Convert Cosmic Velocity - First (v₁) to Cosmic Velocity - Third (v₃) instantly.
About these units
Cosmic Velocity - First (v₁)
The first cosmic velocity is the minimum horizontal speed an object must achieve to enter a stable orbit around a planetary body without additional propulsion. For Earth, this value is about 7.9 km/s. At this speed, an object's forward motion precisely balances with the gravitational pull downward, creating continuous free-fall—the essence of orbital motion. This velocity is foundational in orbital mechanics. Spacecraft reaching Low Earth Orbit (LEO) must achieve at least this horizontal speed, even if their vertical ascent profile varies. Understanding v₁ was essential in the early space age: it represented the threshold between atmospheric flight and true spaceflight, marking human entry into the orbital era.
Cosmic Velocity - Third (v₃)
The third cosmic velocity is the speed required to escape the entire Solar System from Earth's orbit, overcoming the gravitational pull of the Sun. This speed is approximately 16.7 km/s, though missions often achieve this gradually using gravitational assists rather than brute-force acceleration. Space probes such as Voyager 1, Voyager 2, and New Horizons have exceeded v₃, making them interstellar travelers. The third cosmic velocity represents the threshold where an object ceases to be bound to the Sun and begins drifting through the galaxy—one of the most profound expansions of human technological capability.