NASA's Messenger probe is set to make a death plunge into Mercury, as it runs out of fuel after four years collecting data.
Scientists at the agency say the spacecraft will smash into the side of the planet not facing the earth at more than 8,750mph on or around 30 April.
Its mission was initially only supposed to last a year, but researchers extended its life for as long as possible after it returned an array of interesting data and discoveries.
Operators in mission control will carry out the last in a series of manoeuvres designed to prolong the probe's life next week.
"Following this last manoeuvre, we will finally declare the spacecraft out of propellant, as this manoeuvre will deplete nearly all of our remaining helium gas," said Daniel O’Shaughnessy, mission systems engineer.
"At that point, the spacecraft will no longer be capable of fighting the downward push of the sun's gravity."
The probe's key finding, in 2012, was a thick coat of ice in Mercury's polar regions, providing "compelling support for the hypothesis that Mercury harbours abundant frozen water and other volatile materials in its permanently shadowed polar craters".
"For the first time, scientists began seeing clearly a chapter in the story of how the inner planets, including Earth, acquired water and some of the chemical building blocks for life," the agency said in a statement.
Scientists believe the closest planet to the sun probably got its water when comets and volatile-rich asteroids made impact.
Messenger was launched in 2004 and travelled for more than six years before it finally began orbiting Mercury in March 2011.
"For the first time in history we now have real knowledge about the planet Mercury that shows it to be a fascinating world as part of our diverse solar system," said John Grunsfeld, associate administrator for the Science Mission Directorate at NASA.
He added that scientists would continue to analyse data from the craft for years to come.
http://report24.co.uk/article/159630/nasa-spaceship-prepares-to-smash-into-mercuryHats off to NASA. They build stuff that just keeps working and working and working - long after it's supposed design life.
