The next-generation internet could come from above, with fleets of satellites delivering broadband to under-served areas of the world
THE race is on to build a new kind of internet. A host of companies and billions of dollars are in play, with the ultimate goal of ringing the planet with satellites that will allow anyone, anywhere, to get online at broadband speeds.
Presently, satellite internet relies on spacecraft that are in geosynchronous orbit, travelling at the same speed as Earth rotates. But while this ensures the satellites are always in the same spot above Earth, it means there is a large time lag in the service, as radio waves take a quarter of a second to make the round trip up to a geosynchronous satellite and back. Added to the time for the other trips your data must take across the rest of the internet, the lag becomes unworkable for real-time applications like video or voice chat (see diagram).
To speed up the service, firms are looking at using satellites closer to Earth. This month, Virgin Galactic and chip-maker Qualcomm announced their backing of a venture called OneWeb. This plans to put 648 satellites in orbit about 1200 kilometres above Earth's surface, where the round trip time for radio waves is just a few thousands of a second, fine for any online application. SpaceX immediately announced its own plan to do the same, building and launching 4000 satellites to a similar altitude. That would more than double the number of satellites in orbit.
The race has attracted more than just newcomers. Iridium Communications, based in Virginia, has provided satellite telephone services and low-bandwidth internet since the late 1990s. Its existing network of 66 satellites is set to be replaced by a new one called Iridium NEXT. Due to start launching this year, the new satellites will be capable of delivering high-speed internet on a par with what OneWeb and SpaceX envisage.
And O3b, a sister company to OneWeb, already has 12 satellites at an altitude of 8000 kilometres. The firm provides connectivity to Colombia, the Democratic Republic of the Congo, South Sudan and Papua New Guinea.
Even internet giant Google has got in on the rush to space, investing $1 billion in SpaceX's venture. The move is motivated by net neutrality concerns, says Kerri Cahoy, an aerospace engineer at the Massachusetts Institute of Technology. If the internet service providers that rule the physical infrastructure of the internet start charging web services to deliver content to users, the thinking goes, an alternative route to customers via satellites will be invaluable.
It's not the only reason. "It's a very interesting combination of motivations," says Cahoy. "Some of these guys are fuelled by ads. The more eyes they reach and more products they convince people to buy, the more business. There's motivation to get commerce to everyone, even in underserved remote areas."
Will the space around Earth become crowded with all these satellites vying to route our data? "Space is big," says Cahoy. "I'm not worried about the physical interaction of the satellites as much as what they're using for the transmission. If they're using radio waves, those beams will have areas of overlap and interference."
Beaming down
Radio transmission is the most common way to communicate between satellites and Earth. However, as anyone who has had trouble with their wireless router knows, working with radio waves is finicky. So Cahoy and colleagues are working on using light to transfer data instead.
Easier to focus and send over long distances, laser signals could make it possible to build smaller, lower powered satellites that can still talk to the ground easily. "Radio has been the de facto," says Cahoy, "but there are links in the infrastructure that could easily be optical."
Miniaturisation and large drops in the cost of satellite components are boosting the push to space, says James Cutler at the University of Michigan. These have combined to increase access to orbit as never before. "I've got students that will leave with a master's and have built and launched five or six spacecraft," says Cutler. "That's never happened before."
Companies like O3b and SpaceX are planning to launch internet satellites with masses of hundreds of kilograms, but Cutler says those of the future could be closer to 5 or 10 kilograms. Antenna weight can be brought down by using antennas that unfurl themselves in space, like those being developed by Sergio Pellegrino at the California Institute of Technology. This means antennas of similar size to today's can be made of lighter materials as they will only have to support their own weight in microgravity, rather than on Earth's surface.
Cutler says satellite internet will really take off if companies make their equipment small enough to fit in Cubesats – small, lightweight satellites that can piggyback on the launches of other vehicles. "That way every rocket that goes up is kicking off Cubesats," he says, with each small orbiter perhaps holding only a fraction of a functional communications rig.
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