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Pentagon reveals secret nuclear-powered rocket

作者:慕馔    发布时间:2019-03-03 01:17:06    

By DAN CHARLES in WASHINGTON DC The Pentagon revealed last week that it is working on a rocket engine powered by ay nuclear reactor. It has spent $130 million on the secret project since 1987. Critics accused the Pentagon of trying to avoid public scrutiny. ‘This programme reeks of deception,’ says Steve Aftergood of the Federation of American Scientists. According to Aftergood, the Pentagon has revealed only part of its research on nuclear propulsion: a separate programme, with the code name LT, is still classified. The Pentagon refused to disclose the results of studies on the environmental effects of testing the engine. Tests on the reactor fuel are proposed to begin this year at the Nevada nuclear test site. Ground tests of the engine will present its greatest environmental hazard, says Aftergood. The coolant for the reactor is its liquid hydrogen propellant. If the reactor fuel failed during a test, radioactive particles would be spewed with the hydrogen gas into the atmosphere. The Pentagon also provided only vague information on why it needs such a rocket. NASA abandoned its attempt to build a nuclear-powered rocket in 1973 after spending $1.5 billion on it. The US air force’s Phillips Laboratory, in Albuquerque, New Mexico, is in charge of the project, which is known officially as the Space Nuclear Thermal Propulsion programme. Roger Lenard, an air force officer who is managing the programme, says that a nuclear-powered rocket may be a cheaper way to lift heavy loads into orbit. In a nuclear engine, liquid hydrogen is the propellant. It is pumped into the core of a reactor, where the heat turns it instantly into a gas, with explosive force. This drives the rocket forward, and the hot hydrogen gas escapes from the rear. The lighter the atomic weight of the fuel used by a rocket engine, the more efficiently it produces its thrust. In theory, a rocket using only hydrogen would be more than twice as efficient as rockets that rely on chemical combustion, which also require oxygen. Lenard points out that nuclear rockets could make an expedition to Mars more feasible. Some calculations show that nuclear propulsion could cut the time required for a return trip to Mars in half, from more than 400 days to about 200. Aftergood says that if the goal of the programme is a voyage to Mars, NASA should be in charge of it, not the air force. NASA started a new research programme on nuclear propulsion this year, with funding of less than $5 million. The Pentagon’s programme, by contrast, received $50 million from Congress. The Pentagon made its announcement at the beginning of an annual conference on nuclear power in space, held in Albuquerque. By coincidence, scientists from Russia arrived at the conference with a design of a nuclear-powered rocket of their own. They tried to bring a mock-up of the engine to the conference, but customs officials refused to let the stainless steel model leave the airport in Los Angeles. The customs service said that the Russians needed a licence to bring the model into the country. According to Vladimir Smetannikov of the Institute of Power Engineering in Moscow, the Russian reactor has already heated hydrogen gas to 3000 kelvin in tests. This is a key goal for the American researchers. It is difficult to build metal turbines or nuclear fuel that can withstand these high temperatures. The Americans were impressed by the claims, but sceptical. ‘We don’t have any independent verification of that,

 

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