Arcjets and arc heaters are important to a number of government-sponsored aerospace programs and share several common features. Placing satellites in orbit, maintaining proper orbit, and repositioning are major spacecraft mass drivers for a wide range of missions. Arcjets can reduce mission propulsion requirements in many cases and are of interest to many satellite users. Arc heaters are critical to the future development of hypersonic combat aircraft. Design and construction of a hypersonic aircraft for speeds of 4-5 km/s (Mach 12-15) will be complex and will require the development of high-performance arc-heating facilities for the evaluation/validation of new airframe and propulsion technologies. The first objective of this overview is to provide a summary of the basic principles of arcjets and arc heaters for readers unfamiliar with the field. The second objective is to describe fundamental research required to overcome the limitations of both devices, with an emphasis on common research areas. This overview is not comprehensive, but does include national research and development activities. It is intended as a guide to the organization of scientific research serving both arcjet and arc-heater development communities.

Arcjets and arc heaters : an overview of research status and needs

A shooting and bouncing ray (SBR) formulation is presented for treating the electromagnetic scattering from electrically large, inhomogeneous objects. A dense grid of rays representing the incident plane wave is shot toward the inhomogeneous objects. At the scatterer boundary, reflected rays and refracted rays are generated due to the discontinuity of the medium parameters. The trajectory, amplitude, phase and polarization of the rays inside the inhomogeneous object are traced based on geometrical optics. Whenever the rays cross the scatterer surface, additional reflected/refracted rays are generated and are tracked. This is repeated until the intensities of the refracted/reflected rays become negligible. The contributions of the existing rays to the total scattered field are calculated using the equivalence principle in conjunction with a ray-tube integration scheme. The ray formulation is applied to calculate the backscattering from cylinders and spheres and good agreement with the exact series solutions is observed in the high-frequency range. In addition, the backscattering mechanisms in penetrable objects are interpreted in terms of simple ray pictures. >

Electromagnetic scattering from an inhomogeneous object by ray tracing

Development of arcjet and ion propulsion for spacecraft stationkeeping

Electric propulsion - An evolutionary technology

A geometrical optics ray-tracing code has been developed to study the effect of plasma thrusters on communication satellite antennas. This code has e exible three-dimensional geometry and a friendly web-based interface. A study is reported where a thruster is directed perpendicular to a 1-m ree ector antenna 0.5 m away. The thruster is translated away from the ree ector, and the main lobe attenuation, H-plane main lobe full width, and cross polarization are analyzed at 0.2-m increments. These studies are done at 5 and 10 GHz.

Impact Analysis of Hall Thrusters on Satellite Antenna Performance

The objective was to study the effect of the arcjet thruster plume on the performance of an onboard satellite reflector antenna. A project summary is presented along with sections on plasma and electromagnetic modeling. The plasma modeling section includes the following topics: wave propagation; plasma analysis; plume electron density model; and the proposed experimental program. The section on electromagnetic modeling includes new developments in ray modeling and the validation of three dimensional ray results.

Bjorn Birkner

Papers

Near field interaction of microwave signals with a bounded plasma plume