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- [Source: National Space Science Data Center, http://nssdc.gsfc.nasa.gov/nmc/experimentDisplay.do?id=1979-050A-07 ]
The SSD was a limb-scanning ultraviolet spectrometer which measured dayglow emissions from O and N2. The wavelengths of primary interest were at 1356 and 3371 A. Energetic photoelectrons were provided by photoionization of neutral molecules by solar EUV radiation. As these fast photoelectrons lost energy through collisions with neutrals, those with energies near 16 eV excited O and N2 to electronic states of energy higher than the ground states. The subsequent decay to the ground state produced emissions monitored by the SSD. The SSD measured light emitted by molecular nitrogen excitation in the LBH and 2D position bands, and atomic oxygen in the 1356 and 1304 lines. The instrument also had the capability of providing spectral scans from 850 to 1200, from 1100 to 1600, and from 2900 to 3950 A at 4, 6, and 12 A resolution, respectively. Light monitored with narrow collimators that provided a field-of-view of 0.1 deg x 4 deg. The SSD was mechanically driven to scan vertically through the earth's limb from 80 to 480 km. It provided approximately 50 sets of density profiles on the daylight portion of each orbit.
Group: Instrument_Details
Entry_ID: SSD
Group: Instrument_Identification
Instrument_Category: Solar/Space Observing Instruments
Instrument_Class: Ultraviolet Instruments
Short_Name: SSD
Long_Name: Atmospheric Density Sensor
End_Group
Group: Associated_Platforms
Short_Name: DMSP 5D-1/F4
End_Group
Online_Resource: http://nssdc.gsfc.nasa.gov/nmc/experimentDisplay.do?id=1979-050A-07
Creation_Date: 2008-09-25
Group: Instrument_Logistics
Instrument_Owner: Department of Defense-Department of the Air Force (United States)
End_Group
End_Group
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