WASHINGTON — Nigerian authorities are continuing with plans to launch their Chinese-built Nigcomsat-1 multi-band telecommunications satellite in May aboard a Chinese Long March 3B rocket after having reassured themselves and their insurance underwriters that the satellite does not use the technology that caused a similar Chinese spacecraft to fail in orbit in October.

T. Ahmed Rufai, chief executive of Nigerian Communication Satellite (Nigcomsat) Ltd., said Nigcomsat-1 does not include the secondary-deployment feature on its solar arrays that the Chinese say doomed the Sinosat-2 satellite, which was launched for telecommunications operator Sinosat in October. Sinosat-2 was the first of China’s new DFH-4 satellite platforms, a product line that China Aerospace Corp. authorities intend to develop for commercial export.

Nigeria is China’s first export success. Venezuela has also contracted with China Aerospace for a telecommunications satellite, called Venesat, and Rufai said he has witnessed Venesat development first-hand because the spacecraft occupies the same assembly, integration and test facility as Nigcomsat-1.

Chinese authorities have declined to detail what happened to Sinosat-2 beyond saying it did not fully deploy in orbit. Rufai said the Sinosat-2 failure was caused by the malfunctioning of a power-distribution unit that controls explosive bolts holding the craft’s two four-panel solar arrays in their stowed position . Rufai said the power unit, which governs both solar arrays and had no backup, did not deliver the command that would permit the final sequence of solar-array deployment. The first sequence unfolds the first two panels of each array, with the second finishing the job. Each segment unfolds until it snaps into position to form a rigid solar array.

The Chinese DFH-4 satellite is designed to deliver 10 kilowatts of power to the payload. With its solar arrays stuck in their folded position, it is generating only about 3 kilowatts of power. Sinosat has said the satellite is useless for its intended mission of transmitting television signals .

But Rufai said the Sinosat-2 satellite otherwise is functioning normally , permitting many of the subsystems that Nigcomsat-1 will use to be confirmed as acceptable for future missions. The Nigerian satellite’s complicated payload — it has transponders in Ku-, C-, Ka- and L-band — also incorporates systems purchased in Europe and China that have proved their reliability.

Nigcomsat-1 has a pair of two-panel solar arrays, requiring a single deployment mechanism of the kind that has been tested without failure on eight previous Chinese telecommunications satellites.

Rufai said Nigcomsat is nearing completion of a Nigcomsat-1 insurance package whose total value will be around $300 million. About 60 percent of the coverage will be placed among insurance underwriters in Europe and elsewhere outside China and Nigeria, with the rest handled by insurers in those two nations. Telesat Canada is serving as technical consultant for Nigcomsat Ltd.

“The Chinese made a presentation to insurers and to us about a month ago and we are all comfortable with their explanation,” Rufai said here Feb. 23 during the Satellite 2007 conference. “We are reassured that all the other systems on Sinosat-2 appear to work well. We are confident we can find an insurance package with a premium of about 17-18 percent” for coverage of the launch and the first year in orbit.

Nigcomsat Ltd. has issued an announcement of opportunity to prospective investors for an equity stake of up to 70 percent of the company, which was capitalized by the Nigerian government at $500 million. Plans call for the company to become a public-private partnership, with 100 million shares valued at $5 each. The government will retain at least a 30 percent share, and company officials are seeking a private placement for the rest of the equity.

The Nigerian government has justified the purchase of Nigcomsat-1 by saying operators of very small aperture terminals and other satellite communications gear in Nigeria pay more than $90 million a year in satellite transponder-lease fees to foreign operators.

“Our plan is to have around 30-35 percent of the satellite leased by the end of 2007,” Rufai said. “In Nigeria, seeing is believing, and we think that once the satellite is in orbit and in service, people will use it. By the end of 2008 we expect the satellite to be more than 70 percent full as Nigeria and other African governments introduce e-government and tele-education initiatives.”

Nigcomsat-1 is expected to weigh 5,150 kilograms at launch and will operate in geostationary orbit at 42 degrees east longitude.