In the framework of the Jason-3 project, it was decided that the radiation experiments of the Jason-2's JRE (Join Radiation Experiment) would be renewed: Carmen-2 from CNES, and LPT ( Light Particle Telescope) from JAXA. This is the Carmen-3 mission.
Initially, this mission was composed of an ICARE-NG instrument identical to the one aboard Jason-2. However, an additional sensor, AMBRE, able to detect low energy ions and electrons, is also embarked.
In the end, Carmen-3 is the name given to the Carmen architecture aboard the satellite Jason-3 (MEO 1336 km, 66 °). For this mission planned initially for 5 years, Carmen-3 is composed of an ICARE-NG instrument and an AMBRE sensor. The ICARE-NG instrument is however strongly similar to the one of Carmen-2 except for the interfaces with AMBRE.
The Jason-3 satellite will ensure the continuity of operational service of the altimetry mission started with TOPEX-POSEIDON and pursued with Jason-1 and 2. The satellite is dedicated to the oceanic circulation observation. The main scientific objective is to observe the dynamic topography of the oceans thanks to space altimetry. This mission conducted as part of a Europe-United States cooperation (CNES-EUMETSAT-NASA-NOAA) is based on a "mini" class satellite with a PROTEUS platform which embarks, for the operational part, 3 main instruments: a radiometer from JPL (Jet Propulsion Laboratory), a DORIS positioning system and the POSEIDON3 altimeter, both from CNES.
In the frame of the Carmen-3 mission, CNES is the prime contractor and tasked EREMS with flight model development and manufacturing of the ICARE-NG instrument and AMBRE sensor.
The Carmen-3 instrument has particular mission objectives as well as objectives related to the satellite:
- Scientific objectives devoted to ICARE-NG: to measure high energy charged particle fluxes and their effects on test electronic components.
- Scientific objectives devoted to AMBRE: to measure low energy charged particle fluxes involved in electrostatic discharge phenomena.
- Jason-2 associated objectives: to characterize the local radiative environment and to evluate the potential drifts of the equipment in particular due to radiation from the South Atlantic Anomaly (SAA), and to contribute to the instrument cross calibration in the frame of the JRE (Join Radiation Experiment).
|High Energy Environment||ICARE-NG|
Particle flux Measurement
Fast counting ~3E5 cnts/s
1.6 – 3.6 MeV
27 - 292 MeV
|Low Energy Environment||AMBRE|
Particle flux Measurement
some eV – ~30 keV
some eV – ~30 keV
|Radiation Effects on EEE parts||ICARE-NG||~10 -¹ rad|
some ev./d, @1 s
some ev./wk, @1 s
Carmen-3 mission performances
Description and Features
The ICARE-NG/Carmen-1 instrument is composed of a data acquisition unit (SPECTRE) for the set of three radiation detectors and the component test bed (EXPERIENCE Module or MEX) strongly similar to those of Carmen-1. The ICARE-NG instrument provides power supply and manages also telemetry and remote controls for the additional AMBRE sensor (located outside of the satellite). An additional specific DC/DC converter board has been developed in order to provide an isolated power supply for this sensor.
CARMEN-3 functional description
The radiation detectors are made of silicon fully depleted solid state detectors used in single and coincident mode. The SPECTRE unit performs the radiation spectra measurement on various energy ranges. The on-board measurements consist in accumulating energy loss spectra in the junctions over a programmable accumulation period.
The reference levels of the discriminators, the gain of the amplifiers, and the accumulation time are programmable and provide a possible on-board tuning optimization. The reference values are pre-set before launch.
In addition to the on-board acquisition, the SPECTRE unit carries out the functions of power distribution and communication interface via a 1553 bus. It also includes an interface to control one or more external instruments. In the case of Carmen-2, this capability is not used.
The objective of the EXPERIENCE module (MEX) is to measure the flight event rates and the parametric drifts of an advanced electronic component set. This module is slave of the SPECTRE unit of which it depends for power and data exchanges.
The AMBRE sensor is dedicated to the measurement of low energy ions and electrons in the range from 10eV to 30keV. This sensor is able to discriminate particles according to their energy and to provide energy spectra.
The main characteristics of the Carmen-3 instrument are the following:
|Dimensions||200 x 118 x 112 mm|
|Power Consumption (according to operating mode)||6.3 W to 13 W|
|Telemetry Data Rate||420 bits/s|
|Data Volume||4.32 Mb/day|
|Dimensions||206 x 150 x 150 mm|
|Power Consumption||Included in ICARE-NG power consumption|
|Telemetry Data Rate||300 bits/s|
|Data Volume||3.09 Mb/day|
Main features of Carmen-3 instrument
The AMBRE sensor comes from an IRAP(Research Institute in Astrophysics and Planetology) technology and benefits from the previous mission heritages (GIOTTO: Electrons, INTERBALL: Electrons & ions, CLUSTER: Ions, STEREO: Electrons). AMBRE is a compact and smaller model designed to be embarked more systematically and more easily.
Its goal is to detect ions and electrons of low energies in the range 10ev-30keV. It is able to discriminate particles according to their energy and to realize energy spectrums. It is interfaced by the ICARE-NG instrument which provides it power, transmits remote controls, and retrieves telemetries.
The AMBRE sensor is monoblock and has a median part integrating electronics, electric connections as well as mechanical interfaces with the satellite. There are two mounted sensors on each side to measure respectively protons and electrons.
The measure of particles is made on a minimum of 256 channel defined to 5% according to a logarithmic law between 10eV and 30keV. The counting is made according to four acquisition chains having a field of view angle of 180 ° in a direction and 11 ° in the other one. The expected fluxes are from a fraction of pA/cm ² to 10nA/cm ². The sensor is able to measure strong fluxes without saturation.
ICARE-NG integrated on its panel