New plans for first far infrared and sub-millimetre space astronomy mission for 2007

The Far Infra Red and Submillimetre space Telescope (FIRST) mission is an ESA ''cornerstone'' mission planned for the year 2007. This paper describes the new status of the FIRST satellite design following a redefinition of the mission in 1992/3 to better meet the cost targets. One challenging aspect of this redefinition was the substitution of the large liquid helium cryostat by Stirling cycle mechanical coolers. This posed a number of new thermal and configuration problems. In addition, a new payload complement configuration had to be defined which retained as many of the originally planned scientific capabilities of the system as possible, and which also optimised the instruments' compatibility with the cooling system. Other changes to the design included a reduction in the diameter of the primary reflector with corresponding cost and configurational benefits, and the reconfiguration of the attitude control system to use only existing hardware. These measures had to be introduced with minimum loss of mission capability. Copyright (C) 1996 COSPAR