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STARSStories

5 September 1977

The dish that still needs a star

A machine leaves Earth. Years out, past the planets, it still locks on a lamp so it can speak to the world it left.

From Earth, then farther

SPACECRAFT IMAGENASA / JPL-Caltech. Voyager. Spacecraft image, not an artist’s galaxy.

Voyager 1 leaves on 5 September 1977. Jupiter. Saturn. Then the long dark. In August 2012 it crosses into interstellar space. Its twin follows in 2018.

It still has to know which way it faces. Gyroscopes, thrusters, and a star. After a roll in later years it finds Alpha Centauri again, a guide star, and the dish points home.

ASTRONOMY

Alpha Centauri is the nearest star system to the Sun. Distance 4.37 light-years for A and B; Proxima 4.24. A star tracker does not understand a star. It uses a known lamp as a reference so an antenna can face a planet the machine has left.

ANALOGY

A navigator at sea and a spacecraft in the dark are not the same office. Both ask a distant light: where am I pointed?

Question

What does a distant light become when a traveler needs to know where they are?

Sources

Also this sky