@prefix skos: . skos:definition """The Echo 2 spacecraft was a 41-m balloon of aluminum foil-mylar laminate. Echo 2 was designed as a rigidized passive communications spacecraft for testing propagation, tracking, and communication techniques. Instrumentation included a beacon telemetry system that provided a tracking signal, monitored spacecraft skin temperature between -120 deg C and +16 deg C, and measured the internal pressure of the spacecraft between 5E-5 mm of mercury and 0.5 mm of mercury, especially during the initial inflation stages. This system, which consisted of two beacon assemblies, used solar cell panels for power and had a minimum power output of 45 mW at 136.17 MHz and 136.02 MHz. In addition to fulfilling its communications mission, the spacecraft was used for global geometric geodesy. The spacecraft re-entered the atmosphere on June 7, 1969. [Summary provided by NASA.] Group: Platform_Details Entry_ID: ECHO-2 Group: Platform_Identification Platform_Category: Earth Observation Satellites Platform_Series_or_Entity: ECHO Short_Name: ECHO-2 End_Group Group: Orbit Orbit_Inclination: 81.5 degrees Perigee: 1029 km Apogee: 1316 km Orbit_Type: LEO > Low Earth Orbit > Polar Sun-Synchronous End_Group Creation_Date: 2008-10-24 Online_Resource: http://msl.jpl.nasa.gov/QuickLooks/echoQL.html Group: Platform_Logistics Launch_Date: 1964-01-25 Launch_Site: Vandenberg Air Force Base, USA Primary_Sponsor: NASA End_Group End_Group"""@en ; skos:prefLabel "ECHO-2"@en ; skos:inScheme ; skos:broader ; a skos:Concept . skos:prefLabel "ECHO"@en ; a skos:Concept ; skos:narrower .