Leak Shortens Expected Lifespan of Rascom-QAF1

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  Space News Business

Leak Shortens Expected Lifespan of Rascom-QAF1

By PETER B. de SELDING
Space News Staff Writer
posted: 08 January 2008
03:57 pm ET





PARIS —


G


round controllers of the Rascom-QAF1 telecommunications satellite, which was launched Dec. 21, were struggling to raise it into final geostationary position following a leak in its helium-pressurization system that forced a shutdown of its principal motor and likely will limit the satellite’s life – assuming it makes it into final position – to no more than two or three years, according to industry officials.



The decision to attempt the delicate maneuver of bringing Rascom into its intended position was made only after the satellite’s owner and prime contractor concluded that, whatever happens along the way, the spacecraft will have enough fuel to be removed definitively from the geostationary arc, where most telecommunications satellites operate.

Regardless of whether it succeeds in climbing into final position, the Rascom satellite is almost certain to be declared a total loss. The satellite, a ThalesAlenia Space Spacebus 4000B3 model, was insured for $365 million. In an unusual twist to the normal insurance coverage, officials from Rascom and its insurance broker, Willis Inspace, assembled a policy that covers not only the Rascom satellite and its launch, but also a second Rascom satellite.

Jean-Pierre Note, chief financial officer for Port Louis, Mauritius-based RascomStar-QAF, said the startup company had wanted to protect itself against just this sort of event in purchasing insurance.

Insurance officials said Rascom paid a premium of about 11.5 percent for its coverage. “I’ll give them credit, they assembled a savvy policy, especially for a startup company,” said one insurance official with no role in Rascom’s coverage.

In a Jan. 4 interview, Note said Rascom and ThalesAlenia Space, which is also a Rascom shareholder, will not complete the satellite’s ascent to geostationary orbit unless they are certain that sufficient pressure remains in its fuel tank to assure the satellite’s disposal into a graveyard orbit out of the geostationary arc. A final decision is likely by mid




January.



“As of this point, we believe it’s worth the risk to try to bring the satellite into final orbital position,” Note said. “But we will take no risk that the satellite will be stranded in orbit.”



Less than 12 hours after launch, ground controllers became aware of the low helium pressure on Rascom. Officials soon concluded that a leak would make it impossible to use the apogee kick motor to bring the satellite into final position.






Helium is used to pressurize a satellite’s fuel tanks. The apogee kick motor requires a certain level of pressurization to function properly, and this level of pressure was no longer available to Rascom controllers.

After a second ignition of the main engine to bring the satellite into an orbit of 36,000 kilometers by 5,000 kilometers, ground controllers plotted a strategy of using two much smaller motors on board to circularize the orbit at 36,000 kilometers.



These two motors are normally used to make minor adjustments to the satellite’s position during its operational life. Like the overall propulsion system, they are built by Astrium Satellites’ Lampoldshausen, Germany, facility.

Astrium
encountered a similar helium-leak issue in 2004 on board the Amazonas satellite operated by Hispasat of Spain. Madrid-based Hispasat has said the helium issue reduced the satellite’s intended 15-year life to less than 10 years.

An Astrium official said




the similarities between Amazonas and Rascom end there. A board of inquiry isolated the component that caused the Amazonas problem, and this component is no longer manufactured and is not on board the Rascom spacecraft, this official said.

While the small motors now being used to raise Rascom’s orbit need relatively little pressure to operate, the pressure level in Rascom’s fuel tank eventually will drop below the minimum needed to control the spacecraft. Calculating when that will occur is one of the main challenges of the teams now controlling the satellite.

Note said it is too soon to estimate the likely in-orbit life if the satellite is guided into operating position. But other officials said a best-case estimate is three years, or probably less.

But for Rascom, having the satellite in orbit, even for a short period of time, has a large symbolic value to its shareholders and partners





African telecommunications companies in 45 nations.

“It’s very important politically that Rascom demonstrate that it has a satellite in orbit,” one official familiar with the program said. “The ideal situation would be that the satellite operates more or less nominally for the two and one-half years it will take to build a replacement. But even if there is a gap of a few months, it will be worthwhile to be able to point to a Rascom satellite in orbit.” Rascom-QAF1 was launched Dec. 21 aboard an Ariane 5GS rocket from Europe’s Guiana Space Center in French Guiana. The rocket also carried the Horizons-2 telecommunications satellite, which was built by Orbital Sciences Corp. of Dulles, Va., for a joint venture of Intelsat of Washington and JSat Corp. of Tokyo.

Intelsat and JSat will use the satellite for telecommunications services throughout the continental United States, the Caribbean and parts of Canada. Intelsat officials said Horizons-2 is in good health and was already 40 percent booked before launch.



Rascom officials had spent more than 10 years struggling to complete financing of a satellite that is intended to serve 45 African nations that now rely on telecommunications links provided by Intelsat, SES, Eutelsat and other non-African satellite-fleet operators.

After passing through successive configurations and ownership structures over the years, the Rascom project was salvaged in 2003 when the Libya Africa Investment Portfolio, a Libyan investment fund, and the Libyan General Post and Telecommunications Co. agreed to take major financial stakes in the project.

Three African development banks subsequently completed the necessary financing, which Rascom officials say totals about $370 million.



The satellite is designed to operate from 2.85 degrees east longitude, an orbital slot made available by the government of the Ivory Coast.