DHAKA: The American space agency’s (Nasa) mission to Pluto is about to get under way in earnest.

Its New Horizons probe will take the first of a set of critical pictures on approach to the icy world on Sunday, reports the BBC.

At a separation still of 200 million km, Pluto will be hardly discernable in these images - just a speck of light against the stars.

But the mission team says this view is needed to help line up the spacecraft correctly for its flyby on 14 July.

‘Optical navigation is one of those techniques where we image Pluto repetitively on approach to determine the position of the spacecraft relative to Pluto,’ explained Mark Holdridge, from the Johns Hopkins University’s Applied Physics Laboratory (JHUAPL) in Baltimore.

‘We then perform a number of correction manoeuvres to realign our trajectory with the reference trajectory, thus ensuring we hit our aim point to travel through the Pluto system.’

Any initial correction is likely to be made in March.

BDST: 1053 HRS, JAN 25, 2015