DESCRIPTION |
Scientific Overview
===================
The magnetometer (MISCHA) The prime objective of the magnetometer
experiment is to determine the role of the magnetic field in the
interaction between the solar wind and the comet and to identify
the characteristic boundaries of the cometary environment (bow
shock, contact surface, etc.).
Instrument Overview
===================
The sensors of the MISCHA magnetometer are mounted on a boom. A
single-axis sensor and a triaxial sensor are mounted 1 and 2 m,
respectively, from the edge of the solar panel. The advantage of
this dual-sensor fluxgate system is the possibility to determine
the spacecraft's stray magnetic field.
Magnetometer characteristics
----------------------------
Dynamic range +/- 100 nT
Resolution 0.05 nT (12 bit)
Noise level 0.01 nT Hz**-1/2
Zero drift +/- nT/month
Bandwidth 10 Hz
Time resolution 10 vector/s
(high-speed telemetry) 1 spectrum/25 s
Number of frequency points 128/spectrum
Detectors
---------
MASS:
triaxial sensor ... 500 g
one-axis sensor ... 200 g
electronic box ... 2200 g
Operational Consdierations
--------------------------
MODE TRASSA 1
TRASSA 1 (memory mode)
this is the cruise phase mode;
1 vector/2.5 min and 1 averaged spectrum/80 min
MODE TRASSA 2
TRASSA 2 (memory mode)
2 days until 2 hours before Halley encounter and during
selected cruise phase intervals (e.g. Venus tail crossing and
ICE Giacobini-Zinner encounter);
1 vector/min and 1 averaged spectrum/5 min
MODE HIGH SPEED
HIGH SPEED (memory mode)
10 vector/min and 1 averaged spectrum/30 sec
MODE Direct Transmission
DT-65 (direct transmission)
2 hours before until 2 hours after Halley encounter 10
vectors/sec and 1 spectrum/25 sec
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REFERENCES |
Reinhard, R and B. Battrick (eds), 'Space Missions to Halley's Comet', European
Space Agency ESA SP-1066, ESA Pub Div, Moordwijk, Netherlands, 1986.
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