DONG FANG HONG 2A, 3

Those two satellites were the Dong Fang Hong 2 series. The next 24-hr domestic satellite saw the introduction of the Dong Fang Hong 2A series, 3.68 m tall, 441 kg in weight on station, with a design life of four years, and power supplied by 20,000 solar cells. It had four transponders able to transmit five television channels and 3,000 telephone calls at a time. The first, Shiyan Tongbu Tongxin Weixing 2, launched in March 1988, took up position at 87.5°E and doubled its design life, not drifting off station until nine years later in September 1987. Equally successful were Shiyong Tongbu Tongxin 3 that December (110.5°E) and Shiyong Tongbu Tongxin Weixing 4 two years later (98.5°E). These early satellites were used to achieve complete television coverage for China with 30 channels and to permit telephone and fax services to be sent by satellite for the main governmental agencies and development bodies. Thirty thousand receiving dishes were built, education programming going out for more than 30 hr a day, reaching over 30m people. Shiyong Tongbu Tongxin Weixing 3 operated for over 10 years, more than twice its design lifetime, and was the last of the 2A series to cease functioning; 4 left for its graveyard orbit in 1998 after successfully transmitting for almost 10 years.

The run of successes came to an end on 28th December 1991 when a Long March 3 launched what should have been Shiyong Tongbu Tongxin Weixing 5. Rather like the first attempt to send a satellite into geosynchronous orbit in 1984, the third stage failed, this time after burning for only 58 sec. Apparently, the helium pressurizing gas in the third stage sprang a leak and pressure in the combustion chamber fell to zero 135 sec into the burn. To make good the loss in transmissions, the following year, the Chinese space authorities bought an American comsat, Spacenet 1, already in orbit and nearing the end of its useful life, and maneuvered it from its location at 240°E to what may have been the intended destination of Shiyong Tongbu Tongxin Weixing 5 at 115°E. They then renamed it Zhongxing 5

(Zhongxing means “the star of China”), suggesting that Shiyong Tongbu Tongxin Weixing 1-4 were now renamed Zhongxing 1-4. Zhongxing 5 operated at 115.5° until December 1999, when it was retired.

The objective of the third generation of Dong Fang Hong communications satellites was to increase 12-fold the capacity of the previous series and guarantee a working life of eight years. It was broadly equivalent to the American Hughes 276. An important driver of the series was the need to update and improve technical standards. Writing in Jingi Ribao on 30th April 1998, Hang Wen described the quality of China’s domestic satelhtes as “pitiful”, the quality of electronics being especially weak and lagging behind international standards, he warned. There was no point in having great rockets if basic industry is poor. In a homely Chinese metaphor, he compared it to trying to cook a meal without rice. The Dong Fang Hong 3 series had a 20% Western design contribution from Messerschmitt Bolkow Blohm (MBB) of Germany for the solar array. Other parts were contributed by Matra Marconi (central processor), Daimler Chrysler (antenna), and Officine GaUleo (attitude control sensor). At this stage, the drum shape of Dong Fang Hong 2 and 2A gave way to a box-shaped spacecraft with two solar wings. Dong Fang Hong 3 had double the weight of its predecessors – 2,200 kg at launch and 1,145 kg on station. It was 5.71 m tall and had a 2-m-diameter communications dish with six spot beams. The satellite had 24 transponders to transmit six color TV channels and take 8,000 telephone calls at a time, able to cover 90% of China. Its solar wings had a span of 18.1 m, it was able to generate 4,000 W, and it had a

design lifetime of eight years. It required a more powerful rocket, the Long March ЗА.

All did not go well on the first mission. On 29th November 1994, the Dong Fang Hong 3-1 (also called Zhongxing 6 or 6A) failed in its transfer orbit of 181— 36,026 km. Although the Chinese used its propellant over time to raise the perigee to 35,181 km by 29th December, by the time it reached there, all supplies of fuel had been used up and the satellite had to be abandoned. As they had done before, the Chinese bought an American Hughes 276 replacement, but one on the ground this time. They launched it on one of their own Long March 3 rockets in August 1996 but, once again, the transfer maneuver to geosynchronous orbit went wrong and it became stranded between 200 and 17,230 km. Apparently, the pressurizing gas failed and caused the thrust to stall a mere 48 sec before the satellite would have reached orbit. The orbit was later raised to 21,667-46,507 km, so they got some use out of it, but Zhongxing 7 was then abandoned. It was the third such failure in a row in five years. Eventually, a Dong Fang Hong 3 satellite reached orbit successfully – put up on a Long March ЗА on 11th May 1997 (Dong Fang Hong 3-2 or Zhongxing 8) over 125°E and, this time, everything went perfectly. On 1st April 2004, it moved off station and was decommissioned.

Table 5.1 summarizes the DFH-2 and Table 5.2 the DFH-3 series.

Table 5.1. DFH-2, 2A series of communications satellites.