@prefix ns0: <http://gcmd.gsfc.nasa.gov/kms#> .
@prefix skos: <http://www.w3.org/2004/02/skos/core#> .

<https://gcmd.earthdata.nasa.gov/kms/concept/4a23392b-1472-4437-868a-eaf788b6b690>
  ns0:resource [ ] ;
  skos:definition """The Direct Measurement Explorer-A (DME-A) satellite was launched in November 1965 into a near-earth orbit ranging between altitudes of 500 and 3000 km to sample and measure charged particles. The attitude control system is used to keep the spin axis aligned with the orbit normal and to maintain the spin rate. Spin axis control is achieved by a chargeable permanent magnet system which is operated upon command and reacts with the earth's field to produce precession of several degrees per minute. With this system the spin axis was kept within 10 degrees of the orbit normal for several weeks at a time, although larger deviations have been tolerated. The spin rate was observed to decay at 0.05 rpm per day. Periodic use of the spin rate control system has compensated for spin decay. This system is analogous to a DC motor in which the entire satellite is the armature.


Group: Platform_Details
   Entry_ID: EXPLORER-31 (DME-A)
   Group: Platform_Identification
      Platform_Category: Solar/Space Observation Satellites
      Platform_Series_or_Entity: EXPLORER
      Short_Name: EXPLORER-31 (DME-A)
   End_Group
   Group: Synonymous_Platform_Names
      Short_Name: Explorer-A
      Short_Name: Explorer 31
      Short_Name: 01806
   End_Group
   Group: Platform_Associated_Instruments
      Short_Name: SPHERICAL MASS SPECTROMETER
      Short_Name: ELECTROSTATIC ANALYZERS
      Short_Name: ENERGETIC ELECTRON CURRENT MONITOR
      Short_Name: ELECTRON TEMPERATURE PROBE
      Short_Name: MAGNETIC ION-MASS SPECTROMETER
   End_Group
   Group: Orbit
      Orbit_Inclination: 79.80 degrees
      Period: 119.70 min
      Perigee: 505 km
      Apogee: 2833 km
   End_Group
   Creation_Date: 2007-12-14
   Online_Resource: http://stinet.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=AD0656730
   Sample_Image: http://www.daviddarling.info/images/DME.jpg
   Group: Platform_Logistics
      Launch_Date: 1965-11-29
      Launch_Site: Vandenberg Air Force Base, USA
      Primary_Sponsor: NASA
   End_Group
End_Group"""@en ;
  skos:prefLabel "EXPLORER-31 (DME-A)"@en ;
  skos:inScheme <https://gcmd.earthdata.nasa.gov/kms/concepts/concept_scheme/platforms> ;
  skos:broader <https://gcmd.earthdata.nasa.gov/kms/concept/182e52f4-6ce7-42e3-b50e-42a3725eeca3> ;
  a skos:Concept .

<https://gcmd.earthdata.nasa.gov/kms/concept/182e52f4-6ce7-42e3-b50e-42a3725eeca3>
  skos:prefLabel "EXPLORER"@en ;
  a skos:Concept ;
  skos:narrower <https://gcmd.earthdata.nasa.gov/kms/concept/4a23392b-1472-4437-868a-eaf788b6b690> .