@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/e8a927c5-e5a8-43c8-91d4-2ca3785ef019>
  ns0:altLabel [ ] ;
  skos:definition """[Source: NASA/JPL, ftp://podaac.jpl.nasa.gov/pub/grace/doc/ProdSpecDoc_v4.5.pdf ]

The GRACE Thruster Activation System is part of the Cold Gas System.
The GRACE Cold Gas System uses Nitrogen as medium, which is stored
in two tanks at an initial pressure of 350 bar. This upstream pressure
is reduced to the thruster valve working pressure of approximately 1.5
bar by a Pressure  Regulator. For redundancy reasons, the two branches
can be operated individually. Attitude control around the roll, pitch
and yaw axis is performed by 3 sets of 4 thrusters with a nominal thrust
force of 10 mN. The attitude control thrusters are nominally operated
in pairs which are accommodated such, that force free reaction control
is achieved. For orbit maintenance, two 40 mN thrusters are mounted on
the anti-flight direction side with the force vector pointing through
the satellite center of gravity. The cold gas system housekeeping sensor
set consists of two Pressure Transducers, one for the high pressure part
and one for the low pressure part, and temperature sensors on both tanks
and every thruster.

[Summary from GRACE Thruster Specification Document]


Group: Instrument_Details
   Entry_ID: THR
   Group: Instrument_Identification
      Instrument_Category: Earth Remote Sensing Instruments
      Instrument_Class: Passive Remote Sensing
      Instrument_Type: Positioning/Navigation
      Short_Name: THR
      Long_Name: THRuster activation system
   End_Group
   Group: Instrument_Associated_Sensors
      Short_Name: TEMPERATURE SENSORS
      Short_Name: PRESSURE TRANSDUCERS
      Short_Name: TNK
   End_Group
   Group: Associated_Platforms
      Short_Name: GRACE
   End_Group
   Online_Resource: ftp://podaac.jpl.nasa.gov/pub/grace/doc/ProdSpecDoc_v4.5.pdf
   Creation_Date: 2007-05-02
   Group: Instrument_Logistics
      Instrument_Owner: USA/NASA
   End_Group
End_Group"""@en ;
  skos:prefLabel "THR"@en ;
  skos:inScheme <https://gcmd.earthdata.nasa.gov/kms/concepts/concept_scheme/instruments> ;
  skos:broader <https://gcmd.earthdata.nasa.gov/kms/concept/596a5700-b3fd-4261-b8f8-a054d052e3fe> ;
  a skos:Concept .

<https://gcmd.earthdata.nasa.gov/kms/concept/596a5700-b3fd-4261-b8f8-a054d052e3fe>
  skos:prefLabel "Positioning/Navigation"@en ;
  a skos:Concept ;
  skos:narrower <https://gcmd.earthdata.nasa.gov/kms/concept/e8a927c5-e5a8-43c8-91d4-2ca3785ef019> .