MESSENGER (Mercury Surface, Space Environment, Geochemistry and Ranging), a NASA satellite launched in August 2004 has finally reached its destination: Mercury, the innermost planet in our solar system. This is only the second spacecraft in our history to reach Mercury! Mariner 10 in 1974-1975 flew past the planet; MESSENGER will actually orbit Mercury to carry out its scientific mission.
MESSENGER reached its intended orbit earlier this week, on March 17, and engineers will take the next few weeks to check out all 8 instruments and spacecraft systems. On April 4, the mission's scientific phase will begin. Exciting times for planetary science!
The spacecraft's arrival at Mercury is fortuitously timed with our ability to see the planet in the twilight sky! As the Sun sets, look west. The bright "star" that will catch your eye is actually Jupiter, but just near it lies Mercury which is a little dimmer than Jupiter (see this link for more info on where to look).
Viewing Mercury with the naked eye is a rare treat for even the seasoned amateur astronomer so don't miss this opportunity! And as you look at the planet, just imagine a human-made spacecraft orbiting that planet for the first time getting a slightly better view of our innermost planet!