SHI JIAN 4, 5

Despite this demonstrated ability to fly a scientific mission, there was a gap in the series of almost 13 years (Shi Jian 3 was a canceled Earth resources satellite). Shi Jian 4 was flown on the first flight of the Long March ЗА launcher on 8th February 1994 and was the second satellite to benefit from project 863. Shi Jian 4 was a 410-kg drum, 1.6 m in diameter, 2.18 m high, with 11,000 2 x 2-cm solar cells. Its primary purpose was to study the spatial and spectral distribution of the Earth’s charged particle environment, but an important objective was to test its damaging effect on spacecraft instrumentation. There were six scientific instruments of 20 kg, as shown in Table 7.2.

Table 7.2. Shi Jian 4 instruments.

Semi-conductor high-energetic electrons detector

Semi-conductor high-energetic proton and heavy-ion detector

Electrostatic analyzer

Electric potential meter

Static single events upset monitor

The Long March also carried into orbit an unspecified 1,600-kg payload called Kuafu, probably a technology demonstrator (in Chinese mythology, Kuafu chased the Sun), this name being revived recently for a new mission. Shi Jian 4 entered an orbit of 209-36,118 km, 28.5°, period 10.7 hr, calculated to bring it through the charged particles of the Van Allen radiation belts four times a day. Shi Jian 4 was designed to last for six months, before succumbing to the intense radiation of the belts. There were a number of problems with the mission: the power supply gave only 2 V instead of the 5 V for which it was designed and some of the instruments malfunctioned, but it lasted more than the half-year planned.

Shi Jian 4 made the first Chinese wide-range distribution of electrons, ions, and high-energy particles in the 0.1-40-keV range, followed solar particle radiation that did not enter the Earth’s magnetic field, measured the density of high-temperature plasma, detected high-energy charged particles in the radiation belts, and made a cross-section of the radiation belt. A map was made of proton fluxes and trapped electron fluxes and measured against altitude. Chinese scientists found that the in – and-out flow of the field-aligned current was very complex and hard to distinguish.

Dealing with the damage done by radiation to spacecraft systems, it tested a

Shi Jian 4, an important radiation mission. Courtesy: COSPAR China.

10‘ 10’ 10* 10’ I0J 10′ 10°

0 50 100 150 200 2501 X|0;) Altitude /Vm

5000 Altitude km

Shi Jian 4: Trapped protons. Courtesy: COSPAR China.

Shi Jian 4: Trapped electrons. Courtesy: COSPAR China.

system to re-start micro-circuits that had been knocked out by radiation. This happened when systems were hit by high-temperature plasmas up to -2,000 V, with 27 such episodes encountered. At 1,000 km out, Shi Jian recorded multiple large negative potential charging events. Shi Jian recorded 120 single-event upsets in the first 25 days, apparently caused by cosmic rays impacting on the inner radiation belt, averaging out at 3.4 a day in the end. At the end of the mission, the old Handbook of the Low Orbit Space Environment was updated, funded by project 863 [1].

Five years later, in May 1999, Shi Jian 5 was launched, riding piggyback with the meteorological satellite, Feng Yun 1-3 (Chapter 6). Weighing 298 kg, it marked the first operational use of the CAST968 bus made by the Shanghai Academy of Space Technology with the China Electronics Technology Corporation. Instead of the drum shape, it was a box measuring 1.1 x 1.2 x 1.04 m with two solar panels. Its orbit was out to 865 km, 102 min. Its purpose was similar: to study the terrestrial magnetosphere and single-upset events that damaged satellites in orbit. Experiments comprised a suite of cosmic ray detection instruments: a semi-conductor proton and heavy ions detector, a static electrical analyzer, an electrical potentiometer, a static single-event monitor, and a dynamic single-event monitor, with eight measuring points. The project was developed with Brazilian cooperation, but its precise nature is uncertain.

Shi Jian 5 was designed for a short lifetime of 90 days – an approach typical of early Soviet satellites – and the end-of-mission announcement came in August. It duly measured single-event upsets and the effect of the dosage of highly charged particles on the spacecraft. Many years later, it was learned that Shi Jian 5 carried China’s first experiments in fluid physics, to test the convection of bubbles in paraffin and the effects of multilayered thermo-capillary convection on crystalline growth and quality, the outcomes transmitted in real time. This was matched by

Shi Jian 5, a successor mission with a different design and more objectives.

experiments developed on Mir at the same time (1999) and followed by more on Shenzhou 4 (2002), FSW 3-5 (2005), and six experiments on Shi Jian 8 (2006). It also tested a solid-state recorder and high-speed s-band transmission [2].