LATER SHI JIANS

After a long gap, the Shi Jian series resumed on 8th September 2004, the new set bearing no resemblance to its predecessors. No scientific results were announced from the new Shi Jian missions, leading to Western speculation that they were primarily military in purpose, but they are treated here for convenience. Shi Jian 6 was a double mission, named Shi Jian 6A and 6B, launched on the CZ-4B from Taiyuan. It appeared that the double mission comprised quite different spacecraft, 6A being the 375-kg small CAST968 bus, while 6B was the much larger 975-kg Feng Yun satellite (note that some commentaries reverse “A” and “B”). The China Academy of Space Technology (CAST) has showed an image of one of the Shi Jians as similar in shape to its CAST968.

The initial orbits of both spacecraft were 96.6 min, 91.1°, and altitude 593­604 km. After a while, the smaller 6A began to make small maneuvers to enable flying in formation with the larger 6B, reducing its orbital period by 20 km and then lifting it back to 6B (e. g. on 7th and 14th October). Several Western analysts suggested that, because of the involvement of the China Electronics Technology Corporation, these were electronic intelligence satellites. Another explanation, coming indirectly from China itself, is that the larger spacecraft carried a radar imaging system whose accuracy is enhanced by an accompanying satellite making altimetric measurements while flying in formation [3].

Shi Jian 7 was launched into Sun-synchronous orbit as a single satellite on 5th July 2005 on CZ-2D from the new double pad in Jiuquan. It made one small maneuver shortly on entering 97.6° orbit, raising its perigee from 547 km to 558 km and keeping the same apogee, at 570 km. Apart from declaring that it would work three years on a science mission, no details were given, apart from a picture showing that it was a CAST968 model.

Because it was essentially a Fanhui Shi Weixing (FSW) mission, the Shi Jian 8 “seeds satellite” mission was reviewed in Chapter 4. To add to the further confusion over designators, Shi Jian 8 was then followed by Shi Jian 6 and then two more Shi Jian 6 flights, also called by the Chinese “Shi Jian 6 group 2”. They were launched from Taiyuan on CZ-4B on 23rd October 2006, deployed at 11 min and 12 min, respectively, with a similar mission to study the space environment for two years. Two years later, they were joined by another, third set of Shi Jian 6, 6-3A and 6-3B, on a CZ-4B from Taiyuan, into polar orbits of 91.1°, 580-605 km. The fourth set, Shi Jian 6-4A and 4B, came on 6th October 2010 on the CZ-4B, the A in a 588­604 km orbit, the В in a lower, looser intercepting ellipse of 566-604 km, but not apparently maneuvering. The Shi Jian 6-1 group and the 6-2 group were in the same orbital plane. There was also symmetry to the launch pattern: September 2004, October 2006, October 2008, October 2010.

Next up was Shi Jian 11 on 12th November 2009 into a much higher orbit of 699­703 km, 98.3°, but this time on a CZ-2C from Jiuquan. This was numerically puzzling, for Shi Jian 9 and 10 had yet to fly (Shi Jian 10 is a successor to Shi Jian 8, while, that same year, it was explained at the Zhuhai air show that Shi Jian 9 was a new type of spacecraft to test electric propulsion). As for the Shi Jian 11 series, no clear purpose was explained. Some Western commentaries took the view that this series was for missile early warning, being equipped with infrared sensors accordingly – but other space superpowers have always put their early-warning systems in much higher orbits (out to 39,000 km in the case of Russia’s Oko system). Electronic intelligence is also possible, but the favored altitude of the Soviet system was also a higher orbit, at 850 km. In any case, Yaogan appeared to be serving such a purpose.

This was followed six months later on 15th June 2010 by Shi Jian 12 on a CZ-2D from Jiuquan. It was launched into an orbit typical in the series, 575-597 km, 96.3 min, 97.7°, but was the beginning of an unusual set of events in orbit. Five weeks later, on 12th August, it maneuvered close to Shi Jian 6-3A and, on 19th August, to within 200 m – China’s first on-orbit demonstration of an interception. There was even some evidence that Shi Jian 12 came even closer and glanced off Shi Jian 6-ЗА, thus giving it a slight nudge. A closer look at its path showed how a total of six maneuvers had been made to achieve the interception, mainly involving plane changes, then moving to 4 km below and then 7 km above Shi Jian 6-3A. The maneuver was repeated in October [4].

