satellite would be visible from the entire continent during both of its daily apogees. From the pole it would appear to rise to almost 27° form the vertical twice per day in opposite directions. At the northerly coasts of Antarctica, the satellite would rise twice per day, once in the north passing almost directly overhead, and twelve hours later in the south only rising as high as about 50° from the vertical. Intermediate behavior would be observed at intermediate latitudes, and the apparent height of both apparitions would be decreased for sites not on the longitude line passing under both apogees. A system of two Molniya solar power satellites could be used to provide continuous power to a site int he Antarctic (or Arctic). Each satellite would be able to transmit power to the receiver about 2/3 of the time, so there would be overlap while the satellites were low in the sky, allowing a smaller rectenna to be used for a given peak power specification. In addition, the reliability of the system would be enhanced by having more than one satellite - if one fails there would still be power 2/3 of the time. With current upper stage propulsion technology (typically I, = 310 or so) the propellant cost of putting two satellites in Molniya orbit is the same as that of putting a single satellite in Geostationary orbit. The major factor controlling the size of the solar power satellite is the necessary size of the transmitting antenna. In the repeating orbits with n > 2, the distance form the satellite to the receiving station is substantially reduced, reducing the required size of the satellite. A system of such satellites could serve multiple ground stations continuously with one or two more satellites than ground stations (for a relatively small number of ground stations!) if the stations were located appropriately. While solar power satellites would produce no chemical pollution of the Antarctic, their use would introduce significant amounts of heat into an environment where this could be significant. It is unlikely that either the a satellite's transmitting antenna or the ground station receiving antenna would be large enough to ensure that most of the transmitting microwaves were converted to useful energy. Thus, it is likely that rather large amounts of microwave energy would end up heating the Antarctic environment. A total heat input of 1 GW is about equivalent to the solar flux falling on two square kilometers near the south pole during mid summer. While this would not create continent wide effects, it clearly could affect local weather patters, particularly in the winter. REFERENCES [1] Broman, L. previous paper in this issue. [2] Freeman, J.W. (1988) A Polar Orbiting Solar Power Satellite, in Space Power 7 (1) pp. 69-74.
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