Science

Messenger spacecraft crashes into Mercury

NASA's Messenger spacecraft smashed into the surface of the planet Mercury this afternoon, ending four years of orbiting and studying the closest planet to the sun.

NASA spacecraft says final farewell at 3:26 p.m. ET, plunging to planet's surface

Messenger is expected to slip out of orbit and slam into Mercury on Thursday following a successful four-year tour of the rocky planet. (NASA)

NASA's Messenger spacecraft smashed into the surface of the planet Mercury this afternoon, ending four years of orbiting and studying the closest planet to the sun.

The dramatic impact took place at 3:26 p.m. ET today, following a series of goodbye tweets.

The spacecraft had run out of propellant and the force of the sun's gravity was enough to cause it to fall and crash into the surface of Mercury, NASA said.

Messenger, which has been orbiting Mercury since March 2011, was expected to smack into the planet at 3.91 kilometres per second (14,000 kilometres an hour) and leave a crater 16 metres wide on the planet's surface.

The impact took place on the side of Mercury facing away from Earth, giving the spacecraft some privacy during its last moments.

However, Slooh, an organization that broadcasts astronomical events online, offered an opportunity for people to take part in the event via a webcast featuring mission scientists such as Noam Izenberg, who was answering questions from the public.

Messenger, launched in August 2004, is the first spacecraft ever to orbit Mercury. In the past four years, it has snapped more than 270,000 images of the planet and made measurements that have revealed many surprises including:

These are a few of the things Messenger did during its first 10 years. (NASA)