Category China in Space

The success of communications satellites encouraged China to develop a range of applications satellites: weather forecasting in both polar and geostationary orbit (Feng Yun), Earth resources (Ziyuan, China Brazil Earth Resources Satelhte (CBERS), Huanjing), mapping (Tansuo, Tianhui), marine surveillance (Haiyang), and navigation (Beidou). These programs have become ever more specialized in recent years. Some may also have a military dimension (Yaogan) and they are also covered here. Minor applications programs, including micro-satellites, are also reviewed. The formal decision to establish an apphcation program dates to the early 1980s when the Chinese government adopted a decision Applied Satellites and Satellite Application [1].

POLAR WEATHER SATELLITES (FENG YUN 1, 3)

Accurate weather forecasting had always been important for a large country so dependent on agriculture but vulnerable to damaging storms and floods. China suffered heavily from storms, flooding, and weather-related natural disasters, with losses to the economy in the millions – so anything that could be done to reduce that figure would be helpful. The United States launched the first weather satellite in 1960 (Tiros) and the Russians followed with an operational system later (Meteor, 1969). The government approved the concept of a Chinese meteorological satellite in 1970. Development was impeded by the cultural revolution and funds were not allocated until 1978. In the meantime, China set up its first station to receive internationally available meteorological data in Beijing, stations being built subsequently in Urumqi and Guangzhou.

China’s first weather satellite was named Feng Yun (“wind and cloud”) and built by the Shanghai Academy of Space Technology (SAST). The Feng Yun 1 satellite was hexagonal, 1.76 m tall, 1.4 m wide, weighed 757 kg, and had two solar panels spanning 8.6 m. Although photographs were the primary product of the series, there were instruments to provide a three-dimensional atmospheric profile of temperature, moisture, cloud, and rain. The satellite had a scanning radiometer designed to monitor clouds, water color, crops, forests, and pollution, transmitting automatically in real

B. Harvey, China in Space: The Great Leap Forward, Springer Praxis Books,

DOI 10.1007/978-l-4614-5043-6_6, © Springer Science+Business Media New York 2013

time and by tape recorder. Small nitrogen-powered thrusters were used to ensure the satellite pointed the right way.

It was decided to fly Feng Yung into polar, Sun-synchronous orbit and orbit the Earth 14 times a day. It is polar because it flies almost across the poles and Sun – synchronous because it follows the same ground track each day and crosses the same point on the Earth’s surface at the same time each day. Targets are illuminated by the same Sun angle, making it easier to compare weather data from one day to the next. A new launch center was required for a satellite to enter polar, Sun – synchronous orbit. Accordingly, a former missile site near the industrial coal town of Taiyuan, south-west of Beijing, was selected.

With the Long March 2 having insufficient thrust and the Long March 3 too much, a new launcher was developed for the Feng Yun, the Long March 4. The Long March 4 was based on the highly reliable Long March 2C, but with a new, more powerful upper stage. Long March 4, 41.9 m tall at lift-off, with a thrust of 300 tonnes, had a small third stage using conventional fuels.

The first Chinese weather satellite was launched on 6th September 1988 and entered an orbit of 99.1°, 881-904 km. It soon sent back pictures of cyclones, rainstorms, sea fogs, and mountain snow. This first mission was less than entirely successful. One of the radiometers was fogged and the spacecraft failed after 39 days. Apparently, condensation in the spacecraft had not been fully removed before it left the Earth and this fouled up the sensitive radiometer.

Feng Yun 1-2 was launched two years later on 3rd September 1990 and it dropped off two balloons in orbit (Chapter 7). It was heavier (889 kg) but appeared
to suffer radiation damage in February 1991 possibly from a solar flare, but, after a 50-day struggle, ground control in Kashi performed a minor miracle by recovering the satellite fully. There was further radiation damage later in the year and the data eventually became unusable.

By way of a postscript, the upper stage of the launcher that had put Feng Yun 1-2 into orbit exploded on 4th October 1990 when propellants leaked through the bulkhead into the oxidizer and ignited. This was an unwelcome development, for the world’s space powers had begun to realize the threat which orbital debris of this kind caused to manned space station operations. The American space agency, NASA, had even formed an office in Houston, Texas, with the brief of trying to reduce space debris. In 1995, China joined the Inter Agency Space Debris Coordination Committee and, in 2002, 11 countries, including China, had signed a debris mitigation agreement. The same year, China held a national debris mitigation conference and the government allocated ¥30m (€2.5m) to the problem. In advance of the Shenzhou mission, China was tracking up to 9,131 pieces of debris that might pose a hazard. Precautions were taken to safe the CZ-4B upper stage to prevent its venting residual propellants.

The Chinese always made it clear that the first two spacecraft were tests before the system became operational with Feng Yun 1-3, successfully launched in May 1999. Its first images were returned the same day and, by July, good-quality pictures were flowing in on all channels. A top priority for the mission was to ensure a working life measured in years, rather than months. Many precautions were taken against radiation damage and the satellite was first sent to the Lop Nor nuclear test site for checking against a recurrence of the problems that had plagued its predecessors. Feng Yun 1-3 exceeded its design life: two years later, it was still working, in a stable condition, with good power supply and returning clear pictures, crossing China every morning at 8:30 am. The weather satellite carried a 10-channel Multichannel Visible and Infrared Scan Radiometer – four in visible wavebands, three in near

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Feng Yun image of sea ice clinging to the coast. Courtesy: COSPAR China.

infrared, one in short-wave infrared, and two in long-wave infrared, with a resolution of 1.1 m. In its first two years, it collected a range of information on floods, droughts, forest fires, and ice, its cameras picking out a sandstorm that blew from Mongolia into China. Because it had exceeded its design life and was continuing to work satisfactorily, its replacement satellite was delayed. Feng Yun 1­4, the last of the series, was eventually launched on 15th May 2002 and also carried a 10-channel scanning radiometer. In 2002, Feng Yun 1-3 and 1-4 played an important role in monitoring flood levels on the Huaihe River, the size of the flooded area being filmed, transmitted to the ground, and posted on the internet daily.

As a result of the Feng Yun 1 series, China was able to not only improve the timeliness and quality of weather forecasting, but also build satellite-based sea – surface temperature data, estimate the volume of rain in clouds, predict crop growth and yields, and compile a picture of urban heat islands, atmospheric smog and dust, algal blooms, forest pests, pollution, and desertification. The series was also used for scientific as well as applications objectives, such as the monitoring of high-energy charged particles (heavy ions, protons, and electrons) and as a radiation warning system (Chapter 7).

Feng Yun 1-3 achieved notoriety many years later when it was shot down – by China. The satellite had concluded its mission when it was decided that it should be the target of China’s first ever satellite attack. On 11th January 2007, as it passed over Xian, it was closely tracked by radar. At the point 45° over the horizon, a DF – 21 missile was fired from Xi Chang on an intercept trajectory just 94 min before local dawn but still in darkness. A few minutes later, as Feng Yun was in sunhght at 1,100 km, the missile, with pinpoint precision, slammed into the satellite and smashed it into hundreds of tiny pieces. Debris spewed outward at a velocity of up to 2,000 km/hr. The interception was an impressive demonstration of sensors, tracking technology, and computer systems. The Feng Yun target was less than 2 m across, even if its arrays spanned 9 m.

The explosion produced 900 trackable objects over 10 cm immediately, a 10% instant increase in total orbital debris, but with the prediction that the total number may come to several tens of thousands between 200 and 3,800 km. The altitude of the interception was so high that the debris would take thousands of years to fall back to the Earth; 1,951 main debris items were tracked by summer 2011. An impact with any one of them by a spacesuited astronaut would puncture the suit and cause immediate death. The debris was likely to orbit over 100 years and was described by

Nick Johnson, the world’s foremost expert, as the worst fragmentation event in orbit, with some debris over 10 cm likely to stay aloft for centuries. For 20 years, the space powers had been trying to reduce Earth orbital debris and it was exasperating to experience such a deliberate setback. Incidents grew in which the crew of the space station had to evacuate the main part of the station and wait in the Soyuz lifeboats until the danger passed. The State Department reported that it had issued no fewer than 677 collision warnings to space agencies worldwide arising from the Chinese explosion, which, according to NASA, now accounted for 17% of all debris in orbit [2].

