LONDON: Undiscovered rings and moons around Pluto could pose a danger to the New Horizons spacecraft as it hurtles towards the dwarf planet.
So far, the small world is known to have five moons, but it has been theorised it has more – and possibly a ring system as well.
If it does, New Horizons might have to take defensive action in order to protect itself and ensure the journey of more than nine years does not end in failure.
The danger arises because Pluto’s distance from Earth makes it difficult to find out exactly what is orbiting the dwarf planet.
The New Horizons spacecraft is due to make its closest approach on 14 July, but there is a chance – albeit small – that a previously unseen moon could pose a hazard.
And if, like Saturn, Pluto has an extensive ring system composed of tiny rocks, the debris from this could also be a threat.
In July this year New Horizons will become the first spacecraft ever to visit Pluto.
It was launched on 19 January 2006 at a speed of 36,373 mph (58,536 km/h) – the fastest spacecraft ever to leave Earth orbit, 100 times faster than a jetliner
After passing the orbits of all the major planets from Earth to Neptune, New Horizons is now beginning its final leg of its 3 billion-mile (4.8 billion km) journey.
On 14 July 2015 the flyby of Pluto will begin. Using a suite of instruments, the spacecraft will map the surface of Pluto and its moon Charon to a resolution of 25 miles (40km) – far better than anything possible before.
This will reveal the surface features of Pluto – which may include ice.
As it flies past, it will also look back at the two bodies against the sun, to look for telltale signs of an atmosphere.
After passing Pluto, New Horizons will flyby one or several Kuiper Belt Objects (KBOs), other bodies beyond the orbit of Pluto. The mission will officially end in 2026.
At New Horizons’ speed, about 31,300mph (50,400km/h), even a millimetre-sized pebble could ‘cripple or destroy [it],’ project scientist on the mission Dr Hal Weaver said.
Having spent so long making its way to Pluto, this scenario would be a disaster – with no other mission to Pluto in the works.
Drawing ever closer to Pluto, New Horizons is now beginning its first search for new moons or rings that might threaten the spacecraft on its passage through the Pluto system.
If, in the coming weeks, New Horizons does spot a potential hazard, there are two measures that could be employed.
The first would see its high-gain antenna – which it uses to communicate with Earth – point forward and employed like a shield to deflect debris.
The second would involve sending the spacecraft on a different path past Pluto – but this could reduce the amount of useful science that could be performed.
Dr Alan Stern, the principle investigator on the mission from the Southwest Research Institute (SwRI) in Boulder, Colorado, told MailOnline the danger was ‘less than one per cent’.
But while the odds might seem low, having waited so long for this once-in-a-lifetime encounter the team will be nervous of anything going wrong.
‘The science team thinks it is likely we will find new moons, and less likely but possible we could find rings. How likely rings are is a subject of debate,’ he added.
And talking to Space.com, he said: ‘You know how Curiosity had its “seven minutes of terror?” Well, we call this “seven weeks of suspense,”’ referring to the nerve-wracking landing of Nasa’s rover on Mars in August 2012.
