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Instrument: SEM/SSB/X-2
Instrument details
Acronym
SEM/SSB/X-2
Full name
SEM / Special Sensor Gamma/X-ray Detector
Purpose
Location and spectrometry of gamma and X rays from the Earth's atmosphere
Short description
Array-based spectrometer which detects the location, intensity and spectrum of X-rays in the range 3-60 keV and gamma-rays in the range 1.2-10 MeV, emitted from the Earth's atmosphere
Background
Part of the Space Environment Monitor (SEM) package. SEM/SSB/X-2 is the latest version of several SSB sensors flown on previous DMSP satellites
Scanning Technique
Earth's viewing under four angles, from a sunsynchronous orbit
Resolution
N/A (integration over the field of view)
Coverage / Cycle
Full ionosphere in 100 min (orbital period) with sampling at 1 s intervals
Mass
Power
Data Rate
Providing Agency
DoD
Instrument Maturity
Flown on operational programme
Utilization Period:
1976 to 1978-03-19
Last update:
2017-05-21
Detailed characteristics
Satellites this instrument is flying on
Note: a red tag indicates satellites no longer operational, a
green tag indicates operational satellites, a blue tag indicates
future satellites
Instrument classification
Solar and space environment monitors Space radiometer or spectrometer
WIGOS Subcomponents
No WIGOS subcomponents have been defined.
Mission objectives
Primary mission objectives Gamma-ray flux spectrum X-ray flux spectrum
Secondary mission objectives Show all Show fewer
Tentative Evaluation of Measurements
The following list indicates which measurements can typically be
retrieved from this category of instrument. To see a full Gap Analysis by Variable,
click on the respective variable.
Note: table can be sorted by clicking on the column headers
Variable Relevance for measuring this variable Operational limitations Explanation
Gamma-ray flux spectrum 1 - primary No specific limitation. Interplanetary space viewing including the Earth's limb, extending into the X-ray field
X-ray flux spectrum 1 - primary No specific limitation. Interplanetary space viewing, high spectral resolution, extending into the gamma-ray field
Aurora 5 - marginal No specific limitation. Aurora imaged in X-ray observing the Earth's limb