Signal definition progressively deteriorated during the long voyage to Jupiter, resulting in an intensive research effort by members of the Deep Space Network, including the University of South Australia, an important contributor to the Voyager DSP research programme. DSpace is a direct commercial spinout of the university’s Institute for Telecommunications Research and the university’s associated business incubator Itek Pty Ltd. After mapping Jupiter the mission was redefined to map the rest of the outer planets, an extension that had been anticipated during the planning stage provided contact could be maintained with the spacecraft as the planets were then properly aligned for such a mission to be feasible. This second mission was also successfully completed with the mapping of Uranus, and now many years later both spacecraft are approaching the Heliopause at the outer limits of the solar system, an unknown region where the solar wind loses power and stops, giving way to true interstellar space.

The Voyager mission has been redefined for a third time to explore the Heliopause region and report on conditions in interstellar space beyond. Remarkably, and never foreseen during the planning stage, the signal quality received from both spacecraft today on Earth as a direct result of the ongoing digital signal processing research programme is just as sharp, despite the great distance, as the day the spacecraft left the planet more than 30 years ago. The 1970s era transmitters onboard the spacecraft are not very much more powerful than a standard modern mobile phone, and the sun itself, if viewed from the spacecraft today would appear not much bigger than a bright star, one of billions in the Milky Way galaxy.

The single greatest breakthrough in Digital Signal Processing technology was made by researchers associated with France Telecom in the early 90’s, with the discovery of Turbo-Coding, the base technology underpinning EstrellaSat’s EMDP satellite communications system today.