Pluto is no longer an unexplored world.

A new chapter was written in science and exploration and history was made as NASA’s ‘New Horizons’ spacecraft got a look at Pluto on Tuesday evening.

‘New Horizons’ made its point of closest approach – some 12,500 kilometres away – at 9.49pm (AEST) and the moment was met by celebrations at NASA (American space agency) headquarters.

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Because Pluto and Earth are separated by more than 5 billion kilometres, live images were not available.

The earliest that images can be seen will be on Wednesday morning. A NASA announcement expected at around 11am (AEST).

‘New Horizons’ – a space probe the size of a baby grand piano – set off in January 2006 and its passing of Pluto marks the end of a NASA ambition to explore every planet in the solar system. Venus was the first explored, in 1962.

Pluto, which is two-thirds the size of Earth’s moon, had its status downgraded to a ‘dwarf planet’ in 2006.

People waved American flags and music played before a countdown at NASA HQ ended in joy.

Those present sung “USA, USA, USA” and Dr John Grunsfeld, associate administrator for the science mission directorate at NASA, said afterwards: “It’s just amazing. This is truly a hallmark in human history.

“People often think that success to missions like this is engineering but the real success is teamwork. And that’s what NASA excels at.

“We are celebrating the moment that the ‘New Horizons’ spacecraft had its closest possible approach to Pluto.

“Tonight we are going to get the signal that it made it through the system and that it is ready to start sending us the treasure trove of data.”

Dr Alan Stern, principal investigator, added: “It feels good. So many people put so much work into this around the country.

“It’s a moment of celebration because we have just done the anchor leg. It’s really historic what the United States have done.

“The New Horizons team has been really proud to do this.”