Short answers, pulled from the story.
MESSENGER entered orbit around Mercury on the 18th of March, 2011, becoming the first spacecraft ever to do so. The braking maneuver lasted approximately 15 minutes, beginning at 00:45 UTC, and orbital insertion was confirmed at 01:10 UTC.
In November 2012, MESSENGER confirmed the presence of water ice and organic compounds inside permanently shadowed craters near Mercury's north pole. Earth-based radar had long suggested reflective material existed there; MESSENGER provided direct evidence.
MESSENGER launched on the 3rd of August, 2004, and ended on the 30th of April, 2015, spanning nearly eleven years. The spacecraft orbited Mercury from March 2011 until its intentional crash landing, which completed the mission's data collection phase.
Reaching Mercury requires removing a large amount of orbital energy because the Sun's gravity accelerates any inbound spacecraft too fast for direct orbital insertion. MESSENGER used gravity-assist flybys of Earth once, Venus twice, and Mercury three times over six years and seven months to bleed off speed and minimize propellant use, covering 7.9 billion kilometers in the process.
MESSENGER impacted Mercury on Suisei Planitia, near the crater Janacek, at approximately 54.4 degrees north and 149.9 degrees west. The impact occurred on the side of Mercury facing away from Earth, so it was not visible to any observer or instrument. Scientists estimated the crash created a crater about 16 meters wide.
The total cost of the MESSENGER mission, including spacecraft construction, was estimated at under 450 million US dollars.