Positron Dynamics will develop a project for a rocket with a nuclear fission engine. In this respect informs Universe Today.
The key parameter for any rocket engine is specific impulse. The higher it is, the more acceleration a rocket with the same mass of fuel can develop. It’s the very low specific impulse of chemical rocket engines (kerosene or hydrogen) that makes flights to Mars and Jupiter and Uranus and Neptune — along the shortest orbits (which require a lot of fuel) nearly impossible — so difficult. That’s why engineers are looking for alternative means of propulsion, such as solar sails or nuclear rocket engines.
The nuclear fission rocket engine, which the company will develop its concept on, uses the fission energy of uranium nuclei to heat it and generate thrust. However, unlike a conventional nuclear engine, which heats hydrogen in a reactor and blasts its nozzles, these types of power plants must expel nuclear fuel – fissile uranium. This allows you to heat it to several thousand degrees, and the higher the temperature, the greater the specific impulse.
However, conventional materials will not be able to withstand such temperatures, so engineers plan to use a number of innovations. Therefore, it is planned to embed nuclear fuel particles in aerogels, which are ultralight materials with very low thermal conductivity. The airgel will hold the fission products together without using bulky structures. In addition, it will be necessary to create a magnetic nozzle using superconducting magnets. Since the uranium (and the surrounding matter) will heat up and ionize, it will be possible to control the magnetic field by creating a repulsive force by flying it in one direction.
This project is still at an early stage of theoretical work and can only be implemented years later.