February 26 and possibly February 27 during the local AM passes over Colorado the AO-51 U band voice transmitter will be off and the S band will be on in digital mode at 38k4 and 78k4. These mode changes are to facilitate the testing of the US Air Force Academy satellite ground station in preparation for the launch of Falconsat-3.

Falconsat-3 (FS-3) is another in the series of satellites built at the US Air Force Academy. It is presently scheduled to launch March 8 from Cape Canaveral on an Atlas-V (mission STP-01). USAFA Space Systems Research Center satellites are science oriented and university class. FS-3 carries two space weather plasma detection experiments along with a micro pulse plasma thruster attitude control experiment. The objectives of the program are to do real science and educate USAFA cadets about space systems design, construction, testing, and operations. About 40 senior cadets are in the program each year. Falconsats are operated from the ground station at USAFA near Colorado Springs, Colorado.

Once in orbit FS-3’s mission is to collect data from its experiments and provide cadets in the Space Operations major an actual space ops experience. Additionally Astronautics major cadets will analyze telemetry and make operations decisions. FS-3 will perform its primary mission on DOD frequencies with a downlink at 2.220 GHz. Modulation is GMSK at 38k4 or 76k8 bps. All transmissions are in the clear and are AX.25. Additionally FS-3 carries an Amateur transmitter and receiver with a downlink at 435.100 Mhz. Modulation is GMSK at 9k6 with faster bit rates available. The Amateur uplink is in VHF and the frequency will be made available when FS-3 reverts to Amateur mode.

After the primary science mission is completed the satellite will be transferred to the USAFA Amateur Radio Club and operated as an Amateur satellite. It can function much like AO-51 in either an FM voice or digital store and forward configurations. During the first few weeks on orbit FS-3 will be commissioned, which includes uploading software and testing all functions. During that time the Amateur payload will be exercised.

The primary avionics in FS-3 are from SpaceQuest with additional modules built by cadets and faculty at USAFA and contractors. Software modules are from BekTek, SSTL, and Colorado Satellite Services, with additional software by cadets and faculty at USAFA. The satellite is ‘ESPA class’. The basic structure is a cube about 24” on a side. There is a 3 meter gravity gradient boom that will be extended from the ‘top’ on orbit. On the ‘bottom’ are the pulse plasma thrusters and various antennas including an array of S band patch antennas provided by S&L Technologies of Orlando along with omni antennas for S, V and U bands.

The USAFA ground station consists of two complete units with individual masts on the roof of the classroom annex building. Antennas include 6’ and 10’ dishes and Yagis. Rotators are the heavy duty MT-3000 and MT-1000 from M2.

The first USAFA satellite, Falcon Gold, went into GTO and measured the strength of GPS signals from well above the constellation. The results showed signal levels were adequate to warrant further experiments and in part lead to the GPS experiment on AO-40 and other satellites. Falconsat 4 and 5 are in the design stages now. Each is expected to carry an Amateur transmitter and receiver in addition to their primary payloads.

After launch reception reports will be appreciated. Reports may be sent to: fs3reports@coloradosatellite.com

Jim White css@coloradosatellite.com