The MESSENGER mission to Mercury reached the halfway point in its 6.6-year cruise phase, as measured by travel time, on 25 November. Shortly after its first flyby of Mercury in January 2008, the probe’s cruise speed (relative to the Sun) will reach its highest since launch, 62.5 km per second (or 140,000 miles per hour).

MESSENGER will fly within 200 km of the surface of Mercury on 14 January 2008—the first spacecraft to pass the planet since Mariner 10 flew by in 1974 and 1975. DTM Director and Principal Investigator of the mission Sean Solomon commented in the press release, “The halfway point for MESSENGER’s cruise phase is more than a statistical milestone, because in less than two months we’ll have our first close-up view of Mercury. From then until the end of the mission, we’ll be peeling back Mercury’s mysteries, many of which have perplexed the planetary science community for more than three decades.” For more information, see the SpaceRef.com release.