Imagine a communications satellite made up of a 100 000-unit swarm of separate units, each weighing around 20 grams and a few centimetres in diameter, floating near a receiver. Or try to visualise satellites like we know them today tethered together to form a single structure more than an acre in size.
These are two of the more exotic concepts for future satellite design presented to the Satcom Africa conference in Midrand yesterday by Joseph Pelton, executive director of the Arthur C Clarke Institute of Telecommunications and Information.
Science fiction writer Arthur C Clarke published a paper titled "Extra-terrestrial Relays" in 1945, laying the theoretical foundation for geo-stationary communications satellites. Now those following in his footsteps say the current curve of satellite development does not provide the cost-efficiency of fibre optics and it is time to start thinking big again.
"We see low power, low cost and even wearable [two-way] terminals the size of a cereal bowl in future," Pelton said speaking via a satellite link-up. "These would be smaller in size, lower in cost and support computing, voice, navigation and a range of functions."
Such devices would require satellites capable of high-powered transmission. On a more mundane level, the futuristic designs are also geared toward making the satellites cheaper. Pelton says the rotating tethered cluster design could cost more than $1 billion but would still be cost-effective due to its huge capacity. He predicts that such future satellites could focus hundreds of spot beams on the surface of the earth where current models can carry a very limited number of transponders.
While the exotic designs are decades off, American space agency NASA has already constructed a 7m satellite antenna weighing only 25kg, making it feasible for launch. Also coming into favour is on-board processing of signals, which adds the mass of a switch to the satellite launch weight but allows more flexibility.
Yet the advance that holds the most promise is the least exciting. Pelton says satellite modems need only be slightly improved to double or quadruple satellite efficiency.
Clarke`s 1945 paper lamented the fact that long-distance telecommunication was entirely dependent on the vagaries of the ionosphere and declared transoceanic television impossible without orbital platforms. Today satellite operators are seeing low-latency, high-speed and cheap fibre penetrating more and more of the previously inaccessible areas they serviced.
Many speakers at Satcom Africa have stressed that rumours of the death of satellite have been exaggerated. Pelton brought them further hope.
"The satellite industry is just getting started in terms of what it could deliver a decade or so into the future," he says.
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