A Proton rocket hauled three new satellites into orbit
Thursday to replenish Russia's space-based navigation system, marking the
heavy-lift booster's second flight in less than a week.
The Proton rocket launched from the Baikonur Cosmodrome
in Kazakhstan at 0849 GMT (4:49 a.m. EDT) Thursday. The rocket's three lower
stages completed their burns in the first nine minutes of the mission, and the
Block DM upper stage fired twice to propel the three Glonass satellites into a
medium-altitude orbit.
The 3,000-pound satellites were released in a circular
orbit nearly 12,000 miles high with an inclination of 64.8 degrees, completing
the Proton's seventh flight of the year.
The Glonass constellation, Russia's counterpart to the
U.S. Global Positioning System, currently includes 16 satellites.
One spacecraft is undergoing maintenance and another is
being decommissioned, leaving 14 satellites available for daily operations,
according to an update posted on the Russian Space Agency's Web site this week.
Maintained by the Russian military, Glonass satellites
transmit two navigation signals for armed forces and civilian users. The
civilian channel can provide positioning data within about 200 feet, according
to the Russian Space Agency.
A constellation of 18 satellites spread among three
orbital planes is required to provide blanket coverage of Russia, while 24
spacecraft can reach users worldwide. Russian officials want to achieve a full
Glonass constellation of 30 satellites, including spares, by 2011.
Three more Glonass satellites are scheduled for launch in
December, following by more additions next year.
The satellites launched Thursday are expected to operate
for at least seven years, Russian officials said.
Thursday's launch was the second Proton mission in six
days.
Another Proton rocket blasted off Friday with the Nimiq 4
communications satellite. That launch, conducted under the auspices of
International Launch Services, used a Breeze M upper stage to deliver the
10,692-pound payload into an elliptical geosynchronous transfer orbit.
Nimiq 4 will broadcast direct-to-home television services
to Canadian customers for Bell TV, a leading direct broadcasting firm in
Canada.
The spacecraft, which includes Ku-band and Ka-band
transponders, will be operated by Telesat Canada. The communications payload is
geared toward specialty, foreign language and high-definition television
programming.
Nimiq 4 was manufactured by EADS Astrium and will be
located along the equator at 82 degrees west longitude.
The next Proton launch is scheduled for late October or
early November with the ASTRA 1M communications satellite.
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