Monday and Tuesday at GSA Fresno
17 hours ago
At 9:10 p.m. EDT, engineers in the MESSENGER Mission Operations Center at the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., received the anticipated radiometric signals confirming nominal burn shutdown and successful insertion of the MESSENGER probe into orbit around the planet Mercury.
The spacecraft rotated back to the Earth by 9:45 p.m. EDT, and started transmitting data. Upon review of these data, the engineering and operations teams confirmed that the burn executed nominally with all subsystems reporting a clean burn and no logged errors.
MESSENGER’s main thruster fired for approximately 15 minutes at 8:45 p.m., slowing the spacecraft by 1,929 miles per hour (862 meters per second) and easing it into the planned eccentric orbit about Mercury. The rendezvous took place about 96 million miles (155 million kilometers) from Earth.
“Achieving Mercury orbit was by far the biggest milestone since MESSENGER was launched more than six and a half years ago,” says MESSENGER Project Manager Peter Bedini, of APL. “This accomplishment is the fruit of a tremendous amount of labor on the part of the navigation, guidance-and-control, and mission operations teams, who shepherded the spacecraft through its 4.9-billion-mile [7.9-billion-kilometer] journey.”
For the next several weeks, APL engineers will be focused on ensuring that MESSENGER’s systems are all working well in Mercury’s harsh thermal environment. Starting on March 23, the instruments will be turned on and checked out, and on April 4 the primary science phase of the mission will begin.
“Despite its proximity to Earth, the planet Mercury has for decades been comparatively unexplored,” adds MESSENGER Principal Investigator Sean Solomon, of the Carnegie Institution of Washington. “For the first time in history, a scientific observatory is in orbit about our solar system’s innermost planet. Mercury’s secrets, and the implications they hold for the formation and evolution of Earth-like planets, are about to be revealed.”
A stone mason with a powerful phobia of indoor lighting was accused of misrepresenting the "black granite" he used in a counter top. He was charged with basalt, but when his condition came to light, the charges were dismissed due to lamprophyre.Geologists have a perennial gripe with the phrase "black granite," which is like a furry fish: there ain't no such thing. "Charged with basalt" seems obvious, but I don't think I've ever heard this pun before. And I got a giggle out of "lamprophyre" interpreted as a phobia of indoor lighting. Lamprophyres are weird, obscure rocks that no normal person would ever need to know about, therefore, I'm very fond of them. My favorite was an outcrop near the eastern end of lake Nipissing in Ontario with awesome veins of barite, which has sadly been mostly obliterated by road construction.