Convert Cosmic Velocity - First (v₁) to Mach (20°C, 1 atm) (Ma (20°C)) 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.
Mach (20°C, 1 atm) (Ma (20°C))
At 20°C and 1 atmosphere, the speed of sound in air is about 343 m/s, making Mach 1 = 343 m/s under those conditions. Mach numbers classify aerodynamic regimes: Mach 0.3–0.8 (Subsonic), Mach 0.8–1.2 (Transonic), Mach 1–5 (Supersonic), Mach 5+ (Hypersonic). Temperature influences Mach speed significantly; colder air slows sound, while warmer air increases its speed. Aircraft design, jet engines, wind tunnels, aerospace testing, and atmospheric re-entry physics all rely heavily on Mach numbers referenced to standard conditions.