Missions
Earth Orbits and Lagrange Points: Where Missions Go
Compare low Earth, geostationary, and polar orbits, then understand why some observatories operate around L1 or L2.
Prepared with AI assistance using the primary sources linked below. How Astroboat works
Orbit is motion under gravity
An orbiting spacecraft continually falls under gravity while moving sideways fast enough to follow a curved path around a body. It has not escaped gravity simply because astronauts float inside. Its trajectory depends on both position and velocity.
Low Earth orbit brings a satellite relatively near the surface, useful for crewed flight and many observing missions. Polar orbits pass near the poles and can build coverage as Earth turns beneath them. Mission goals determine which geometry is useful.
Geostationary has a specific meaning
A geostationary satellite follows a circular orbit above the equator with Earth's sidereal rotation period, appearing fixed over one longitude. This is useful for communications and continuous regional weather views. Not every high orbit or geosynchronous orbit is geostationary.
An orbit's altitude alone does not describe the whole path. Inclination, shape, and period also matter. A launch may initially place a payload into a transfer orbit rather than its final working orbit.
Lagrange points move with the system
In a system such as the Sun and Earth, five Lagrange points describe special locations in a frame rotating with those bodies. Spacecraft near L1 can monitor the Sun; the L2 region is useful for observatories that need controlled lighting and thermal conditions.
Spacecraft commonly follow paths around these regions rather than sitting motionless at a point. L1 and L2 missions need orbit corrections. When a mission appears in Astroboat's Briefs, checking its destination orbit often explains its design more clearly than the launch vehicle name does.