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Instruments |
Instrument Housing
Image from
SwRI
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Fields:
Spin Plane Double Probe (SDP)
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The SDP consists of four wire-boom elements that are 40-m in length.
At the end of each boom, a 2-m long wire antenna is deployed with an 8-centimeter
diameter spherical sensor. A major design goal of the measurements is to maintain the
source of information coming in without damaging the actual spacecraft. Getting as
close to the solar storm as possible is the risk. The elongated boom ensures the
safety of the probe, and at the same time minimizes the damage done against the spacecraft,
nearby surfaces, and other elements affecting the probe.
Image from
SwRI
Axial Double Probe (ADP)
The ADP consists of two 10-m antennas deployed, after launch, near the spin-axis
of the probe. A 3-D model representing the electric field vectors can then be shown and
measured. The ADP boom uses a retractable 10-m boom. So when fully extended, a 20-m
boom antenna is formed. This option is used to increase the accuracy of the incoming data.
There is a risk though, with the extension of such a boom, the possibility of instability
is common. With that in mind, the ADP has a stabilizing feature to correct this problem.
At the end of each retractable boom, is a 70-cm cylindrical sensor.
Image from
SwRI
Electron Drift Instrument (EDI)
The EDI provides an absolute measurement of the electric field around the probes.
It does this by firing electrons in a gyro-orbit around the probe. After the beams
have traveled for a whole gyro-obit, once around, the electrons are accepted back into
the spacecraft. The mission uses this EDI technique as an in-flight monitor. It is
insensitive to spacecraft effects, meaning that the EDI is independent of the probe
and is not affected the same way that the probe may be affected from an outside source.
Image from
SwRI
Analog Flux Gate Magnetometer (AFG)
The ADI is a magnetometer sensor. It consists of a triad of low-noise sensors,
which will provide highly accurate measurements at the higher field strengths.
Digital Flux Gate (DFG)
The DFG is also a magnetometer sensor, but with a newer,
lightweight sensor used mainly for stability. The DFG gets its
data by compensating the field strengths. The DFG uses two, 3-m,
booms with both sensors on each end. Also, the thermal design of
the DFG allows for excellent flight in different environmental states.
Search Coil Magnetometer (SCM)
The SCM is a single high-frequency coil used to tell the
difference between the different types of waves near the plasma.
The instrument is made of magnetic material and windings.
Image from
SwRI
Central Electronics Box (CEB)
The main use of the CEB is to house the main power supply
for the FIELDS instruments.
Image from
SwRI
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Hot Plasma:
Fast Plasma Instrument (FPI)
The spacecraft of the MMS
Mission will each be equipped a Fast Plasma Instrument. This instrument will be
used to measure the composition of the plasma
in The Solar Wind. Every FPI will have four pairs of Dual Electron Sensors
(DES), used to measure the concentration of electrons
, and four pairs of Dual Ion Spectrometers (DES), used to measure the
concentration of ions
. These sensors will grouped into four clusters which share basic electronics
such as power sources, and equally spaced around the spacecraft. All of the
clusters are controlled by and cooperate through a Instrument Data Processing
Unit (IDPU)
The Earth's magnetosphere
Image from
NASA
Dual Electron Sensors (DES)
The spacecraft of
the MMS mission will each be equipped with four pairs of electron sensors.
These sensors will provide the scientists back on earth with valuable
information regarding the intensity of electrons in The Solar
Wind (NEEDS DEFINITION).
Dual Ion Spectrometers (DIS)
As with the DES,
each spacecraft will have four pairs of ion spectrometers. These measure
energy spectrum of the low energy particle s that cause the aurora and
other high latitude phenomena.
Hot Plasma Composition Analyzer (HPCA)
Each of
the 4 spacecraft will carry one Hot Plasma Composition Analyzer. This
instrument, developed by SwRI, can be used to determine what elements
a given plasma
is made of. In this mission, each spacecraft will use a HPCA to
detect small amounts of oxygen ions in the earth’s magnetosphere
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A picture of the HCPA designed by SwRI
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Energetic Particles:
Fly’s Eye Energetic Particle Sensor (FEEPS)
FEEPS originated from the Ions and Electron Spectrometer (EIS); supply
fast “all sky” total ion and electron size. It is composed of a total
of 16 sensors clustered into 2 sensor heads. Both sensor heads are placed
totally opposite from each other on the spacecraft so an “all-sky” view
can be seen instantly.In each electron sensor,
electrons go through a square hole and are then measure
with another square. Electrons with energies greater than
20 K are sensed. FEEPS ion sensors and EIS (Energetic Ion Spectrometer)
measurements provide information required to determine when caution is
necessary, when above 300 K. These detectors are designed so thin that
electrons greater than 40 K fully pierce them. During unusually intense
electron events, EIS proton measurements provide information needed to
determine stages of caution.
Image from
SwRI
Energetic Ion Spectrometer (EIS):
Ions come in through the collimator and produce
secondary electrons in the “start foil”, and these
electrons are guided onto the MCP detector start area.
The ions go on to a “stop foil”, where more secondary
electrons are produced and guided to an MCP detector stop
area.
Image from
SwRI
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