What characteristic defines the lifespan potential of RTG technology, as exemplified by the Transit 4A power unit?
Extremely high reliability and a lifespan measured in decades due to no moving parts
The RTG technology, relying on the natural decay of Plutonium-238 on Transit 4A, possesses distinct advantages regarding longevity and reliability. Because the RTG operates purely on the heat from radioactive decay and requires no moving mechanical parts or external initiation to sustain power generation, it achieves extremely high reliability. This passive nature ensures continuous operation over very long durations, often measured in decades, although the power output slowly declines over time. This resilience is what makes RTGs the preferred workhorse for long-term deep-space missions, unlike the fission reactor which was primarily a short-duration experiment.
