Autophage Engines: Toward a Throttleable Solid Motor

Abstract

This paper describes the instrumented test-firing of a rocket which seeks to combine the throttleability of a liquid-fueled engine with the simplicity of a solid motor. The concept is that a differentiated fuel and oxidizer rod is forced into a vaporization unit where its constituents transition into separate propellant gases, which are then mixed in a combustion chamber. The vaporization unit is heated by the combustion and the throttle setting is adjusted by changing the force used to drive the solid propellant rod into the vaporizer, which naturally influences the propellant feed rate. In experiments using a solid propellant rod consisting of polypropylene fuel and a 1:1.5 mixture of NH4ClO4 and NH4NO3 oxidizer, we have sustained operations for around sixty seconds. During testing, using propellant feed forces of between 250 N and 900 N, we have achieved propellant feed rates of between 100 mm/min and 300 mm/min, which are in turn correlated to chamber pressures of between approximately 300 kPa and 700 kPa. These correlated cycles of control input (the feed force), throttle response (the propellant feed rate) and implied thrust (the chamber pressure) demonstrate, for the first time, a simple solid rocket that can be throttled in real time.

Analysis of ballistic aspects in the combined method for removing space objects from the near­Earth orbits

“…A given method makes it possible to ensure the guaranteed removal of an object within a specified time both in dense layers of the Earth's atmosphere and in higher orbit, including deep space. To implement a given method, tugs and various rocket propulsion systems are employed [6,7], including thrusters [8,9]. The disadvantage of this method is significant energy costs related to the need for fuel components to operate the systems that enable the removal process, which leads to the high cost of a particular implementation.…”

“…The prospects for further research include construction of a combined method for removal using thrusters and electrojet engines. In addition, it is of considerable interest to develop a design-ballistic support for the removal using auto-firing rockets-carriers [8], less costly, and environmentally friendlier, compared to conventional rocket-carriers.…”

Development of the combined method to de-orbit space objects using an electric rocket propulsion system

“…Thus, article [16] addresses the development of the design and ballistic maintenance for the flight of an autophase launch vehicle, taking into consideration the peculiarities of its JPS operation. Works [17,18] report the results of testing an auto-phase JPS. Research is also underway to find the optimal chemical composition of fuel for the autophase launch vehicles [19].…”

The stressed­strained state of a rod at crystallization considering the mutual influence of temperature and mechanical fields

“…Examples include a series of problems related to modern technology. The aerodynamic heating and destruction of bodies when moving in the atmosphere are considered in [1]; high-temperature processes in rocket enginesin work [2]. Accounting for temperature stresses in the structural elements at high-temperature heat loads is necessary for the development of a new class of small solid-fuel rocket engines [3].…”