Messenger Probe Crashing Into Mercury Thursday – 10-Year Mission Illuminated Boring Planet

It’s been an amazing era of exploration for NASA’s Messenger probe. On Thursday that era will come to an end in spectacular fashion.

After 5 billion miles and 15 trips around the sun, the probe will smash into the planet it’s been investigating for a decade at nearly 9,000 miles an hour, ABC News reported.

The probe simply doesn’t have enough fuel to go on. And since entering Mercury’s orbit in 2011, Messenger has been dragged down more and more by the Sun’s gravity and can no longer fight it, Space.com added.

When the Messenger probe collides with the planet, the spacecraft will leave a 50-foot-wide crater on the surface. But this will happen away from human eyes – the crash will occur on the far side. When the probe doesn’t appear a few hours later, NASA will know it’s gone.

“Unfortunately, it’s going to be a little anticlimactic,” principal mission investigator Sean C. Solomon, told the New York Times. “It will be a somber moment.”

Science owes a lot to the Messenger probe – it was the first spacecraft to fly so close to the mysterious world. Before the probe, us earthlings knew little about our solar system’s smallest planet, save a few snapshots dating to the Mariner 10 mission of the 1970s.

The Messenger probe launched in 2004, circled the planet’s solar system, then eased into its orbit in 2011. Since then, Messenger has illuminated some remarkable details, NASA Science Mission Directorate administrator John Grunsfeld told Popular Science.

“For the first time in history we now have real knowledge about … Mercury that shows it to be a fascinating world as part of our diverse solar system.”

Messenger told the world that Mercury, much like the Moon in appearance and size, is not the boring rock we thought. It shrank as it cooled, was striped with ancient lava flows and covered in some weird hollows on the surface – possibly a sign of volcanoes. The Messenger probe also found ice near the poles, coated in a tar-like, carbon-rich compound similar to that found in meteorites and comets.

Most exciting of Messenger’s discoveries are so-called “volatiles” (chlorine, sulfur, potassium and sodium), which were very abundant on the planet, but should have boiled away. Their presence poses the question – how was Mercury actually formed?

These discoveries, and the questions they raise, have made Messenger a fascinating mission, Solomon told the Times.

“It’s really been exciting to see a planet unfold, a planet that is one is our neighbors. Almost every aspect of Mercury has had its share of surprises.”

The discoveries won’t end either. The European/Japanase mission BepiColombo will pick up the torch where Messenger left off; one spacecraft will study the planet, the other its surrounding environment. Back in the U.S., the New Horizons mission will start investigating the lonely planet Pluto in July.

[Photos Courtesy NASA]