At around 2 a.m. this morning, NASA scientists and a team from Brown University were the first to see images of Mercury sent back from the Messenger spacecraft.
"We're going to really see the details for the first time," NASA Project Scientist Ralph McNutt said yesterday. McNutt said the images would cover about a third of Mercury's surface, never before seen from space. "This is exploration and new science at its best, unknown and unseen territory being seen for the first time."
The Messenger spacecraft flew by Mercury yesterday for the second time, taking measurements and recording images, as it swung just 125 miles above the smallest planet in the solar system. The first of three flybys occurred on January 14 and provided scientists with a wealth of new data about the planet, which they're hoping will be augmented today.
"Mercury is really enigmatic in a lot ways," said Jim Head, professor of geological sciences and chair of the geology working group for the Messenger mission. "One of the big issues was whether Mercury actually had volcanism or not. On the first flyby, we got unequivocal evidence that there were volcanic vents."
Head is spending the week at the Johns Hopkins University Applied Physics Laboratory outside Washington, D.C., analyzing data with a team from Brown including David Baker GS, post-doctoral research associate Caleb Fassett and research analyst James Dickson.
"Studying Earth is like studying the last two chapters of a book. You know the ending but you don't know what came about to make it that way," Head said. "Mercury has a very ancient surface. It's solidified and stabilized and preserved the history."
Head said that he and the team had been "eagerly awaiting" the images and called the mission a "real success." He cited color photographs that provided "distinctive data" about impact craters and the sediment that's filling them, as well as evidence of faults which indicates that Mercury is shrinking, as among the most significant geological discoveries from the Messenger mission thus far.
Thomas Zurbuchen, professor of space science and aerospace engineering at the University of Michigan and member of the Messenger team, said, "The biggest strength of the Messenger mission is being able to connect measurements. It's really truly interdisciplinary." Zurbuchen has made some of Messenger's most surprising discoveries with his fast imaging plasma spectrometer, which scoops up and measures samples of Mercury's atmosphere. "We found water essentially blowing off the top of Mercury which was a big surprise to a lot of us," he said.
"By the time we get the images down (today), we'll have imaged pretty close to 95 percent of Mercury," said Sean Solomon, principal investigator for the Messenger mission.
The spacecraft relies on Mercury's gravitational pull to slow itself down with each of its three successive flybys, until it is finally traveling at a speed low enough to enter into orbit. A third flyby in late September 2009 will further slow the craft down, and NASA scientists expect that Messenger will be able to enter stable orbit around Mercury in 2011, allowing for more long-term, detailed research to be done.
"These flybys are not only testing our instruments but are also bringing us close to Mercury at the equator. The flybys are giving us observations that will not be repeated in orbit," Solomon said.
Solomon emphasized the time and effort that's been put into this mission and called the flybys "a wonderful validation" of more than a decade of planning. Both Solomon and Zurbuchen praised the work of the group from Brown, which also includes what Professor Head called a "home team" - a group of graduate students who help to process and compute the data sent back from the spacecraft, based in the Geological Sciences building on Lincoln Field.
Head discussed the Messenger mission via teleconference with students in his class, GEOL 0050 "Mars, Moon and the Earth" yesterday afternoon, using images from the first flyby to illustrate geological concepts.
Head explained to the class how the color photographs taken by Messenger were able to provide far more detailed and significant data than black-and-white photos taken by another NASA mission, Mariner 10, in 1975.
Students in Head's class expressed enthusiasm about the opportunity to learn from cutting-edge research. "That's one reason I took this class," said Anna Kentros '09. "It's cool that he's so prominent in his field. That's what I like to see from Brown professors."
Andrew Underberg '09 agreed. "It gives the class a lot more credibility."
"Science is all about exploration and discovery," Head told The Herald. "This shows the students what the payoff is for scientific inquiry."
