Reflection Coefficient

Author: Tianjiang Says

Website: https://cislunarspace.cn

Definition

The reflection coefficient (CRC_R) is a dimensionless parameter describing the reflection characteristics of a spacecraft surface to sunlight, also known as the light pressure coefficient. Its value range is:

  • CR=1C_R = 1: completely diffuse reflection (Lambertian reflection)
  • CR=2C_R = 2: completely specular reflection
  • 1<CR<21 < C_R < 2: partial specular reflection

Role in Solar Radiation Pressure Calculation

The reflection coefficient is a key parameter in the SRP acceleration formula:

aSRP=kCRS0cAm(R0R)2n^a_{SRP} = k C_R \frac{S_0}{c} \frac{A}{m} \left(\frac{R_0}{R}\right)^2 \hat{n}

CRC_R directly determines the magnitude of solar radiation pressure on the spacecraft. For spacecraft in DRO orbits, far from Earth's atmosphere and magnetic field, solar radiation pressure is the primary environmental perturbation, making accurate determination of CRC_R essential for orbit prediction.

Typical Values

Spacecraft TypeTypical CRC_R Value
Large solar panelsClose to 2
High-reflectivity satellites1.5 ~ 1.8
Dark-surface satellites1.0 ~ 1.3

References

  • Chen Yuju. DRO Orbit Design and Control Research for Cislunar Space Situation Awareness[D]. 2024.