Geostationary satellites offer virtual networks
For about a year, Celso Azevedo has been briefing potential government users, mostly military ones, about instant broadband networking via forthcoming geostationary satellites. Azevedo is president and chief executive officer of Astrolink International Ltd. of Bethesda, Md., a venture of Lockheed Martin Corp. that expects to begin launching new geostationary satellites in 2002.
For about a year, Celso Azevedo has been briefing potential government users, mostly
military ones, about instant broadband networking via forthcoming geostationary
satellites.
Azevedo is president and chief executive officer of Astrolink International Ltd. of
Bethesda, Md., a venture of Lockheed Martin Corp. that expects to begin launching new
geostationary satellites in 2002.
Astrolink plans a minimal four-satellite fleet that can communicate across much of the
planet via uplinked servers or over terrestrial voice and data networks. The satellites
will cost about $3.5 billion, Azevedo said, and their K-band frequency will provide enough
bandwidth for 10-Mbps uplinks and 100-Mbps downlinks. The K-band covers the 10.9- to
36-GHz frequencies.
Satellites are not yet available with onboard switching to set up a space network, but
the geostationary orbits will enable limited service as soon as the first such satellite
is launched. The four satellites will orbit over areas that generate about 85 percent of
the Earths wealth, Azevedo said.
He has no plans for true global coverage, however.
We are not going to waste satellite power on oceans, deserts and jungles where
there isnt enough wealth to pay for the service, he said. We are going
to concentrate the capacity where there is demand.
Astrolink, at first an in-house project, became a wholly owned subsidiary of Lockheed
Martin Global Telecommunications in 1997. A decade earlier, Astrolink might well have been
a government program, Azevedo said.
Now its the other way around, with the end of the Cold War and the squeeze
in military budgets, he said.
Onboard switching between multiple beams on a satellite will let a customer site use
one or more satellites as a virtual network. Each K-band satellite will have 58 beams,
each with a relatively small footprint of about 400 kilometers at the surface.
Because the satellites will be in geostationary orbit, their footprints will be stable
and signals will not have to be handed off from one to another. Each beam on each
satellite can use the same frequencies, giving a large overall capacity.
Each customer site will have a server equipped with a small dish antenna as a satellite
link. Installing the server on a LAN sets up an instant metropolitan or wide area network,
Azevedo said. Traffic can go directly through the satellite to other servers, or through
gateways to the public switched network or the Internet. Each satellite can support up to
70 gateways.
The server specifications are set, and two competing makers will be awarded contracts,
Azevedo said. After the first satellite goes up in early 2002, three more will follow at
six-month intervals. Commercial service will begin about six months after the first launch
in Europe and on the east coasts of the United States and Brazil, he said.
Subsequent launches will cover the rest of North and South America, Europe, Africa and
the Middle East, and Asia.