CATSAT Update
by Frank Hludik
As in the recent issues of Signals and Noise, we will continue to keep you updated about the Cooperative Astrophysics and Technology Satellite (CATSAT) project. NASA funds the project through the Student Explorer Demonstration Initiative (STEDI) program of the University Space Research Association (USRA).
The STEDI program seeks to demonstrate that university-led teams can successfully carry out high-quality space science and technology missions for relatively low cost on a time scale of two years from go-ahead to ready-for-launch. Students and entry-level professionals are closely involved in every aspect of this pilot program. Supervised by experienced space scientists and engineers, the students gain invaluable hands-on experience in the design, development, test, and operation of a real space project. Three projects were selected from a total of 66 proposals submitted: the University of Colorado’s SNOE, Boston University’s TERRIERS, and the University of New Hampshire’s CATSAT.
The excitement continues to build as the challenge of completing the satellite in time for final integration, testing, and launch quickly approaches. We reported in the past that the final launch date had been set, only to have it change. Another launch date has been scheduled, which seems quite firm at this time, for the fall of 2001. Currently eight ECE students along with students from the Mechanical Engineering (ME), Computer Science (CS), and Physics departments are employed full time during the summer months and part-time during the spring and fall semesters.
Kevin Meyer, a May 2000 ECE graduate, is working on the digital systems integration and mission flight software. He is coding the software that will interface the spacecraft system to the ground communication channel. Starting this fall, Kevin will be a CATSAT supported graduate student. Sean Prindle, an ECE senior, is developing the power control subsystems. Assane Faye and Jim Leonard, both ECE students, are working on the power switching circuits and satellite attitude, current, voltage, and temperature sensor inputs. These sensor inputs will help determine the status of the satellite’s subsystems while in orbit. Cihangir Yuksel, an ECE graduate student on an educational leave from the Turkish Navy (submarine corps), is developing the battery selection and testing procedures. Jessica Luan and Karen Vaccari are currently working with Cihangir and will conduct battery testing and selection this fall. Jeremy Saunders, an ECE undergraduate, is completing the development and calibration of the sun and attitude sensors.
The integration of the satellite frame and electronic enclosures is nearing completion. The ME students will be developing the wiring harness installation procedure. The flight units of most of the electronic subsystems are built and awaiting the next testing phase. Starting in early 2001, the complete satellite will undergo a series of qualifying tests. A number of vibration tests will be done at Sanders, a Lockheed Martin Company, in Manchester NH. At UNH, shock testing will be done to determine if the satellite’s subsystems can withstand the launch-vehicle/satellite separation mechanisms. The separation mechanisms are comprised of exploding bolts that release the satellite’s launch ring from the launch vehicle. The final series of environmental tests will be conducted at NASA’s Goddard Space Flight Center. Goddard tests will include thermal balance, thermal vacuum, and acoustic vibration, which will mimic the actual launch and orbital conditions.
The S-band bi-directional radio link antenna has been installed on the roof of Morse Hall and the satellite’s transmitter and receiver are on order. Because of the new frequency allocations, CATSAT will now use S-band communication equipment on both the down-link and up-link channels. A one-box solar array simulator (SAS) is being used to simulate the properties (current, voltage, and temperature profiles) of the selected solar cells. The SAS is a dc power source that simulates the output characteristics of a solar array. The SAS is primarily a current source with very low output capacitance and is capable of simulating the I-V curve of different arrays under various conditions.
We hope that past CATSAT team members and ECE alumni enjoy keeping track of the satellite’s progress. Hopefully, in next year’s issue of Signals and Noise we can report on the activities leading up to the actual launch. For more information, go to http://www.catsat.sr.unh.edu on the World Wide Web.
