Monochromatic and covered in craters, Mercury may outwardly resemble our Moon but the similarities abruptly end there. Ever since the MESSENGER spacecraft entered orbit around Mercury in 2011, and indeed even since Mariner 10‘s flyby in 1974, peculiar “dark spots” observed on the planet’s surface have intrigued scientists as to their composition and origin. Now, thanks to high-resolution spectral data acquired by MESSENGER during the last few months of its mission, researchers have confirmed that Mercury’s dark spots contain a form of carbon called graphite, excavated by impacts from its ancient crust.
On April 30, 2015, after more than ten years in space – four of those in orbit – MESSENGER‘s mission and operational life came to its conclusive (and expected) end when it impacted the surface of Mercury. While the spacecraft’s approximate impact location was predicted by mission engineers (it was out of sight of Earth at the time) it wasn’t until nearly a month later that the exact site was determined.
The image above shows the spacecraft’s final path and the point of impact. See a closer view of the region below:
At 3:34 p.m. EDT (19:34 UTC) today, April 30, 2015, after more than ten years in space – and four of them in orbit – the MESSENGER spacecraft’s operational life came to a conclusive end when it impacted the surface of Mercury, as planned.
After revealing the surface of the innermost planet like no mission ever before, MESSENGER’s last act was to contribute one more crater to Mercury’s battered and Sun-scoured face.
The impact site was out of view (and thus out of communication range) of Earth at the time, but based on the spacecraft’s trajectory and time when its signal was last received it’s known that it very likely struck a low ridge just north of a basin named Shakespeare, near 54.5 degrees north latitude and 210.1 degrees east longitude.
Colliding at a velocity of 8,700 mph, MESSENGER’s impact is estimated to have made a crater about 52 feet (16 meters) across.
“Going out with a bang as it impacts the surface of Mercury, we are celebrating MESSENGER as more than a successful mission,” said John Grunsfeld, associate administrator for NASA’s Science Mission Directorate. “The MESSENGER mission will continue to provide scientists with a bonanza of new results as we begin the next phase of this mission – analyzing the exciting data already in the archives, and unraveling the mysteries of Mercury.”
See MESSENGER’s very last transmitted image below.
The 72-mile (116-km) -wide crater Adedin is seen at an oblique angle in this mosaic made from images acquired by NASA’s MESSENGER spacecraft. The angle highlights the crater’s central peak complex which surrounds a shallow depression that could have a volcanic origin, as well as fine cracks in the floor of its basin and a slumped and terraced section of its far wall. The crater was named after the Bangladeshi painter Zainul Abedin (1914-1976).
And I suggest you enjoy it – it will be one of the last images we see from MESSENGER!
On March 18, 2011, MESSENGER became the first human-made spacecraft to enter orbit around Mercury. Now almost four years, eight billion miles, and over 260,000 images later, MESSENGER is nearing the end of its operational life.
To commemorate the many achievements of the mission, scientists from NASA and the MESSENGER teams at the Johns Hopkins University Applied Physics Laboratory and the Carnegie Institution for Science are giving people around the world the opportunity to name five craters on Mercury — names which, once selected, will become official through the IAU!