NASA's Mercury mission comes to a crashing end

Running out of fuel, NASA's Messenger spacecraft crashed into Mercury's surface on Thursday at 3.26.02 p.m. EDT (Eastern Daylight Time), thereby putting a historic end to its four years of orbital operations.

The Messenger was the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unravelling the history and evolution of the Solar System's innermost planet.

Travelling at 3.91 km per second or 14,000 kmph, the Messenger spacecraft's crash created a crater estimated to be 16 metres (52 feet) in diameter, NASA said.

The mission has far exceeded its primary plan of one year in orbit.

"Today we bid a fond farewell to one of the most resilient and accomplished spacecraft ever to have explored our neighbouring planets," said Sean Solomon, Messenger's principal investigator and director of the Columbia University's Lamont-Doherty Earth Observatory.

"Our craft set a record for planetary flybys, spent more than four years in orbit about the planet closest to the Sun, and survived both punishing heat and extreme doses of radiation," Solomon noted.

Messenger was launched on August 3, 2004, and began orbiting Mercury on March 18, 2011. The spacecraft completed its primary science objectives by March 2012.

Because Messenger's initial discoveries raised important new questions and the payload remained healthy, the mission was extended twice, allowing the spacecraft to make observations from extraordinarily low altitudes and capture images and information about the planet in unprecedented detail.

Messenger has acquired over 270,000 images and extensive other data sets, NASA said.

"Among its other achievements, Messenger determined Mercury's surface composition, revealed its geological history, discovered that its internal magnetic field is offset from the planet's centre, taught us about Mercury's unusual internal structure, followed the chemical inventory of its exosphere with season and time of day, discovered novel aspects of its extraordinarily active magnetosphere, and verified that its polar deposits are dominantly water ice," Solomon pointed out.