The attack was reported quickly in the West and not admitted by the Chinese until a week later. State news agencies seem to have been caught quite off guard by the event. The political leadership shrugged off the militarization arguments of the Americans, but was quite stung by the unexpected criticism about orbital debris. There seems good reason to suspect that, whilst the military was authorized to make the test, it had not sufficiently briefed the leadership as to when it would take place

or the negative debris consequences. China later told the United States through back channels that it would not happen again. The Americans revealed later that they knew the test was coining but chose not to attempt to prevent it. As if to make good the problem, Chinese scientists in Tsinghua University began to study the use of hexagonal, square, and triangular meshes to capture unwanted orbital debris [3].

The test, whilst an impressive demonstration of a high-altitude, high-speed interception, attracted worldwide criticism. Western analysts pondered the precise nature and purpose of the Chinese challenge [4]. American criticism focused on China’s belligerent militarization of space, but the United States were on shaky ground, for they themselves had used an F-15 fighter missile to shoot down their own Solwind in 1985 and even maintained an anti-satellite squadron (76 Space Control Squadron at Peterson Air Force Base, Colorado). The Bush administration issued its National Space Policy in October 2006. This was not well received in China, for the policy appeared to claim unilateral hegemony in space – the right to deploy assets there and to deny it to anyone else. A year after this event, a missile from the USS Lake Erie shot down a decaying failed American spy satellite, NROL 21, officially to prevent its falling into enemy hands but possibly as a reminder to the Chinese.

With this uneasy checkmate, the situation rested a little. Then, in November 2011, the US-China Economic and Security Review Commission alleged that Chinese ground trackers on the Norwegian tracking station in Svalbard, Spitzbergen, had hacked into the American Landsat 7 and the Terra Earth observation satellites. Both had experienced the type of interference that one would associate with attempted hacking and, in the case of Terra, actually managed to take over control, although no control commands were subsequently issued. Republican presidential candidate Michelle Bachmann of Minnesota, presumably using information available to her as a member of the House of Representatives Intelligence Committee, alleged that

Table 6.1. Feng Yun 3 series instruments.

Visible and Infrared Radiometer (VIRR), 10 channels Infrared Atmosphere Sounder (IRAS), 26 channels Microwave Temperature Sounder (MWTS), 4 channels Microwave Humidity Sounder (MWHS), 5 channels

Medium-Resolution Spectral Imager (MERSI), 20 channels, resolution 250 m Solar Backscatter Ultraviolet Sounder (SBUS)

Total Ozone Unit (TOU)

Microwave Radiation Imager (MWRI)

Atmospheric Sounding Interferometer (ASI)

Earth Radiation Measurement (ERM)

Space Environment Monitor (SEM)

Solar Irradiation Monitor (SIM)

China had blinded American satellites with lasers. The committee published a list of Chinese attempts to interfere with satellites dating back to 2005, when they tried to jam satellites, followed in 2006 by laser dazzling of an American reconnaissance satellite and a French spacecraft [5].

With the Feng Yun 1 series complete, China moved on to the Feng Yun 3 series, 2,500-kg observation satellites with instrumentation as shown in Table 6.1.

The MWHS was a new instrument development by Li Jing with a team of 30 young scientists, based on his work on Shenzhou 4. The first Feng Yun 3, 3-1, was launched on 27th May 2008 on CZ-4C from Taiyuan into a 804-811 km orbit, 101.4 min, 98.8°. Soon, it was sending down 88 pictures daily, with a resolution of 250 m and a temperature measurement accuracy of 0.1 °С. The second flew on 5th November 2010 from Taiyuan and went into operation the following May. Its orbital plane was 130° apart from FY 3-1, so as to give afternoon coverage, the idea being that the series would alternate between morning and afternoon paths. The atmospheric sounder enabled China to build up a picture of atmospheric methane (CH4), one of the main greenhouse gases. In 2012, Zhang Xingying of the National Satellite Meteorological Centre pubhshed a six-year dataset of mid-tropospheric methane covering 2003-08. Its main findings were that levels of methane varied a lot over China, being lowest in the west (due to low levels of industry and agriculture) and south (where winds carry it out to sea), had seasonal summer and winter peaks, and reached especially high levels in 2007. The experiment should enable greenhouse gas to be accurately measured, located, and, hopefully, their reduction tracked as climate control measures take effect.

For later Feng Yun 3 satellites, China stated that there would be two variants: the AM and PM series, alternating between polar and 55° orbits. The original program envisaged two experimental and five operational satellites but, later, China announced that up to 12 would fly by 2020. Starting in 2013, a sub-variant would be devoted to tropical rainfall analysis.

Despite the interest of Zhao Jiuzhang in the space environment, dedicated spacecraft were slow to emerge. The first space environment program, started in 1988 and called Meridian, was ground-based using 15 locations, including Zhongshan base at the South Pole, and later extended to sounding rockets. Europe offered a new opportunity. China and Europe had first agreed a cooperation program in 1980 (Chapter 3), which took concrete form 12 years later when China made arrange-

ments with the European Space Agency to take data from the Cluster project, an upcoming major venture with four satellites to study the Sun’s interaction with the Earth’s magnetosphere. China may have spotted an opportunity to participate in an international scientific program at relatively low cost and, in 1997, China proposed its own complementary project, Doublestar, called Tan Ce or “explorer” in Chinese. A feasibihty study concluded in 1999 and the program was approved by the Chinese government in 2000, leading on 9th July 2001 to an agreement in Paris with the European Space Agency. Cluster was originally to fly in 1996, but the probes were blown apart when Europe’s Ariane 5 exploded on its maiden mission. The backup models were taken out of storage to fly into orbit on the Russian Soyuz in summer 2000, so Tan Ce was very timely.

The notion of multiple satellites to explore the magnetosphere was well established, the main example being the Russian Interball project in which two sets of satellites had explored the magnetosphere from 1994 to 1995. Like Interball, China’s Doublestar system also comprised two satellites – hence the title “Double­star” – and proposed, using similar instruments, that their findings be cross – referenced to those of Cluster. Doublestar was a complementary mission insofar as the Chinese planned to reach regions of the sky inaccessible to the Cluster probes and build up a three-dimensional picture. Tan Ce 1 was originally to orbit out to 8 Earth radii, but Chinese scientist Zuyin Pu proposed that be lengthened to 12 Earth radii so as to extend the Cluster data. Their orbits were synchronized in such a way that all six satellites would, from time to time, be in the same line to observe solar activity.

The Doublestar mission design was for a first, equatorial satellite concentrated on the Earth’s magnetic tail, while the second, polar satellite checked out the magnetic poles and the resulting auroras. The mission aimed to improve scientists’ knowledge of magnetic storms which can upset communications, radar, and navigation systems on the Earth. It was anticipated that each mission would last a year, this short length determined by the damage resulting from regular passage through intense radiation belts. The European Space Agency contributed a modest €8m to the mission in return for four hours a day of data over the planned 18 months of the missions. The instrumentation is detailed in Table 7.4.

These were small satellites, about 350 kg in weight, 1.2 m high, 2.1 m in diameter, with a solar array of 6.33 m2 able to generate 280 W, with a design life of 12­18 months. Ground receiving stations were configured to receive data in Beijing, Shanghai, and Villafranca, Spain, while data centers were established in Beijing, China; Toulouse, France; Noordwijk, the Netherlands; Didcot, Britain; and Graz, Austria. The program got under way very quickly, despite interruptions from the Severe Acute Respiratory Syndrome (SARS) medical emergency.

