Applying the space program

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

Feng Yun panel test.

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).

The box shape and panels of the Feng Yun polar weather satellite.

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.