In-Space Transportation No dedicated in-space transportation infrastructure is required for this concept. Individual modules are equipped with onboard ion electric propulsion (EP) and argon propellant for efficient orbit transfer from LEO to GEO. The EP subsystem would also perform station keeping and some attitude control functions. As an option, some degree of “solar sailing” could be utilized to augment or replace the EP subsystem for orbit transfer. GEO Millimeter Wave: Space Segment The GF.O/mm space segment is composed of two major elements: a Power Generation Platform responsible for converting solar energy into electrical, and a Power Transmission Platform which converts the electrical energy into a millimeter wave beam for downlink to the ground receiving station. As the pointing requirements of the Transmission Platform are much greater than that of the larger Generation Platform, the two platforms are mechanically “delinked”, so as not drive the stiffiiess and mass of the entire structure. A power conducting cable relays electrical power between the two platforms. The Generation Platform remains inertially sun pointing, while the Transmission Platform nadir points in order to track the ground station. The two platforms would either “formation fly” in close proximity, or be connected at either end of a gravity-oriented tether. The 200 MWe electrical Power Generation Platform is composed of 20 identical Power Modules, which independently and autonomously self-deploy in LEO, self-transport to GEO station, using onboard electric propulsion, and rendezvous and dock with the evolving platform. Each module has an initial wet mass of 20 MT and generates 10 MWe of electrical power from a 250 meter diameter inflatable copper indium selenide (CIS) or multijunction thin film photovoltaic array. An inflatable thin film array was selected as being the most likely candidate for achieving highly aggressive performance targets of 1000 W/kg specific power and 0.5 - 10 $/W in cost. These targets are respectively one and two-three orders of magnitude beyond the current state-of-art. Argon ion thrusters operating at 3000-5000 seconds specific impulse are used for LEO to GEO orbit transfer, GEO station keeping and some attitude control Solar “trim tabs” are used for primary attitude control 2.3 MT of argon propellant is required to boost each 20 MT module to GEO. Each module also contains power management and distribution (PMAD), command, communications, thermal, structure and docking subsystems. As the platform is illuminated virtually continuously in GEO, no significant onboard energy storage capability is envisioned. The Power Transmission Platform beams power to the ground station at via a 1.22 mm, 245 GHz “millimeter” wave. The transmitter is 100 meters in diameter and is comprised of 100 Transmitter Modules, each with a 10 meter diameter “hard” reflector and two 1.0 MW gyrotrons. The platform has its own subsystems, independent of the Generation Platform The platform features attitude control and a high structural stiffiiess for precise pointing and tracking (0.1-0.5 deg) of the ground station. In-Space Infrastructure No dedicated in-space infrastructure is required for this concept. Component modules are self-deploying in LEO, self-transporting from LEO to GEO, and self assembled in GEO.
RkJQdWJsaXNoZXIy MTU5NjU0Mg==