Convert Cosmic Velocity - First (v₁) to Cosmic Velocity - Second (v₂) 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 - Second (v₂)
The second cosmic velocity is the escape velocity, the speed required to completely overcome a planet's gravitational attraction without further propulsion. For Earth, this speed is about 11.2 km/s. It is higher than v₁ because escaping gravity requires exceeding orbital balance entirely, not merely achieving stable free fall. Escape velocity underlies missions to the Moon, other planets, and deep space probes. Reaching v₂ allows spacecraft to travel along trajectories that leave Earth's gravitational well permanently unless acted on by external forces. This value symbolizes humanity's ability to break free from its home world—a critical milestone in exploration.