These maneuvers were not announced by the Chinese, nor were they denied. They were first published in Novosti Kosmonautiki, following space journalist Igor Lissov’s analysis of orbital data published by the American military. Western opinion was divided as to whether these interceptions were harmless tests of orbital rendezvous maneuvers, or a sinister development paving the way for the interception and destruction of hostile satellites. Suspicions about the latter, though, were fuelled by a report of the Small Satellite Research Institute of CAST of a ground test of a system of parasitic nano-satellites which would, at a time of tension, attach themselves unnoticed to enemy satellites following a surreptitious rendezvous maneuver. Being very small, they would be unnoticed until it was too late. Attached to their hosts, they would await the command to disable them, either by explosion or by electronic interference. Whether this fiendish plan was a paper study, a threat, or a real project is difficult to tell.

The events of mid-August were only the beginning. After the August interceptions, Shi Jian 12 held a steady distance while maintaining orbit at around the 600-km mark, the altitude at which all subsequent maneuvers took place. Then, on 16th November 2010, Shi Jian 12 maneuvered to approach a second satellite, Shi Jian 6-1 A, holding at 5 km away, but moving to 1 km away on 4th December. Shi Jian 12 then maneuvered on 6th December to approach a third satellite, Shi Jian 6- 4A, on 6th December 2010, keeping formation at 1 km until breaking away on 26th December. Shi Jian 12 departed on 12th January 2011 to follow its original target, Shi Jian 6-1 A, now 180° away. This was its last reported maneuver, but, nine months later on 23rd September 2011, the hitherto passive Shi Jian 6-3A raised its orbit to 609 km and could be observed holding distant formation with Shi Jian 12. In other words, Shi Jian 12 conducted rendezvous with a series of different satellite targets in sequence – an impressive demonstration of planning and maneuvering.

Just as had been the case before, the next Shi Jians came from an earlier series and, to confuse things even further, the next Shi Jian was Shi Jian 11-3, even though 11-2 had not been launched. Shi Jian 11-3 was launched into a 689-704 km, 98.1° orbit, similar to 11-1 but with a different orbital plane. It was quickly followed by Shi Jian 11-2, which in turn was followed by 11-4, though it failed to reach orbit. The role of these single spacecraft is unclear and they have not served as rendezvous targets.

The Chinese have said almost nothing about the Shi Jian 6, 11, or 12 satellites or acknowledged their maneuvers, and no scientific papers have been pubhshed about their activities, even though they were officially studying “radiation and the space environment”. Even if they were testing new technologies, these outcomes have not been published either. There are, though, some official sources which may shed light on these missions. China Space Science and Technology, the principal journal of spaceflight in China, published a series of articles in 2010-11 that could have been connected to these experiments, such as “Rotated Formation Flying for Tethered Micro-Satellites”, “Hovering Method at Any Selected Position over Space Target in Elliptical Orbit”, “Guidance for Dynamic Obstacle Avoidance of Autonomous Rendezvous and Docking with Non-Cooperative Target”, “Application of Relative Measurement for Three Satellites in Formation”, “Rendezvous Orbit Design and Control of the Target Spacecraft”, “Target Spacecraft Phasing Strategy in Orbital Rendezvous”, “A New Kinematic Method for Flying-Around Satellite Formation Design”, “Orbit Design for Approaching Multiple Spacecraft Repeatedly”, and “Beam Synchronization Strategy for Distributed SAR SatelUtes Formation”. Chinese scientific literature is abundant with papers on formation flying, some very complex [5]. These papers demonstrate a high level of interest in formation flying and interceptions, but tell us little as to their ultimate purpose, be that for manned rendezvous and docking (the upcoming Tiangong mission), Earth resources (the Americans use formation flying for Earth observations, called the А-train), or for more sinister purposes. According to one set of these authors, Fanghu Jiang et al., “formations offer greater flexibility and redundancy at lower costs”.

There was nothing new about satellite interceptions or formation flying, for the Soviet Union developed an interceptor system in the late 1960s and formation flying with small Czech satellites from the late 1970s. The pattern of double satelhte missions (Shi Jian 6 groups 1, 2, 3, 4) to serve as targets for an interceptor (Shi Jian 12) is something new in astronautics, while the purpose of the single Shi Jian 11 missions (1, 3, 2) remains obscure. Table 7.3 summarizes the series.