October 8, 2008
Second Mercury MESSENGER Flyby Exceeds Expectations
NASA's Mercury Messenger passed within 200km of the planet on Monday collecting about 1,200 new images.
On Oct. 6, 2008, at roughly 4:40 a.m. ET, Messenger flew by Mercury for the second time this year, according to NASA.NASA officials said the flyby also gave Messenger the gravity tug it needed to get on to the right path to go into orbit in 2011.
"The Messenger team is extremely pleased by the superb performance of the spacecraft and the payload," said chief scientist Sean Solomon of the Carnegie Institution of Washington.
"We are now on the correct trajectory for eventual insertion into orbit around Mercury, and all of our instruments returned data as planned from the side of the planet opposite to the one we viewed during our first flyby," he added.
"When these data have been digested and compared, we will have a global perspective of Mercury for the first time."
Mercury Messenger's flyby marks the second attempt since to map Mercury's surface since the 1970s when the Mariner 10 spacecraft succeeded in three passes by of the planet but was only able to collect enough images to map half of the planet's surface.
Messenger made its first sweep over the planet in January, collecting pictures of about 20 percent of the surface area missed by Mariner 10.
On Tuesday's pass, Messenger captured another 1,200 high-resolution and color images, revealing a further 30 percent of Mercury's surface that had never before been seen by spacecraft before.
Images reveal a mix of craters, ridges and scarps as well as unseen regions displaying an extensive pattern of rays that run from north to south.
NASA hopes to gain new insight from Messenger how a terrestrial planet evolves.
Interest in Mercury has been revitalized among space agencies across the world. The European Space Agency (ESA) has recently approved construction of a mission to the planet called BepiColombo.
It will be launched in 2013. The mission consists of two spacecraft - an orbiter for planetary investigation, led by Esa, and one for magnetospheric studies, led by the Jaxa (Japan Aerospace Exploration Agency).
The satellite duo will reach Mercury in 2019 after a six-year, seven-billion-km flight towards the inner Solar System.
Image Caption: Machaut is the name of a crater, approximately 100 kilometer (60 mile) in diameter, first seen under high-sun conditions by Mariner 10 in the 1970s. The crater is named for the medieval French poet and composer Guillaume de Machaut. This NAC image shows an amazing new view of Machaut taken during MESSENGER's second flyby of Mercury on Oct. 6, 2008. The slanting rays of the Sun cast shadows that reveal numerous small craters and intricate features. The largest crater within Machaut appears to have been inundated by lava flows similar to those that have filled most of the floor of the larger feature. The adjacent, slightly smaller crater was formed at a later time and excavated material below the lava-formed surface. MESSENGER science team members will also be studying the shallow ridges that crisscross Machaut's floor. Courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
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