The equatorial satellite was launched first, lifting off from Taiyuan on a Long March 2C on 29th December 2003, broadcast on Chinese TV. It entered a highly elliptical orbit of 570-78,948 km, the furthest orbit ever achieved by China, inclination 28.5°. One boom did not deploy but this did not have a large negative impact. It made its first observations on 21st January 2004, a 6.1 solar flare. The next day, 12.6 Earth radii out, it noted that the pressure of the solar wind had

Table 7.4. Tan Ce instruments.

Both spacecraft

TC-1 equatorial/ tail

Active space potential controller Austria

Hot-ion analyzer France

TC-2 polar

Energetic neutral atom imager Ireland

Low-frequency electromagnetic wave detector China

increased by five times. Tan Ce 2 was duly launched on 25th July 2004, entering a somewhat different orbit, of 560-38,278 km, 90°, circling the Earth every 7.3 hr. By operating with Cluster, data could be collected from six data points. In August

2004, for example, Tan Ce 1 and 2 were in the trapped region behind the Earth, while the four Cluster satellites were further behind in the neutral sheet. In February

2005, by contrast, Tan Ce 1 was on the sunward side, Tac Ce above the Earth at the cusp, and Cluster in the magnetosheath.

The initial mission lasted a year to August 2005. By May 2006, ground controllers had received 175 GB from Tan Ce 1 and 145 GB from Tan Ce 2. Tan Ce l’s backup attitude controller failed during a big magnetic storm, but ground controllers were able to keep the spacecraft under control. Both missions were extended to September 2007, the official mission termination point. Tan Ce 1 decayed on 14th October 2007. Tan Ce 2 was lost in August 2007 but, to some surprise, was recovered that November.

The Tan Ce and Cluster missions led to at least 1,000 scientific papers. The International Academy of Astronautics (IAA) conferred the prestigious Laurels for Team Achievement Award on the Double Star/Cluster Team for providing unprecedented measurement capability and discoveries in geospace. The main fields covered by the two spacecraft were geomagnetic storms; magnetospheric sub-storms;

magnetic reconnection; the interaction of the solar wind with the magnetosphere and ionosphere; changes in the radiation belt, the ring current, and the plasmasphere; the plasma sheet; geomagnetic pulsations; space plasma; and the magnetosheath, magnetopause, cusp, and polar cap.

The first results of the mission were presented at a symposium on Cluster and Doublestar in Noordwijk, the Netherlands, in September 2005, which took in the results of 21 simultaneous magnetopause crossings. The initial scientific results from Tan Ce were:

• they confirmed the theory of magnetic reconnection in the Earth’s magneto­sphere; they found multiple reconnection sites and flux ropes 6.3 Earth radii out in the Earth’s fragmented magnetotail; Flux Transfer Events (FTEs) were noted at the points of reconnection, speeding at between 170 and 250 km/sec;

• they discovered 140 ion density holes in the solar wind upstream of the bow shock, several thousands of kilometers apart, in upstreaming particles;

• Tan Се 1 detected cracks in a neutron star crust during a starquake;

• they found density holes ahead of the bow shock;

• ultra-low-frequency waves made the magnetic field lines wobble; and

• low latitude is the best place for ultra-low-frequency waves to assist solar wind particles to penetrate the magnetopause [6].

Later, two detailed mission reports were issued [7]. The principal highlights were:

• Tan Се 1 recorded 516 tailward flow events at between 7 and 13 Earth radii and found eight magnetic flux ropes;

• individual magnetic storms were studied in detail, such as the “Halloween storm” of 31st October 2003 and the violent storm of 21st-22nd January 2005 (mach 5.4); Tan Се 1 observed a sub-storm on 12th October 2004, noting low-density, high-temperature ions originating from the ionosphere and flowing along the magnetic field – observations matched with the American Geotail;

• two oxygen-rich Bursty Bulk flows (BBFs) were observed during the magnetic storm of 8th November 2004;

• Tan Се 1 measured bursts of flows from the Sun, typically 48-103 sec during storms, their velocity (rising from 390 km/sec to 520 km/sec), and ion densities (ranging from 0.14 cm-3 to 0.28 cm-3);

• Tan Ce 2 observed 14 dawn chorus events in November 2004, the outbreak of radio noise associated with solar storms near the equatorial plane and their spreading to the mid and higher latitudes; and

• the polar spacecraft found vortex-like plasma flows at the boundary of the outer radiation belt and the ring current, going in opposite rotational directions.

FTEs were a feature of particular interest. Between February and April 2004, Tan Се 1 detected 27 FTEs, mainly at low latitudes, moving along the sides of the magnetosphere into the magnetotail, this time being matched with Europe’s Cluster spacecraft. Individual FTEs that affected both the four Cluster spacecraft and Tan Се 1 were studied, such as the 10-min FTE of 13th March 2004, enabling the profiling of an individual event in extraordinary detail. The typical duration of an FTE was measured: 130 sec.

A scientist who won particular recognition for his part in the mission was Zuyin Pu, who was awarded the 2010 COSPAR Vikram Sarabhai gold medal for his work on the anti-parallel reconnection of the magnetosphere at low and high latitudes, magnetic nulls, and energy transport from the solar wind to the magnetosphere, generating micro-pulsations [8]. Another was Susan McKenna-Lawlor of Space Technology Ireland, located on the campus of the National University of Ireland, Maynooth, who was responsible for Tan Ce 2’s NeUtral Atom Detector Unit (NUADU – the name of a Celtic warrior). NUADU was designed to monitor the ring current during geomagnetic storms and data were received up to mission end.

Tan Ce results: the ring current (right). Courtesy: Susan McKenna-Lawlor.

The unit featured the capability to record four Energetic Neutral Atom (ENA) distributions. These ENA data were used to remotely monitor the evolution of the terrestrial ring current during significant geomagnetic storms, thereby providing new insights into solar-related dynamic magnetospheric processes [9]. Bright ENA emissions recorded at the feet of terrestrial magnetic field lines during magnetic storm events indicated the presence of strong related increases in the fluxes of trapped energetic charged particles. ENA data recorded by NUADU and by NASA’s IMAGE/HENA instrument while viewing the northern and southern hemispheres during a major magnetic storm provided the first views of the ring current to be simultaneously obtained in both hemispheres.

The successor to Doublestar is the MIT mission, which stands for Magnetosphere- Ionosphere-Thermosphere, now in development. The purpose of MIT is to study:

• the processes that trigger magnetospheric storms and enable their recovery;

• the transport of ionospheric ions in the magnetosphere;

• the behavior of electrical fields during storms, with their temporal and spatial parameters;

• temperature variations during geomagnetic storms, their seasonal and diurnal variations; and

• the generation, propagation, and dissipation of large-scale gravity waves during storms.

Four satellites are involved: two in perpendicular polar orbits about the Earth at 600 km, called the thermosphere satellites (T1 and T2); a magnetospheric satellite in polar orbit between 1 and 7 Earth radii (M); and a solar wind satellite (S), in an equatorial orbit of 3-25 Earth radii. The instrument package has already been indicated and is outlined in Table 7.5.

Table 7.5. MIT instruments.

Magnetic field detector Electrical field detector Neutral particle spectrometer Plasma analysis system Neutral atom imaging suite Aurora imager

Limb aurora and airglow imager Atmospheric wind and temperature remote sensor

One will carry a new Neutral Atom Detector Unit following NUADU (NAIS-H) but featuring higher spatial resolution combined with a Low Energy Neutral Atom Imager (NAIS-L).

By summer 2007, something like an Asian Moon race was hotting up, with China, Japan, and India all preparing to send probes to the Moon within a relatively short period. First off the starting blocks were the Japanese with Kaguya (also known as Selene) on 14th September 2007 (India’s Chandrayan was last, in 2008). This was Japan’s second Moon mission – a sophisticated spacecraft with two subsatellites, which had been long in preparation and benefitted from the quick publication of its eye-catching pictures and videos.

