Next week, NASA's Messenger spacecraft will become the first probe ever to orbit Mercury. Scientists are hoping the mission will solve a host of mysteries about our neighboring planet.
Entering orbit will be "the culmination of the mission, the principle objective," said Messenger principal investigator Sean Solomon, speaking at the annual meeting of the American Association for the Advancement of Science in February.
"We can look forward to an enormous increase in understanding of one of our nearest planetary neighbors," said Solomon, who also serves as the director of the Department of Terrestrial Magnetism at the Carnegie Institution of Washington.
Messenger (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) is slated to conduct a 14-minute engine burn on March 17 at 8:45 p.m. EDT to arrive in orbit around Mercury. After a short checkout, the spacecraft will begin high-resolution mapping of the planet's surface by April 4.
"We cannot wait for orbital insertion," Solomon told Space.com. "The science team is ready to start taking orbital observations, so we are very much looking forward to what all of us hope is a successful orbit insertion into the desired science orbit."
The $446 million Messenger probe launched in August 2004. Over the course of three flybys of Mercury, the spacecraft has already furthered scientists' understanding of the closest planet to the sun.
It has revealed a tenuous atmosphere around the small planet, and evidence for a volcanic past. ...
recent studies from Messenger imaging provide further evidence for volcanic activity on Mercury in the last 1 million to 2 million years.
"We're building up a catalog of probable volcanic centers, many of which seem to have involved explosive volcanism," Solomon said. "That's surprising."
Messenger has also revealed features called lobate scarps, where one block of the planet's crust has been thrust over another, in what seems to be the result of a planet-wide contraction. ...
via At last! Messenger craft poised to orbit Mercury - Technology & science - Space - Space.com - msnbc.com.
Okay, the image above is not Mercury, it is actually... the moon. Did you know the moon is shrinking?
by Denise Chow, SPACE.com Staff Writer Date: 19 August 2010
... The moon is shrinking ever so slightly, but there is no cause for alarm, according to a new study that has discovered a clutch of previously unseen faults on the lunar surface from photos taken by a NASA probe.
In all, 14 previously undetected small thrust faults ? the physical markers of contraction on the lunar surface? were found to be globally distributed around the moon in thousands of photos returned by NASA's Lunar Reconnaissance Orbiter. ...
Lobate scarps were first recognized in photographs taken of the moon's equatorial region by panoramic cameras flown on the Apollo 15, 16 and 17 missions in the early 1970s.
"Since the Apollo missions were designed to land men on the moon, coverage from the Apollo photography was very limited, and only in the portion of the equatorial zone," Watters said.
Photos from the Lunar Reconnaissance Orbiter Camera have now revealed how widely distributed these landforms actually are on the lunar surface.
"We found that these landforms occur not only elsewhere in the equatorial zone, but also at high latitudes," Watters explained. "At least half of the 14 that we report on were at latitudes higher than 60 degrees. Several of them are near the lunar poles."
He expects that as the LRO mission continues researchers will discover even more of these structures.
"The ultra-high resolution images from the Narrow Angle Cameras are changing our view of the moon," said study co-author Mark Robinson, who is the principal investigator of the Lunar Reconnaissance Orbiter Camera at Arizona State University. "We've not only detected many previously unknown lunar scarps, we're seeing much greater detail on the scarps identified in the Apollo photographs."
The incredible shrinking moon
According to the study, there has been about 328 feet (100 meters) of change in the moon's radius over the course of about 1 billion years, said Watters.
"This is a very small amount," he said. "I don't want to give the impression that the moon is dramatically shrinking away." ...