How we got to Pluto

New Horizons was the first spacecraft to visit Pluto, but there were plenty of proposals for a mission before it

Voyager 1 – 1977

After Voyager 1 launched, there were plans to fly to Pluto in March

1986. They were dropped in favour of Saturn’s moon Titan. Voyager 2 also skipped past since Pluto’s alignment made an encounter impossible.

Pluto 350 – 1990

When Voyager 1 completed its flyby of Triton, Robert Farquhar of the Goddard Space Flight Center looked into a mission to Pluto, called

Pluto 350. The spacecraft was to weigh just 350 kilograms, travel fast and be cost-effective.

Mariner Mark II – 1991

A project that aimed to create a series of spacecraft for the exploration of the outer Solar

System. After planned missions to

Saturn and Titan, attention was paid to Pluto, but Mariner Mark II was deemed too expensive.

Pluto Fast Flyby – 1992

NASA’s JPL devised the Pluto Fast

Flyby mission concept as a cheaper alternative to both the Mariner

Mark II and Pluto 350 proposals.

Weighing no more than 50 kilograms, it was to fly two spacecraft to Pluto.

Pluto Express – 1995

The Pluto Fast Flyby advanced over a number of years, and it became known as Pluto Express in

1995. But it was still considered too expensive even when the concept was subsequently scaled back to a single spacecraft.

New Horizons – 2006

17 years after a dozen planetary scientists got together, called themselves Pluto Underground and sought ways of getting to the then-planet, New Horizons launched. It made its closest approach to Pluto on 14 July 2015.