Here are six things Raines wants you to know about MESSENGER's impending impact with Mercury on Thursday:
"1. Meteors with the same mass as MESSENGER (513 kg) slam into Mercury about every month or two, and typically with 10 times the speed and 100 times the energy. The planet doesn't have a thick atmosphere that would slow down objects headed for the surface.
2. The 1,131-pound spacecraft will hit with the energy of about a ton of TNT, or the force of a car traveling at about 2,000 mph.
3. At almost 9,000 mph, the craft will be traveling three times faster than a speeding bullet and nearly twelve times the speed of sound.
4. On MESSENGER's last orbit, it will pass just 900 to 1,800 feet over the planet's surface. We have buildings that tall on Earth.
5. The crater the craft will leave near Mercury's north pole is predicted to be about 50 feet wide. That's the width of an NBA basketball court.
6. Nearly 55 percent of MESSENGER's weight at launch was fuel -- which is about to run out."