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One of the most exciting aspects of amateur radio is the ability to communicate through space. Since the launch of OSCAR 1 in 1961 — just four years after Sputnik — radio amateurs have been building, launching, and operating their own satellites. Today, the intersection of amateur radio and space extends well beyond satellites to include contacts with the International Space Station, bouncing signals off the Moon, and exploiting the brief ionized trails left by meteors.
Space-based communication offers amateur radio operators something unique: the ability to make contacts over vast distances using relatively modest equipment. A handheld radio and a small directional antenna can be enough to communicate through a satellite hundreds of kilometres overhead. With more sophisticated setups, you can bounce signals off the lunar surface — a round trip of roughly 770,000 km (478,000 miles).
These activities combine radio operating skills with an understanding of orbital mechanics, propagation physics, and antenna design. For many operators, the challenge of working through a satellite during a brief overhead pass or detecting a faint signal reflected from the Moon is what makes the hobby endlessly engaging.
The amateur satellite programme is one of the oldest non-governmental space efforts in the world. Dozens of amateur satellites are in orbit at any given time, providing FM repeaters in space, linear transponders for SSB and CW, digital store-and-forward systems, and experimental payloads. Organizations like AMSAT coordinate the construction and launch of these spacecraft.
The International Space Station carries amateur radio equipment that crew members use to make contacts with operators on the ground, and for scheduled educational outreach events with schools. Making contact with the ISS is one of the most accessible and thrilling space-related activities in amateur radio.
Working satellites requires knowing when they will be visible from your location and where to point your antenna. Satellite tracking covers the software, tools, and techniques for predicting passes and following a satellite across the sky in real time.
While some satellite contacts can be made with a handheld radio, a dedicated satellite station typically includes directional antennas (often a Yagi or crossed-Yagi), an azimuth/elevation rotator, a dual-band transceiver, and software for Doppler correction. The requirements vary significantly depending on which satellites you want to work.
Earth-Moon-Earth (EME) communication is among the most technically demanding activities in amateur radio. Operators transmit a signal toward the Moon and listen for the extremely faint echo roughly 2.5 seconds later. Path losses exceed 250 dB, requiring large antennas and sensitive receivers. Despite the difficulty, EME contacts are made regularly on bands from 144 MHz through microwave frequencies.
Meteor scatter communication uses the ionized trails left by meteors entering the Earth's atmosphere to reflect VHF signals far beyond their normal line-of-sight range. Contacts are often brief — sometimes only a few seconds — making digital modes like MSK144 particularly well suited to this mode. Meteor scatter works on the 6-metre and 2-metre bands and is most productive during major annual meteor showers.
If you are new to space-related amateur radio, the easiest entry point is satellite operation. Many FM amateur satellites can be worked with an inexpensive handheld dual-band radio (VHF/UHF) and a simple antenna — even a handheld Arrow or Elk antenna. From there, you can progress to more advanced satellite work, try for an ISS contact, or begin experimenting with meteor scatter using digital modes.
EME is typically the most advanced activity in this category and usually requires significant investment in antenna systems and low-noise receiving equipment, though modern digital modes like JT65 and Q65 have lowered the entry barrier considerably.