Scientists have regained contact with the probe before its encounter with the dwarf planet, after a nine-year journey from Earth

Nasa is all set for next week’s historic Pluto fly-by having reactivated the New Horizons spacecraft following a malfunction last weekend.

The 14 July fly-by will take place on the 50th anniversary of Mariner 4’s visit to Mars, which was America’s first successful planetary fly-by.

New Horizons was launched on 19 January 2006, and has been travelling through space for the past nine years. Just over a year after launch, it passed Jupiter and used the giant world’s gravity to boost its velocity, as well as making scientific observations. This boost shortened the time to reach Pluto by years but last weekend, just 10 days before the encounter, the mission was suddenly cast into doubt. Contact was lost with the spacecraft for about 90 minutes. When communications were established, ground controllers found the spacecraft had entered “safe mode”, a low-power sleep designed to protect the spacecraft when something goes wrong.

Pluto: Nasa probe set for fly-past of frozen ‘dwarf planet’ Read more

The problem was diagnosed as an operator error, in which the ground staff had asked the spacecraft to do too many things at once, crashing the onboard computer. This will not happen during the fly-by itself, and science operations resumed on 7 July.

At closest approach, New Horizons will be less than 12,500km above the dwarf planet’s icy surface, but 4.5bn kilometres from Earth. The radio connection is so weak at that distance that the data recorded by its instruments will take more than a year to trickle back. However, Nasa expects the first close-up pictures on 15 July.

Twitter: @DrStuClark