NASA MESSENGER Spacecraft Is Only One Week From Mercury

MESSENGER’s mid-December trajectory correction maneuver (TCM-19) went so well that the mission design and navigation teams have decided that a TCM scheduled for January 10 will not be needed.

Cancellation of this maneuver is a demonstration of the near-perfect execution of TCM-19 just prior to the start of the holiday season, says Mission Systems Engineer Eric Finnegan of the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.

On January 9, MESSENGERs Mercury Dual Imaging System cameras will begin gathering pictures of Mercury as the probe zeros in on the planet. With just one week to go before the flyby, the spacecraft is on target to encounter the planet at an altitude of 202 kilometers, Finnegan says. All subsystems and instruments are operating nominally and configured for the start of the flyby sequence, except for the Mercury Laser Altimeter and part of the Gamma-Ray Spectrometer, which well turn on just before the flyby.

Over the next week, the team will make final flyby preparations and upload the final command sequences for the encounter.

We are about to visit Mercury for the first time in more than 30 years, and we cant wait, says MESSENGER Principal Investigator Sean Solomon of the Carnegie Institution of Washington. In addition to providing the critical gravity assist that will move MESSENGER along its path toward Mercury orbit insertion in March 2011, this flyby will let us see parts of Mercury never before viewed by spacecraft. Well be making close-in observations of the composition of Mercury’s surface and atmosphere, and well be probing deeper into the planets magnetosphere than weve ever been. We expect many surprises.

Experience MESSENGERs Mercury Flyby Virtually

See Mercury through the eyes of MESSENGERs imagers with the Mercury Flyby Visualization Tool, now available at http://messenger.jhuapl.edu/encounters/. This new Web feature offers a unique opportunity to see simulated views of Mercury from MESSENGERs perspective, during approach, flyby, and departure, or in real-time (as the observations actually occur).

This tool combines the best available image map of Mercurys surface with observation sequences for the Mercury Dual Imaging System (MDIS), Mercury Atmospheric and Surface Composition Spectrometer (MASCS), and Mercury Laser Altimeter (MLA). The map of Mercurys surface combines Earth-based low-resolution radar images from the Arecibo Observatory in Puerto Rico and image mosaics from the Mariner 10 spacecraft flybys of Mercury in 1974 and 1975.

There are many helpful tips available on the pages of this visualization tool. Pointing and clicking on any color bar will either reveal the projection of each completed image mosaic on Mercury or show the end of the active MLA or MASCS observation. Information accompanying each simulated image includes the latitude and longitude of the point at the center of each image, the resolution in meters (or kilometers when farther from the planet) per pixel (picture element) at the image center, the altitude (how far the spacecraft is above Mercury’s surface), and the time relative to closest approach.

Upcoming Mercury Flyby 1 Events

• January 10, 1 p.m. EST. NASA Media Teleconference to preview the flyby.
• January 14, 2:04 p.m. EST. MESSENGER’s closest approach to Mercury.
• January 14, 7 p.m. EST. APL and The Planetary Society co-host a public lecture in APLs Parsons Auditorium featuring University of Arizona Professor Emeritus Robert Strom, the only MESSENGER Science Team member who also participated in the Mariner 10 investigation of Mercury. RSVP online at http://messenger.jhuapl.edu/RSVP/.
• January 30, 1 p.m. EST. NASA Space Science Update on the Mercury flyby. NASA Headquarters.

Details on all these events will be posted as they become available on the MESSENGER Mercury Flyby 1 Web site at http://messenger.jhuapl.edu/mer_flyby1.html.

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 launched on August 3, 2004, and after flybys of Earth, Venus, and Mercury will start a yearlong study of its target planet in March 2011. Dr. Sean C. Solomon, of the Carnegie Institution of Washington, leads the mission as Principal Investigator. The Johns Hopkins University Applied Physics Laboratory built and operates the MESSENGER spacecraft and manages this Discovery-class mission for NASA.