occurred near the nose cone stagnation region.
Thermal gradients were highest during initial atmospheric entry.
Findings
Reusable TPS significantly reduces mission costs.
Ceramic composites outperform conventional insulation materials.
Optimized TPS thickness reduces vehicle mass.
CFD accurately predicts aerodynamic heating distribution.
Conclusion

Advanced thermal protection systems remain one of the most critical technologies enabling reusable spacecraft. Combining CFD with thermal analysis allows engineers to optimize TPS materials while minimizing weight and improving mission reliability.