Space Solar Power Technologies, Economics, Financing and Development Research Papers (original) (raw)

Provide an overview of emerging US space launch and space systems trends that are critical to the future of new space business cases –like space solar power

The development of an economically viable space-based solar power (SBSP) system is critical to the Earth's future and for future space development. PowerSat technology is also critical to supporting sustainable private and government space ventures, including space lift, space exploration and space infrastructure development. Such a system would greatly expand the need for space lift capability from small reusable launch vehicles for SBSP satellite maintenance to large expendable launch vehicles for deploying GW class SBSP satellites into orbit. The technology needed for SBSP is also needed for in-space solar electric transportation systems needed for space colonization as the technology is the same. The hope has been that gradual improvement in photovoltaic or other technologies such as thermal systems would solve the mass to orbit problem for SBSP systems. However, this in itself does not appear sufficient to make SBSP economically viable. This paper presents a new architectural option for SBSP using a Sun-synchronous orbit (SS-O), wireless power transmission (WPT) and a space power relay (SPR). This new concept is called The Space Grid. The Space Grid relies on the use of two separate satellite constellations. The power satellite (PowerSat) constellation is placed in SS-O dusk to dawn orbit at 800km and has access to constant sunlight and is used to produce the power. The Equatorial reflector satellite (ReflectorSat) constellation is in a 4,000km equatorial orbit and is used to distribute the power to the rectenna on the Earth's surface. The power is produced by the PowerSats in SS-O and beamed to the ReflectorSats in equatorial orbit and then bounced to the rectenna on the ground. This combination allows for the production and distribution of power to the Earth's surface without the problems normally associated with non-Geostationary (GEO) PowerSat concepts and without having to place the PowerSats in GEO. The Space Grid reduces the mass of a PowerSat transmitter by approximately 67% by moving it closer then past GEO concepts and allows for higher power levels and therefore much smaller (60%) and less costly rectenna on the ground and reduces the minimum size from 5GW to only 2GW allowing quicker deployment of space energy to solve the Earth's energy problems. WPT transmission could be microwave or laser but for this paper microwave will be used for easier comparison with past concepts.

Lightweight mirrors have been proposed in geosynchronous orbit for the generation of Space Solar Power 24 hours per day. Alternatively, lightweight space mirrors have been proposed in sun-synchronous polar orbits for illuminating terrestrial solar fields at dawn and dusk for additional terrestrial solar electric power in the early morning and evening hours. In any case, the trade offs between lightweight, stiffness, and optical quality for low cost space mirrors need to be explored. These trade-offs can be explored by developing and demonstrating a lightweight mirror on the International Space Station. The astronauts on the ISS will see dawn and dusk 15 times per day. Herein, it is noted that a first step in a space mirror development road-map could be the construction of a 12 square meter space mirror to demonstrate full moon intensity illumination in Disney Parks in the evenings. The 400 km altitude of the ISS is an advantage in that a small 12 sq m mirror can produce full-moon intensity on a 4 km diameter spot on the ground provided that the mirror is flat to within 0.5 degrees, i.e. the sun disc size. There are multiple websites to allow one to locate the ISS in the evening demonstrating that the ISS is visible for up to 6 minutes routinely in the evenings at any ground location between +/-52 degrees latitude. How might one mount a mirror on the ISS? The ISS has potential external mounting locations. As one possibility, a mirror could be attached at the bottom of a nadir pointing beam with the top end of the beam attached to the ISS ELC4 or ELC1 locations. An elevation and azimuth pointing mechanism could be located at the bottom of this beam and attached to the centre body of the space mirror. While a space mirror concept for space solar power may be in the very distant future, in addition to providing a space mirror development opportunity, mounting a mirror on the ISS could also have a public relations benefit in that it will make the ISS and the NASA and ESA space development activities more visible for the public. Demonstrating a flat pointing moonbeam space mirror on the ISS would be a significant accomplishment.

Lunar industrial development can enable sustainable development for humankind for centuries to come, however the combination of extremely high costs to operate on the Moon coupled with the lack of markets for lunar materials demands significant public investment for decades to come. Budgets for NASA and other space agencies are a political decision weighed against other national priorities. The risk of never achieving breakthrough to a self-sustaining space economy is high. Proposed is a Big Push, an economic development approach to concurrently undertake multiple private and public initiatives to drive to take-off of a self-sustaining space economy based on resources of the Moon, asteroids and other cosmic bodies. A Big Push approach would require sustained large investment. It is proposed to structure the space resource economy on the basis of Modern Monetary Theory where a Space Bank would create as much money as needed to meet milestones in the long term plan for lunar industrial development.