PDS_VERSION_ID                = PDS3
RECORD_TYPE                   = STREAM

OBJECT                        = INSTRUMENT
INSTRUMENT_HOST_ID            = LP
INSTRUMENT_ID                 = MAGER

OBJECT                        = INSTRUMENT_INFORMATION
INSTRUMENT_NAME               = "MAGNETOMETER - ELECTRON REFLECTOMETER"
INSTRUMENT_TYPE               = {"MAGNETOMETER",
                                 "ELECTRON REFLECTOMETER"}
INSTRUMENT_DESC               = "

Instrument Overview
===================

The Lunar Prospector Magnetometer and Electron Reflectometer (MAGER)
instruments are based on the instruments flown on the Mars Global
Surveyor spacecraft [ACUNAETAL1992].  Some changes were made to the
Lunar Prospector versions to account for the spinning spacecraft.
Also, there is only one magnetometer sensor on Lunar Prospector.  The
instrumentation consists of a 3-axis fluxgate magnetometer, a
symmetric hemispherical electrostatic analyzer, and their common
electronics box.  The magnetometer (MAG) sensor is a wide-range (up to
+/- 65,536 nT), low noise (6 pT RMS), high sensitivity (as low as +/-
2 pT), triaxial fluxgate magnetometer.  The MAG sensor is an 11 x 6.5
x 9 cm box.  The electron reflectometer (ER) has a 360 degree
disk-shaped field-of-view.  The electrostatic optics select energy and
focus the particles onto an imaging detector.  The ER sensor is a 12
cm diameter cylinder, 9 cm high.

The combined mass of the Magnetometer and Electron Reflectometer is
about 5 kg, and the two instruments use about 4.5 w of power.
 
Science Objectives
==================

The MAG/ER experiment will investigate the origin and nature of lunar
crustal magnetic fields and constrain the size of a metallic core.
The experiment will also provide global maps of the lunar crustal
magnetic fields and provide estimates of the lunar induced magnetic
dipole moment [BINDERETAL1998].
 
Platform Mounting Descriptions
==============================

The MAG sensor is mounted at the end of the MAG/ER boom about 2.6 m
away from the spacecraft bus.  The ER and electronics box are mounted
at the ends of a small cross bar, about 1 m inboard from the MAG.  The
ER unit is mounted so that its field-of-view includes the spin axis
and is perpendicular to the boom.  The only blockage of the ER
field-of-view is the boom itself.

Operational Considerations
==========================

The MAG sensor uses a combination of thermal blanketing and heaters to
maintain its operating temperature.  The ER unit maintains its
temperature using thermal blanketing, surface finishes, and its
internal power dissipation.

The magnetic fields measured by the MAG will be a combination of the
Earth's magnetic field, the field carried from the Sun by the solar
wind, and the Moon's field, which is extremely weak.  The magnetic
field at the lunar surface is also affected by local deposits of
magnetic material.

The ER can measure magnetic fields as weak as one-millionth of the
strength of the Earth's magnetic field.

Operation and Sampling Modes
============================

The magnetometer data are sampled 16 times a second, synchronous with
the telemetry clock.  Data are compressed by delta-modulation to
6-bits per axis per channel.  Occasional full samples (12 bits per
axis plus range) are collected.
 
Principal Investigator
======================

The Co-I and magnetics group leader for the Lunar Prospector
Magnetometer and Electron Reflector experiment is Dr. Robert Lin of
the University of California, Berkeley. "
  
 END_OBJECT                    = INSTRUMENT_INFORMATION
  
 OBJECT                        = INSTRUMENT_REFERENCE_INFO
   REFERENCE_KEY_ID            = "BINDERETAL1998"
 END_OBJECT                    = INSTRUMENT_REFERENCE_INFO

 OBJECT                        = INSTRUMENT_REFERENCE_INFO
   REFERENCE_KEY_ID            = "ACUNAETAL1992"
 END_OBJECT                    = INSTRUMENT_REFERENCE_INFO

 OBJECT                        = INSTRUMENT_REFERENCE_INFO
   REFERENCE_KEY_ID            = "CARLSONETAL1983"
 END_OBJECT                    = INSTRUMENT_REFERENCE_INFO

END_OBJECT                    = INSTRUMENT
END