Chang e arrived on the pad at Xi Chang in early October 2007. Granted the prestigious nature of the mission, tightly controlled news coverage was expected. The opposite turned out to be the case, for the launch was covered live on television on worldwide feed. In the spirit of the new commercial China, two grandstands were erected for 2,500 paying spectators some 2,500 m from the pad, the charge being €80 a go. Celestial mechanics dictated a launch on the 24th, 25th, or 26th October, failing which the next opportunity would be the following April. In the event, the CZ-3A counted down smoothly on the 24th, lifting off at 18:06 China time. There was no countdown clock visible and ignition came quite suddenly against voice-over commands in Chinese. The Long March rocket moved off the pad slowly, set against the background of the rolling hills of Sichuan, picking up speed, and bending over in its climb. Minutes later, it was learned that Chang e had entered a highly elliptical Earth orbit of 205-50,930 km, 26°, period 16 hr, and that the solar panels had deployed. On the next day, the perigee was raised to 600 km.

Chang e’s trajectory was quite different from the first Moon probes of the two space superpowers far back in 1958-59. They had shot directly for the Moon, with the Soviet Union’s First Cosmic Ship passing the Moon only 34 hr after launch. Because the 2,300-kg Chang e was at the limits of the Long March’s lifting capability, the strategy was to put the spacecraft into a high Earth orbit and gradually raise the ellipse over a month so as to nudge it into lunar orbit. This was risky, for it made for a heavy fuel load and required multiple precise maneuvers over two weeks.

The second maneuver took place on the 26th, controlled by the Yuan Wang 3 tracking ship, raising the orbit from 50,000 km to 70,000 km, period 24 hr. Despite being rolled in a storm, on the 29th, the ship commanded the third maneuver, to raise the orbit again, to 120,000 km, 48 hr. The new computer on Chang e was the “smartest ever”, with a self-navigating and repair capacity, it was announced. The first mission instrument, the high-energy particle detector, was now turned on and it recorded the Chang e crossing the radiation belts.

On the 31st, the fourth maneuver raised the apogee to 380,000 km, a 13-min burn of sufficient velocity (10.9 km/sec) to reach the lunar environment. This was a critical do-or-die maneuver through a narrow entry gate which, if it failed, would strand the spacecraft in either Earth or solar orbit. The ultraviolet instrument was switched on to image the Earth-Moon system.

Finally, on the fifth maneuver, Chang e was nudged into lunar orbit at 11:37 on 5th November. The braking maneuver was made some 300 km distant from the

Moon, cutting the speed from 2,300 m/sec to 1,948 m/sec to achieve an elliptical lunar orbit of 200-8,600 km, 12 hr, the maneuver being followed by the ground in real time [3]. A second maneuver on 6th November reduced velocity to 1,800 m/sec and adjusted altitude to 213-1,700 km, 3.5 hr. A final burn was carried out on 7th November that set a velocity of 1,590 m/sec and put the spacecraft into its working orbit of 200 km, 2 hr 7 min. The precise orbit was later calculated as 195.53-202.07 km, inclination 88.2°. Seven engine firings had been made and some of the original 1,150 kg of fuel still remained.

The cameras were switched on first, the other instruments one by one after them. The first images from lunar orbit were received on 21st November. They were formally unveiled at a ceremony in Beijing by Prime Minister Wen Jiabao on the 27th, as “The East Is Red” and “Ode to the Motherland” played in the background. The first photoset comprised 19 tracks or orbits of images, each 60 km across – a total area of 280 x 460 km of the south-eastern quadrant of the Moon (54-70°S and 57-83°E). A commentary described the area as basalt with plagioclase highland. The camera took pictures in 60-m swaths, taking images downward, forward (+17°), and backward (-17°) so as to develop stereo pictures. The cameras were developed by the Xian Institute of Optics and Precision Mechanics.

Photography concentrated first on 75°N to 75°S and then the polar regions. Chang e flew at a solar minimum and the solar x-ray spectrometer detected no activity at all until 5th December, when a sunspot appeared. It followed a 2 hr 50 min solar flare on 31st December. When the Sun-Moon-Earth were aligned in this order for the first time, on 8th December, the solar wind ion detector first detected the solar plasma and measured the levels of helium, lithium, and calcium therein. The solar wind was streaming toward the Earth-Moon system at 2,000 km/ sec [4].

The orbit was adjusted three times in February 2008 and there was still 270 kg of fuel to hand. On 1st August 2008, a progress report was issued, announcing that over 700 hr of data had been received in the course of 3,024 orbits, coming down to the two main tracking stations of Kunming, Yunan, and Miyun, Beijing.

China had always intended to crash Chang e on the Moon once it had completed its scientific mission. In January 2009, a 1.627-m/sec burn lowered Chang e’s orbit to 100 km (it is not clear whether this was circular at 100 km or whether it kept its 200­km apogee). China finally reached the surface of the Moon on 1st March 2009, when Chang e impacted near the crater Taruntius at 1.5°S and 52.36°E, along the equator in the Sea of Fertility, just west of Luna 16’s landing site, after 495 days. The camera was turned on for the last 59 km of the descent.

What is the ultimate aim of the Chinese space program? For many Chinese, the development of an indigenous space program has been a source of pride and, as already noted, inspiring “lofty thoughts”. They are conscious that they have developed their program almost entirely on their own, using indigenous human and industrial resources, and despite varying levels of American blockade. As far back as April 1970, Zhou Enlai had proclaimed “We did this through our own unaided efforts” and the program remained the most nationally self-sufficient ever since.

China became, with its first manned spaceflight and then space station, the world’s third most prominent spacefaring nation, following the original space superpowers of Russia and the United States. Many of our planet’s nationalities have now been into space, but as guests of the superpowers; only three countries have the ability to do so on their own. From 2011, there were two manned space stations circling the Earth: an international one, led by the United States, Russia, Europe, Canada, and Japan; and a Chinese one: Tiangong. All this had been achieved by a country where, a little over 50 years earlier, the bicycle, the tractor, and the truck represented the limits of its technology, though never of its imagination. China’s space achievements were all the more remarkable for having been developed in a country so isolated from the world community. Now, China’s cosmodromes, space centers, and satellite factories are humming with activity. Its scientific institutes are expanding, peopled by a young and enthusiastic workforce. The biggest Earthbound space construction project is now taking place at Wenchang, Hainan, with enormous launch pads in the making for entire new launcher fleets. Roadmap 2050 promises a space program on a truly heroic scale.

In Western writings of future space missions, or in what might be called near-term science fiction, China has rarely played any part. An honorable exception is Arthur C. Clarke. In his famous novel, 2010: Odyssey Two (1982, Granada), Arthur C. Clarke had a manned Chinese interplanetary spaceship called, appropriately, the Tsien Hsue Shen, racing to Jupiter and its life-giving moon Europa, ahead of the Americans and the Russians. The Chinese did indeed get there first, but what happened after that is another tale. The Chinese part of the adventure was, in the event, disappointingly dropped from the film version. What a story it would have made!

Fantasy? Maybe, but, when Zhou Enlai and Tsien Hsue Shen set up the Chinese space program on 8th October 1956, who could have imagined that Chinese yuhangyuan would circle the Earth in less than 50 years? And that they would fly to a station in orbit in less than 60 years? The Chinese space program has been forged in a hard factory of technological backwardness, pohtical upheaval, and interna­tional isolation. The imagination, dreams, patience, and dogged determination of Tsien Hsue Shen and his colleagues ensured that China could develop a space program worthy of the country’s ancient achievements in science and engineering. Would it be surprising if an interplanetary spaceship called the Tsien Hsue Shen one day traveled to that lunar base, Mars, Jupiter, or to the far ends of the solar system? Considering all that is now happening, it might be more surprising if one did not.

