The Spartan Packet Radio Experiment (SPRE) was an Amateur Radio (Ham radio) communications experiment. The primary mission of SPRE was to test satellite tracking using amateur packet radio and Global Positioning System (GPS). SPRE was developed and built by the University of Maryland Amateur Radio Association (UMARA) with assistance from NASA, volunteer engineers, and volunteer software professionals.

SPRE was one of four experiments on NASA's Spartan/OAST-Flyer spacecraft. The Spartan spacecraft was scheduled for launched on January 11, 1996 aboard the space shuttle Endeavour as part of mission STS-72. The spacecraft is a cube shaped, battery powered, retrievable satellite. Spartan was deployed by the shuttle's robot arm and likewise retrieved after approximately 48 hours of free flight.

Mission Objectives:

• Promote amateur radio and amateur satellite communications.
• Test GPS and packet radio based tracking system using a Low Earth Orbit (LEO) satellite.
• Provide an educational tool to inspire elementary and high school students to pursue science and engineering.
• Provide a unique hands-on educational opportunity for college students.

SPRE was designed to relay ground station positions and transmit telemetry containing the GPS location of the spacecraft and housekeeping data. The GPS data was generated by another Spartan experiment.

Special software called APRtrak (tm) was used at SPRE ground stations to plot the positions of stations and objects world-wide using SPRE transmissions. APRtrak uses full color maps and graphics with the capability to display detail maps of selected geographic regions. Amateur radio ground stations transmitted their locations to SPRE, and when heard, SPRE relayed the GPS information back to Earth. All ground stations within range of SPRE saw the relayed stations plotted on the map at the correct geographic location. The APRtrak software also decoded and displayed SPRE housekeeping telemetry including temperatures, voltages, and system status. This software is freely available on the Internet for installation on IBM compatible computers.

This technology has many applications in the amateur radio as well as the commercial worlds. Low cost Low Earth Orbit (LEO) satellites could be used to track storms, weather balloons, boats at sea, trucks, etc. Satellites could collect the location data from ground targets and download it to ground control stations. Since the SPRE mission was successful, this capability may be incorporated into future amateur spacecraft, thus supporting the amateur's effort for technological improvement.

The operational aspects of SPRE included amateur radio operators throughout the world. Elementary and High Schools were encouraged to enlist the aid of local amateur radio operators to set up ground stations and participate in the SPRE experiment. SPRE was designed to be used as an educational tool in many classes including math, science, and geography.

SPRE could still have been used as an educational tool even if a school was not in session during a fly-over. A simple amateur packet radio station could have been configured to listen to the SPRE telemetry and record the data for later study.

Amateurs and schools who participated were encouraged to send the data they collected to the SPRE Project to help to piece together a composite picture of the mission. The final results are available to participating schools and the amateur radio community.

SPRE used a ground control network, SPREnet, consisting of specially equipped amateur radio stations to distribute data via the Internet. These control stations successfully monitored the health and activity of SPRE.

In addition to the amateur radio experiment, the SPRE system forwarded to Earth a sampling of real-time telemetry for two of OAST Flyer's experiments: REFLEX and GADACS. Spartan's were equipped with on-board recorders to capture data from each of the experiments. Traditionally, an experimenter must wait several weeks to receive any mission data. SPRE provided a low cost, innovative solution giving experimenters the opportunity to view a small sample of data during the mission while advancing amateur radio satellite technology.

The sample REFLEX data from the mass spectrometer was used by the experimenters to provide feedback on how well their experiment was performing. SPRE provided GPS location and time information from the GADACS experiment. This information did provide some insight on the health of the GADACS GPS receivers. Using the APRtrak software described above, amateur radio stations and schools were able to observe the track of the satellite as it passes overhead.

Data were transmitted on a downlink frequency of 145.550 MHz. This was the same frequency used by the MIR space station and the Shuttle Amateur Radio EXperiment (SAREX). The data format was completely printable ASCII characters and therefore is fully compatible with all amateur packet radio equipment in common use today.

All of the hardware and software was designed and constructed by students and volunteers. This low cost project provided a great hands-on opportunity to gain experience in space communications. Several students earned college credit for their work on SPRE.

The core SPRE Team posing with the Spartan/OAST-Flyer (SP-206).

See the following pages for more detailed information.

• Community Participation

• Chronology

• SPRE Project Statistics

• Technical Reference

• UMARA Satellite Ground Station

• Flight Operations

• Project Results

• SPRE FAQ