Preliminary performance characterizations of an engineering model multipropellant resistojet for space station application

Abstract

SUMMARYlhis paper presents the results of a program to describe the operational characteristics of an engineering model multipropellant resistojet for application as an auxiliary propulsion system for space station. Performance was measured on hydrogen, helium, methane, water (steam), nitrogen, air, argon, and carbon dioxide. Thrust levels ranged from 109 to 355 mN, power levels ranged 2 from 167 to 506 W , and specific impulse values ranged from 93 to 385 sec, depending upon the propellant, chamber pressure, and heater current level cr: selected.obtained for operation with carbon dioxide. Detailed thermal maps of the heater and heat exchanger were alsoINTRODUCl ION lhis paper presents the results of a test program designed to describe the operating characteristics of an engineering model multipropellant resistojet. lhe multipropellant resistojet has been baselined as the low-thrust option for the space station propulsion system. The resistojet can provide low levels of thrust for drag make-up while disposing of a variety of fluids expected t o be present in excess quantities on board space station. The use of such fluids as propellants will result in significant reductions in Space Transportation System costs which would be associated with launching of the necessary propellants as well as the removal of waste fluids from space station. Recent studies have explored these and other potential benefits of a propulsion system incorporating low-thrust resistojets (refs. 1 and 2). goals emphasize thruster life, reliability, and multipropellant capability rather than optimum performance. The design life goal is a minimum of 10 000 hr for thrusters operating on hydrogen, helium, methane, water (steam), nitrogen, air, argon, and carbon dioxide at specific impulse and thrust levels of 100 to 500/sec and 130 to 450 mN, respectively.The main objective of this program was to evaluate the operating characteristics of an engineering model multipropellant resistojet which was designed and fabricated by the Rocketdyne Division of Rockwell International and Technion Incorporated as part of the Space Station Advanced Development Program. The engineering model thruster incorporates design features which enable it to operate on a wide variety o f fluids for extended periods of time. This thruster was characterized on the above mentioned fluids. Performance data were obtained for each propellant (except steam) at two thrust levels for each of two input electric power levels. Data were obtained for steam operation at a variety of power levels for each of two conditions: steam supplied to the thruster from a water vaporizer and liquid fed directly to the thruster. Detailed informatlon about the temperature distribution within the heater and heat exchanger was also obtained for operation with carbon dioxide. The thermal transient behavior of the engineering model was investigated for operation with carbon dioxide and argon. The information gained from these tests served as input to a design iteration intended to enhance the operational ...

Aerospace Fuels from Nonpetroleum Raw Materials

“…The cold gas specific impulse for the hydrogen resistojet is approximately 380 sec at a power level of 329 W. In comparison, the cold gas hydrogen performance (with no heater power) is 250 sec (Ref. 35). …”

Waste Management Options for Long-Duration Space Missions: When to Reject, Reuse, or Recycle

“…5. 12 The average molecular weight of the gases produced from the steam reforming is 36.3 gm/mole, resulting in a resistojet specific impulse of 134.3 sec and a coldgas specific impulse of 64.4 sec. If secondary reactors are included to take the waste processing all the way to oxygen and methane, the mass ratio produced is approximately 1.5 to 1.…”

Trash-to-Gas: Using Waste Products to Minimize Logistical Mass During Long Duration Space Missions

“…The TtG system could be tailored to maximize recovery of water from the waste, or produce other gasses depending on the application. In addition to methane propolusion, gasses produced from the oxidation of waste, such as carbon dioxide and carbon monoxide, can be used for resistojet propulsion 2 . TtG technologies will process all combustible waste, including human metabolic waste, thereby reducing the volume of waste that needs to be stored, and stabilizing the waste, minimizing the possibility of unwanted microbial activity on a spacecraft.…”

“…(1) (2) Previous studies have investigated incineration and gasification for processing of spaceflight waste. 4 ' 5 These studies demonstrated feasibility of the process and identified critical reaction parameters for different waste materials.…”