Ariane 5 rocket gives weighty cargo ride into orbit
BY STEPHEN CLARK
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.