NASA Plans to send a manned mission to Mars Over the next 10 years – but A journey of 140 million miles (225 million kilometers) to the red planet The round trip can take months or even years..
This relatively long travel time is a result of the use of traditional chemical rocket fuel. Alternative technologies to chemically propelled rockets currently being developed by the agency use nuclear fission and one day power rocket Then the travel time will be completed in just half.
Nuclear fission involves harvesting the enormous amounts of energy released when atoms are split by neutrons. this The reaction is known as a fission reaction.. Nuclear fission technology is well established in power generation and nuclear submarines, and its application to drive or power rockets could one day provide NASA with a faster, more powerful alternative to chemically powered rockets.
NASA and the Defense Advanced Research Projects Agency Joint development of NTP technology. They plan to deploy and demonstrate the capabilities of the prototype system in space in 2027, potentially making it one of the first systems built and operated by the United States.
Nuclear thermal propulsion may one day provide electricity maneuverable space platformIt will protect U.S. satellites in and out of Earth orbit. However, the technology is still under development.
I am Associate Professor of Nuclear Engineering at Georgia Institute of Technology whose research group Build models and simulations to improve and optimize the design of nuclear thermal propulsion systems. My hope and passion is to help design a nuclear thermal propulsion engine for a manned mission to Mars.
Nuclear Propulsion and Chemical Propulsion
Conventional chemical propulsion systems use a chemical reaction involving a light propellant, such as hydrogen, and an oxidizer. When these two are mixed together, they ignite and cause the propellant to escape the nozzle very quickly, propelling the rocket.
Scientists and engineers are studying nuclear thermal propulsion systems that use hydrogen propellant to generate energy by pumping it into a nuclear reactor and expelling the propellant out of a nozzle to lift the rocket. NASA Glenn Research Center
These systems do not require any kind of ignition system and are therefore reliable. However, this rocket must carry oxygen into space, which could reduce the rocket’s weight. Unlike chemical propulsion systems, nuclear thermal propulsion systems rely on nuclear fission reactions to heat the propellant, which is then expelled from a nozzle to produce thrust or thrust.
In many nuclear fission reactions, researchers direct neutrons in the following directions: lighter uranium isotopesUranium-235. Uranium absorbs neutrons to produce uranium-236. Uranium-236 then splits into two fragments, or fission products, and the reaction releases several different particles.
Nuclear fission reactions produce a lot of heat energy.
More than 400 nuclear power plants Operating globally Nuclear fission technology is currently being used. Most of the nuclear reactors currently in operation are light water reactor. These nuclear fission reactors use water to slow down neutrons and to absorb and transfer heat. Water can produce steam directly in the core or in a steam generator to drive a turbine to produce electricity.
nuclear thermal propulsion system It works in a similar way but uses a different nuclear fuel with more uranium-235. They also operate at much higher temperatures, making them very powerful and compact. Nuclear thermal propulsion systems have a power density approximately 10 times higher than that of conventional light water reactors.
Nuclear propulsion may have advantages over chemical propulsion. some reasons.
Nuclear propulsion expels propellant very quickly from the engine nozzle, high thrust. This high thrust allows the rocket to accelerate faster.
These systems also have high specific impulses. specific impulse It measures how efficiently propellant is used to generate thrust. Nuclear thermal propulsion systems have approximately twice the specific thrust of chemical rockets, allowing travel times to be reduced by a factor of two.
Nuclear thermal propulsion history
For decades, the U.S. government has funded the development of nuclear thermal propulsion technology. From 1955 to 1973, the program NASA, general electricand argonne national laboratoryTwenty nuclear thermal propulsion engines were produced and ground tested.
However, these pre-1973 designs relied on highly enriched uranium fuel. This fuel is no longer used. risk of spreador risks associated with the proliferation of nuclear materials and technology.
that Global Threat Reduction InitiativeLaunched by the Department of Energy National Nuclear Security Administrationaims to convert many research reactors using highly enriched uranium fuel to highly analyzed low-enriched uranium (HALEU) fuel.
High-analyte, low-enriched uranium fuel contains fewer substances that can cause a nuclear fission reaction compared to highly enriched uranium fuel. Therefore, the rocket must carry more HALEU fuel, making the engine heavier. To solve this problem, researchers are investigating special materials that could allow nuclear reactors to use fuel more efficiently.
NASA and DARPA Demonstration rocket for agile Cislunar operationsAlternatively, the DRACO program plans to use this high-yield, low-enriched uranium fuel in nuclear thermal propulsion engines. The program plans to launch a rocket in 2027.
As part of the DRACO program, aerospace company Lockheed Martin has partnered with BWX Technologies. Reactor and fuel design development.
Nuclear thermal propulsion engines being developed by these groups must comply with specific performance and safety standards. We need a core that can operate for the duration of the mission and perform the maneuvers needed for a quick trip to Mars.
Ideally, the engine should be able to produce high specific thrust while meeting the high thrust and low engine mass requirements.
ongoing research
Before engineers can design an engine that meets all of these standards, they must start with models and simulations. These models help researchers like our group understand how engines handle starting and stopping. This is a task that requires rapid and large temperature and pressure changes.
Because nuclear thermal propulsion engines are different from all existing nuclear fission power systems, engineers must build software tools that work with these new engines.
my group Design and Analysis Nuclear thermal propulsion reactor using model. We model these complex nuclear reactor systems to see how changes in temperature and more can affect the safety of the reactor and rocket. However, simulating these effects can require a lot of expensive computing power.
we have been trying Develop new computational tools This is a model of how a nuclear reactor behaves during operation. Start-up and operation Without using much computing power.
My colleagues and I hope that this research will one day help develop models that can autonomously control rockets.
Dan Kotlyar is an associate professor of nuclear and radiological engineering at Georgia Institute of Technology. This article is republished from: conversation below Creative Commons License. read original article.
