Cosmic Velocity - First to Earth's Velocity

The first cosmic velocity (escape velocity from Earth's surface to orbit) is approximately 7,900 m/s (7.9 km/s), the minimum speed needed to achieve Earth orbit.

v₁ = √(GM/r) where G is gravitational constant, M is Earth's mass, r is Earth's radius. Approximately 7.9 km/s.

To km/h: × 3,600. To mph: × 17,672. 7.9 km/s = 28,440 km/h = 17,672 mph.

Minimum speed for satellites, space station orbit, and low Earth orbit (LEO) calculations.

ISS orbits at ~7.66 km/s. Below this speed, you fall back to Earth. Above it, you stay in orbit (if horizontal).

Confusing with escape velocity (second cosmic velocity, 11.2 km/s) — orbital velocity is lower.

Remember: ~8 km/s for orbit, ~11 km/s to escape. v₁ is minimum for orbit, not escape.

Earth's orbital velocity around the Sun is approximately 29,765 m/s (29.8 km/s), the speed at which our planet travels through space.

v = 2πr/T where r is Earth's orbital radius (~150 million km) and T is one year. Result: ~29.8 km/s.

To km/h: × 3,600. To mph: × 66,600. 29.8 km/s = 107,280 km/h = 66,660 mph.

Interplanetary mission Δv calculations, understanding Earth's motion, and cosmic velocity references.

We're all traveling at ~30 km/s around the Sun right now. In one second, Earth moves 30 km — about 19 miles!

Forgetting about Earth's motion when calculating interplanetary trajectories — it provides free velocity!

~30 km/s around the Sun. We travel 940 million km per year at this speed. Missions to other planets add/subtract from this.