Image of the Month - September 2004

A Messenger to Mercury

The innermost Planet in the Solar System, Mercury, has been visited only once by a spacecraft - and even that mission of Mariner 10 ended nearly 30 years ago in 1975. Less then half of the planets surface has been imaged by Mariner. Time to take another close at the planet, which is named after the winged messenger of the Gods in Roman mythology!

A spacecraft appropriately named Messenger has been launched by NASA on August 3, 2004. It will swing into orbit around Mercury in 2011, after several flybys at the Earth, Venus, and Mercury itself.

Messenger spacecraft
Credit & Copyright: Bill Dillon and Joe Dellinger, Fort Bend Astronomy Club, Texas, USA

Soon after its launch, the Messenger spacecraft has been caught by Bill Dillon and Joe Dellinger using the Fort Bend Astronomy Club's 0.46m reflector and a Apogee AP-8 CCD camera, at a distance of about 350.000km from Earth (roughly the Moon's distance from Earth). The animation shown above consists of frames, each a stack of four 30 second exposures. The spacecraft can be seen moving from the left edge of the images towards the bright star near the center, being lost in the glare of that star in the fifth image. The burn of the third stage of the spacecraft was somewhat shorter than planned, so the image of the spacecraft was located right at the edge of the CCD frame (of which only about 4% of the total area is shown here).


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