A full system test of a solar thermal engine will be carried out by year- end by Surrey Satellite Technology (SSTL) researchers in the USA.
A solar thermal engine (STE) uses heat from the Sun directed on to a propellant to generate thrust to propel the spacecraft. SSTL's design uses many small Sun-tracking mirrors on a spacecraft's exterior and optical fibres to direct the reflected sunlight on to the propellant. Work is focused on the light transfer efficiency of the fibres. An STE is considered to be an efficient engine with a specific impulse of up to 300s. The Space Shuttle's main engines have an impulse of 460s.