Spacelift Washington: Space Laser Test will Challenge Technology, Launch Options

WASHINGTON – Bush administration plans for a 2012 launch of a prototype space laser will challenge U.S. space technology development in ways that have little to do with the vehicle’s laser and optical systems. Launching options for the satellite will also test the upper limits of today’s expendable booster designs, if the original concept of the SBL Integrated Flight Experiment (SBL/IFX) is flown on current or possibly accelerated schedules. Recent statements by U.S. Army officials that moving up the launch of an SBL prototype would require funding schedule changes for the estimated $2-3 billion cost of the test flight, which is aimed at demonstrating the feasibility of a space-based laser intercept of an ascending ballistic missile. A full 20-satellite constellation could cost $40 billion, plus launch costs, some estimates have predicted.

As it stands now the Pentagon has elected to advance funding for the Space-Based Laser Integrated Flight Experiment. The schedule for the actual test remains on track for a launch in 2012, although advancing that timetable is increasingly possible from a policy standpoint.

Whether it is feasible from a technology standpoint is another matter. The SBL is planned as a massive spacecraft weighting 17,500 kg. With a length of 20 meters and a diameter of 4.57 meters, weight growth could push the satellite closer to 19,000 kg, which would make it the heaviest payload planned for launch aboard either of the Evolved Expendable Launch Vehicle (EELV) heavy lifters, Delta IV heavy (with a maximum 23,040 kg.) or Atlas V 505 (with a maximum 20,520 kg.). The Delta IV Medium Plus 5.4 can lift only 11,475 kg. These masses are to an equatorial inclination low Earth orbit. Plans are for the SBL IFX test to launch in 2012 with an intercept test to be conducted in 2013. The SBL test facility is to be built at NASA’s Stennis Space Center in Mississippi, with construction set to begin this fall. The project has passed the Systems Requirements Review last March, with System Definition Review planned for this fall. A Lockheed/Boeing/TRW team received a $125 million down payment in February 1999 on what could end up being a $2-3 billion contract for the test flight.

While the huge size of the satellite will press U.S. launch options, the technology of the vehicle will also require advances. SBL will need to be refueled on-orbit, which will require development of operational autonomous rendezvous and docking capability. Such a capability is being designed for testing by the X-37 research vehicle and other test craft being designed by the Air Force Research Laboratory. If a future version of the SBL requires optical cooling (the IFX may use special lens coatings that eliminate the need for cooling), then the cryogenic coolant will also need to be replenished from unpiloted orbital tankers. The laser is to be powered by a hydrogen-flouride chemical mix.