  In the most common space solar power (SSP) system architectures, solar energy
harvested by large satellites in geostationary orbit is transmitted to Earth
via microwave radiation. Currently, only limited information about the
interactions of microwave beams with energy densities of several tens to
hundreds of W/m$^2$ with the different layers of the atmosphere is available.
Governmental bodies will likely require detailed investigations of safety and
atmospheric effects of microwave power beams before issuing launch licenses for
SSP satellite systems. This paper proposes to collect representative and
comprehensive data of the interaction of power beams with the atmosphere by
extending the infrastructure of the High Frequency Active Auroral Research
Program (HAARP) facility in Alaska, USA. Estimates of the transmission
infrastructure performance as well as measurement devices and scientific
capabilities of possible upgrade scenarios will be discussed. The proposed
upgrade of the HAARP facility is expected to deliver a wealth of data and
information which could serve as a decision base for governmental launch
licensing of SSP satellites, and which can be used in addition to deepen public
acceptance of SSP as a large-scale renewable energy source.
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Space Physics;Instrumentation and Methods for Astrophysics