Convert Orbital Speed (ISS) to Speed of Light
Convert Orbital Speed (ISS) (v_orb) to Speed of Light (c) instantly and accurately.
Conversion Formula
c = v_orb × 2.555100969e-5
About Orbital Speed (ISS)
The ISS orbits at ~408 km altitude at ≈7,660 m/s (27,576 km/h) - the practical LEO benchmark. At this speed it completes one orbit in 92.68 min (15.5 orbits per day), giving astronauts 16 sunrises and sunsets every 24 hours. Delta-v to reach LEO from Earth's surface is ~9,400 m/s (with gravity and drag losses). GEO at 35,786 km requires only ~3,075 m/s per Kepler's third law. 1 ISS speed ≈ 7,660 m/s.
About Speed of Light
The speed of light in vacuum (c) = exactly 299,792,458 m/s - the defined SI constant from which the metre is derived (since 1983) and the universal speed limit of causality. Light from the Sun reaches Earth in 8 min 20 s; from the Moon in 1.28 s; from Proxima Centauri in 4.24 years. Mars communication delay 3-22 minutes. In optical fibre (n ≈ 1.467), c/n ≈ 200,000 km/s. GPS clocks must correct for both special and general relativistic effects. c = 299,792,458 m/s.
Quick Reference Table
| Orbital Speed (ISS) (v_orb) | Speed of Light (c) |
|---|---|
| 1 v_orb | 2.555 × 10-5 c |
| 2 v_orb | 5.11 × 10-5 c |
| 5 v_orb | 0.000127755 c |
| 10 v_orb | 0.00025551 c |
| 25 v_orb | 0.000638775 c |
| 50 v_orb | 0.00127755 c |
| 100 v_orb | 0.0025551 c |