Mercury to send message to Earth

William Atkins
Sunday, 27 September 2009 20:02

Science - Space

MESSENGER will be taking up to 1,500 high-resolution, color photographs of the southern hemisphere, specifically of targets that are of interest to scientists.

While the camera is taking pictures, a spectrometer (actually the Mercury Atmospheric and Surface Composition Spectrometer) will be making measurements of these targets of interest.

In all, five primary scientific instruments are onboard the spacecraft: the Mercury Dual Imaging System (MDIS), the Gamma-Ray and Neutron Spectrometer (GRNS), the X-ray Spectrometer (XRS), the Mercury Laser Altimeter (MLA), and the Mercury Atmospheric and Surface Composition Spectrometer (MASCS).

Dr. Noam Izenberg, of the Applied Physics Laboratory at Johns Hopkins University, stated, "Scans of the planet's tail will provide important clues regarding the processes that maintain Mercury's fascinating atmosphere. The Mercury Atmospheric and Surface Composition Spectrometer will give us a snapshot of how the distribution of sodium and calcium in Mercury's atmosphere vary with solar and planetary conditions. [We also plan to] look for several new atmospheric constituents." [NASA]

One important investigation of the planet will concern the hypothesis that Mercury is shrinking in size. In the mid-1970s, the last spacecraft to visit Mercury, Mariner 2, took images of the planet that indicated large scarps (cliffs and hills caused by faulting of the planet) formed into the surface of Mercury.

Astronomers think that such scarps were formed as the planet’s interior is slowly cooling (actually, freezing), and is thus shrinking in size.

One such scarp, or escarpment, is called “Discovery Rupes,” which is about 650 kilometers (400 miles) in length and around two kilometers (approximately 6,500 feet) in altitude.

Additional information about the MESSENGER mission is found at NASA’s website: “MESSENGER: Mission to Mercury” and at the JHU Applied Physics Lab’s website “MESSENGER.”