Typical lifetime of a geostationary communications satellite What is a representative design lifetime for a modern geostationary communications satellite bus (from launch to end-of-life), considering fuel for station-keeping and expected component degradation?

Introduction / Context:
Satellite lifetime planning trades off launch mass, propellant for station-keeping, power subsystem margins, and radiation effects to ensure reliable service over the intended mission duration.

Given Data / Assumptions:

• Traditional GEO comsats historically designed for ~10–15 years.
• Fuel usage for north-south and east-west station-keeping is a limiting factor.
• Solar array and battery degradation also limit usable lifetime.

Concept / Approach:
Classical textbook and exam figures often cite 10 years as the nominal design life, with many modern platforms achieving 12–15+ years. For standardized MCQ context, 10 years is the canonical choice.

Step-by-Step Solution:
Identify major life limiters: propellant, solar array degradation, battery cycle life.Select the typical value used in foundational questions: ~10 years.Note that actual missions may exceed nominal life depending on fuel margins.

Verification / Alternative check:
Many legacy GEO platforms exceeded 10 years, but exam conventions commonly use the 10-year benchmark.

Why Other Options Are Wrong:
5 years is short for GEO comsats; 20 or 50 years exceed typical propellant and component limits for conventional buses.

Common Pitfalls:
Confusing modern extended-life buses with standard textbook values used for concept checks.

Final Answer:
10 years