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

<https://gcmd.earthdata.nasa.gov/kms/concept/3466eed1-2fbb-49bf-ab0b-dc08731d502b>
  skos:prefLabel "Earth Observation Satellites"@en ;
  a skos:Concept ;
  skos:narrower <https://gcmd.earthdata.nasa.gov/kms/concept/976e92c4-150c-4068-bed5-60d5f030d7e2> .

<https://gcmd.earthdata.nasa.gov/kms/concept/976e92c4-150c-4068-bed5-60d5f030d7e2>
  ns0:resource [ ] ;
  ns0:altLabel [ ] ;
  skos:definition """GFZ-1 (GeoForschungsZentrum-1) is a geodetic satellite designed to improve the
current knowledge of the Earth's gravity field. The satellite, a passive system
with no onboard sensors or electronics, is covered with retroreflectors that
reflect laser beams sent from ground stations. By measuring the round trip time
of the transmitted light, the distance between the satellite and the station
can be determined with approximately 1 centimeter. These measurements are used
to determine variations in the rotational characteristics of the Earth and for
measurement of the Earth's gravitational field. As the vehicle's orbit decays,
the satellite's orbital motion will also be used calculate to atmospheric
densities. Deployed from the Mir space station, GFZ-1 was the first non-Russian
satellite launched from MIR. GFZ-1 was developed in under 12 months and cost
approximately &#36700,000 (including design, fabrication, test, and launch).
Data collection, distribution and evaluation is coor dinated by the project's
scientists at the GeoForschungsZentrum Potsdam.

Spacecraft The satellite consists of a spherical body made from brass with 60
corner cube reflectors distributed regularly over the satellite's surface.
These retroreflectors are quartz prisms placed in special holders that are
recessed in the satellite's body. External metallic surfaces are covered with
white paint for thermal control purposes and to facilitate visual observation
in space. The vehicle's size was limited by the maximum allowable dimensions of
the Mir airlock (30 cm). The vehicle carries no electronics or sensors and is
not attitude controlled.

[Source: NASA Mission and Spacecraft Library]


Group: Platform_Details
   Entry_ID: GFZ-1
   Group: Platform_Identification
      Platform_Category: Earth Observation Satellites
      Short_Name: GFZ-1
      Long_Name: GeoForschungsZentrum-1
   End_Group
   Group: Synonymous_Platform_Names
      Short_Name: GFZ-1
   End_Group
   Group: Platform_Associated_Instruments
      Short_Name: SLR
   End_Group
   Group: Orbit
      Orbit_Altitude: 400 km
   End_Group
   Creation_Date: 2007-11-19
   Online_Resource: http://www.gfz-potsdam.de/pb1/op/gfz1/index_GFZ1.html
   Sample_Image: http://www.gfz-potsdam.de/pb1/op/gfz1/GFZ1_1.small.gif
   Group: Platform_Logistics
      Launch_Date: 1995-04-09
      Launch_Site: 1999-06-23
      Design_Life: 3.5-5 years
      Primary_Sponsor: GeoForschungsZentrum Potsdam
   End_Group
End_Group"""@en ;
  skos:prefLabel "GFZ-1"@en ;
  skos:inScheme <https://gcmd.earthdata.nasa.gov/kms/concepts/concept_scheme/platforms> ;
  skos:broader <https://gcmd.earthdata.nasa.gov/kms/concept/3466eed1-2fbb-49bf-ab0b-dc08731d502b> ;
  a skos:Concept .