RESEARCH & DEVELOPMENT
1. CONVENTIONAL CHEMICAL PROPULSION SYSTEMS
While working as a space propulsion engineer for a NASA subcontractor, during the pre-INTERPLANETARY EXPEDITIONS period, initial research and development experience focussed on conventional chemical propulsion systems. Composite solid propellant using phased stabilised ammonium nitrate (PSAN), magnesium metal powder, hydroxy terminated polybutadiene and a curing agent were formulated and filled into rocket chambers in a core burner configuration and test fired prior to installing into a test vehicle to determine flight characteristics.
4 inch rocket motor test (courtesy Wickman Spacecraft & Propulsion Company)
One unique engine concept using conventional chemicals developed was a LOX/RP-1 "monopropellant". This logic of this concept was to formulate and test fire a small engine using kerosene particles suspended in liquid oxygen. Safely storing the propellant in one tank allows dramatic reduction in vehicle dry mass.
2. IN-SITU RESOURCE UTILISATION
Any serious road-map to missions beyond CIS-Lunar orbit should involve in-situ resource utilisation (ISRU) technologies in one form or another. It is entirely logical that continued exploration of nearby planets employ local resources in order to reduce the mass of life support and propellants required from Earth and extend overall mission duration. Although initial investment will prove costly, the mid to long term economical benefit is immense - provided the public sector space organisations are serious about long term space exploration and not simply one-off missions.
An ISRU concept for Mars missions was developed using carbon dioxide as an oxidiser and magnesium metal powder as the fuel. Both chemicals comprise of 95% of the Martian atmosphere and 4% of the Martian soil, respectively. Following a series of successful engine tests, performed by Wickman Spacecraft & Propulsion Company under contract to the Jet Propulsion Laboratory, INTERPLANETARY EXPEDITIONS was employed as a principal investigator on a European Space Agency Phase 0 study contract in order to draw on the experiences while working as a propulsion engineer on the same concept.
ISRU propulsion systems, although productive in any long term space exploration road map, is still far from practical implementation.
INTERPLANETARY EXPEDITIONS is presently formulating the theoretical calculations for an ISRU propulsion system with an aim to design an engine with an objective to conduct static test firings by 2010.
3. ANTIMATTER PROPULSION
Chemical propulsion systems have achieved their theoretical maximum and there is little more that one can do to improve on existing technology. Even so, any human expedition using conventional chemical propulsion systems on a Type 2 trajectory to Mars would still take on the order of 9 months to complete a one-way journey. This is unacceptable. The only way to reduce transit time of such missions is to focus on the development of advanced propulsion systems. The successful implementation of an advanced propulsion system would see a dramatic reduction in over all spacecraft subsystem mass as well as the required consumables.
Proton-antiproton annihilations afford the largest known energy release but the terrestrial production of anti-protons plus the technical challenges in storing large quantities of anti-hydrogen make this proposed propulsion system a very futuristic concept.
One near term alternative is to employ electron-positron annihilations. Although the energy release is three orders of magnitude less than proton-antiproton annihilations, the production of positrons is less taxing although the storage will still prove to be a challenge. Electron-positron annihilations produce two high energy gamma rays but if the positron beam is directed towards a high density material such as tungsten or lead, then a fluid passing through channels may be superheated to produce a unidirectional high energy exhaust which could be accelerated via a nozzle to produce thrust.