If you had to orbit the earth, travel to the moon or just hover around in the outer reaches of space, you might not have fared well with normal power generation systems. The far reaches of space, with a total lack of gravity and sheer, bone-chilling cold is quite an obstacle for carrying your favorite large diesel generator for producing electric power out there.

There ought to be some way out to counter that coldness, to counter the harsh radiation effects of the sun or Jupiter's Razzle-dazzle or even those one-off comets and hurtling meteors. Something those satellites and space-borne airships have to use, since they are really out of solar energy and other normal generators

- Nuclear Power generation systems have served us with this onerous task of providing for energy for more than two decades and radioisotope thermoelectric generators are one such way of doing the same.

The Radioisotope Thermoelectric generator consists of two parts: One part which is responsible for producing heat and the other helps in converting this heat into electricity. The heat is produced due to its self - decaying intense radioactive waves by the plutonium - 238, a radioisotope. This resulting heat is converted by a thermo electric converter by utilizing the seebeck effect, a basic thermo electric principle, founded in 1822. A voltage is formed by the diffusion of electrons across the junction of two different metals which then forms a thermocouple.

This technology is now being used on space programs and the Galileo Mission, the Mars mission and more modern space programs have employed the nuclear technology for heat and electricity production. Other examples include the Pioneer, Viking, Voyager and Apollo Missions.

Safety is a major issue when it comes to producing nuclear energy and lack of adherence to safety norms has resulted in nothing less than fatality. However, radioisotope thermoelectric generators are relatively safer and need only to be contained within secure elements or shells to avoid contamination to the neighboring surroundings. These devices require no maintenance since there are no moving parts and can generate electricity for a number of years.

A constant demand for innovation in the way electricity has to be produced for different systems in a sheer variety of situations has made a wide range of types of generators to choose from. Complicated systems have evolved over time to cater to all kinds of electrical needs. RTGs are just the beginning.