OTV'S CATCH INDUSTRY'S EYE.

Unmanned rocket systems called orbital transfer vehicles (OTVs) are considered. These spacecraft are designed to transport satellites from low earth orbits reached by the shuttle into high earth orbit and to place unmanned space probes into interplanetary trajectories. Their reliability is underscored, as their applications for the delivery of communication satellites into useful orbits are expected to grow. Three types of OTVs are described: payload assisted modules (PAMs), inertial upper stages (IUSs) and modified Centaur boosters, all used by the NASA. The development of a low-cost OTV, called the transfer orbit stage (TOS), is reported.