Description
Objective: To develop a storable propellant blend based on Nitrous Oxide and identify the challenges of implementing a system based on this type of propellant.
Targeted improvements: 5-10% improvement in payload capacity and a comparable reduction in manufacturing costs.
Background:
Nitrous Oxided Fuel Blend propellants are re-emerging and a candidate next generation propellant for Telecoms applications. This is an old propellant combination that was passed up in favour of hydrazine alternatives. It has recently emerged in the US as a capable propellant. It is a premixed bi-propellant. It consists of nitrous oxide and a pure hydrocarbon (such as ethylene) the mode of operation allows monopropellant simplicity (single tanking) with bi-propellant levels of performance (~320-340s ISP). This outstrips any European green propellant alternative and is a potentially disruptive technology that could replace hydrazine as the propellant of choice in telecom satellites. The current US engine design is gas cooled and runs sufficiently cool to allow integration within the structure. It will be tested shortly on the ISS.
A monopropellant like system with bi-propellant performance levels would dramatically improve the design and production of telecommunication satellites. Single tank configurations with vastly simpler AIT overheads, reduced failure modes and lower cost handling requirements would be possible. In addition the propellant would be free of export licenses and compliant with the EU?s Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) regulation. All this while maintaining comparable, or better, performance than current systems. There are significant issues to implementing such a system: The tanking pressure is higher than current bi-propellant systems however the benign nature of the propellant would allow for self pressurising by rerouting some decomposition gases into the feed tank. This would eliminate the riskier high pressure helium feed system of current propulsion system designs and allow for low pressure operations during launcher integration. These issues need to be evaluated in parallel to the performance aspects.
Starting point:
Existing Bi-propellant systems used on-board telecommunication satellites.
Work logic:
1. Propellant development (formulation and preparation of the mixture)
2. Engine testing: using a test specimen, investigate the ISP and combustion parameters using various mixture ratios and chamber geometrics.
3. Propellant handling study
4. Assessment of the impact on telecommunication propulsion systems.