As a follow on to the success of the Hyperion I program,
the Air Force Research Lab's Propulsion Directorate (Phillips
Laboratory) in conjunction with eAc continued development
of hybrid propulsion systems that used high-density storable
oxidizers such as S-5 HAN, ANNA, and colloidal oxidizers
with gas generator fuels. Studies involved advanced tactical
hybrids with the end goal of programmable thrust profiles
to optimize trajectory to the target. The secondary goal
was to achieve the maximum density impulse. eAc carried
out a series of tests with a 6" diameter motor to characterize
these advanced gas generator fuels with an azide based
polymer such as GAP and BAMO. The tests demonstrated very
high fuel regression rates, stable combustion, on-demand
throttling, and the ability to extinguish during burn
and restart. Multiple patents were issued based on these
studies.
Having specialized in N2O oxidizers and developed high-density
oxidizer systems for tactical applications, our scope
has expanded to include liquid oxygen. LOX is the preferred
oxidizer for space propulsion because of it's cost and
performance advantages. A series of six inch test motors
have been developed and fired using LOX. A second series
of 12" lox motors is in development and will be fired
shortly. A 20k lb thrust demonstration motor is in the
early stages.
Nozzle erosion is an issue for all rocket propulsion systems
and hybrids are no exception. eAc has done a series of
tests to develop nozzle throat technologies. The primary
objective is to minimize erosion in an oxidative exhaust
environment. Nozzle samples supplied by Cesaroni Technologies
and Plasma Processing have been tested in long burn 6"
motors with a water-cooled copper nozzle as a baseline.
Current work includes development of neutral surface area
rod and tube grain geometry that allows easy integration
with aerospike nozzles. Additional development programs
include aft-injected hybrids and cold and hot-gas inertial
reaction control.
