Session
Technical Poster Session 4
Location
Utah State University, Logan, UT
Abstract
Most spacecraft propulsion systems require specific propellants with stringent quallity requirements. Examples include high purity xenon, krypton or argon used by many Hall and ion thrusters, where propellant contamination can corrode parts of the thruster, in particular the neutraliser cathode, leading to thruster failure[1]. The same is true in most chemical thrusters, which often require not only high propellant purity, but filtration to prevent particulate intrusion [2].
Propellant purity requirements lead to availability restrictions, which impacts propellant pricing. The standard defining RP-1, the refined kerosene derivative utilised in many launch vehicles, stipulates such stringent composition requirements that only petroleum sourced from a few wells is considered economic to refine into RP-1 due to the scale of the market and quality required [3, 4]. Similarly, the purity restrictions on aerospace grade noble gasses limits their production to only a few atmosphere separation units worldwide, which has led to supply shocks due to the Russo-Ukrainian War. These shocks have abated somewhat in the last few months, but the scarcity of these feedstocks makes them vulnerable to similar disruptions in future. Recent reductions in launch cost has seen the cost of Xe propellant become a more important factor in mission cost analysis than was previously the case. The aggregate costs of propellant for a small satellite constellation has, recently, become a larger fraction of total mission costs, and thus has driven innovation in gas-fed electric propulsion systems[5, 6].
Alternative propulsion technologies can utilise fundamentally different propellants to the noble gasses and reactive chemicals of traditional propulsion systems. One such example of this are Pulsed Cathodic Arc Thrusters (PCAT). This technology requires solid conductive propellants, which naturally suggests most metals and their alloys for consideration, as well as materials such as graphitic carbon [7]. Some of the better performing metals in PCAT are used industrially for producing various useful alloys, as well as being used as sputtering targets and source cathodes in related plasma deposition sources [8]. Additionally, common aerospace alloys can be used as propellant, enabling a use-case for on-orbit recycling to mitigate the growing orbital debris population [9].
In this work we describe the operating principles of this technology before describing work done to fly operational systems. Current projects to further develop the technology in collaboration with partners are also discussed.
Propellant Variety and Affordability: A Strength of Pulsed Cathodic Arc Propulsion Systems
Utah State University, Logan, UT
Most spacecraft propulsion systems require specific propellants with stringent quallity requirements. Examples include high purity xenon, krypton or argon used by many Hall and ion thrusters, where propellant contamination can corrode parts of the thruster, in particular the neutraliser cathode, leading to thruster failure[1]. The same is true in most chemical thrusters, which often require not only high propellant purity, but filtration to prevent particulate intrusion [2].
Propellant purity requirements lead to availability restrictions, which impacts propellant pricing. The standard defining RP-1, the refined kerosene derivative utilised in many launch vehicles, stipulates such stringent composition requirements that only petroleum sourced from a few wells is considered economic to refine into RP-1 due to the scale of the market and quality required [3, 4]. Similarly, the purity restrictions on aerospace grade noble gasses limits their production to only a few atmosphere separation units worldwide, which has led to supply shocks due to the Russo-Ukrainian War. These shocks have abated somewhat in the last few months, but the scarcity of these feedstocks makes them vulnerable to similar disruptions in future. Recent reductions in launch cost has seen the cost of Xe propellant become a more important factor in mission cost analysis than was previously the case. The aggregate costs of propellant for a small satellite constellation has, recently, become a larger fraction of total mission costs, and thus has driven innovation in gas-fed electric propulsion systems[5, 6].
Alternative propulsion technologies can utilise fundamentally different propellants to the noble gasses and reactive chemicals of traditional propulsion systems. One such example of this are Pulsed Cathodic Arc Thrusters (PCAT). This technology requires solid conductive propellants, which naturally suggests most metals and their alloys for consideration, as well as materials such as graphitic carbon [7]. Some of the better performing metals in PCAT are used industrially for producing various useful alloys, as well as being used as sputtering targets and source cathodes in related plasma deposition sources [8]. Additionally, common aerospace alloys can be used as propellant, enabling a use-case for on-orbit recycling to mitigate the growing orbital debris population [9].
In this work we describe the operating principles of this technology before describing work done to fly operational systems. Current projects to further develop the technology in collaboration with partners are also discussed.
