Satellites orbit the Earth at various altitudes, serving many purposes such as communication, navigation, and Earth observation. However, these orbits are not perfectly stable over time. One significant factor affecting satellite longevity and performance is orbital decay.

What is Orbital Decay?

Orbital decay refers to the gradual decrease in a satellite's altitude due to atmospheric drag and other perturbing forces. Even at high altitudes, residual atmospheric particles exert a small but continuous drag force, causing the satellite's orbit to slowly shrink.

Impact on Delta V Requirements

Delta V, or change in velocity, is a critical measure in space missions. When a satellite experiences orbital decay, it requires additional Delta V to maintain its desired orbit or to re-boost it to a higher altitude. The more decay that occurs, the greater the fuel and propulsion needed.

Factors Influencing Decay and Delta V Needs

  • Altitude: Lower orbits experience more atmospheric drag, increasing decay.
  • Solar activity: Increased solar radiation expands the atmosphere, intensifying drag.
  • Satellite design: Surface area and mass influence how quickly decay occurs.

Strategies to Mitigate Orbital Decay

Satellite operators use several methods to reduce the impact of orbital decay:

  • Periodic re-boost maneuvers to raise the orbit.
  • Designing satellites with minimal surface area exposed to drag.
  • Choosing higher orbits to naturally reduce atmospheric effects.

Understanding and planning for orbital decay is essential for mission success, as it directly influences fuel budgets, satellite lifespan, and operational costs.