After roughly 7.5 billion kilometres, and a nine-and-a-half year journey, NASA's New Horizons spacecraft made its closest approach to Pluto.

Before the flyby, NASA posted its most detailed image of Pluto yet to Instagram, as a "sneak peak." The same image was posted to Twitter moments after the approach.

"Hello #Pluto! We're at closest approach. Congrats to all!" the tweet said.

According to NASA's calculations, at its closest approach, the spacecraft came within 13,000 kilometres of Pluto, at a speed of about 50,000 kph.

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With files from The Associated Press