New Delhi, Nov. 4 -- Nearly 50 years after leaving Earth, NASA's Voyager 1 is approaching an extraordinary milestone that will demonstrate just how far humanity's most distant spacecraft has travelled. However, keeping the ageing explorer operational has become increasingly challenging as its power supply continues to decline, Science Daily reported.

NASA engineers have recently made two important developments in their efforts to extend the mission. In September, they completed a complex energy conservation project aimed at preserving the spacecraft's remaining scientific capabilities. On October 20, Voyager 1 also unexpectedly resumed communication with Earth following a mysterious 48-hour interruption.

In early September, the Voyager ...