Performance, contamination, electromagnetic, and optical flight measurement development for the Electric Propulsion Space Experiment

The Electric Propulsion Space Experiment (ESEX)—A demonstration of high power arcjets for orbit transfer applications

“…The team is divided into four groups based on the type of data that will be returned by the ESEX diagnostics (LeDuc 1996). A brief description, as well as a status, of each of these areas is summarized below.…”

“…The experiment will demonstrate the feasibility of a high power arcjet system, as well as measure and record flight data for subsequent comparison to ground results (Kriebel 1992, Sutton 1995, and LeDuc 1996. The flight diagnostic suite includes four thermo-electrically-cooled quartz crystal microbalance (TQCM) sensors, four radiometers, near-and far-field electromagnetic interference (EMI) antennas, a section of eight gallium-arsenide (Ga-As) solar array cells, a video camera, and an accelerometer.…”

An Overview of the On-Obit Results from the ESEX Flight Experiment

“…This behavior was eventually traced to a signal-to-noise problem, but effectively eliminated the ability of the receiver to support ESEX operations as originally planned. 3 The second issue was an inability to perform ranging, commanding, and telemetry downlink simultaneously with the AFSCN standard uplink power and command modulation index. This problem first appeared during ground test, and was somewhat expected, but was mostly eliminated a few days into Phase I.…”

“…This test is performed by replacing the nominal PRN ranging code on the satellite with a test pattern from CPCA and determining the number of bit errors on the return signal using a BER counter. 3 ' 10,1 A series of baseline measurements were made while the arcjet was off, and with the vehicle in several transmit configurations for comparison with firing data. Figure 3 shows an example of the BER data with the arcjet firing vs. a baseline measurement in which there is no definitive effect from the arcjet.…”