326,400 km out: the Earth-Moon L1 point
Published
Earth-Moon L1 is 326,400 km from Earth’s centre, 84.9 % of the way to the Moon[1]. It is the point on the line between them where the two bodies’ pulls balance[2].
What a Lagrange point is
A Lagrange point is a place where the pulls of two bodies orbiting each other combine to produce a balance[2]. L1 is the one that lies on the line between them, here between Earth and the Moon.
With the Moon on average 384,400 km from Earth[3], L1 is about 58,000 km short of the Moon’s centre.
In game: the gateway
In Hostile Flagship, L1 is the one door between the Moon and Earth.
- Where: 326,400 km from Earth’s centre, on the line to the Moon, as in the real sky[1].
- Links: L1 connects to all three geostationary points and to the Moon’s east and west points. Every geostationary point’s “up” is L1.
- The far side: there is no link from the Moon’s far side to L1, because the Moon is in the way and nothing jumps through a body. You go round to the east or west point first.
- No shortcut down: a direct L1 to low-orbit link was tried and dropped. The way to Earth is step by step: far side → east or west → L1 → geostationary → low orbit.
- The view: from L1, Earth is a small, fully lit disc about 2.3° across.
In game, L1 to the Moon’s east or west point is about 59,200 km, and L1 to geostationary 100° E is about 288,000 km: about 3 hours at 1 g, and about 1,160 m³ of the carrier’s fuel. See Jump drives and fuel and the rocket equation.
Related
- 384,400 km apart: the Earth and the Moon at true scale
- Why fuel is mass: the rocket equation, explained
- 36 tanks to Pluto: jump fuel from the rocket equation
Sources
- Lagrange point, Wikipedia.
E.g. for the Moon, L1 is 326400 km from Earth's center, which is 84.9% of the Earth–Moon distance or 15.1%
- Lagrange point, Wikipedia.
It is the point where the gravitational attraction of M2 and that of M1 combine to produce an equilibrium.
- Moon Fact Sheet, NASA Space Science Data Coordinated Archive.
Semimajor axis (10^6 km) 0.3844