MESSENGER's Final Image: A Farewell from Mercury

Ten years ago, on April 30, 2015, the MESSENGER spacecraft transmitted its final image of Mercury before its planned, fiery end. Originally designed for a one-year orbit, MESSENGER vastly exceeded expectations, completing over four years of groundbreaking research on the solar system's innermost planet.

Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

This last image captures a view within the floor of the 93-kilometer-diameter Jokai crater, located near the planet's north pole, just north of the Shakespeare basin. As the first spacecraft to ever orbit Mercury, MESSENGER revolutionized our understanding of this enigmatic world, pushing technological boundaries in the process.

The Dramatic End of a Mission

The mission concluded with a spectacular, albeit planned, impact. Having exhausted its fuel, MESSENGER succumbed to Mercury's gravitational pull, crashing into the surface at an astounding speed of approximately 8,750 miles per hour (14,080 kilometers per hour). This high-speed impact created a new crater on Mercury's surface.

Putting the Crash into Perspective:

To help us understand the scale of this event, here are some fascinating details about MESSENGER's final moments:

• Frequent Visitors: Meteors of a similar mass to MESSENGER (513 kg) impact Mercury roughly every one to two months, typically at ten times the speed and with one hundred times the energy of MESSENGER's crash. Mercury's lack of a substantial atmosphere offers no protection.
• A New Crater: The impact created a crater estimated to be about 50 feet wide (15 meters) – roughly the width of an NBA basketball court.
• Impact Energy: The 1,131-pound spacecraft hit with the energy equivalent to about a ton of TNT, comparable to the force of a car traveling at 2,000 mph.
• Super-Sonic Speed: Traveling at nearly 9,000 mph, MESSENGER was moving three times faster than a speeding bullet and nearly twelve times the speed of sound.
• Close Encounters: During its final orbit, MESSENGER passed as low as 900 to 1,800 feet (548.64 meters) above the planet's surface. Some Earth buildings reach similar heights.
• Fuel for the Journey: Nearly 55 percent of MESSENGER's weight at launch was comprised of fuel.

The Final Image: A Glimpse Before Impact

While the exact altitude of this final image has been a subject of discussion, expert analysis suggests it was taken from approximately 38 km above the surface, just under ten seconds before impact. It showcases an area about 780 km away from the eventual impact site. The 'streaks' visible in the image are known as lineaments.

This final transmission served as a poignant farewell, a last look at the planet that MESSENGER had studied so intimately, leaving behind a legacy of invaluable scientific data that continues to shape our understanding of Mercury.