| CATSAT is Scheduled to Fly Excitement ran high in the halls of Morse and Kingsbury this May when the Cooperative Astrophysics and Technology SATellite (CATSAT) project team received notice of full funding from NASA/USRA and a launch date of July 1998. In last year's issue of Signals and Noise we described the project and the progress that had been made during the 1994/1995 academic year. Over the past year the four CATSAT funded graduate students Dino Milani, Glen Forrest, David Gerry, and Steve Lynch have been busy designing and testing electronic subsystems of the satellite along with supervising a number of undergraduate students. CATSAT will be launched in orbit by a Pegasus XL three-stage solid rocket booster. The Pegasus rocket will first be carried to an altitude of approximately 39,000 ft by Orbital Sciences Corporation's L-1011 carrier aircraft from Vandenberg Air Force Base and then released. The Pegasus rocket will then carry CATSAT to its final orbit altitude. CATSAT will be launched into a sun synchronous, polar, dawn/dusk orbit at an altitude of 550 km. The satellite will have an operational lifetime of at least two years. The polar orbit will keep the soft x-ray detector system (SXR) pointing away from the sun and the solar panels facing toward the sun. This orbit will also allow access to the two ground stations that will communicate with the satellite. UNH and Weber State University (WSU) will communicate with CATSAT for housekeeping and attitude control using UHF transmission. Scientific data from the instrument memory will be downloaded to UNH via S-band transmission.
Glen Forrest (son of Dr. David Forrest - the principal investigator of CATSAT) characterized the avalanche photodiodes (APD) which will be used in the SXR. The SXR system is the primary instrument aboard the satellite. The SXR's APD will detect photon energies from 0.5 to 20 keV. Glen will be graduating in September 1996 and will join Allegro Microsystems, Inc. Steve Lynch has developed the analog electronics which interface the sensor systems to the digital data gathering system. Steve has been working over the past year to develop the electronics to meet stringent power, cost, radiation tolerant, speed, and space constraints. This has been no easy task considering all these constraints. Steve has been assisted by Pedro Irazoqui-Pastor an ECE undergraduate student. David Gerry developed the automatic high-voltage gain control system. This system automatically adjusts the APD's 1500 volt bias voltage to keep the sensors in calibration. Dave's FPGA based controller system has the task of keeping 112 sensors in calibration. David wins the "First PCB Award" for completing the first multilayer PCB in the CATSAT project. Jon Frain an ECE undergraduate (our resident PCB expert) did the PCB layout on our Mentor Graphics CAD system. Dino Milani, aka Mr. DEU, has developed the 80C186 based CPU
subsystem that will be used in both the scientific computing system and WSU
spacecraft control system. The CPU subsystem is part of the digital electronics
unit (DEU) which also has subsystems for extended memory, electronic instrument
control, communications, and data gathering. All DEU subsystems are radiation
tolerant and low power. Dino is assisted by ECE undergraduates Jeff Butler
(software development), Jon Frain (design and layout of the extended memory
boards), Ryan Rousseau (PCB layout and prototyping), Joel Mellin (interconnect
and wire harness system), and CS undergraduate Dale Lepine (software
development).
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