LAGEOS 1&2
Full Name: LAGEOS
Phase: Operating
Launch Date: May 04, 1976
Mission Project Home Page: http://ilrs.gsfc.nasa.gov/satellite_missions/list_of_satellites/lag1_general.html
LAGEOS, or Laser Geodynamics Satellites, are a series of satellites designed to provide an orbiting benchmark for geodynamical studies of the Earth.
The LAGEOS satellites are able to determine positions of points on the Earth with extremely high accuracy due to the stability of their orbits.
The high mass-to-area ratio and the precise, stable (attitude-independent) geometry of the LAGEOS spacecrafts, together with the extremely regular orbits, make these satellites the most precise position references available.
The LAGEOS mission consists of the following key goals:
Provide an accurate measurement of the satellite's position with respect to Earth,
- Determine the planet's shape (geoid) and,
- Determine tectonic plate movements associated with continental drift.
- The spacecraft are aluminum spheres covered with reflecting surfaces, which have the appearance of giant golf balls.
Measurements are made by transmitting pulsed laser beams from Earth ground stations to the satellites. The laser beams then return to Earth after hitting the reflecting surfaces; the travel times are precisely measured, permitting ground stations in different parts of the Earth to measure their separations to better than one inch in thousands of miles.