[1] Times given in this book are normally Universal Time (UT or UTC), associated with the 0° meridian (Greenwich Mean Time) unless, as here, local time is stated. China is one time zone, normally UT + 8 hr.

REFERENCES

[3] For detailed information and timelines on Shenzhou 8 and 9 and Tiangong, see Christy, R. China: Piloted Programs and Other Missions, available online at www. zarya. info.

[2] For a description of Tiangong, see Coue, P. China’s Heavenly Palace. Spaceflight, 54 (1) (January 2012); The Second Generation Shenzhou. Space­flight, 54 (2) (February 2012).

[3] Xu, W. Chinese Space Film Drama. Spaceflight, 53 (9) (September 2011).

[4] For the origins and evolution of Tiangong and subsequent planning, see Pirard, T. Appel chinois a la cooperation internationale. Wallonie Espace Infos, 54 (janvier-fevrier 2011); Lin, K.-P. Space Station Orbital Mission Design Using Dynamic Programming. Paper presented to 61st International Astronautical Congress (IAC henceforth), Prague, 2010.

[5] Li, Y. et al. Progress in Space Medicine in 2008-2010. China Journal of Space Science, 30 (5) (2010).

[6] Guo, H.; Wu, J. (eds). Science and Technology in China: Roadmap to 2050. China Academy of Sciences (2009).

In the first decade of the twenty-first century, observers of the night sky were able to watch the construction of the International Space Station in the sky above. A conspicuous, steady star would blaze across the dark sky from west to east, becoming ever brighter as new modules and cargoes were brought up until it outshone all the other objects in the heavens in what was humankind’s largest ever construction project.

From 2011, observers were able to spot a new, rival space station, the Tiangong, cross the sky. They could pick out the much smaller Shenzhou spacecraft as they chased Tiangong across the night skies to bring crews up to the station. Now planet Earth had two space stations: one belonging to the traditional big space powers; and one made in China.

The emergence of China as a spacefaring nation should, over the long course of history, be no surprise. Way back in what were sometimes called the Dark Ages in Europe, the rocket was invented in China. In the twentieth century, many of the engineering calculations necessary for rocket flight were done by one of the world’s great space designers, Tsien Hsue Shen. The Chinese space program was founded on 8th October 1956, a year before the first Sputnik was even launched. On that day, China’s political leadership decreed the foundation of the Fifth Academy to spearhead China’s space effort and requisitioned two abandoned sanatoria to be its first laboratories. Had it not been for subsequent political upheaval – the great leap forward and the cultural revolution – China might have achieved much more, much sooner.

As it was, China’s first satelhte in orbit was the biggest of the superpowers. China was the third space power to recover its own satellites, put animals in orbit, and develop hydrogen-fuelled upper stages. China developed a broad program for Earth observations, navigation, communications, weather forecasting, and materials processing. China achieved space superpower status in 2003 when Yang Liwei flew into orbit. China overtook Europe in launchings per year and, in 2011, surpassed the United States.

The Chinese space program has sometimes been called the last of the secret space programs. Details of its early history still remain obscure. Writing about the early

Chinese space program is like trying to assemble a jigsaw where some of the pieces are not colored in and others are missing altogether. Even today, its facilities are still the least accessible of the space powers. In more recent times, China has become more forthcoming in detailing information on its current programs and future intentions.

Penetrating the fog enveloping some aspects of the Chinese space program is one problem. The level of Western misunderstanding of the program is a challenge of similar magnitude. With some honorable exceptions, many in the Western media who ought to know better responded to Chinese space developments with a mixture of puzzlement, patronizing down-putting, and dismissal. Chinese capabilities are often played down on the basis that their equipment is alternately primitive or imitative. If it works, the presumption is that it must have been stolen. There was, and remains, an extraordinary reluctance to concede to the Chinese the credit of having created, designed, and built their own equipment. This is a problem not peculiar to the space program, for the West often forgets how China pioneered so many things – from medicine to mathematics and public administration, as well as such inventions as the suspension bridge, paper-making, the compass, chemistry, printing, paper money, the stirrup, the plough, the lock gate, the wheelbarrow, and clockwork. The observations by the ancient Chinese astronomers are renowned for their accuracy.

This book is the third in a series. It was originally published as The Chinese Space Program – From Conception to Future Capabilities by Praxis/Wiley in 1998 and told the story of the program from its pre-history, through its first launch (1970), and its subsequent development in the 1980s and 1990s. The story was brought fully up to date, when Yang Liwei circled the Earth, as China’s Space Program – From Conception to Manned Spaceflight (Praxis/Springer, 2004). This book begins with the construction of China’s space station, the Tiangong (Chapter 1), and is a detailed account of the contemporary Chinese space program. The earlier history is condensed into a single chapter (Chapter 2) and those interested in the detail of the early history should re-read the previous two books in the series. The subsequent chapters take the reader through the contemporary program: organization, infrastructure, and launchers (Chapter 3), recoverable satellites (Chapter 4), communications satelhtes (Chapter 5), applications satellites (Chapter 6) and space science (Chapter 7). Chapter 8 describes the manned spaceflight program, while Chapter 9 examines current Chinese exploration of the Moon and Mars. Finally, Chapter 10 looks at China’s ambitions in space, future programs, and their most likely lines of development.

Finally, a note on terminology. A complicating feature – one familiar to students of the Soviet space program – is the use of different designators for the same satellites. In the West, Chinese satellites were named China 1, 2, 3, and so on, also PRC-1, PRC-2 (People’s Republic of China), and even Mao 1, 2, and 3. At the time, the Chinese simply referred to these missions by their date of launch or in connection with political events. Eventually, the Chinese introduced a set of designators and applied them retrospectively. That should have been an end to the matter, but the Chinese then revised some of these designators several times over – and then changed them again! Even to this day, different designators are applied to the same program. As if this were not complicated enough, inconsistent translations mean that many institutes, bodies, and organizations acquire, over time, slightly different names. Sometimes similar-sounding names turn out to be the same thing – but sometimes not. The Chinese also applied a series of numerical codes to their various space projects. Some were based on dates, others not. All this must be carefully disentangled. Here, the most consistent and most universally understandable systems have been used, but readers should be aware that others are also in use. We must also note that the Chinese have sometimes, though not always, followed the Soviet practice of not giving a number to the first satellite of a series. Finally, in the area of personal names, this book generally follows the Chinese practice of identifying people by their surname first.

Perhaps the most important and expensive infrastructural element of any space program is its launch site facilities. China has three launch sites, with a fourth in construction. The first, Jiuquan, was built in northern China for China’s first satellite, Dong Fang Hong, and is the base for the manned space program. The second, Xi Chang, was built in Sichuan in south-western China for launches to equatorial orbit. The third, Taiyuan, near Beijing, was built for launches to polar orbit. Construction has already started of a large launch site on Hainan, China’s largest and most southerly island. For the sake of completeness, one should mention a minor launch site for sounding rockets, Haikou, also on the island of Hainan. Details are given in Table 3.1.

Of the three main launch sites, the busiest is Xi Chang. Table 3.2 lists the total number of launches from each.

The FSW 1 series was introduced in September 1987, barely a month after the conclusion of the FSW 0 series. The “1” series was heavier (2,100 kg), with a greater payload and able to orbit up to 10 days (although eight days was the norm). A digital control system was introduced, new gyroscopes were added to help control attitude, new sensors were added, the satellite could be reprogrammed when in orbit, a control computer was installed, and the pressure inside the cabin could be regulated. Later, the Chinese stated that the FSW 1 series was a cartographical and mapping satellite, making it comparable to the Russian Kometa series.

