Hainan home base

China's workhorse space booster fleet is composed mostly of variants of its Long March booster, which is based on its venerable Dong-Feng family of intercontinental ballistic missiles (ICBMs). These rockets have been used to launch military, scientific, and civil applications satellites and have by and large satisfied both Chinese domestic users and commercial customers. However, within the past year, the nation's rocket experts have announced bold plans for an entire new family of space boosters to be developed over the next 10 years [see "Year of the Rocket," IEEE Spectrum, May 2001, pp. 62-68].

Whereas the most powerful current Chinese booster can place 9200 kg in orbit, the new family will be able to orbit up to 25 000 kg. That puts it on a par with the U.S. Titan-4, and ahead of the U.S. Space Shuttle and Russia's Proton booster.

The Long March boosters, like their ICBM ancestors, were designed to be transported from their factories to their inland launch sites by rail, a severe constraint on their dimensions. Inland launch sites "are undesirable," according to a recent newspaper interview of a Chinese space official named Long Yuehao. A chief designer at Beijing's Chinese Academy of Launching Technology, where the Long March rockets were designed, Long Yuehao said the inland sites pose a danger to the surrounding areas following launch, and are difficult for larger carrier rockets to reach by rail.

The individual stages of the new boosters will be large enough to require transport by barge, rather than rail, from factory to launch site. This requirement necessitates a base with access to deep water. A coastal region with open ocean to the east and south would be ideal, and such a base is now under construction at Wenchang on Hainan Island, the site of the recent U.S. EP-3 spy plane incident. Initially, two launch pads for Long March boosters are being built. Within the next decade, the base could replace two of China's three inland space launch sites.

The Heavenly Vessel

Key to the future of Chinese astronaut missions is a 7200-kg spacecraft called the Shenzhou, or Heavenly Vessel [see drawing]. Previously known as Project 921, the vehicle made its first space mission, on autopilot without a crew, on 20-21 November 1999. It circled Earth 14 times, then landed, and only then was an announcement of its flight released.

The Shenzhou was launched from Jiuquan in Inner Mongolia, heading a bit to south of due east, atop a Long March-2F rocket, which resembles the U.S. Titan-4 [see map].

The second flight of the spacecraft, still without any crew, took place last January. Dubbed Shenzhou-2, it was more complex than the previous year's mission. It lasted six days and involved frequent firings of steering rockets to change orbit. It also carried a broader suite of scientific research equipment and recoverable samples as well as some live animal subjects. (As this article went to press, preparations were in full swing for a third unmanned test flight.)

Shenzhou-2 incorporated notable improvements. Power and data cabling was upgraded, weighing over 100 kg less than on the first vehicle. "Thanks to the cable modularity design, the cables in the [re-entry and orbital modules] are far less susceptible to damage, as the cables are no longer exposed," a newspaper account stated in July. The spacecraft's center of mass was moved farther aft, which improved the vehicle's controllability.

The spacecraft has three sections: a forward orbital module providing living quarters, a re-entry module behind it, and a service module with rocket engines and a pair of solar power panels with a total area of 20 m². The re-entry module with a crew of up to three returns to Earth via parachute.

Photographs of the Shenzhou's landing capsule show striking similarities to the Russian Soyuz vehicle. In fact, the Chinese admitted to buying a Soyuz capsule early in the 1990s from the Russians. Accordingly, many observers concluded that the entire Shenzhou spacecraft was a copy. It was "little more than a slightly modified version of the old Soviet workhorse of space, the Soyuz," wrote Richard Ingham of Agence France Presse soon after its first flight in 1999.

"No, it's not," countered U.S. space engineer Andrew LePage, an independent consultant in Colorado. "All the vital systems and most of the hardware are of Chinese design." Most other independent experts agree, as do later reports. Apparently, while the Chinese had asked to purchase a fully functional Soyuz vehicle for study, the price demanded by Russia was so high that the deal never took place. The capsule they did get had been stripped before delivery of almost all space systems.

