With reference to radioisotope thermoelectric generators (RTGs), consider the following statements:
1. RTGs are miniature fission reactors.
2. RTGs are used for powering the onboard systems of spacecrafts.
3. RTGs can use Plutonium-238, which is a by-product of weapons development.

Which of the statements given above are correct?

Correct Option: (b) 2 and 3 only

Radioisotope thermoelectric generators (RTGs) are not miniature fission reactors; rather, they use passive radioactive decay (typically of Plutonium-238) to generate heat, which is then converted into electricity. They are widely used for powering deep-space probes and spacecraft where solar power is unviable. Plutonium-238 is indeed a by-product of nuclear weapons development. Hence, statements 2 and 3 are correct.