Space-Enhanced Terrestrial Solar Power for Equatorial Regions

Abstract

This paper investigates the concept of solar mirrors in a Earth orbit to provide large-scale terrestrial equatorial solar farms with additional solar power during the hours of darkness. A ower constellation of mirrors is considered in highly-eccentric orbits (semi-major axis=20270.4 km) in order to increase the time of visibility over the solar farms and, through this architecture, only two mirrors are needed to provide a complete night-coverage over three equatorial locations. Selecting the proper value for the orbit eccentricity, solar radiation pressure and Earth's oblateness perturbations act on the mirrors so that the apsidal motion of the orbit due to these perturbations is synchronized with the apparent motion of the Sun. Therefore, it can be guaranteed that the perigee always points towards the Sun and that the mirrors orbit mostly above the night side of the Earth. With respect to Geostationary orbit (GEO), the family of orbits considered in this paper allow a passive means to overcome issues related to orbital perturbations. Moreover, because of the large slant range from GEOs, a larger mirror is required to deliver the same energy that could be delivered from a lower orbit with a smaller mirror. As a result, a single anti-heliotropic ower constellation comprised of two mirrors of 50 km 2 would be able to deliver energy in the range of 4.60 − 5.20 GW h per day to 1000 km 2-solar farms on the equator. Finally, it is estimated that, deploying 90 of these constellations, the price of electricity could be reduced from 9.1 cents to 6 cents per kWh.

Magnetic Attitude Control of Gossamer Spacecraft using a 3D-printed, Electrically Conducting Support Structure

“…cos θ (11) where B 0 = 3.12 × 10 −5 T is the mean value of the magnetic field at the magnetic equator on the Earth's surface [18]. The angle ψ lies between the z-axis and the line of intersection between the reflector surface and the orbital plane.…”

“…A key difference to the previous detumbling simulation is that the magnetic field direction is no longer constant, instead it's components are given by Eq. (11). Due to the constrained geometry of the system, these torques will always lie on the y-axis, and so deliver an angular acceleration around the Sun-reflector direction.…”

“…Development of the concept has included discussion of reflector constellations, and which families of orbits could best deliver power to target solar power farms. Reference [11] proposes a "flower" constellation of reflectors in elliptical orbits which could provide additional solar power to equatorial regions, and develops steering laws for such a constellation. Another design is proposed in Ref.…”

Enhancing terrestrial solar power using orbiting solar reflectors

“…Further recent studies include Bonetti and McInnes who considered the use of so-called heliotropic orbits. These are elliptical equatorial orbits whose apse line is artificially precessed using solar radiation pressure to ensure that the orbit perigee is always directed to towards the Sun [15]. This enables a long dwell time for the reflectors over the night-side of the Earth at the orbit apogee.…”