Session
Technical Session V: Propulsion
Abstract
Safe propulsion for orbit adjustment and de-orbit is a critical capability for the deployment of large constellations of small satellites. ‘Rideshare,’ in which a CubeSat or other small satellite is provided a ride to orbit on a large launch vehicle, is the primary method of getting CubeSats into orbit; however, when riding as a secondary payload, there is little or no influence on the final orbit. Therefore, a high Δ V, high thrust propulsion system is an enabling technology permitting the CubeSat to be redirected to a desired orbit, after the initial insertion. End of life deorbiting of small satellites is necessary to reduce the presence of space junk and this will require the use of compact, high performing thrusters. However, there is a catch-22 in that one needs a high-Δ V propulsion to fully realize the potential of small satellites, but as secondary payloads, the risk to the main payload of lifting a highly hazardous propulsion system on a rideshare often precludes it. Given the short lifetime (often the end of a university student project) and often small budgets of these very small satellites, getting to the target orbit in a short time is important to enable basic scientific missions. LANL’s segmented solid-fuel, solid-oxidizer system is uniquely non-detonable and safe, making it the perfect solution.
The LANL Segregated Fuel-Oxidizer System (SFOS) is a combination of novel materials that allow for a radically new propulsion design that is unique in its high level of safety and energy density. Inheriting from the development of high-nitrogen/high-hydrogen energetics at LANL that contain little or no oxygen, a segregated tandem system has been designed. The decomposition of solid energetic material provides fuel-rich gasses that are oxidized downstream by reaction with a solid oxidizer grain. Because the fuel and the oxidizer are separated until combustion and both are relatively (or completely) insensitive to shock, the chance of accidental detonation or initiation of the rocket is dramatically reduced. The fuel used is non-detonable and decomposes into gaseous products such as hydrogen and nitrogen upon ignition. Additional safety is gained as the oxidizer doesn’t burn in the absence of fuel and heat. Fuel rich products react with the oxidizer in a diffusion flame above the surface of the oxidizer grain. Thermochemical analysis predicts rocket performances in excess of standard solid propellants and hypergolic propellants. With a theoretical characteristic exhaust velocity (c*) of approximately 1600 m/s and vacuum specific impulse (Isp ) as high as 260 s, this new propulsion system is a competitive, safe, low-cost, non-toxic alternative to existing hydrazine based and composite solid propulsion systems. In this work, we will discuss the fundamental research in the development of this propulsion system, and its integration on to an existing LANL CubeSat platform in arrays to provide multiple orbital maneuvers. Current efforts are focused on the design of 12-50 mm diameter motors, but like any conventional solid propellant system, the size is scalable to different dimensions depending on mission requirements.
High DeltaV Solid Propulsion System fort Small Satellites
Safe propulsion for orbit adjustment and de-orbit is a critical capability for the deployment of large constellations of small satellites. ‘Rideshare,’ in which a CubeSat or other small satellite is provided a ride to orbit on a large launch vehicle, is the primary method of getting CubeSats into orbit; however, when riding as a secondary payload, there is little or no influence on the final orbit. Therefore, a high Δ V, high thrust propulsion system is an enabling technology permitting the CubeSat to be redirected to a desired orbit, after the initial insertion. End of life deorbiting of small satellites is necessary to reduce the presence of space junk and this will require the use of compact, high performing thrusters. However, there is a catch-22 in that one needs a high-Δ V propulsion to fully realize the potential of small satellites, but as secondary payloads, the risk to the main payload of lifting a highly hazardous propulsion system on a rideshare often precludes it. Given the short lifetime (often the end of a university student project) and often small budgets of these very small satellites, getting to the target orbit in a short time is important to enable basic scientific missions. LANL’s segmented solid-fuel, solid-oxidizer system is uniquely non-detonable and safe, making it the perfect solution.
The LANL Segregated Fuel-Oxidizer System (SFOS) is a combination of novel materials that allow for a radically new propulsion design that is unique in its high level of safety and energy density. Inheriting from the development of high-nitrogen/high-hydrogen energetics at LANL that contain little or no oxygen, a segregated tandem system has been designed. The decomposition of solid energetic material provides fuel-rich gasses that are oxidized downstream by reaction with a solid oxidizer grain. Because the fuel and the oxidizer are separated until combustion and both are relatively (or completely) insensitive to shock, the chance of accidental detonation or initiation of the rocket is dramatically reduced. The fuel used is non-detonable and decomposes into gaseous products such as hydrogen and nitrogen upon ignition. Additional safety is gained as the oxidizer doesn’t burn in the absence of fuel and heat. Fuel rich products react with the oxidizer in a diffusion flame above the surface of the oxidizer grain. Thermochemical analysis predicts rocket performances in excess of standard solid propellants and hypergolic propellants. With a theoretical characteristic exhaust velocity (c*) of approximately 1600 m/s and vacuum specific impulse (Isp ) as high as 260 s, this new propulsion system is a competitive, safe, low-cost, non-toxic alternative to existing hydrazine based and composite solid propulsion systems. In this work, we will discuss the fundamental research in the development of this propulsion system, and its integration on to an existing LANL CubeSat platform in arrays to provide multiple orbital maneuvers. Current efforts are focused on the design of 12-50 mm diameter motors, but like any conventional solid propellant system, the size is scalable to different dimensions depending on mission requirements.
