First view of Mercury from orbit
The MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) space probe successfully entered into orbit around Mercury on March 17, 2011, and sent back the first images early this morning. This is the first time a space probe has been placed in orbit around the innermost planet of our solar system, which makes for a historic occasion.
According to the NASA press release, once MESSENGER successfully entered into orbit around Mercury, a comprehensive series of system checks were started. Those checks completed yesterday, and the probe began transmitting images back to Earth at 05:20 EDT this morning.
The MESSENGER probe was launched in 2004, made flyby passes of Mercury in January and October of 2008 and again in September 2009, before finally inserting into orbit March 17 of this year. Placing a satellite into orbit around Mercury is particularly challenging because of the energy the spacecraft picks up from the gravitational attraction of the sun. Since Mercury’s atmosphere is too sparse for aerobraking, a complex series of maneuvers involving Earth, Venus, and Mercury was required to slow the craft down sufficiently. This multi-flyby added many years and almost 5 billion miles to the trip for the probe.
MESSENGER is currently transmitting several hundred images, and NASA is in the process of releasing many more of these images in a teleconference taking place at the time of this article’s publication. See the new images released.
MESSENGER carries a slew of observational instruments, and according to Wikipedia, its mission objectives include the following:
- determine accurately the surface composition of Mercury
- characterize the geological history of the planet
- determine the precise strength of the magnetic field and its variation with position and altitude
- investigate the presence of a liquid outer core by measuring Mercury’s libration
- determine the nature of the radar reflective materials at Mercury’s poles
- investigate the important volatile species and their sources and sinks on and near Mercury
For the near-term, NASA states that the year-long primary science phase of the MESSENGER mission will begin on April 4, and the orbital observation plan calls for MDIS to acquire more than 75,000 images in support of MESSENGER’s science goals.
If you are interested in learning more, the MESSENGER Wikipedia page and NASA pages have plenty of information.
Artist's rendering of the MESSENGER probe