One of Puerto Ricans' most basic needs in the wake of Hurricane Maria
is communication with the outside world. Cell phone companies on the
island are still working to repair infrastructure after the hurricane
took 95 percent of the island's cell phone towers out of service.
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| Enlarge / A balloon launches from Nevada on its way to Puerto Rico. |
So X, Alphabet's
company devoted to
technological "moonshots," is sending a fleet of balloons to serve as
cell phone towers in the sky. "We are now collaborating with AT&T to
deliver emergency Internet service to the hardest hit parts of the
island," writes Alastair Westgarth, who leads the company's balloon-based Internet efforts.
The idea of providing Internet service via balloons sounds crazy—indeed it has sounded crazy since Google first announced the effort, dubbed Project Loon, in 2013. But Google—now X—is deadly serious about making balloon-powered Internet access a real thing.
Westgarth acknowledges that “Project Loon is still an experimental
technology and we’re not quite sure how well it will work.” But the
company has been making steady progress over the last four years. The
company can keep its balloons in the air for more than three months at a
time, powered by solar energy. It has figured out how to efficiently
steer flocks of balloons to keep them over an area that needs service.
How Project Loon works
Fundamentally, the balloons are a way to extend the range of an
existing cellular network. A terrestrial cell phone tower communicates
with a balloon soaring as much as 20 kilometers overhead. At that
height, a balloon has a clear line of sight to a large area of the
ground below. A single balloon can serve an area the size of Rhode Island.
Phones on the ground communicate with the balloon the same way they
would communicate with any other cell phone tower. X says that
one balloon can serve thousands of customers simultaneously.
There's a big, obvious challenge, of course: wind. If you send a
balloon up 20 kilometers in the air, it will quickly blow away from the
desired coverage zone. Past balloon-based transmission schemes have tethered balloons with a cable, but that limits how high the balloons can go, and it increases the cost and complexity of the system.
At high altitudes, the winds mostly move in one direction, so the
company's original plan was to just release a steady stream of balloons
and have them slowly float around the world. As one balloon floated out
of range for any given customer, there would be another one behind
it. With enough balloons, people at certain latitudes would be within
range of at least one balloon at all times.
But as X experimented with its balloons, the company realized that
it could actually use wind to steer them north, south, east, and west.
The balloons have on-board pumps that allow them to move up and down.
“From our millions of kilometers of test flights, we’ve been able to
develop sophisticated models that allow us to more accurately predict
the wind patterns at different altitudes,” a Project Loon post said in 2016.
“Using this data, our software algorithms are able to determine which
altitude has a wind pattern that gives us the best chance of keeping our
balloons close to the areas where we want them.”
“We figured out how to cluster balloons in teams, dancing in small loops on the stratospheric winds, over a particular region,” wrote X CEO Astro Teller.
In one 2016 test, a balloon took 12 days to travel from Puerto Rico
to Peru and then spent 14 weeks hovering in Peruvian airspace.
The technique wasn't perfect; the balloon would occasionally get
blown out over the Pacific Ocean before being steered back over Peru.
The Peruvian experiment proved useful earlier this year when the
country suffered from serious flooding. Because X had already done work
in the country, X was able to quickly get its balloons aloft and provide connectivity to thousands of Peruvians who had been cut off from conventional communications infrastructure.
The company has developed other technologies to make this whole
system practical. For example, an early challenge was that balloons
would get blown away before they had been fully prepped for release. The
team designed a balloon launchpad, depicted at the top of this article.
The launchpad rotates so its open side is always pointed downwind,
shielding the balloon from direct wind as it's prepared for release.
Bringing balloon Internet to Puerto Rico
X has solved a number of thorny technical problems for getting
balloon Internet technology working. But using that technology to
quickly provide service to ordinary Puerto Ricans was still a big
challenge.
First and foremost, X needed on-the-ground partners. Project Loon's
technology is fundamentally a way to extend the range of an existing
cellular network, so X needed to partner with an existing Puerto Rican
cellular provider. That local provider needed to modify some of its
towers to communicate with the Project Loon balloons and correctly route
customer traffic that came back from them. AT&T agreed to partner
with X on the project.
X also needed approval from the Federal Communications Commission to operate in the area, which it got earlier this month.
X says it also worked with the Federal Aviation
Administration—presumably to get the rights to operate in the airspace
above Puerto Rico.
"Project Loon is now supporting basic communication and Internet
activities like sending text messages and accessing information
online for some people with LTE enabled phones," Loon reported in a Friday blog post.
Puerto Rico is about three times as large as Rhode Island, so (in
principle) you should be able to cover most of the island with
three balloons. In practice, of course, X needs more than that since
steering the balloons with air currents is far from an exact science. At
any given time, some balloons will be drifting off-course or working to
get back on-course. More balloons will be needed to provide reasonable
levels of reliability.
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