Close Encounters: Spacecraft Orbiting Mercury Spots Two Comets
NASA’s MESSENGER spacecraft is orbiting Mercury and has been able to snag images of two comets: 2P/Encke and C/2012 S1 (ISON.
Later this month, both of these comets will be substantially brighter and much closer to Mercury and the Sun.
MESSENGER has been poised for several weeks to collect observations of ISON.
From November 9 through November 11, the probe’s Mercury Dual Instrument System (MDIS) captured its first images of the comet.
A few days earlier, from November 6 through November 8, MESSENGER’s imagers picked up its first snapshots of Encke.
Improved images coming
“By next week, we expect Encke to brighten by approximately a factor of 200 as seen from Mercury, and ISON by a factor of 15 or more,” said Ron Vervack, of the Johns Hopkins University Applied Physics Laboratory – home base for controlling MESSENGER.
Three of MESSENGER’s instruments — MDIS, the Mercury Atmospheric and Surface Composition Spectrometer, and the X-Ray Spectrometer — will be trained on the two comets and will collect as many observations as payload operational constraints will allow.
Vervack said that he expects improved images next week when the comets make their closest approaches to MESSENGER and Mercury.
MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) is a NASA-sponsored scientific investigation of the planet Mercury and the first space mission designed to orbit the planet closest to the Sun.
The MESSENGER spacecraft was launched on August 3, 2004, and entered orbit about Mercury on March 17, 2011.
On September 10, the MESSENGER project celebrated the posting of the 1,000th featured image from Mercury.
For more information on NASA’s MESSENGER and its on-going mission, go to: