Ariane 5 rocket gives weighty cargo ride into orbit
BY STEPHEN CLARK
SPACEFLIGHT NOW
Posted: August 11, 2005
Europe's Ariane 5 rocket proved up to the task this morning as it flew
into space to deliver the world's heaviest commercial communications
satellite that will extend high-speed broadband Internet services to the
the most remote locales in the most populated region on Earth.
The first Ariane rocket to fly in six months roared into mostly clear
pre-dawn skies around its ELA-3 launch pad at 0820:44 GMT (4:20:44 a.m.
EDT). The ascent turned night into day across Kourou, situated along
French Guiana's northeast Atlantic coastline.
It was the 22nd Ariane 5 launcher used since 1996, but the first of the
Ariane 5GS variant that features an improved set of solid rocket
boosters and additional upper stage propellant.
A first launch attempt was aborted with 15 seconds left in the
countdown, and officials ordered a delay of 101 minutes as ground teams
worked to resolve an errant reading indicating problems with an igniter
system used to burn off excess hydrogen molecules seconds before the
first stage's Vulcain main engine fires before liftoff.
Once that problem was fixed, it only took 28 minutes for the rocket to
complete its role to leave the 14,300-pound iPSTAR satellite in an orbit
very close to pre-launch predictions. Spacecraft separation occurred at
an altitude of 1,170 miles in an egg-shaped orbit that will take the
craft to a high point of about 22,293 miles and a low point of 357 miles.
Over the coming weeks, iPSTAR will use its propulsion system to raise
the orbit's perigee to geostationary altitude and reduce inclination
from seven to zero degrees. It will then be guided to a permanent
location along the equator at 120 degrees East longitude above Indonesia.
Once checked out by manufacturer Space Systems/Loral, control of iPSTAR
-- also known as Thaicom 4 -- will be handed over to Shin Satellite, a
Thailand-based company that also operates three other space
communications birds launched in the 1990s.
"The iPSTAR is probably one of the company's most prestigious
accomplishments in constructing a satellite," said C. Patrick DeWitt,
president of Space Systems/Loral. "It is truly something to behold when
you look at the spacecraft."
The craft's five-panel solar arrays stretch over 85 feet tip-to-tip and
provide a maximum of 17.6 kilowatts of power at the beginning of
iPSTAR's guaranteed lifetime of 12 years. It is also the heaviest
commercial satellite to ever be placed into a geostationary orbit.
All three of Shin Satellite's older satellite assets were trucked into
space by Ariane 4 rockets from 1993 through 1997.
Shin Satellite developed iPSTAR over the past five years as the
cornerstone of its new broadband communications architecture that will
offer more users access to high-speed Internet products for around $50 a
month. The goal is to ensure the services are comparable to ground lines
that serve cable and DSL connections.
"Ariane 5 took the challenge of launching the world's biggest commercial
payload," said Dumrong Kasemset, the executive chairman of Shin
Satellite. "The successful launch of Thaicom 4 represents the final step
in the overall content (improvement).
With a high-power complement of Ku-band and Ka-band frequency
transponders, iPSTAR can reach customers in at least 14 nations across
Asia and the Pacific from India to Japan, and south to Australia and New
Zealand.
Eighty-four Ku-band spot beams can be aimed toward population centers,
while 10 shaped and regional beams can provide more general coverage to
rural markets. The spot beams offer 20 times more bandwidth than
traditional Ku-band systems. The Ka-band payload operates 18 feeder
beams and uses gateways to connect to external networks such as the
Internet backbone and telephone lines.
The total digital capacity aboard iPSTAR equals that offered by over
1,000 transponders using conventional coding, or somewhere around 45
gigabytes per second.
Terminals in homes, urban apartments, businesses, and public locations
-- or "hotspots" -- can transmit and receive broadband signals to and
from iPSTAR.
Space-based broadband access has several advantages over terrestrial
Internet services because users to not have to wrestle with the normal
worries of congestion and slow connections that are a product of land
lines. Larger coverage areas are available when compared to conventional
wireless systems, and services can be deployed more quickly, officials say.
Essentially, more people should be served by the type of Internet access
that only recently was reserved for the most connected and populated
parts of the Asian continent.
Corporate applications for this capability include voice transmission
via telephony, broadcasting via the web, videoconferencing, and virtual
private networking at lower cost compared to the wide area networks
often used today.
This morning's mission was just the second conducted this year by launch
provider Arianespace, after a test flight of the Ariane 5 ECA was
successfully carried out on February 12. Since then, launch teams have
awaited the delivery of several payloads and the resolution of technical
problems encountered with both satellites and rockets being readied for
liftoff.
In particular, Flight 166 faced several delays before iPSTAR finally
arrived from its Loral factory in California in early June. In addition,
an incident occurred during the fueling operations of the Ariane 5's
storable propellant upper stage before a planned launch attempt last month.
"As a safety measure it was decided to replace the stage by another
one," Arianespace spokesman Aaron Lewis said.
Arianespace officials say they expect about four more missions this
year, including one flight of the upgraded Ariane 5 ECA version. The
next liftoff is expected on September 29 when another Ariane 5G will
conduct a dual-payload launch, which Arianespace is calling Flight 168.
With iPSTAR now in space, payload processing teams are now focusing
their attention on four other satellites currently in Kourou.
The Spaceway 2 direct-to-home broadcasting satellite is now ready to be
fueled, although a launch date remains uncertain due a power supply
issue with its counterpart Telkom 2, which had to be transported back to
an Orbital Sciences facility in Virginia. The duo was to be launched in
tandem in June before the problem was discovered.
The French military's Syracuse 3A communications satellite and the
European MSG-2 observatory are currently in storage in Kourou waiting to
be paired with other payloads. Meanwhile, the Galaxy 15 and Insat 4A
spacecraft are expected to arrive over the next one or two months from
the United States and India, respectively.
The star-crossed Satmex 6 communications satellite is also in Kourou in
standby mode awaiting orders to ship back to its Loral factory. The
craft has been in South America for almost two years after Satmex filed
for bankruptcy, which stranded Satmex 6 in its processing facility with
not enough funds to pay for launch insurance.
After extensive legal battles between the parties involved, an agreement
was finally forged last month that will allow Satmex 6 to get off the
ground some time next year. But first it must travel back to the United
States to be further inspected and tested to ensure that it remains in
good health.
Overall, Arianespace's backlog now contains a total of 40 payloads,
including nine launches due to begin next year of the European Automated
Transfer Vehicle for the International Space Station.
--
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