FORMATION KEEPING OF MAX, A NEW CONCEPT OF GAMMA RAY TELESCOPE

This paper presents the latest results on the formation keeping studies conducted by Alcatel for a new concept of gamma raytelescope proposed to be implemented in the MAX mission. The primary scientific objective of this mission is the study of type Ia supernovae by measuring intensities, shifts and shapes of their nuclear gamma-raylines. When finally understood and calibrated, these profoundly radioactive events will be determining in measuring the size, shape, and ageof the Universe. The concept of MAX is radically different from traditional gamma-raytelescopes: for the first time in this energy range, gamma-raysare focused from the large collecting area of a crystal diffraction lens onto a very small detector volume. As a consequence, the background noise is extremely low, making possible unprecedented sensitivities. MAX constitutes a breakthrough for the study of compact sources by combining exceptional line sensitivities with high energy resolution (E/dE>500) and very good positioning. To achieve such sensitivities, a master-slavetandem on an Earthbounded orbitis envisaged for MAX where the distance between both satellites is roughly equal to 100 m. The main challenge of the control is to keep constant this distance within a few centimetres and also the line of viewing of the telescope.