Amateur Radio in Space By Steve Ford, WB8IMY

Overview Amateurs have been building satellites since the earliest days of space travel. These satellites are known as “OSCARs”—Orbiting Satellite Carrying Amateur Radio. The first Amateur Radio satellite was OSCAR 1 and it reached orbit in 1961.

Satellites: Relays in the Sky Like commercial satellites, Amateur Radio satellites are primarily used to relay signals from one location to another. From their vantage points in orbit, satellites can “see” large portions of the Earth. This is known as a satellite’s “footprint.” Every station within the footprint can communicate through the satellite

The Footprint of OSCAR 27 In this illustration, every station within the circular footprint of OSCAR 27 (AO-27) can communicate through the satellite.

Satellite Orbits Most Amateur Radio satellites travel in low Earth orbits at altitudes of 800 to 1500 km. At this altitude, a satellite completes one orbit every 90 to 100 minutes. At the same time, the Earth is turning beneath the satellite. The result is that all stations on the ground will enjoy several 15-minute communication sessions with each satellite each day.

Station Equipment Because of the low orbits and sensitive receivers, many Amateur Radio satellites can be used with simple equipment.

Amateur Satellites Today Several Amateur Radio satellites are active today. All are low-Earth orbiters. OSCARs 27, 50 and 51 relay FM voice transmissions.

OSCAR 29 OSCAR 29 relays Single Sideband (SSB) voice and CW transmissions.

Digital Communication OSCARs 32 and 46 relay digital signals. They are also capable of capturing images of the Earth and sending these images as digital files.

Amateur Radio on the International Space Station There is also a fully equipped amateur facility aboard the International Space Station.

The Future New Amateur Radio satellites are being built now and should be in orbit within 5 years. One of these will be a high-altitude satellite known as Eagle.

Amateur Radio Operators: Pioneers in Space Amateur Radio operators continue to explore new technology, which includes space communication. With the projects currently scheduled, the future looks bright indeed!