For over forty years, the Observatoire de Paris – via its LESIA department – has been developing, among other instruments, radio detectors as well as spectro-imagers in the visible and infra-red domains, for space probes ; the department has a world wide reputation in this activity.
In February 2013, the LESIA, having already delivered SORBET, a radio HF receptor, will be delivering the electronics module for VIHI, a last generation spectro-imager for the BepiColombo space probe.
These instruments, which will be assembled by the European Space Agency (ESA) in 2014, will be launched into space in August 2015. They will be in orbiting round Mercury in 2022, and will furnish valuable information on the composition and magnetic environment of this iron planet.
BepiColombo : an ESA/JAXA Project
The BepiColombo project is managed by ESA in cooperation with Japan. The JAXA is responsible for the orbiter MMO (Mercury Magnetospheric Orbiter). The ESA is in charge of the rest of the project, i.e. the orbiter MPO (Mercury Planetary Orbiter), the launch, the flight to Mercury, and orbit injection of the probes around Mercury.
Launch is programmed for 2015, with arrival at Mercury in 2022.The MPO probe will study the surface and internal structure of the planet, as well as the exosphere, while the MMO probe will be dedicated to the study of the magnetosphere and the exosphere. The nominal lifetime of the mission is one year, with an optional extra year.
There are 11 instruments on MPO and 5 on MMO. Between them, these two vessels and their scientific payloads will furnish the detailed information necessary to understand Mercury and its magnetospheric environment, and to find some clues about the origin and evolution of a planet which is close to its star.
LESIA’s instrumental participation
For each of the two satellites, the LESIA designed and built one instrument :
- SORBET (acronym "Spectroscopie des Ondes Radio et du Bruit Electrostatique Thermique" - « Radio wave and electrostatic noise spectroscopy ») is an HF (2.5kHz-10MHz) radio receiver, to analyze the radio plasma over a large dynamic with excellent resolution as well as temporal frequency. This receiver is one of the key elements which is a part of the PWI (Plasma Waves Investigation) experiment which will study for the very first time in situ in the radio frequency domain, the small magnetosphere of Mercury and its interaction with the solar wind.
- The electronics unit for VIHI (Visual and Infrared Hyper-spectral Imager) is a spectro-imager in the visible and infra-red domains, one of the three channels for the group of instruments SIMBIO-SYS which will gather in situ 80 % of the data flow.
Delivery schedule
- SORBET was delivered to RISH (the PI laboratory in Kyoto) on August 20th 2012, then transported at the beginning of September to the integration site of MMO at the ISAS (Tokyo-Sagamihara), where its performance was successfully tested prior to integration (the tests ended on the 10th of January 2013). It is now awaiting installation on MMO (at the latest, end of 2013 for the entire payload) ; delivery of this satellite by JAXA to ESTEC (ESA) is in turn programmed for 2014.
- The electronics unit for VIHI left the LESIA on the 14th of February 2013 by special transport, for assembly in Italy at ASI (Italian space agency), before being sent to in 2014. The LESIA built the electronics which controls the VIHI instrument. In particular, it developed the test bench OBAMA, one of its kind, to characterize in fine detail the performance of the visible-infrared detector of VIHI.
The LESIA has an unequalled experience in the realization of this type of instrument, which enhances our knowledge of planets and their close environments.