Convert Cosmic Velocity - First (v₁) to Mile/Hour (mi/h) 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.
Mile/Hour (mi/h)
The mile per hour represents the number of miles traveled in one hour and is commonly used in the United States, the UK (in road contexts), and several other countries with legacy imperial systems. mph is deeply woven into cultural habits: driver training, speed limits, vehicular performance, and even athletic achievements are often expressed in miles per hour. In science and engineering, however, mph is rarely used because the mile and hour are not SI units. Still, mph retains strong emotional and historical associations—for example, the significance of a car "breaking 200 mph" or the legendary "88 mph" in popular culture. It persists because measurement units often survive long after their historical origins fade.