In study Phase n, this concept was updated to use ReflectArrays as relays in GEO to avoid the use of laser frequencies (particularly high-powered lasers directed at Earth) and Airstats. The growth penalty in the size of both the relay and Sun Tower transmitter, associated with moving to the the lower frequency of 5.8 GHz is an understood consequence of that decision. However, an additional benefit of the updated concept is that the use ReflectArrays as part of the relay configuration provides a potential evolutionary path for market growth, since those systems are particularly well-suited to initial application as power relay satellites for long range ground-to-ground wireless power transmission. The two major components of the LEO-GEO Relay concept are again the sun-synchronous LEO Sun Tower and the ReflectArray relay satellite. Both have been discussed and notionally sketched above in section 3.4 and Figures 3-6 and 3-7. The unique aspects of the LEO-GEO Relay concept are contained in its architectural context provided in Figure 3-9. LEO-GEO Relay Development and Manufacturing Both the Sun Tower satellites and the Reflect/Arrays are extensively modular so that relatively small individual components can be developed, tested and fabricated at a moderate cost. Sytem elements would be mass produced in customized manufacturing facilities. Automated assembly in space must be factored in during the development phase and incorporated in the hardware design, packaging scheme and operational procedures. Ground Launch Infrastructure No concept-unique infrastructure is required beyond those facilities necessary to support extremely low launch costs - around $200/kg. However, launch rates may be need to be on the order of one per day for extended periods of time to support the in-space concstruction of such large elements as the relays and transmitters. Earth to Orbit Transportation Sun Tower power modules along with transmitters and relays would be sized for 20-25 metric ton launch vehicles. This is consistent with STS or Titan IV/NUS payload profiles and with proposed RLV and HRST systems. Increased ETO capability in the range of25-50 metric tons might be necessary if not enabling. The presumed payload volume for a RLV class vehicle is based on a 4.6 meter diameter and 10 meter long cylinder. LEO-GEO Relay: In-Space Transportation Efficient delivery of the relays to GEO would impose requirements for highly mass-efficient and affordable SEP-based OTV’s similar to those recommended for the LEO-MEO Relay concept, or the relays themselves could be equipped with an on-board electric propulsion system Such a system would also provide the needed on-orbit capability for station keeping and attitude control LEO-GEO Relay: Space Segment A description of the basic sun-synchronous Sun Tower concept is given in Section 3.3, and its proposed modification for use as in relay applications is discussed in Section 3.4 above. Ignoring the original LEO-
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