@prefix skos: . @prefix ns0: . skos:prefLabel "LAGEOS (Laser Geodetic Satellite)"@en ; a skos:Concept ; skos:narrower . ns0:resource [ ] ; ns0:altLabel [ ] ; skos:definition """The LAGEOS satellites are passive vehicles covered with retroreflectors designed to reflect laser beams transmitted from ground stations. By measuring the time between transmission of the beam and reception of the reflected signal from the satellite, stations can precisely measure the distance between themselves and the satellite. These distances can be used to calculate station positions to within 1-3 cm. Long term data sets can be used to monitor the motion of the Earth's tectonic plates, measure the Earth's gravitational field, measure the "wobble" in the Earth's axis of rotation, and better determine the length of an Earth day. LAGEOS 2 was a joint program between NASA and the Italian space agency (ASI), which built the satellite using LAGEOS 1 drawings and specifications, handling fixtures, and other materials provided by NASA. LAGEOS 2's orbit was selected to provide more coverage of seismically active areas, such as the Mediterranean Basin and California, and may help scientists understand irregularities noted in the motion of LAGEOS 1. Ground tracking stations are located in many countries (including the US, Mexico, France, Germany, Poland, Australia, Egypt, China, Peru, Italy, and Japan) and data from these stations is available world-wide to investigators studying crustal dynamics. LAGEOS 1 also contains a message plaque addressed to human and other beings of the far distant future with maps of the Earth from 3 different eras - 268 million years in the past, present day, and 8 million years in the future (the satellite's estimated decay date). Spacecraft: Both satellites are spherical bodies with an aluminum shell wrapped around a brass core. The design was a compromise between numerous factors including the need to be as heavy as possible to minimise the effects of non-gravitational forces vs. being light enough to be placed in a high orbit and the need to accommodate as many retroreflectors as possible vs. the need to minimise surface area to minimise the effects of solar pressure. The materials were chosen to reduce the effects of the Earth's magnetic field on the satellite's orbit.426 cube-corner retroreflectors are imbedded in the satellites' surface.422 of these are made of fused silica glass while the other 4 are made of germanium. The vehicles have no onboard sensors or electronics, and are not attitude controlled. Payload: Science is performed by reflecting laser light from the vehicle's 426 retroreflectors. Additional characteristics: -50 years design life -0.6m total length -0.6m maximum diameter -405 kg total mass Additional information available at "http://www.astronautix.com/craft/lageos.htm" [Summary provided by SpaceBank.com] Group: Platform_Details Entry_ID: LAGEOS-2 Group: Platform_Identification Platform_Category: Earth Observation Satellites Platform_Series_or_Entity: LAGEOS (Laser Geodetic Satellite) Short_Name: LAGEOS-2 Long_Name: Laser Geodetic Satellite-2 End_Group Group: Synonymous_Platform_Names Short_Name: LAGEOS-2 End_Group Group: Platform_Associated_Instruments Short_Name: LASER TRACKING REFLECTOR End_Group Group: Orbit Orbit_Inclination: 52.70 deg Period: 222.50 min Perigee: 5,616 km Apogee: 5,952 km End_Group Creation_Date: 2007-10-10 Online_Resource: http://www.astronautix.com/craft/lageos.htm Online_Resource: http://ilrs.gsfc.nasa.gov/satellite_missions/list_of_satellites/lag1_general.html Online_Resource: http://nasascience.nasa.gov/missions/lageos-1-2 Sample_Image: http://msl.jpl.nasa.gov/QuickLooks/pictures/lageos.gif Group: Platform_Logistics Launch_Date: 1992-10-22 Launch_Site: Cape Canaveral/Kennedy Space Center, USA Design_Life: 50 year Primary_Sponsor: USA/NASA End_Group End_Group"""@en ; skos:prefLabel "LAGEOS-2"@en ; skos:inScheme ; skos:broader ; a skos:Concept .