The primary challenge for space solar power towers is economics. Over half the cost of current SBSP systems is associated with launch costs. To reduce launch costs the size of the SBSP system must be reduced. In order for SBSP concepts to become an economically viable source of clean energy, it is necessary to lower the SPS satellite’s mass and size to the point that it can be launched into working orbit with currently available commercial launch vehicles – and without requiring any on-orbit astronaut assembly or unnecessary infrastructure. This is only possible by designing a smaller, yet more efficient, SPS system that would operate in an orbit closer to Earth.

For the last two years I have been focused on developing alternative solutions for Space-based Solar Power (SBSP). This started with an extensive review of past concepts to determine why SBSP remained uneconomical forty years after its invention by Dr. Peter Glaser. The conclusion was that locating the SBSP Satellites in GEO posed a substantial mass penalty on the Satellites due to the need for a very large satellite transmitter and the need for in-space transportation from low Earth orbit (LEO) to geostationary orbit (GEO). So the question then became – If not GEO where?

The recovery of manned spaceflight from the vicissitudes of the Shuttle programme continued in 2008, though at a barely perceptible rate.

Hopefully the pace will pick up in 2009 and beyond.  Total man-days in space in 2008 come to 1,581.77, if my figures are accurate. This continues the recovery of the last few years, from a low of 794 in 2004, but does not yet challenge the record peak of 1746 man-days in the year 1997.