Voyager 2, which was launched in August 1977 and is still functioning despite the mind-boggling distances and numbers involved, has set course for Sirius – the brightest star in the sky.
Astonishingly, even travelling at around 40,000mph it will take 296,000 years to reach Sirius.
Most experts believe mankind will have long since become extinct, or will have evolved into an entirely different species by that time.
Voyager 2 on mind-boggling 296,000 year journey to Sirius
The satellite's sister craft Voyager 1 will wander interstellar space for a mere 40,000 years before it passes by the star AC+79 3888, in the constellation of Camelopardalis.
Already Voyager 2 is 10 billion miles (16 billion kilometres) from Earth at the edge of the heliosheath where our Sun finally runs out of steam.
In this outermost layer of the heliosphere the solar wind, which streams out from the Sun, is slowed by the pressure of interstellar gas.
NASA engineers sent a coded instruction to Voyager 2 to change course but even travelling at the speed of light the instruction took 14 hours to reach the satellite.
The change allows engineers to reduce the amount of power that the 38-year-old spacecraft needs to operate by turning off the heater that keeps the fuel to the primary thrusters warm.
Although the rate of energy generated by Voyager 2's nuclear power source continues to decline, by reducing its power requirements, engineers expect the spacecraft will continue to operate, and communicate with Earth, for at least another decade.