A paper on the concept of the high altitude balloon platform was presented in a separate session by E.C. Okress and R.K. Soberman (Franklin Institute, Philadelphia, PA) entitled, “Solar Thermal Aerostat Research Station (STARS).” A preprint was available (79-F-35). Of particular relevance to the SPS concept is the possibility that by receiving laser energy at high altitudes and retransmitting the microwaves from the balloon to the ground, one could sidestep the restrictions on intensity of the microwave beam in the ionosphere and side lobe intensity restrictions on the ground based rectenna. Considerable economies of scale may be possible in the power reception equipment and it may be economical to build rectennas which receive only a few hundred megawatts. Sixteen different missions or tasks were listed for the STARS which might aid in generating a wide range of support for the development of such atmospheric devices. Most scenarios for the construction of SPS assume the need for large platforms or structures in space. Session 42 (Symposium on Manned Operations in Space — Large Space Structures) contained several papers of direct interest. J.F. Garibotti, A.J. Cwiertny, R. Johnson (McDonnell Douglas Astronautics) and T.J. Dunn (JSC/NASA) presented “Construction of Large Space Structures,” which is available as preprint 79-F-106. They reviewed preliminary results of cost and performance studies which indicate that on-orbit fabrication and assembly of geodetic structures by use of beam building machines operating from the Space Shuttle Orbiter may be economically superior to the deployable and erectable modes of construction for many near-term operations. They feel that the SPS will require the beam building approach. A. Bertram (Institut fur Aeroelastic, Deutsche Forschungs und Versuchsanstalt fur Luft- und Raumfahrt, Gottingen, West Germany) presented the paper, “Dynamic Qualification of Large Space Structures by Means of Modal Coupling Techniques” (79-107). He concluded that the structural qualification methods available today are no longer adequate to qualify expected large space structures and proposed a procedure based on both analyses and tests whereby the damping properties of the light structure subsections are measured on earth and in orbit and information supplied to an analysis program. In-orbit tests of structural responses will be used to confirm the analytic predictions on various combinations of substructures prior to construction of the final large structures. “Superlight Rotating Reflectors in Space,” by A.V. Luk'yanov (Department of Physics, University of Moscow) was available as preprint 79-F-l 12. He proposes the use of thin-film reflectors which are pulled into the desired geometrical shapes by the use of tension members and centrifugal forces. Specific masses of 1 g/m2 are considered to be obtainable. Films could be used to construct reflectors several kilometers in diameter to be used for earth illumination, weather control and solar sails. Two analytic papers were presented in Session 43 (Astrodynamics II) of direct relevance to large space structures. The first was by K.W. Lips and V.J. Modi (Department of Mechanical Engineering, University of British Columbia), “General Dynamics of a Large Class of Flexible Satellite Systems,” (79-192). They presented a general formulation for librational dynamics of satellites with an arbitrary number, type and orientation of deploying flexible appendages. Three cases of practical importance were examined: (1) planar structures with pitch and appendage oscillations in the orbital plane; (2) general attitude with planar vibrations of flexible members and (3) the above cases with out-of-plane components of vibration. T.C. Huang (Department of Mechanical Engineering, University of Wisconsin) and A. Das (General Electric Company, Pennsylvania) provided the paper, “Stability and Control of
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