1302. Manned Maneuvering Unit Assembly Support of Large Space Structures

Paper

Abstract

Direct crewmember involvement in the assembly, operation, and maintenance of large space structures may offer design and cost advantages over fully automated or remotely operated systems. Extra vehicular activity
(EVA) utilizing the manned maneuvering unit (MMU) will become routine during the Shuttle era. Many space construction, checkout, and maintenance tasks might best be accomplished by a crewmember using the MMU. The maneuvering unit is a propulsive backpack which provides mobility to extend the crewmember’s visual, mental, and manipulative capabilities beyond the Orbiter cabin to on-the-spot operations. The applicability of EVA to space construction tasks is discussed, Shuttle MMU design features are described, and the use of the MMU for specific large space structure tasks is illustrated.
The advantages of EVA for the performance of some on-orbit tasks may include decreased design complexity, lower cost, and greater mission flexibility. Even the limited results from previous programs have proved the value of EVA in either planned or contingency modes. The Space Shuttle system will allow EVA to be conducted as normal orbital operation, if the application requires such tasks.
The manned maneuvering units being developed by the NASA Johnson Space Center, and uses designs and components derived from the flight experience of the Skylab Experiment M509 test bed MMU. An untethered EVA crewmember can utilize the modular MMU to complete a wide variety of tasks within several hundred feet of the Orbiter. Full six degree-of-freedom control of the MMU is maintained by the crewmember. Work site aids such as ancillary power, lighting, and restraint systems are also provided by the MMU.
Tasks related to the assembly or maintenance of large space structures which the MMU can support include routing-cables or lines between discontinuous points, adjustment of instruments, replacement of failed modules, inspection, and malfunction assessment and corrective action, The versatility of the crewmember/MMU combination allows many designs and procedural options to be considered to accomplish such tasks. Designers of large platforms in space should include EVA and the MMU in their complement of potential support tools.