PDS_VERSION_ID = PDS3
RECORD_TYPE = STREAM
LABEL_REVISION_NOTE               = "
          2014-12-27 JUNO: Janssen    Revision 1"

OBJECT                            = INSTRUMENT
  INSTRUMENT_ID                   = "MWR"
  INSTRUMENT_HOST_ID = JNO

  OBJECT                          = INSTRUMENT_INFORMATION
    INSTRUMENT_NAME               = "MWR"
    INSTRUMENT_TYPE               = "RADIOMETER"
    INSTRUMENT_DESC          = "


  Instrument Host Overview
  =========================

The Microwave Radiometer (MWR) is one of a suite of instruments on Juno.
The Juno mission has the overall goal of answering the outstanding questions
outstanding about Jupiter's structure and origin. Specifically, the MWR was
designed to characterize Jupiter's atmosphere as following:

   -  Determine the global O/H ratio (water abundance) in Jupiter's
      atmosphere
   -  Measure latitudinal variations in Jupiter's deep atmosphere
      (composition, temperature, cloud opacity, and dynamics)
   -  Measure the microwave brightness temperatures of Jupiter over all
      latitudes at wavelengths that fully sample the atmospheric thermal
      emission at all altitude levels from the ammonia cloud-forming
      region to below the water cloud-forming region

To achieve this the MWR experiment uses a microwave sounding approach describe
in Janssen et al., 2005. The MWR instrument measures the atmospheric thermal
emission at six frequencies. Thermal emission from an atmosphere arises becaus
of the presence of absorbing constituents in the atmosphere, and the measured
emission contains information on both the concentration and temperature of the
constituents. The information content changes with frequency, and the determin
of the spectrum of atmospheric thermal emission can be used to infer key param
of both the temperature and compositional structure of the atmosphere. Water a
ammonia are the only significant sources of microwave opacity in Jupiter's atm
sphere, so their concentrations are the unique target of any microwave soundin
approach.

The MWR instrument comprises what are essentially six independent radiometers,
of which measures the microwave emission viewed through its own independent an
The six antennas are distributed around the spacecraft body and view in a dire
perpendicular to the spin axis of the spacecraft.  Since the spin axis of the
spacecraft is oriented approximately perpendicular to the orbit plane, the bea
each antenna sweeps through a great circle on the sky that passes along the su
spacecraft track on Jupiter and through the nadir direction.  Each point along
track is thus observed numerous times, at different emission angles, as the sp
spins and moves along its orbit.  The accumulated data at each such point and 
dependence on emission angle an frequency is then analyzed to obtain vertical 
spheric composition and structure using a radiative transfer model.

Each receiver makes contiguous radiometric measurements, or integrations, of f
100-ms duration. In a typical sequence of such integrations an internal switch
cycled from the antenna input to periodically view an internal load, and three
independent internal reference noise sources are periodically switched on and 
for calibration. The cycle for such switching is synchronous for all receivers
set by selecting from a table contained in the flight software. The table may 
changed by an uplink command. The choice of specific sequences depends on inst
performance and optimization of the calibration algorithm.

For the key observations to be made in the four-hour window around Jupiter per
the MWR is desiged to downlink all contiguous 100-ms observations. Outside thi
window, however, not all of this data is essential and in most cases the resul
data would quickly fill the MWR's partition on the spacecraft. To avoid this, 
command is sent to downlink only a fraction of the data obtained. The instrume
organizes its data stream into time-contiguous units of ten 100-ms observation
thus corresponding to one second's worth of observation. Successive units may 
contiguous in time (full data rate) or separated by n seconds each (reduced da
rate). A different on-board switching sequence is typically commanded in order
optimize the calibration for reduced sampling rates.

Documents that describe the major components of the MWR instrument and its ope
will be found in the DOCUMENTS folder and include:
   1. The MWR volume SIS
   2. The MWR instrument paper (Janssen et al., 2015, not yet available)
   3. The MWR Operations Guide (not yet available)
   4. The MWR Instrument Users Guide
   5. The MWR Flight Software Users Guide
   6. The MWR Algorithm and Theoretical Basis Document and Error Analysis

The canonical paper that describes the design, operation, calibration, and ana
of the MWR data to achieve the scientific objectives of the MWR experiment wil
found in Janssen et al., 2015."


END_OBJECT                        = INSTRUMENT_INFORMATION

  OBJECT                          = INSTRUMENT_REFERENCE_INFO
    REFERENCE_KEY_ID              = "JANSSENETAL2005"
  END_OBJECT                      = INSTRUMENT_REFERENCE_INFO


END_OBJECT                        = INSTRUMENT
END