|Mission type||Earth science|
|Manufacturer||Applied Physics Laboratory|
|Launch mass||469 kg (1,034 lb)|
|Start of mission|
|Launch date||January 11, 1968, 16:16:10UTC|
|Launch site||Vandenberg SLC-2E|
|Perigee altitude||1,082 kilometers (672 mi)|
|Apogee altitude||1,570 kilometers (980 mi)|
|Epoch||11 January 1968|
Explorer 36 (also called GEOS 2 or GEOS B, acronym to Geodetic Earth Orbiting Satellite) was a U.S. satellite launched as part of the Explorers program, being the second of the two satellites GEOS. Explorer 36 was launched on January 11, 1968 from Vandenberg Air Force Base, with Delta rocket.
Non-geodetic systems included a laser detector and a Minitrack interferometer beacon. The objectives of the spacecraft were to optimize optical station visibility periods and to provide complementary data for inclination-dependent terms established by the Explorer 29 (GEOS 1) gravimetric studies. The spacecraft was placed into a retrograde orbit to accomplish these objectives. Operational problems occurred in the main power system, optical beacon flash system, and the spacecraft clock, and adjustments in scheduling resulted in nominal operations.