FSW 1 continued the significant move into microgravity experiments [4]. The first mission, FSW 1-1, was devoted to biological and material processing: seeing how algae would grow in orbit and processing gallium arsenide. One of the biological cargoes was rice and other seeds, which were planted afterwards on the Earth on a 660-ha plot. It was found that space-flown rice grew taller, tilted wider, lasted longer, generated seeds of longer duration, and had greater yield and higher fat content. Whereas a ground version of Japonica rice had a yield of 4,500 kg/ha, the space – flown variety had a yield of 7,500 kg/ha. Indica rice had a 12% higher yield. Green pepper seeds were promising, generating peppers of 300 g and a yield up by 122%. Tomatoes had 20% higher yield and better disease resistance. Wheat and barley were flown in 1988 and 1990 and had greater height, except for those hit by high-energy particles, which did not germinate. Garlic, though, did not like the space environment and growth was weak but, by contrast, rape benefitted [5].

FSW 1-2 carried both a Chinese remote sensing package and a German protein crystal growth experimental package called Cosima. The German experiment, developed by Messerschmitt Bolkow Blohm and the German space agency, DLR, was intended to find new ways of producing the medical drug interferon from large and pure protein-based crystal. Germany paid €440,000 and the package was handed back to DLR the day after landing.

Guinea pigs and plants were carried on FSW 1-3 as part of a microgravity experiment. In doing so, China became the third nation to send animals into orbit and recover them. FSW 1-4 carried a Swedish satellite, Freja, piggybacked into orbit while the main spacecraft carried Chinese and Japanese microgravity experiments (the latter being a 710°C microgravity furnace). The Chinese experiments involved testing how rice, tomatoes, wheat, and asparagus would grow in orbit (apparently,

much faster). One of the early missions carried mice, but they died after five days due to a pollutant in the atmosphere in the cabin. Subsequent examination found that, prior to that, there were changes in the blood vessels in their brain and lung tissue as a result of weightlessness. Later mice experiments showed a clear shift of blood concentration to the brain [6].

The FSW 1 series carried a suite of three furnaces:

• Temperature Gradient Furnace for gallium arsenide;

• Advanced Gradient Temperature Furnace for remelting; and

• Solution Growth Facility for crystal growth from solutions.

For gallium arsenide, a small 11-kg furnace was used, able to work for 270 min, drawing 150 W of power and able to generate a maximum temperature of 1,260°C. Pioneer of gallium arsenide was Li Lin and she was able to show that

superconductors made in orbit were superior to Earthly ones. Chen Wanchun was the pioneer of lithium and he grew more than 50 crystals on the FSWs of August 1988, October 1992, and July 1994. The 1996 mission experiments were led by the Institute of Physics of the Academy of Sciences and the Institute of Physics in Lanzhou. They cut a 20-mm silicon gallium arsenide crystal ingot with uniform results, solidified nitrate and phosphorous alloys, and grew 51 boules of calcium hthium crystals. According to experimenters Chen and Wei, the processes of crystal growth in orbit were very complex, involving a mixture of factors that are still not well understood. Iron samples were also smelted [7].

One satellite failed spectacularly – FSW 1-5, which did not return to the Earth when commanded to do so in October 1993. The satellite failed to rotate downward for the return to the Earth, but instead the engine fired in the direction of travel, propelling the FSW into a much higher orbit, as far out as 3,023 km. More critically, its perigee of 181 km was deteriorating fast, with the risk that the uncontrolled satellite might survive the fireball re-entry and crash on inhabited zones of our

planet. These developments were especially unfortunate, for FSW 1-5 was flying a number of unusual cargoes. In addition to scientific equipment, the cabin had 1,000 stamps, 3,000 first-day covers, credit cards, photos, 194 calling cards, and 235 ornaments and gold-studded medallions of Mao Zedong – apparently destined for sale to Japanese collectors, where such items reached premium prices. The media, as ever, warmed to the apocalyptic prospect of a rogue satellite plunging destructively to the Earth, only to be disappointed when, after several days of bouncing off the upper layers of the atmosphere, FSW 1-5 came down in the southern Atlantic on 12th March 1996.

The FSW 2 series was introduced in August 1992, even before the FSW 1 series had come to an end. Its principal innovation was the ability to maneuver in orbit, but there were other improvements. Compared to the FSW 1 series, the “2” model had a greater weight (3,100 kg), 53% heavier payload (350 kg), 20% greater cabin volume, and it could stay in orbit for up to 18 days. The length of the spacecraft was increased by a third to 4.6 m, with a much larger service module, part of which was pressurized. FSW 2 carried a more sophisticated attitude control system and an advanced computer. The much-increased size of the FSW 2 meant that it required a larger launch vehicle, the Long March 2D, an improved version of the 2C (although the C continued in operation for other missions).

FSW 2-1 (August 1992) was a dual-purpose mission, with both remote sensing

and microgravity experiments (in this case, cadmium, mercury, tellurium, and protein crystal growth). It used its maneuvering system to change orbit three times during the mission. The first attempt to re-enter, on the 12th day of the mission, failed but, after going through the procedures again carefully, ground controllers were successful on the 16th day. FSW 2-1 marked the first tests of protein crystal growth in orbit devised by professors Gong and Bi of the Institute of Biophysics of the Academy of Sciences. Sixty percent of proteins grew better than on the ground. There were 10 protein growth experiments in 48 cells, one including snake venom: crystals were grown in a multi-purpose finishing stove, a furnace able to provide heating of 813°C. The results were encouraging, with space crystals growing larger, more uniform, and clearer than the control group on the Earth. The Institute of Superconductors flew an experiment to make a perfect 10-mm single crystal, one of the four attempts being successful. This experiment was repeated on the later FSW 1­4 mission, this time with lithium crystals, 30 being grown. Both the cell culture experiment and microbial cultivation experiment were declared a success [8].

FSW 2-2 flew in July 1994 and also maneuvered in orbit; it carried an even more exotic cargo: rice, water melon, sesame seeds, and more animals. Fourteen protein crystals were tested, with much better results than on FSW 2-1, the experiment being repeated on shuttle mission STS-69, where three proteins were crystallized using a liquid diffusion method but, overall, that experiment was less successful. FSW 2-2 carried a tuber-like vapor diffusion apparatus. With 48 samples, nine proteins crystallized, the highest qualities coming from egg white, snake venom, and hemoglobin from the bareheaded goose. Twenty-two lithium crystals were also grown, the quality being more consistent than those grown on the Earth. DNA chromosomes were modified in large-grained rice [9].

FSW 2-3 carried Japanese microgravity experiments for the Japanese Marubeni Corporation with Waseda University, involving the development of indium and gallium mono-crystals. The Chinese materials processing experiments concerned the production of mono-crystalline silicon, photoconductive fiber with impurities of 10-7, and medicines to prevent hemophilia. China also carried its own microgravity materials processing experiments, as well as a biology package of insect eggs, algae, plant seeds, and small animals for the Shanghai Institute for Technical Physics. For the first time, the information collected by the satellite in orbit was stored on compact disk. FSW left, as normal, the equipment module behind in an orbit of 167— 293 km. In an innovation, its engines were re-lit on 11th November to lift it into a higher orbit of 212-299 km – a maneuver not explained at the time.

For the Chinese, the next stage was to operate a weather satelhte in geosynchronous orbit. Called the Feng Yun 2, this would complement the Feng Yun 1 series. The concept was that Feng Yun 2 would send back constantly scanning pictures of China and the western Pacific from its high vantage point 36,000 km out, while Feng Yun 1 and 3 would send back detailed weather maps from their lower, regular 100-min passes over China from an altitude of 900 km. Locations set for the new series were 86.5°E and 105°E. The original program envisaged two experimental and then operational satellites, with three and five channels, respectively. Chief designer of the imaging system was Tong Kai (1931-2005), a graduate of the Leningrad Institute of Telecommunications Engineering, who later went on to the navigation satelhte project. Construction of ground systems began in 1988 and was completed in 1994.

