Recruiting Home-Powered Hams for a NASA Electron Beam Experiment Michael Mideke WB6EER excerpted by Karen Perez KA7ETV A group of hams is recruiting help for a space shuttle experiment, due to launch on March 10, 1992. Space Experiments with Particle Accelerators (SEPAC) will be of particular interest to whistler hunters as it involves the operation of a plasma bean modulated at frequencies from below 1kHz to 8 kHz to form a "virtual antenna" within the magnetosphere. The experiments, designed to investigate the nature of magnetospheric wave-particle interactions, may well generate whistler mode signals that can be heard by listeners on the ground. Ground stations will play an important role in the experiment. NASA has given the go-ahead to proceed with amateur/student participation. INSPIRE The ground station project is called Interactive Space Physics Ionosphere Radio Experiments (INSPIRE). They want to recruit a few hams who live beyond the power grid (radio quiet sites) and can operate highly sensitive monitors with relatively little inconvenience. The group has prepared an E- Field receiver kit (receiver kit, instructions, demo tape, follow-up mailings for $49.95) similar to the RS-3. However, there is nothing magic about the "kit" receiver - any system that works for hearing and recording whistlers is a potential contributor. Since the SEPAC transmissions will be harmonic rich, conventional receivers operating in the 10 to 30 kHz range will also have a place. Nobody knows whether ANY ground station will hear ANYTHING from SEPAC. However, the greater the number of stations and the better their coordination, the better the odds of success. How Can You Help For the project to reach its full potential, it will be thanks to a large number of people contributing their time and expertise. How can YOU help? Perhaps you know of a school, class or instructor who should know about this. Maybe you could help initiate student kit-builders into the mysteries of soldering and circuit de-bugging. Maybe you could scout vehicle accessible quiet sites or provide a few good cassette recorders, or use Ham Radio to maintain liaison between a monitoring group and the experiment. Maybe you could cook up a far better receiver, take it out to the middle of nowhere and come back with the best records of SEPAC. Maybe you could donate money or equipment... SEPAC Operations: FO7 SEPAC constitutes but one small part of the ATLAS 1 mission, and the North American ground station campaign is only part of SEPAC's program. The part that directly concerns us is known as Functional Objective #7 (FO7). FO7 calls for the modulation of SEPAC's electron beam on a progression of 20 frequencies between 50 Hz and 7.04 kHz, beginning at the highest frequency. Each frequency will be occupied for 0.1 second. The interval between operations of the modulated electron beam varies along with the three beam power levels. At 1.45 kW the interval is 0.4 seconds. At 3.52 kW it is 1 second and at 6.2 kW, 1.5 seconds. One minute is required to perform the stepped frequency progression at all three power levels. An FO7 operation will repeat the complete format 5 times, for five minutes of operation. In that time, the Orbiter will have traversed about 2100 km in a generally North- South path, pretty well covering North America. Ground Station Objectives The primary objective of the ground stations is to determine the footprint of radio wave propagation from the pulsed electron beam in the ionosphere to the ground. Secondarily, the ground stations will attempt to detect any effects such as triggered emissions produced by FO7. In addition, they will produce a comprehensive record of VLF conditions before, during and after the experimental operation. And More We received a very detailed report about this project but unfortunately we ran out of room. If this small bit piques your interest more detailed information can be had from Michael Mideke, WB6EER, Box 123, San Simeon, CA 93452- 0123 (too remote to have a phone!) or Jim Ericson, KG6EK, 226 Charles St, Sunnyside, CA 94086-6063, 408-773-8947.