2. Payload dimensions. If parts of the equipment are to be transported in the interior of the cargo module, their size will be limited by the cargo bay dimensions (2 m in diameter and 2.3 m in length) and the hatch diameter (0.8 m). For equipment mounted on the outside of the Progress spacecraft, the dynamic envelope of the Soyuz rocket fairing with 3 m diameter has to be respected. 3. Orbit constraints. The Mir space station is in an orbit of 320-330 km altitude with an inclination of 51.6 degrees. 4. Power constraints. The total solar array power of the Mir space station is about 25 kW. About 10 kW of power could be available continuously for periods of 1 hour. [Burgasov, 1992] The frequency of these periods will depend on the power load of the Mir station but several beaming experiments per day should be possible. The on-board voltage on Mir is 27 V. 5. Time constraints. The Mir space station will probably be operational only until 1996. Therefore the experiment should be carried out by mid 1996. 6. Cost constraints. The overall project budget should not exceed $80M. Figure 10.2.4 Flight Operation Flowchart Power Beaming Cost and time constraints are the main drivers for the choice of the power beaming system. It must be cheap, which means that only well-known technology should be used, and it must be realized in a very short time, which means that we may not undertake any long design study. The proposed scenario should provide new knowledge about phased array technology, which probably will be used for future demonstrations of space to ground power transmission. A “large scale”, “low” frequency phased array of 2.45 GHz has been chosen. In this frequency range, solidstate components are readily available. The size of the array is a trade-off between cost, feasibility and demonstration value. It must be large enough to be innovative without exceeding the cost and time constraints mentioned above. Some additional mechanical constraints arise as this payload must
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