An unmanned NASA spacecraft is expected to give the first detailed glimpse of Pluto after shaving past the dwarf planet following a near decade-long journey.

New Horizons is due to accomplish the mission at 1149GMT on Tuesday, but it will be hours before scientists hear back from the spacecraft. It will be busy snapping pictures and collecting data from a distance of 12,500 km.

Whatever these images will show will be an amazing discovery

Francisco Diego, Senior Research Fellow, Department of Physics and Astronomy, University College London

"The cameras will resolve details to about 50m only in size on the surface of Pluto, which is completely unprecedented," Francisco Diego, Senior Research Fellow at the Department of Physics and Astronomy, University College London, told Al Jazeera.

"Whatever these images will show will be an amazing discovery."

Diego said the spacecraft did not have any fuel or any powerful rockets to decrease the speed and go around orbit so it would just fly past.

The $700m spacecraft - the first to visit an unexplored planet since the NASA Voyager missions launched in the 1970s -  is supposed to send a "phone home" signal to Earth at 2020GMT, but that will take almost five hours to reach scientists.

So NASA won't announce until about 13 hours after the flyby, at 0102GMT on Wednesday, whether or not the fastest ever spacecraft - travelling at a speed of 49,570 km per hour - survived the high-speed encounter.

According to principal investigator Alan Stern, there is a one in 10,000 chance that the spacecraft could be lost in a collision with debris around Pluto, long considered the farthest planet from the Sun until it was reclassified as a dwarf planet in 2006.

Stern described the Kuiper Belt, where Pluto resides on the edge of the solar system, as "more or less a shooting gallery, with lots of small primordial comets and other things much smaller than Pluto".

Never before has a spacecraft ventured into the Kuiper Belt, and New Horizons has been on its way there for more than nine years - a journey of almost five billion km.

"We are flying into the unknown," Stern said.

The New Horizons spacecraft lifted off aboard an Atlas V rocket on January 19, 2006 at Cape Canaveral, Florida [NASA/Getty Images]

What is currently known about Pluto could probably fit on a few index cards, Stern has said. New Horizons' data will enable entire textbooks to be written about the mysterious celestial body.

Already, the pioneering NASA mission has confirmed the existence of a polar ice cap on Pluto, and found nitrogen escaping from Pluto's atmosphere.

Stern also said the dwarf planet appears slightly larger than previously thought, with a radius of 1,185 km.

Stunning visual features are coming into focus for the first time, including a light-coloured heart shape nestled near a dark spot nicknamed "The Whale".

And more detail is expected in the days to come, according to deputy project scientist Cathy Olkin.

"Right now, we are taking data that if you could transport (New York's) Central Park to Pluto you would be able to identify the ponds in Central Park, that is the kind of resolution we will be getting," she said.

Next, scientists will watch the sun rise and set behind Pluto, use New Horizons' seven instruments to create a full picture of Pluto and its five moons, and study the dust in the outer solar system and the atmosphere around Pluto and its largest moon, Charon.

Learning more about Pluto has captured the public's attention because it speaks to the origins of the Earth and the larger questions of whether life could exist elsewhere, according to NASA's John Grunsfeld, associate administrator of NASA's science mission directorate.

"The Pluto system is a fossil remnant of the beginnings of our solar system," Grunsfeld said. "We are going to learn about where we are coming from. It is opening up a new realm of exploration."

Source: Al Jazeera And AFP