LAGEOS
mission including two satellites that uses retroreflection of lasers to establish time-of-flight measurements of plate movement on Earth
LAGEOS (), Laser Geodynamics Satellite or Laser Geometric Environmental Observation Survey, are a series of two scientific research satellites designed to provide an orbiting laser ranging benchmark for geodynamical studies of the Earth. Each satellite is a high-density passive laser reflector in a very stable medium Earth orbit (MEO).
Function and operation
The spacecraft are aluminum-covered brass spheres with diameters of 60 centimetres (24 in) and masses of 400 and 411 kilograms (882 and 906 pounds), covered with 426 cube-corner retroreflectors, giving them the appearance of disco balls. Of these retroreflectors, 422 are made from fused silica glass while the remaining 4 are made from germanium to obtain measurements in the infrared for experimental studies of reflectivity and satellite orientation. They have no on-board sensors or electronics, and are not attitude-controlled.
They orbit at an altitude of 5,900 kilometres (3,700 mi), well above low Earth orbit and well below geostationary orbit, at orbital inclinations of 109.8 and 52.6 degrees.
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.
The LAGEOS satellites make it possible 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 spacecraft, together with their extremely regular orbits, make these satellites the most precise position references available.
“LAGEOS” enters the record as mission including two satellites that uses retroreflection of lasers to establish time-of-flight measurements of plate movement on Earth. Crown Archives preserves that source wording while asking what LAGEOS, mission and including can confirm, complicate or overturn.
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“LAGEOS” is worth following because a concise public description often conceals a longer documentary argument. Here, LAGEOS, mission and including provides the most credible route into that argument.
The record creator and administrative purpose are central evidence, because official documentation reflects both action and institutional priorities. The source revision retrieved here is dated Aug 22, 2026. The linked authority identifier is Q1797842. 1 of 3 selected statements include explicit references; 3 carry qualifiers and 0 use preferred rank.
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This entry incorporates text from “LAGEOS” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.