AAS 97-711
LOW-COST MODIFIED LAUNCH MODE FOR HIGH-C3 INTERPLANETARY MISSIONS
H.F. Meissinger, J.R. Wertz, and S. Dawson - Microcosm, Inc.
Abstract
A novel method of spacecraft injection to interplanetary trajectories is described that can increase the net spacecraft mass by 50 to 100 percent or more in high-C3 missions. This launch mode employs an unconventional staging sequence, separating the spacecraft from its launch vehicle at a velocity equal or close to Earth escape, i.e., an energy near C3 = 0, and then using onboard propulsion to reach the required final C3-value. It is particularly suitable for missions that require subsequent deep-space maneuvers for which an onboard propulsion system is carried. - The large payload mass gain shown for some representative mission examples is due to applying the required final velocity impulse only to the spacecraft, but not to the launch vehicle's generally large upper-stage dry mass. - DV penalties inherent in using a lower than the conventional upper-stage thrust acceleration can be minimized so as not to exceed a few percentage points.