9.3 Construction/Assembly Operations 9.3.1 Construction of Erectable Structures As previously mentioned, the near-term space solar power program experiments and demonstrations are likely to be performed using small, inexpensive, deployable satellites. The larger systems envisioned in long term, commercial satellites will, however, almost certainly require construction and assembly capabilities in space. Many of these capabilities such as EVA construction and optimal construction configuration selection are currently being developed while others such as joining systems and engineering overlap issues are better understood. To better evaluate construction of erectable structures, a basic knowledge base is needed in each of these areas. One of the first issues to be addressed in the erectability of space systems is joining systems. These can be separate into quick disconnect systems, basically systems that take a minimal amount of time and require very few tools, and permanent systems. Quick disconnect systems include Space Station Freedom(SSF) Quick Attachment Joints (QAJ), quick disconnect fluid lines and attach-disconnect electrical harnesses. These have reached a point where even such constraints as the use of bulky astronaut gloves have been overcome. The example of the QAJ demonstrates this in that an out-of-axis, easy to use, assembly joint was developed. Permanent systems, shown in Table 9.1 on the other hand, have been developed quite differently. [Nii, 1990] The use of welding for on-orbit repair of Soyuz-12 and the successful demonstration of welding and brazing on Skylab have been the primary milestones. [Anderson, 1988, Stuhlinger, 1975] It is through these successful demonstration that operational studies of erectable systems has been allowed. Table 9.1 Classes of Permanent Joining Systems. The second major issue for quantifying the effectiveness of space construction is Extra Vehicular Activity (EVA). Currently, large scale EVA operations have been in maintenance tasks by the former Soviet Space Program and have been very limited in the area of construction EVA operations. The primary reason for this is because of the high cost of shuttle flights and because of the limited simulation capability of the neutral buoyancy facilities listed in Table 9.2. Table 9.2 US. Neutral Buoyancy Facilities
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