After a six year journey in which it traveled over 6 billion miles, the Messenger spacecraft is finally anticipated to enter Mercury's orbit in a tricky maneuver which is scheduled today, which should mark the first man-made object to orbit the tiny planet. The goal of the mission is to provide scientists with data on Mercury unparalleled since the Mariner 10 spacecraft passed by three decades ago. And the more we understand about Mercury, NASA says, the more we'll understand about how the other rocky planets in the solar system--Venus, Mars, and of course, Earth--formed and evolved.
At 8.45pm EDT, the probe will power on its largest thruster - pointed very close to the direction of travel - for nearly 14 minutes. Other thrusters will fire for a minute more, slowing the spacecraft by 1,929 mph. The procedure will be so energy consuming that the space-craft will burn a third of its original fuel tank with which it launched more than six years ago.
Messenger will fly a 12-hour orbit at a minimum altitude of about 124 miles. The spacecraft's science instruments will be turned on and checked out starting on March 24.
"This is a milestone event for our small, but highly experienced, operations team, marking the end of six and one half years of successfully shepherding the spacecraft through six planetary flybys, five major propulsive maneuvers, and sixteen trajectory-correction maneuvers, all while simultaneously preparing for orbit injection and primary mission operations," says Messenger systems engineer Eric Finnegan.
Messenger's seven sets of instruments will map its surface and look for any signs of water ice at its poles. The probe will also gather date regarding Mercury's magnetic field and atmosphere. It will stay in orbit for a year, time in which it will revolve around the first planet from the sun 730 times and send over 75,000 photos back home on Earth. This all of course will be possible if Messenger will successfully manage to enter the planet's orbit, case otherwise the $446 million spacecraft will end up circling around the sun.