# How big is Voyager 1?

Its main dish is 3.7 metres across, its longest boom 13 metres, and the whole craft weighs 721.9 kilograms. See it on its real trajectory in a 3D model.

## The short answer

Voyager 1 weighs 721.9 kilograms and most of what you would see is antenna: the high-gain dish it talks to Earth through is 3.7 metres across. Its longest single part is the magnetometer boom, a mast 13 metres long and about 23 centimetres thick that unrolled itself in space after launch. Sunlight is too weak where it was going for solar panels, so power comes from three radioisotope thermoelectric generators that each produced about 158 watts at launch, mounted on a boom of their own.

## Why the magnetometers live on a 13 metre mast

The spacecraft itself is made of metal and electronics, which means it carries its own faint magnetic field. To measure the far fainter fields of interplanetary space the sensors had to be moved away from the craft: one sits seven metres out along the boom, the second at the far end, 13 metres out, where the requirement was that boom and spacecraft together contribute almost nothing to what the sensor reads.

## And Voyager 2 is its twin

The two Voyagers are the same design and the same 721.9 kilograms, so every figure here answers for both. What separates them is where they went: Voyager 2 took the slower path past all four giant planets, and the two are now leaving the solar system in nearly opposite directions out of the plane the planets orbit in.

## Small craft, long reach

That 3.7 metre dish is the reason a 721.9 kilogram machine can still be heard: Voyager 1 is now so far away that its radio signal takes almost a full day to arrive, and the model behind the link below shows where it is on its recorded trajectory at any date you set.

See it in the model: https://astro.observer/orrery/?body=voyager-1

Sources:
- NASA, Voyager 1 mission page: https://science.nasa.gov/mission/voyager-1/
- NASA, Voyager spacecraft: https://science.nasa.gov/mission/voyager/spacecraft/
- Miller, The Voyager Magnetometer Boom, JPL: https://ntrs.nasa.gov/citations/19790013187

Gallery: https://astro.observer/