the Voyager spacecraft are indeed powered by Radioisotope Thermoelectric Generators (RTGs), which convert the heat generated from the decay of radioactive material into electricity. Over time, the power output of the RTGs decreases as the radioactive material decays.
If another probe were to be launched in the future with the intention of reaching the outer regions of the solar system, such as the Oort Cloud, there are a few potential power options to consider:
Improved RTGs: Scientists and engineers continue to research and develop more efficient and longer-lasting RTGs. By using advanced materials and design improvements, it may be possible to create RTGs with extended power output, allowing a probe to operate for an extended period.
Solar power: Another option is to utilize solar power, particularly if the probe is intended to operate closer to the Sun where sunlight is more abundant. Solar panels could be used to convert sunlight into electricity, providing a continuous power source. However, solar power becomes less viable as a spacecraft moves farther from the Sun, as the intensity of sunlight decreases.
Advanced energy storage: By incorporating advanced energy storage systems, such as high-capacity batteries or innovative energy storage technologies, a spacecraft could store energy during periods of high power generation (e.g., closer to the Sun) and utilize it during periods of low power generation (e.g., farther from the Sun). This approach would help sustain the spacecraft's operations over an extended duration.
It's worth noting that the choice of power source for a future probe would depend on several factors, including the mission's specific requirements, the target distance, and the duration of the mission. The development of advanced propulsion systems, more efficient power sources, and energy management techniques are active areas of research in space exploration, so future missions may benefit from technological advancements that extend their operational lifetimes.