The use of electro-optic devices for high speed digital links in space on-board systems or high bandwidth analogue links for diagnostics in large physics experiments could be limited by their reliability in radiative environment. The technology of emitters, and specially the laser diodes, is in rapid progress, driven by ground applications such as telecommunication systems. New structures created to increase performances introduce radiation sensitive areas.In space applications, particles (protons, heavy ions) can induce permanent damages as well as transient errors. Thus it is of major interest to study the vulnerability of new laser diodes structure to single particles and determine their role in the reliability of a whole data link.A transmission data link has been simulated using a high speed digital signal to modulate a 1300 nm laser diode. A Nd:YAG laser was used to simulate ionizing effects induced by transient particle irradiation on the laser diode by creating carriers only in the laser cavity. With this method, calibration of ionizing effects, error amplitude and influence of operational parameters of the link (frequency, amplitude of modulation...) have been studied. Heavy ions at different energies have been used to confirm transient effects, but the perturbation duration, too short compared with the Nd:YAG, have limited observation of the transient error due to ionizing effects. Permanent damages have been observed and their origin linked with the particle.

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This paper describes a concept of a formation flyer for ASPICS (Association de Satellites Pour l'Imagerie Coronagraphique Solaire, see [1]), a giant 100 m base, externally occulted coronagraph aimed at observing the inner corona (and the solar disk) in the visible and ultra-violet. The two-satellite formation approach, based on existing space systems, is composed of a Myriade micro-satellite supporting the occulter and a Proteus platform as the main system carrying the coronagraph and the disk-imager scientific instruments. The two spacecrafts are launched as a single composite and deployed once in orbit, preferably a 3-day orbit, or at the L1 Lagrange point. The coronagraph satellite acts as the "master" and provides the main functions of the mission (data handling, communication, propulsion, guidance navigation and control) while the occulter satellite acts as the "slave". The control of the formation is performed in two steps: i) RF metrology for deployment and preliminary pointing, ii) classical optical attitude sensors and metrology based on diverging laser beams. This solution will satisfy the nominal requirement of a lateral positioning with an accuracy of 1 mm and a longitudinal positioning with an accuracy of 500 mm.

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Natural and anthropogenic trace constituents play an important role for the ozone budget and climate as well as in other problems of the environment. In order to prevent the dramatic impact of any climate change, exchange processes between the stratosphere and troposphere as well as the distribution and deposition of tropospheric trace constituents are investigated.The Limb Infrared Fourier Transform spectrometer (LIFT) will globally provide calibrated spectra of the atmosphere as a function of the tangent altitude.LIFT field of view will be 30 km × 30 km. The resolution is 30 km in azimuth corresponding to the full field of view, and 2 km in elevation, obtained by using a matrix of 15×15 detectors. The instrument will cover the spectral domain 5.7-14.7 μm through 2 different bands respectively 13.0-9.5 μm, 9.5-5.7 μm.With a spectral resolution of 0.1 cm -1 , LIFT is a high class Fourier Transform Spectrometer compliant with the challenging constraints of limb viewing and spaceborne implementation.