1442. A Towing Concept for Orbital Transfer of Large Space Structures

Paper

Abstract

Many studies are being made to determine the most efficient method for the transfer of large
space structures from low Earth orbits (LEO) to higher altitudes, principally geosynchronous
orbits. The overall physical size of the structures coupled with low mass of individual
members leads to the consideration of unconventional orbital transfer systems and operations
such as: the use of rocket engines with very low thrust and flights with long trip times,
multiple engines distributed over the structure, or added structure to distribute the thrust
load from the transferring vehicle. In this paper, towing is proposed as a possible means
of orbital transfer of large space structures. A potential towing arrangement is identified
and some the the systems sized for the transfer of a 2460-ft (750 meter) diameter antenna
weighing approximately 154,000 (70 metric tons). A savings of approximately 23 metric tons
in propellants and structure resulted from the use of a towing arrangement using six towlines
in parallel when compared to the use of a single tug hard mounted to the structure being
towed. The towing concept appears practical and affords a means of applying loads using
multiple towlines to a wide variety of structures without special adaptors.