Lunar and Planetary Institute
Lunar and Planetary Institute


MESSENGER’s First Mercury Flyby Scheduled for January

December 17, 2007

Artist's impression of the MESSENGER spacecraft in orbit at Mercury.The MESSENGER spacecraft will complete the first ever flyby of Mercury on January 14, 2008, at 19:04:42 UTC.

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft was launched on August 3, 2004, onboard a Boeing Delta II rocket from Cape Canaveral Air Force Station, Florida. The spacecraft will have traveled more than six and a half years when it begins to orbit Mercury in March 2011.

To become the first spacecraft to orbit Mercury, MESSENGER must follow a path through the inner solar system, including one flyby of Earth (August 2005), two flybys of Venus (October 2006 and June 2007), and three flybys of Mercury (January 2008, October 2008, and September 2009). This impressive journey will return the first new data from Mercury in more than 30 years.

The MESSENGER mission, spacecraft, and science instruments are focused on answering six key outstanding questions that will allow us to understand Mercury as a planet. The data retrieved from MESSENGER should help explain the planet’s density, geologic history, magnetic field, and core structure; identify any unusual materials at its poles; and use measurements of the composition of the exosphere to provide insights into the processes responsible for the planet’s existence.

The average data downlink rate while in Mercury orbit will be 15 megabytes (MB) per day, but the rate will vary enormously during the mission because of the large variation in distance between Mercury and Earth over one year. While at Mercury, MESSENGER will transmit data for about 80 hours per week. Depending on Mercury's location, signals from MESSENGER can take anywhere from 4 to 12 minutes to reach Earth.

The MESSENGER team is composed of many different individuals, with a wide variety of roles and responsibilities. Scientists and engineers from across the country are involved in all aspects of the mission. All these individuals have and will continue to work together to make the MESSENGER mission possible and ensure its success.

To view high-resolution images of Mercury, visit:

Mercury Map Catalog

To view an animation of MESSENGER’s upcoming flyby of Mercury, visit:

Preview MESSENGER’s flyby of Mercury


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