NASA’s Spacecraft Revealed More Hidden Territory On Mercury.

A NASA spacecraft gliding over the surface of Mercury for the second time this year has revealed more unseen real estate on the innermost planet. The probe also has produced several science firsts and is returning hundreds of new photos and measurements of the planet’s surface, atmosphere and magnetic field.The Mercury Surface, Space Environment, Geochemistry, and Ranging, or MESSENGER, spacecraft flew by Mercury shortly after 4:40 a.m. EDT, on Oct. 6. It completed a critical gravity assist to keep it on course to orbit Mercury in 2011 and unveiled 30 percent of Mercury’s surface never before seen by a spacecraft.

Sean Solomon,principal investigator and director of the Department of Terrestrial Magnetism at the Carnegie Institution of Washington,said “The region of Mercury’s surface that we viewed at close range for the first time this month is bigger than the land area of South America,” He further said “When combined with data from our first flyby and from Mariner 10, our latest coverage means that we have now seen about 95 percent of the planet.”

The spacecraft’s Cameras snapped more than 1,200 pictures of the surface, while topography beneath the spacecraft was profiled with a laser altimeter,which has provided key new insight into the nature of Mercury’s internal magnetic field and revealed new features of its magnetosphere. The magnetosphere is the volume surrounding Mercury that is controlled by the planet’s magnetic field.for the first time,the probe’s Mercury Laser Altimeter, measured the planet’s topography, allowing scientists, to correlate high-resolution topography measurements with high-resolution images.

Brian Anderson from the Johns Hopkins University Applied Physics Laboratory, known as APL, in Laurel, Md.explained “The previous flybys by MESSENGER and Mariner 10 provided data only about Mercury’s eastern hemisphere,” He further said “The most recent flyby gave us our first measurements on Mercury’s western hemisphere, and with them we discovered that the planet’s magnetic field is highly symmetric.”

Maria Zuber, co-investigator and head of the Department of Earth, Atmospheric, and Planetary Sciences at the Massachusetts Institute of Technology,said “The MLA collected altimetry in regions where images from MESSENGER and Mariner 10 data are available, and new images were obtained of the region sampled by the altimeter in January,”.She said “These topographic measurements now improve considerably the ability to interpret surface geology.”

The Mercury Atmospheric and Surface Composition Spectrometer observed Mercury’s exosphere. The instrument searched for emissions from sodium, calcium, magnesium, and hydrogen atoms. Analysis suggests that the spatial distributions of sodium, calcium, and magnesium are different. Simultaneous observations of these spatial distributions, have opened an unprecedented window into the interaction of Mercury’s surface.Spacecraft images also are revealing for the first time vast geologic differences on the surface.

Mark Robinson, co-investigator of Arizona State University in Tempe,said “Now that MESSENGER’s cameras have imaged more than 80 percent of Mercury, it is clear that, unlike the moon and Mars, Mercury’s surface is more homogeneously ancient and heavily cratered, with large extents of younger volcanic plains lying within and between giant impact basins,”.