The American space agency NASA is teaming up with a military research agency to develop a nuclear rocket designed to fly astronauts to Mars.
美国航天局 NASA 正在与一家军事研究机构合作开发一种核火箭，旨在将宇航员送往火星。
 
NASA recently announced it would partner with the U.S. Defense Department's Defense Advanced Research Projects Agency (DARPA) on the effort. As the military's research and development group, DARPA has historically helped lead many notable inventions, including the beginnings of the internet.
NASA 最近宣布将与美国国防部的国防高级研究计划局 (DARPA) 合作开展这项工作。作为军方的研发团队，DARPA 在历史上帮助领导了许多著名的发明，包括互联网的开端。
 
NASA Administrator Bill Nelson said the first nuclear-powered rocket test flight could be launched as soon as 2027.
美国宇航局局长比尔尼尔森表示，第一次核动力火箭试飞最早可能在 2027 年进行。
 
The developing technology is called nuclear thermal propulsion. A rocket powered with this technology can travel much faster than with traditional chemical propulsion systems.
正在开发的技术称为核热 推进。与传统的化学推进系统相比，采用这种技术的火箭的飞行速度要快得多。
 
NASA has long studied nuclear thermal propulsion for possible use for space travel. But its last engine tests using the technology took place more than 50 years ago. The government ended the development program for budget reasons and because of tensions linked to the Cold War.
NASA 长期以来一直在研究核热推进，以期将其用于太空旅行。但它最近一次使用该技术进行的发动机测试是在 50 多年前进行的。由于预算原因以及与冷战相关的紧张局势，政府终止了开发计划。
 
NASA has said with nuclear thermal propulsion, a trip to Mars could be completed in three to four months. This compares to about seven months with chemical propulsion. Building nuclear-powered rockets would permit more crewed trips and improve the safety of astronauts, the space agency says. Shorter trips would also require less equipment and other supplies.
美国国家航空航天局表示，借助核热推进，火星之旅可以在三到四个月内完成。相比之下，化学推进大约需要七个月。航天局表示，建造核动力火箭将允许更多的载人旅行并提高宇航员的安全。较短的行程也需要较少的设备和其他用品。
 
Reducing travel times will be an important part of NASA's future plans. It expects to increase the number of crewed flights as it seeks to send humans back to the moon by the mid-2020s and later to Mars.
减少旅行时间将是美国宇航局未来计划的重要组成部分。它希望增加载人飞行的数量，因为它寻求在 2020 年代中期将人类送回月球，然后再送往火星。
 
Nelson said in a statement, "With the help of this new technology, astronauts could journey to and from deep space faster than ever - a major capability to prepare for crewed missions to Mars."
尼尔森在一份声明中说：“在这项新技术的帮助下，宇航员可以比以往更快地往返深空——这是为载人火星任务做准备的主要能力。”
 
Nuclear thermal propulsion engines operate at a far higher energy density and are twice as efficient as rocket engines, officials say.
官方表示，核热推进发动机的运行能量密度高得多，效率是火箭发动机的两倍。
 
The U.S. Department of Energy describes on its website how a nuclear thermal propulsion system works. It needs a radioactive material like uranium and another element, such as hydrogen, in liquid form. This forms a propellant that is forced through the central part of a nuclear reactor. This causes uranium atoms to break apart inside the reactor and release heat. The heat turns the propellant into gas, which expands through an opening to produce thrust.
美国能源部在其网站上描述了核热推进系统的工作原理。它需要液态的铀等放射性物质和氢等另一种元素。这形成了一种推进剂，被迫通过核反应堆的中心部分。这导致铀原子在反应堆内分解并释放热量。热量将推进剂变成气体，气体通过开口膨胀产生推力。
 
This kind of energy reaction, called fission, is necessary to create the extremely high temperatures needed to push heavy spacecraft during far trips.
这种称为裂变的能量反应对于产生在远距离旅行中推动重型航天器所需的极高温度是必要的。
 
DARPA and the U.S. Department of Energy have already been jointly developing a nuclear thermal propulsion system to be used during a demonstration test flight. In 2021, DARPA awarded money to contractors General Atomics, Lockheed Martin and Blue Origin to study designs of nuclear reactors and spacecraft.
DARPA 和美国能源部已经联合开发了一种核热推进系统，用于示范试飞。2021 年，DARPA 向承包商通用原子公司、洛克希德马丁公司和蓝色起源公司拨款，用于研究核反应堆和航天器的设计。
 
Tabitha Dodson oversees DARPA's efforts on the test program. She told Reuters news agency that by March, the agency is expected to choose a company to build the nuclear spacecraft for the 2027 demonstration.
塔比莎·多德森 (Tabitha Dodson) 负责监督 DARPA 在测试项目方面的工作。她告诉路透社，到 3 月，该机构有望选择一家公司来建造用于 2027 年演示的核航天器。
 
NASA said it plans to continue studying and developing modern space nuclear technologies for other areas of the space program. This includes plans to put nuclear reactor power systems on the moon, and later Mars, to support future human space activities.
美国宇航局表示，它计划继续为太空计划的其他领域研究和开发现代太空核技术。这包括计划将核反应堆动力系统放在月球上，然后再放在火星上，以支持未来的人类太空活动。