Geosynchronous meteorological satelhtes are expensive, requiring a big launcher and high operating standards. However, the vantage point of 36,000 km can provide quality weather coverage of large land masses around the clock. The United States operated their first geosynchronous metsat in 1974 (Synchronous Meteorological Satellite 1), Japan and Europe in 1977 (Himawari and Meteosat, respectively), and Russia not until 1994 (Elektro).

Feng Yun 2 was a drum-shaped satellite, 4.5 m tall, with a diameter of 2.1 m and a weight of 1,380 kg. It carried a five-channel Visible and Infrared Spin Scan Radiometer, which transmitted a visible picture of 2,500 lines and 1,250-m resolution every 30 min, infrared images of 2,500-m resolution, and water vapor images of 2,500-m resolution to stations in China and Melbourne, Australia, made by the Institute for Technical Physics in Shanghai. It was intended to provide cloud, temperature, and wind maps. It was designed by SAST, developed by the Shanghai Aerospace Technology Research Institute of the China Aerospace Corporation, and built in the Hauyin machinery plant. Service life was three years, the last to fly in 2013 before the FY-4 came in. The FG-36 solid-fuel apogee motor was designed to achieve the final insertion: it was 1.53 m long, 900 mm in diameter, 729 kg in weight, with a thrust of 44 kN or 289 sec ISP.

The Feng Yun 2 series got off to a disastrous start. When Feng Yun 2-1 was being loaded with propellant in the processing hall at Xi Chang launch site on 2nd April 1994, the satelhte exploded, killing one technician and injuring 31 others. The satellite itself, valued at over €88m, was a write-off and it took over three years to redesign the propellant tank system so as to make sure this accident would never happen again.

The replacement Feng Yun 2-1 was eventually launched on the Long March 3 rocket from Xi Chang on at 9:00 pm Beijing time on 10th June 1997. Twenty-three minutes after launch, the hydrogen-powered third stage fired to send it on its way to its permanent position at 105°E, with a scheduled lifetime of three years. It also carried a solar x-ray spectrometer and space particle detector. By September, it had completed its full range of systems testing and was ready for handing over to the state meteorological administration. Its instruments were calibrated against those of Feng Yun 1-3 using, as a ground-based reference point, Qinhai Lake.

Feng Yun 2-1 lasted until 10th April 1998, only six months of full operations, when it was lost. Ground controllers managed to regain control at the end of the year, but the resumption was limited to six images a day. Contact was off and on during the year, good images being returned from time to time. In March 2000, meteorological operations with the satellite appear to have ended and the satelhte was moved to 86°E by the end of April. Station-keeping maneuvers continued there so it must have still returned some data. It was taken out of orbit on 1st September 2006.

The gap in operations did not last for long, for a replacement satellite, Feng Yun 2-2, was lofted into orbit by Long March 3 on 25th June 2000, soon arriving at 2-1’s old station, 105°E. A month later, following on-orbit testing, the imaging systems were turned on by the National Satellite Monitoring Centre. Twenty-five minutes later, after they had completed a full scan of the Earth, full disk images in color, infrared, and water vapor came flooding into the center, showing clouds swirling over south-east Asia, a clear view of southern Australia, and tropical storm Tembin menacing Japan. Resolution was as sharp as 5 km, which, from 36,000 km out, was good. Three images in each format were, from thereon, sent to the monitoring center every 25 min. Feng Yun also collected and retransmitted data

from automatic weather platforms at sea. Feng Yun 2-2 was even designed to monitor solar radiation, carrying a solar x-ray spectrometer and space particle detector to monitor solar activity and charged particle radiation. It was taken off orbit on 7th October 2006 when it was moved to 123°E and began drifting [6].

Feng Yun 2-3 was launched to 105°E on 19th October 2004, with visible and infrared equipment to watch ocean conditions, fog, hailstorms, sandstorms, and fires. It was declared operational the following May and was described as the first operational version. It was the first Feng Yun to use the CZ-3A, the 3 having been retired. Feng Yun 2-4 was launched on CZ-3A on 8th December 2006 to form a pair with 2-3 but at 86.5°E. The next Feng Yun, 2-5, was launched on CZ-3A on 23rd December 2008, entering transfer orbit after 24 min. At this stage, the series, which had a relatively simple numbering system, began to get complicated. First, the Chinese began to applying lettering, so that the missions were called 2A, 2B, etc. Second, it was announced that the December 2008 launch was 2-6, not 2-5 as expected – a move designed to acknowledge the loss of the first intended mission (now 2-1). Whatever the number, Feng Yun 2-5 was unusual in that the CZ-3A final stage was reignited after 1,500 sec to take the stage out of orbit, a debris mitigation measure.

China reported that, as a result of the Feng Yun system, the country had received advance warnings of typhoons, been able to take flood diversion measures, brought ships back to port ahead of storms, harvested crops before bad weather, and controlled river flows through dams. They had enabled China to estimate crop growth from vegetation and moisture indices, map land use and desertification, and provide data on urban hot spots, smog and dust, algal blooms, forest pests and diseases, pollutants, and even the ozone hole over the Antarctic. By 2006, China had over 100 receiving stations for Feng Yun data. That year, it signed an agreement for eight countries to take the data – Peru, Thailand, Bangladesh, Thailand, Pakistan, Mongolia, Iran, and Indonesia. An information dissemination system was established, called FengyunCast, for domestic and foreign users in Asia and Australia (Europe has EumetCast and the Americans have GeonetCast).

The Feng Yun 4 series will replace the “2” series from the mid-2010s, with 10 visible and infrared channels and microwave sounder. Locations will be 86.5°E and 107°E and six will be launched in 2013-20. The “4” series will have optical and microwave sounders to enable the compiling of three-dimensional maps of atmospheric temperature and humidity, supplemented by four instruments: solar x-ray imager, extreme ultraviolet imager, solar x-ray radiometer, and extreme ultraviolet radiometer. China’s objective is to have an integrated system of FY-3s and FY-4s by 2020 providing data on the atmosphere, hydrosphere, biosphere, lithosphere, and cryosphere, with morning and afternoon FY-3s and a three-satellite system of radar rain measurers. The series is summarized in Table 6.2.

As had been the practice in the Russian space program, Chinese scientists used applications satellites to carry scientific instruments (equivalent Russian add-on packages were called пайка modules, “nauk” being the Russian word for “science”). These were flown on the first communications satellites in 1984 and 1986. Both the first, Shiyan Tongbu Tongxin Weixing, and the second, Shiyong Tongbu Tongxing Weixing 1, carried particle detectors (semi-conductor and electron detector, semi­conductor proton detector) and a broadband soft x-ray detector to measure solar bursts and resultant x-ray storms. Their purpose was to measure changes in the intensity of electrons and protons in 24-hr orbit, as well as static electricity on the spacecraft. A small telescope studied proton fluxes in the 10-30-MeV range and electrons from 0.5 MeV to 1 MeV. Solar bursts were detected and measured on 21st April 1984 and 4th February 1986. Solar x-rays were surveyed in the 1-8-A range.

Scientific instruments were then fitted to weather satellites. Feng Yun 1-1 carried equipment to detect cosmic rays, protons, and alpha particles, as well as carbon, nitrogen, oxygen, and ion particles in the Earth’s radiation belts. Feng Yun 1-2 carried a cosmic ray composition monitor in the range of 4-23 MeV to detect and measure both solar proton events and galactic cosmic rays, and these were matched against readings at the Zhongshan Antarctic base. It detected helium, nitrogen, oxygen, heavy ion, and anomalous iron particles in the inner radiation belt and five solar proton events over September 1990 to February 1991. It flew through the inner radiation belt South Atlantic Anomaly and measured the changing intensities of protons, alpha particles, and carbon ion and iron atoms. Doing so at a time of solar maximum proved to be harmful to the satellite, for the radiation levels disrupted its logic board, causing a complete breakdown at one stage. Energetic particle detectors were designed to measure how heavy ions, protons, and electrons affect weather, one outcome being a mapping of the South Atlantic Magnetic Anomaly.

