Moscow. Nuclear power could greatly contribute to spacecraft capabilities.The Soviet Union first developed nuclear powered generators for spacecraft in the 1960s. Since 1970 it has launched more than 30 military radar satellites equipped with the Buk unit, which can generate up to 3 kW of electricity.

In 1987-1988, the Topol unit (Topaz), with a generating capacity of 6 kW, was successfully flight-tested. Some of its power drove the craft’s electric jet engines, making nuclear jet propulsion a reality for the first time.

The Yenisei (Topaz-2) also underwent all mandatory tests. Efforts were made to develop nuclear powered generators ranging from a few kW to tens of MW, as well as energy converters, including mechanical ones.

But in 1990 Russia stopped work on nuclear spacecraft due to the deteriorating economic situation in the country.

It took professionals almost 10 years to realize that their decision was putting the country at risk and could threaten its security.

In 1999, a special program was adopted to develop basic dualcapable technologies for use on spacecraft as both power and propulsion sources. The program was intended to improve the country’s defense, scientific and economic capabilities, and gave priority to defense.

One of the most pressing tasks at the moment is detailed round-the-clock monitoring of vast swathes of territory.Such monitoring is best done from geostationary orbit. But the power requirements are so stupendous (45-50 kW) and the weight of the craft so great (9-10 tons) that even an Angara heavy rocket would be unable to put such a craft into orbit.

A transport energy module using nuclear power (a sort of booster unit) could be the solution.

It could both help put the craft into orbit and power its onboard systems once there. Nuclear power could also thoroughly alter the character of deep-space missions.

Nuclear-electric jet engines will make it possible to establish unmanned interplanetary stations to observe the bodies of the solar system from vantage points so far unattainable. Such engines will speed up freight travel and reduce delivery times. They will also straighten trajectories, rid flight programs of the need for gravity maneuvers, shorten travel periods, and widen “launch windows.”

Another area of application will be planet-based power plants. Estimates show that first expeditions to Mars
will require between 50 and 100 kW of power to carry out their tasks on the planet’s surface (including the generation of fuel from local sources for a return to Earth).

Russian engineers have designed a series of such planet-based plants, using either a thermo-emissive converter reactor or a lithiumcooled reactor with a turbine energy converter.

We can also now envisage the engineering particulars of a nuclear rocket engine for a reusable lunar tug. In one trip, using such an engine, the tug could deliver up to 10 tons of cargo to the Moon’s surface. This would be enough not only to establish a permanent habitable base there, but also to deliver equipment for the production of “lunar” oxygen.

A string of several compact nuclear generators from the lunar craft could be used as a propulsion unit for a Martian vehicle. A Martian expedition could also take advantage of a combined nuclear-driven propulsion and power-generating system able to generate up to 25 kW on top of providing thrust.

More and more countries are showing interest in compact-sized sources of nuclear power for use in space projects.

The European Union and China are particularly energetic in pursuing nuclear space technologies. Also important is the fact that there are already a number of problems in space exploration that are impossble to solve without nuclear technology.