SECOND SATELLITE: SHI JIAN 1

China’s second satellite followed Dong Fang Hong into orbit nearly a year later, using the Long March 1 on its second and final flight. Now that the propaganda value of launching a first satellite had been demonstrated, China’s second satellite could concentrate on scientific tasks. In effect, this second satellite achieved what the first one had been intended to do had political and propaganda imperatives not risen to the fore during the early design stage. Chief designer was Yang Yiachi (1919— 2006), who spent the years 1947-55 studying in and acquiring qualifications from Harvard, Pennsylvania University, and the Rockefeller Institute.

The tasks of the second satellite were agreed at a conference held in the Chinese Academy for Space Technology in Beijing in May 1970. The second satellite received a new designation, Shi Jian (meaning “practice” in Chinese). Slightly heavier at 221 kg, Shi Jian eventually entered orbit on the evening of 3rd March 1971. The mission got off to a problematic start, for, although the explosive bolts separating the satelhte from the third stage fired, the satellite did not separate from its carrier rocket. Enveloped within the third stage, the signals transmitted were weak – only about 1 % of what had been hoped for. The designers were, as one might imagine, perplexed and worried. On the eighth day, the signals suddenly came through loud and clear. Ground observations confirmed that the satellite had now separated from the launcher. Beijing did not announce the launch until 16th March, presumably when separation had been confirmed and stronger signals had been received.

Shi Jian was, like its predecessor, a 72-side polyhedron, but covered in solar cells which charged a long-Ufe two-watt nickel-cadmium battery. In place of the anthem­playing tape recorder, Shi Jian carried three scientific instruments – an 11-mm cosmic ray detector, a 3-mm x-ray detector (1-8 A), and a magnetometer. A hundred automatic thermal shutters closed as the spacecraft entered darkness, opening again as it entered Ught (a similar system was carried by Sputnik 3). Using four short-wave antennae, the radio transmitter emitted a stream of scientific data on 16 channels which could be picked up 3,000 km away. The instruments recorded solar x-ray electrons over 0.88 MeV and protons over 16.9 MeV, while the magnetometer made the first Chinese mapping of the Earth’s magnetic field. Shi Jian continued to transmit scientific data until it burned up in the upper atmosphere on 17th June 1979. The battery and telemetry systems showed no evidence of deterioration and maintained the same high level of performance throughout the mission, despite 10,000 charging and recharging cycles (one for each orbit as the satelhte went into and came out of darkness). The design teams rightly received commendations for these achievements in 1978. The 3,028-day mission appears to have been completely successful. The satellite enabled geophysicists to publish a reference Handbook of the Artificial Satellite Environment.

Shi Jian was very much the achievement of Professor Zhao Jiuzhang, the pioneer of Chinese space science and the founder of the Institute of Applied Physics, which became the Institute of Space Physics [4]. Despite his importance, he is hardly known outside China. Zhao Jiuzhang was bom on 15th October 1907, in Kaifeng, Henan. First, he went to study electrical engineering at Zhejiang Industrial School, now University, in Hangzhou, going on to graduate in physics at Tsinghua University in 1933 and, like most of his colleagues, he went abroad for further study, going to the most scientifically advanced country in Europe – Germany, where he was awarded his doctorate in dynamic meteorology in Berlin in 1938. He returned to China in 1949, where he became director of the Institute of Geophysics immediately after the revolution. He became an expert in the atmosphere, air masses, trade winds, solar energy, charged particles, and magnetic fields. His main achievement was to ensure an early scientific orientation for the space program and set a benchmark for the future. He died on 26th October 1968. Much later, his contribution became ever more appreciated. In 1989, an award for “young and middle-aged scientists” was established in his honor, with 79 scientists winning this much-coveted award in the subsequent 20 years. An asteroid, §7811, was named after him, a COSPAR prize was established to commemorate him in 2006 in the fields of space and atmospheric physics, and the Academy of Sciences held a meeting to commemorate his centenary on 29th October 2009.