spacecraft

The measurements from the spacecraft’s instruments indicated that the planets and moons were inactive, unlike the other moons in the outer solar system.

Much of what we know about them was gathered by Nasa’s Voyager 2 spacecraft which visited nearly 40 years ago.

“Some of the instruments for the future spacecraft are very much being designed with ideas from what we learned from Voyager 2 when it flew past the system when it was experiencing an abnormal event. So we need to rethink how exactly we are going to design the instruments on the new mission so that we can best capture the science we need to make discoveries”.

When the spacecraft ceased working a few years later, gravity might have been expected to pull it even further to the east, out over the Indian Ocean.

Orbital mechanics mean it's unlikely the half-tonne military spacecraft simply drifted to its current location.