Boeing's solar orbit transfer vehicle (SOTV) is to be launched aboard one of the company's Delta III or Evolved Expendable Launch Vehicles in October 2001.
The company has received a $48 million contract from the US Air Force Research Laboratory at Kirtland AFB, New Mexico, to produce the first solar powered, 2.4m-long, SOTV space experiment module. The vehicle is to be built at Boeing's Phantom Works.
An operational SOTV will save weight by reducing the need for orbital manoeuvring propellants when changing orbits. It will achieve this by using the energy from the Sun to achieve transfer orbits, as well as generating electric power for the craft.
Launch vehicles now transport less than 1% of their initial ground launch mass into geostationary orbit (GEO). An advanced solar thermal propulsion engine can transfer 50-100% more payload into GEO.
This type of propulsion system has a low thrust and takes 20-30 days to move from low Earth orbit to GEO. Once in orbit, the unit can provide power for the spacecraft's payload for a further seven years.
Boeing says that a fully operational system could be flying by 2010, for example, for manoeuvrable reconnaissance satellites.
Source: Flight International
