Atomic power for rockets

The heart of a nuclear-rocket engine, of course, is the react­or that converts nuclear energy into heat.

The fuel of the reactor consists of a special kind of “iso­tope” of uranium, called Uranium-235. When properly bom­barded with neutrons the uranium nuclei break up or “fission” into a pair of fragments and emit more neutrons in the process, thus keeping the reaction going.

The fission process releases energy and the excess energy is carried away by the neutrons and by gamma rays. Since all of the fragments and most of the neutrons and gamma rays are stopped within the reactor, the energy that is released by U-235 fission will heat the reactor.

For making a nuclear-rocket engine thermally efficient the reactor’s temperature must be as high as possible. The melting point of uranium, 2,070 degrees F., sets a theoretical limit. Graphite, which withstands much higher temperatures, is a very good material for the reactor’s “moderator”. So all present experimental reactors for nuclear-rocket engines are made of U-235 metal powder placed in graphite.

A cold gas, the hydrogen, enters several hundred narrow passages drilled through the graphite-uranium reactor core and is heated almost to the white-hot operating temperature. On coming from the passages, the hot gas expands through a nozzle in which it attains supersonic speed. The exhaust speed of the nuclear-rocket engine can probably reach 23,000 to 30,000 feet per second, which is twice as much as from a rocket engine using chemical combustion of hydrogen and oxygen.

Notes:

thus keeping the reaction going ……………………... the white-hot operating temperature ……………….

таким образом продолжая реакцию рабочая температура “белого кале-ния”

Atomic power for space travel

Many scientists believe that nuclear engines prove to be the best as propulsion for the spaceships – ships that make extremely long voyages through the vast expanses of interplanetary space.

Atomic engines are relatively light in weight and are able to de-liver power for years without running out of fuel.

Up to now, thermical power has been used to drive rock­et engines. This power is obtained by burning oxygen and hydrogen.

In both the chemical and the nuclear rocket engines it is the heat energy that expands the hydrogen gas and causes it to escape through the nozzle at high speed. In the first case it is the heat of the chemical burning of hydrogen and oxy­gen; in the second – the heat from the fissioning or split­ting of atoms inside the reactor.

In an atomic engine designed for providing a large thrust, heat is generated by carefully controlled atomic fission in a reactor. This heat is used to heat hydrogen, which then thrusts out of the exhaust nozzle at a great speed to push the rocket.

Tremendous power is needed to drive a rocket or space­ship beyond the forces of the earth’s gravity. But when the ship is already deep in space, much smaller power supplies are necessary to propel the ship. Atomic power can provide both these propulsion requirements. Significant progress is being made on the use of nuclear energy as propulsion – getting ships into space and equipping them with power for travelling over long distances.

As the nuclear engines are lighter in weight and can op­erate for very long periods of time, atomic energy has made a great contribution to space research.

Notes:

propulsion ………. nozzle …………... fissioning ……….. thrust …………….

силовая установка наконечник, выпускное отверстие деление, расщепление давление, нагрузка