Feng Yun 1-2 carried two additional experiments – two balloons called Qi Qi 1 and 2 (the name Da Qi has also been used). Their purpose was to measure the density of the upper atmosphere between 400 km and 900 km, and they were tracked by seven ground stations. Made out of polyester film and measuring 2.5 m and 3 m in diameter, deployed in similar orbits, they decayed from orbit the following year, one in March, the other in July. Diagrams were duly published of fluctuations in atmospheric density over the first 90 days of the mission. They were the first scientific satellites to benefit from project 863. Combined with accurate ground observations, they proved to be a cheap but effective way of measuring atmospheric density during solar maximum.

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The geosynchronous Feng Yun 2-1 carried a high-energy particle detector and solar x-ray detector to measure solar proton and high-energy particle events, while later 2-3 carried a solar x-ray detector to measure x-rays from the Sun above 4 keY in 10 channels and the results were compared to the American Geostationary Operational Environmental Satellite (GOES). The spacecraft also carried two scientific detectors, one to measure 3-300-MeV protons and the other to measure

0. 15-5.70-MeV electrons. For 2008-09, they measured little, due to the solar

minimum, only finding electrons in the South Atlantic Magnetic Anomaly and around the North and South Poles. The problem of radiation damage to satellites operating in 24-hr orbit continued to bother the Chinese, for they fitted high-energy electron detectors to Feng Yun 2-3. They supplied three years of data, from 2005 to 2008, giving more accurate predictions of the frequency of upset events. Later FY-3s will be fitted with instruments to measure the ionosphere and auroras [10].

The scientific results of the Chang e mission were substantial. Data return was 1.4 ТВ of raw data, transformed into 4 ТВ of science data, but, more importantly, they enabled China to start building its own repository of scientific knowledge.

The first objective was for China to compile its own Moon map, essential for its subsequent rover and sample return missions. The map combined both the imaging system and the altimeter, whose purpose was to give a precise topography. To do this, the imaging system made 589 tracks of data (or complete photographic passes), matched against 9.16m altimeter measurements.

The definitive map from the Chang e mission was published in December 2009 in Science in China and the Chinese Science Bulletin, authored by Jinsong Ping, Qian Huang, Chao Chen, and Qing Lieng. This made China the third country to publish its own Moon maps, after the Soviet Union and the United States, with the bonus of three-dimensionality. It was a 1:2,500,000 map with contours at every 500 m. It provided a full topography with elevation – moreover one that revealed fresh details of the Moon, such as a possible fault structure along the Apennines Uke one of the Earth’s tectonic plates. Analysts put forward the idea that the Apennine chain was a fault line similar to the Himalayas on the Earth [5]. Five tectonic maps were also in preparation for later publication. A bilingual Chinese-English atlas was published in 2010.

The map refined existing maps and found new features. A new impact basin was identified – the 470-km-wide Guanghangong basin – and a new crater, 190 km across – Wugang. There was a new volcano, Yutu, 2 km tall and 300 km across in

the Ocean of Storms, with another volcano nearby – Guisho. New craters were named after leading Chinese scientists: Cai Lun, after the first-century вс inventor of paper; Bi Sheng, after the eleventh-century inventor of movable type; and astronomer Zhang Yuzhe (1902-86). Following representations from China, the International Astronautical Union approved the naming of 14 features on the Moon after Chinese scientists – a small but growing Chinese proportion of the 1993 named features of the Moon [6].

The use of the altimeter enabled a much-improved knowledge of lunar topography, with an accuracy of at least 31 m. It determined that the Moon was

more spherical than the Earth by a factor of 1/963.7256 compared to the Earth’s 1/298.257. The radius of the Moon was re-measured as 1,737.013 km. Mare Ignii was identified as the biggest mass concentration (mascon). Profiles were published of individual features, such as Mare Moscoviense. Several years later, a critical account of the imaging system praised its definition (“better than the American Clementine”), but criticized its handling of bright light levels [7].

The gamma-ray spectrometer enabled Chinese scientists to make a chemical map of the Moon. The gamma-ray spectrometer scanned the Moon every three seconds between 27th November 2007 and 25th July 2008 and sent over 2.4m spectra to Miyun and Kunming ground stations. A global map of uranium, iron, titanium, and KREEP abundance was published. Chang e provided the most detailed iron and titanium maps since the American Clementine probe. Such maps were especially important in reconstructing the history of the Moon: iron was generally found on the top of lava flows and its presence indicated the order in which the lunar seas were flooded. The imaging interferometer compiled an iron and titanium abundance map of 84% of the Moon between 70°N and 70°S and a cross-section of the Mare Crisium was published. Further analysis showed the distribution of orthopyroxines, clinopyroxenes, olivine, pigeonite, and plagioclase across highland and mare areas, with more detailed studies made of Copernicus, Zucchius, Mare Orientale, Ariastarchus, Tsiolkovsky, and Tycho. A new model of these processes was put forward by Lu Yangxiaoyi, showing how melts of basaltic lava reached the mare from deep in the lunar interior in three periods of lunar history over 2bn—4bn years ago [8].

The amount of Helium 3 was recalculated downward from 5bn tonnes to lbn tonnes: 658,000 tonnes on the near side and 286,000 tonnes on the far side. The presence of Helium 3 was closely connected to levels of solar wind, the age of the lunar surface, and the presence of titanium. Chinese scientists then turned to the long-standing problem of whether there might still be water ice on the Moon. Chang e’s four-channel microwave radiometer first made a temperature map of the south polar region. Then it focused on Cabeus crater, where the American LCROSS mission had already impacted and offered comparative data. It found that the temperature in the bottom and permanently shaded part of Cabeus was 70 К and suggested a water ice content there of 2.8% [9].

The microwave sounder led to a detailed knowledge of the regolith, published by the Lunar and Planetary Research Centre, in “Methods and Advances on Lunar Soil Thickness” (Acta Minneralogica Sinica, 27(1) (2007)). Based on the temperature measurements of the microwave sounder, an algorithm was devised that made it possible to calculate the depth of the regolith all over, dividing it into a dust layer, regolith layer, and bedrock. The regolith was found to be much thinner than previous assumptions, but thicker on the far side:

• mare regolith ranged from 1.2 m to 11 m, the average being 4.5 m;

• it was thinnest in the Mare Imbrium, thickest in the Sea of Fertility and Mare Nectaris;

• highland thickness was 1-15 m, averaging 7.6 m;

• far-side thickness was thicker, at more than 8 m.

Using the same instrument, a temperature brightness map of the Moon was published, the equatorial regions showing up as bright red, with greens appearing the farther away one went and, at the poles themselves, the blues of shaded craters. The temperature brightness was higher in mare than in uplands, higher at the equator than at the poles, and higher on the near side than on the far side [10].

Chinese scientists compared their results with earlier American results (notably Clementine and Apollo), Russian findings (Luna), and their contemporaries (Chandrayan of India and Kaguya of Japan), especially to iron out differences between them due either to the calibration of instruments or interpretation of data. They specifically compared results to data gathered at Apollo landing sites, Apollo 16 being the benchmark. They later corrected their altimeter findings when a discrepancy of 145 m was identified. They also re-photographed the landing sites for Apollo 12, 14, and 15 [11]. Finally, the solar wind detector found few disturbances and low temperatures in the solar wind, except when the Moon passed through the Earth’s magnetotail.

Chang e achieved its four objectives of making a map, analyzing the chemistry and thickness of the lunar surface and characterizing the lunar environment, as well as overcoming the technically demanding trajectory used to reach the Moon in the first place. Chinese scientists should have been more than satisfied with the results and now had important data and analysis to share internationally.