Further, the Chinese re-entry module is about 13 percent larger in all dimensions than the Russian Soyuz on which its design was based [see diagram]. Still, its interior arrangement is similar. There are three side-by-side reclining seats, as well as instrument panels mounted on the cabin wall and at the crew's feet. There are also hand controls and an optical sighting device, crucial for a space rendezvous.

But the other two modules used by China are quite different from their Russian and U.S. counterparts. The propulsion module has four large main engines, whereas the Apollo service module had one, and the Russian Soyuz has one main and one back-up engine. The orbital module sports its own solar panels and independent flight control system, so that it can continue as a free-flying mini-laboratory long after the re-entry module has brought the crew back to Earth.

Design influences in evidence

In at least two of the Shenzhou's features, however, direct copying of Soyuz designs is obvious. In both cases, and probably many more, the Chinese economized significantly on their development effort by using the mature, existing designs.

One feature they borrowed is the launch escape system. In the early 1960s, the Soviets adapted the tractor rocket design originally used by NASA on Mercury capsules, a nose-mounted rocket for pulling a spacecraft away from a malfunctioning booster. But during and after the intense 20-gravity rocket firing, severe stability problems made a safe separation of the crew module from the booster far from assured. As a simple fix, the Russians added four square flaps to the spacecraft's aerodynamic shroud; these flipped open during the escape tower firing and kept the vehicle on a steady course. The Chinese simply copied the Soviet four-flap kludge [see photo].

The Russians also built a rugged pressure survival suit for their cosmonauts inside Soyuz. Called the Sokol, the suit was introduced in 1972 after three cosmonauts died in a freak cabin depressurization during their return to Earth. The suit protects the crew but allows only arm and hand movements for flight control (a much more sophisticated version is used for space walks in orbit). The Chinese needed a suit with similar functions to the Sokol, so after obtaining samples of the suit's design, they copied it exactly, down to the stitching and color scheme [see feature photo].

So how imminent is the flight of Chinese astronauts? In spite of nationwide enthusiasm, no date has been set. Program officials are being quite cautious in their predictions.

Ground and sea catching up

In recent years, China has vastly improved the surface infrastructure of its space program. A new China Space Center in the southwestern suburbs of Beijing is home to a collection of pressure chambers, space vehicle simulators, an astronaut-carrying centrifuge, and a landing impact tower, where manned training capsules are dropped onto the ground. There are also classrooms and medical facilities for future space travelers. Two Chinese pilots went through general training courses at Russia's Gagarin Space Flight Training Center in Star City in 1996-97, and they reportedly are now directing the training program for China's flight candidates.

Also completed were four ocean-going tracking ships in the Yuan Wang (Long View) series, the last in July 1999. They have been deployed in the Pacific, Indian, and Atlantic oceans to monitor military missile tests and control rocket maneuvers putting satellites into geosynchronous orbit. To support Shenzhou flights, they were sent into the Indian Ocean [again, see map]. (Note that the Russians no longer have a similar fleet and rely on Western allies to extend their coverage.)

Chinese accounts have stressed the weather's challenge to the operation of ocean-going tracking ships. In the Southern Hemisphere, the calmest conditions occur in spring and summer, and the two Shenzhou flights so far have occurred in those periods.

A South Atlantic site is another necessity because the critical ground control functions for the return to China must be performed half an orbit before landing. In December 2000, the Chinese signed an agreement with Namibia in southwestern Africa for construction of a tracking site near the town of Swakopmund. An 85-by-150-meter compound inside a 2-meter-high wall will house administration and living quarters, a generator facility, and two main tracking antennas, 5 and 9 meters in diameter. A staff of 20 during missions will shrink to five between times.

Construction started earlier this year and the station is expected to be operational by year's end. Maps shown on Chinese television of the Xian space flight control center also indicate a ground site in or near Pakistan, but further details are unavailable. Chinese officials did tell Namibian officials that the tracking facility planned for that country was not their first foreign site, and another site may exist somewhere in the scattered island nation of Kiribati in the South Pacific.