[ExI] Large scale energy sources

[Keith Henson]

Just got back from the Space Access conference.

The most interesting presentation to me was by Reaction Engines on the
big ESA review of the projected performance of the Skylon vehicle.

The conclusion was that the engineering is sound and the vehicle
should meet the performance specifications.

Skylon gets the equal of 10.5 km/s exhaust velocity till it runs out
of air at 26 km and 2000 m/s.

If you want to get space transportation down to where power satellites
make sense, that's a very good start.

If you could get only 8 km/s for the rest of the way to orbit, the
vehicle mass ratio would be 3 and the cost down to well under $100/kg
to LEO and just about $100/kg to GEO.  That is low enough for power
satellites to become the dominate world wide energy source.

Because it offered an even less than SBSP cost, I have spent the last
year working on StratoSolar.  I have not found a showstopper in the
design to date, but it has taken a lot of conceptual design work to
get around the problems in the original design.  It is a difficult
engineering project that is sensitive to peak wind loads.

Keith