Convert Cosmic Velocity - First (v₁) to Millimeter/Hour (mm/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.
Millimeter/Hour (mm/h)
A millimeter per hour is extraordinarily slow, used in geology, meteorology, and materials science to measure phenomena like soil creep, tectonic plate micro-motion, or extremely light precipitation (drizzle). In manufacturing, mm/h may describe slow deposition rates in thin-film fabrication or high-precision milling processes. Despite seeming negligible, speeds measured in mm/h can accumulate into significant changes over weeks, months, or years—making them essential for long-term studies.