On this day: Australia’s first amateur satellite
The Australis-OSCAR-5 and its Stanley tape antennae. (Credit: Courtesy Richard Tonkin)
ON 23 JANUARY 1970, Australia's first amateur radio satellite was launched. Built in 1966, Australis-OSCAR-5 was the first amateur radio satellite constructed outside of the United States.
In the 1950s and '60s amateur radio was a popular hobby. The Melbourne University Astronautical Society began tracking amateur radio satellites, which developed into a project with the Melbourne University Radio Club to build their own amateur radio satellite.
The US Air Force and NASA provided free launches opportunities when there was spare capacity available on the launch of their larger satellites. In Australia, however, the OSCAR-5 had to wait several years for this type of launching opportunity to arise.
Unfortunately, the delay meant that it was beaten to the status of Australia's first satellite by the Weapons Research Establishment's satellite, WRESAT, which was launched from the Woomera rocket range in November 1967.
Successful satellite launch and signal
In the 1970s, William Dunkerley was a member of the board of directors of AMSAT – the American organisation that prepared OSCAR-5 for launch. He transmitted the first successful ground command to control the satellite.
"Everyone was waiting for reception reports that would confirm that OSCAR-5 was really working in orbit," William says. "The first such report came from a NASA tracking station in Madagascar."
Australis-OSCAR-5 was built to act as a beacon broadcasting a signal on two wavebands popularly used by radio amateurs around the world.
Each broadcast began with the letters 'HI' in Morse code and was followed by data from seven different onboard sensors (battery voltage, temperature at two points on the satellite, and information that established the satellite's orientation in space).
This meant amateur radio groups, or radio physics university groups, could use the signals from the satellite to help glean information about the properties of the upper atmosphere from the way the signals were distorted when they were received on the ground.
Australia enters the space age
Kerrie Dougherty, curator of space technology the Powerhouse Museum in Sydney, says it was an important boost to space science in Australia. "It was a really interesting project because it demonstrated that the necessary skills for Australia to move into the space arena existed within our universities and industry at that time," she says.
The story of building OSCAR-5 , however, was in some ways typically Aussie. "The satellite was built on a shoestring budget and the students improvised much of the equipment," says Kerrie.
"They couldn't afford a spring release mechanism so they used specially-made bed springs; the satellite's antennae were actually cut down Stanley tape."
These make-shift instruments worked perfectly well in the circumstances for which they were designed. "For their cold soak test they basically used an Esky filled with dry ice and immersed the satellite in it to make sure it would function properly in the cold of space."
Exactly how many people actually tracked the satellite is unknown but reports were submitted to AMSAT headquarters from several hundred tracking stations in more than 27 different countries.
The satellite transmitted its 2m signal until 14 February 1970, and the 10m signal transmitted until 9 March 1970, when its batteries failed. It is still in orbit and will remain so for another few hundred years.
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