DEMETER (Detection
of Electro-Magnetic Emissions Transmitted from Earthquake Regions) is devoted
to the investigation of the Earth ionosphere disturbances due to seismic and
volcanic activities.
Scientific
Objectives
The
scientific objectives of the DEMETER mission are :
-
to study the ionospheric disturbances in relation
to the seismic activity and to examine the pre- and post-seismic effects,
-
to study the ionospheric disturbances in
relation to the volcano activity,
-
to survey the ionospheric disturbances in
relation to the anthropogenic activity,
-
to contribute to the understanding of the generation mechanism of these disturbances,
-
to give a global information on the
Earth electromagnetic environment.
Scientific
Payload
To achieve
theses goals, DEMETER allows the measurements of the six components of the electromagnetic
wave field in a wide frequency interval and the determination of the plasma
parameters, ion composition, electron density and temperature, energetic electron
flux.
The science
payload is composed of
five instruments :
-
ICE, three electric sensors from DC up to 3.5 MHz,
-
IMSC, three magnetic sensors from a few Hz up to 18 kHz,
-
IAP, an ion analyzer,
-
IDP, an energetic particle detector,
-
ISL, a Langmuir probe,
associated
with the BANT common electronic module for onboard data processing and
handling.
A large
onboard memory (8Gbits) is used to collect the data all around the Earth and a high bit rate telemetry in X band (16 Mb/s) will download
these data.
Working
Modes
DEMETER has
two science modes of operation:
(i)
the Survey mode collecting averaged data all around the Earth; onboard
processing are performed to reduce the telemetry flow to 25 kb/s;
(ii)
the Burst mode collecting data with a
high bit rate of 1.7 Mb/s above the seismic regions.
The
triggering of the Burst mode is automatically realized when the satellite crosses
a seismic zone defined in the programmation plan.
Orbit
parameters
DEMETER is
a micro-satellite (130 kg) with a low-altitude of 710 km and an inclination of
98.3°.
Demeter has been successfully launched on June 29 at 6h30 UT by a Dnepr rocket from Baļkonour.
