A team of researchers is looking to build an electromagnetic gun that could launch aircraft into space at high speeds.
China's spaceplane design. Photo: Weibo
Chinese scientists and engineers are working to combine major advances in both electromagnetic launch and hypersonic flight in recent years. Essentially, their goal is to use a giant electromagnetic launch track to accelerate a hypersonic aircraft to Mach 1.6 (1,975 km/h). The aircraft would then separate from the track, fire its engines and rocket into space at seven times the speed of sound (8,643 km/h). The 50-ton spaceplane, which is longer than a Boeing 737, is part of the Tengyun project, announced in 2016, the Mail reported on March 14.
Using the plane’s own power to take off requires a huge amount of fuel. To ensure safety during low-speed takeoffs, scientists and engineers need to adjust the aerodynamic design and engine layout, which affects the performance of high-speed flights. However, the team of experts working on the project is confident that they can solve many of the problems.
"Electromagnetic launch technology provides a promising solution to overcome the above challenges, becoming a strategic technology pursued by leading countries in the world," said scientist Li Shaowei at the Air Vehicle Technology Research Institute of the China Aerospace Science and Industry Corporation (CASIC) in an article published in the journal Acta Aeronautica.
To test the hypothesis, CASIC, one of China’s leading defense and aerospace contractors, built a 2-kilometer low-vacuum high-speed maglev test facility in Datong, Shanxi Province. The facility can propel heavy objects to speeds of 1,000 km/h, close to the speed of sound. In the coming years, the length of the test track will be increased to reach a maximum operating speed of 5,000 km/h.
This is a dedicated electromagnetic propulsion facility supporting the development of next-generation high-speed rail, and is also collecting important scientific and technical data for the electromagnetic space launch project. Meanwhile, in Jinan, the capital of Shandong Province, another giant maglev track supporting an ultra-high-speed electromagnetic rickshaw experiment is also operating under the supervision of the Chinese Academy of Sciences (CAS).
China is not the first country to propose an electromagnetic space launch system. The idea dates back to the Cold War. In the 1990s, NASA tried to turn the idea into reality, first building a 15-meter mini-test track. However, due to lack of funding and technical difficulties, the actual length of the completed track was less than 10 meters. Ultimately, the project was abandoned, and government and military leaders instead shifted resources to developing low-speed electromagnetic catapult technology for aircraft carriers. But the USS Ford, the first aircraft carrier to be equipped with this new technology, also encountered problems. Due to major setbacks in electromagnetic launch technology, the US military stopped developing related projects such as railguns and focused its budget on hypersonic missiles.
Early in the research, Li and his colleagues discovered that NASA had not conducted any wind tunnel tests to ensure the spacecraft’s ability to separate from the track. NASA’s original idea was to accelerate the shuttle to 700 km/h, enough to eliminate the need for rockets, but Chinese scientists thought that speed was too low. However, as speeds increase, the airflow between the aircraft, the electromagnetic rickshaw, and the track on the ground becomes very complicated. So one of the first things the project team had to confirm was that the aircraft would separate from the track safely.
Li’s team conducted computer simulations and wind tunnel tests. The results revealed that as the aircraft crossed the sound barrier, multiple shock waves spread along its underside, hitting the ground and generating reflections. The shock waves disrupted the airflow, sending infrasonic air pockets between the aircraft, the electromagnetic sled, and the track. When the sled later reached its target speed, released the aircraft, and braked abruptly, the turbulent airflow initially lifted the aircraft, then switched to downward thrust after four seconds, according to the wind tunnel test results.
If passengers were on board, they might experience brief periods of vertigo or weightlessness. But as the distance between the plane and the groove increases, the intensity of the airflow gradually decreases until it disappears completely. With the sound of the engines, the plane enters a rapid climb. While more real-world testing is needed, the team concluded that the method is safe and feasible. While SpaceX’s reusable rockets have reduced the cost of launching satellites to $3,000 per kilogram, some scientists estimate that electromagnetic space launch systems could reduce the cost to $60 per kilogram.
An Khang (According to Mail )
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