More on Long Round-Trip Times
Long signal propagation times
- Very long distances.
- The speed of light in a vacuum is fixed.
- So signal propagation delay is on the order of minutes or hours rather than milliseconds.
Intermittent connectivity – natural
- Planetary bodies block radio waves.
- Orbital motion and planetary rotation insert planetary bodies between communicating entities.
- So some loss of connectivity is inevitable.
- But orbital mechanics and knowledge of ephemerides make these losses predictable months or years in advance.