A few years ago, the US National Aeronautics and Space Administration announced that it would revive its nuclear program for the development of space engines. In 2023, it selected the first dual-mode nuclear propulsion concept using a wave rotor excitation cycle, which would reduce the flight time to Mars to 45 days. Now the agency has chosen a contractor to create an atomic engine that will be used to probe nearby star systems and collect samples of interstellar objects.

NASA has grandiose plans for space exploration for the next decade . The agency plans to send several astrobiological missions to Venus and Mars to search for signs of extraterrestrial life. This will occur simultaneously with manned flights to the moon (for the first time since Apollo). There are still plans to send robotic missions to Jupiter’s and Saturn’s moons Europa and Titan, as well as other similar worlds where sub-icy oceans and thus exotic life forms might exist.

To achieve these and other goals NASA started the program NASA Innovative Advanced Concepts (NIAC). Each year, the agency selects revolutionary concepts in aerospace and then funds their development.

For example, this year the options fell on solar-powered drones, bioreactors, light sails, astrobiological experiments and the thin-layer isotope nuclear engine concept (TFINER), suggested by James Bickford (James Bickford) is a senior researcher at an American non-profit organization. research organization Lab.

In the documentation NASA It is stated that such a facility is necessary to perform many next-generation tasks that require high speed; It is impossible to achieve such speeds with the aid of conventional modern rocket technology.” Launching a solar-gravitational telescope that will use the Sun’s gravitational lens (as an amplifier) ​​to observe objects on the surface of distant exoplanets, as well as interstellar objects (which are not mentioned).

In recent years, two types of space-oriented nuclear facilities have been most popular: nuclear thermal engines (NTP) and nuclear electric motors (NEP), can provide the necessary traction and maneuverability. But such setups are bulky, heavy and expensive, according to Bickford.

“On the contrary, we offer a cheap and lighter alternative: a thin-layer nuclear isotope engine that uses the decay energy of radioactive isotopes. This facility will have sufficient capacity to approach fast-moving interstellar objects and take samples from them. With its help it will be possible to study neighboring star systems In addition, our technology will allow us to reorient the Solar Gravitational Observatory so that multiple key targets can be observed during a single mission,” Bickford explained.

The thin-layer isotope nuclear engine concept is based on lightweight sail technology; Only thin layers of the radioactive isotope thorium-228, about 10 micrometers (0.01 millimeters) thick, will be used in the installation. The momentum of the isotope’s decay products will be used to create thrust. Thorium-228 is characterized by alpha decay, its half-life is 1.9 years.

Thorium is a radioactive metal found in most rocks and soil. According to geologists, Earth’s reserves are three to four times greater than uranium reserves.

According to scientists, the spacecraft will need 30 kilograms of thorium-228 distributed over an area of ​​​​more than 250 square meters, which will create the necessary thrust to develop a speed of more than 150 kilometers per second. For comparison, probe NASA Parker Solar ProbeUsing a series of engines powered by hydrazine, the vehicle manages to develop speeds of up to 163 kilometers per hour. However, this speed is mostly due to the gravitational maneuver of Venus in its orbit and the gravitational force of the Sun.

Bickford explained the main advantage of his setup: The design is based on known physics and known materials. At the same time, unlike light sail technology, the new engine will allow the spacecraft to easily maneuver in space and effectively change its flight path.

The engineer noted that in addition to thorium-228 layers, actinium-227 layers or other isotopes with longer half-lives can also be used. This will allow you to develop a higher speed. It is also possible to use the decay of the thorium-233 isotope, which results in the formation of uranium-232, which will increase the performance of the propulsion system by approximately 500 percent.

The proposed technology will be put into use NASA The scientist emphasized that in addition to the many opportunities in space, it will be possible to carry out multiple space missions simultaneously with its help.

James Bickford’s thin-sheet isotope nuclear engine isn’t the first installation to attract attention NASA. Within the scope of the program in 2023 NASA Innovative Advanced Concepts The agency chose the wave rotor peak cycle dual-mode nuclear power plant proposed by Professor Ryan Gosse (Ryan Goss) from the University of Florida (USA). This design is based on solid fuel reactor NERVAwhich will provide a certain stimulus (ISP) in 900 seconds, which is twice the characteristic of modern rocket engines.

According to Gosse, the development of this vehicle will potentially enable a flight to Mars within 45 days. This would reduce the total duration of missions to several months and reduce the main risks associated with flights to the Red Planet, including radiation exposure and microgravity.