Data from MESSENGER's first flyby of Mercury have been released to the public by the Planetary Data System (PDS), an organization that archives and distributes all of NASA's planetary mission data.

"This delivery, while not the first for the MESSENGER mission, represents a significant milestone," says MESSENGER Mission Archive Coordinator Alan Mick, of the Johns Hopkins University Applied Physics Laboratory.

"We had delivered data from MESSENGER to the PDS before, but not Mercury data," he says.

"This delivery was particularly significant - the first MESSENGER flyby of Mercury was mankind's return to this planet after an absence of over three decades. In this one flyby we imaged previously unseen areas of Mercury's surface, greatly improved the resolution in areas already covered, and made observations of a kind that had never been made before."

Calibrated data from three of the probe's science instruments - the Magnetometer (MAG), the Mercury Atmospheric and Surface Composition Spectrometer (MASCS), and the Mercury Dual Imaging System (MDIS) - are included in this release.

"The science results from these instruments have already shed light on questions about Mercury that have lingered for more than three decades," says MESSENGER Project Scientist Ralph McNutt of APL.

For instance, analyses of data from MDIS have shown that volcanoes were involved in plains formation, and MAG results confirm that the planet's magnetic field is actively produced in the planet's core and is not a frozen relic.

The MASCS instrument has provided new insights into the extent and complexity of the planet's tenuous exosphere. "The availability of these data via PDS will allow scientists around the world to study the data and begin making even more connections and discoveries," McNutt adds.

Since the mid-1990s, NASA has required all of its planetary missions to archive data in the PDS, an active archive that makes available well-documented, peer-reviewed data to the research community. "An essential element of the implementation of NASA missions is the dissemination of collected data to the science community at large," explains Marilyn Lindstrom, NASA Program Scientist for MESSENGER.

"It's critical to maintain a planetary data archive that will withstand the test of time so that future generations of scientists can access, understand, and use pre-existing planetary data."

The PDS includes eight university/research center science teams, called discipline nodes, each of which specializes in specific areas of planetary data. The contributions from these nodes provide a data-rich source for scientists, researchers, and developers. Steven Joy of the University of California, Los Angeles, is MESSENGER's PDS liaison.

His challenge was to coordinate the efforts of the nodes responsible for validating the various datasets before they could be released. "The PDS validation process needs to be comprehensive and unforgiving to ensure that only high-quality, well-documented data are released for use by the science community," Joy says.

"The data archives do not need to be perfect, but they do need to be documented well enough that future users, unfamiliar with how the data were acquired, can understand the data and apply them to new problems."

The "formal" public release makes mission data available for several applications, including the MESSENGER Mercury flyby visualization tool, available online at http://messenger.jhuapl.edu/encountersactual/.

"The tool now includes actual, unprocessed images from the narrow-angle and wide-angle cameras, taken during the January flyby," says APL's James McAdams, who designed MESSENGER's trajectory. "Viewers will see the same images that told the team that the cameras were not only on target, but were revealing Mercury as it had never been seen before."

In addition, the "Science on a Sphere" exhibit at NASA's Goddard Space Flight Center's Visitor Center has now incorporated MESSENGER images into its collection of Solar System displays. This exhibit utilizes four video projectors to display three-dimensional data onto the surface of a six-foot, suspended sphere.

"It's a unique opportunity to project high-resolution NASA data for educational purposes," notes MESSENGER Education and Public Outreach Project Manager Stephanie Stockman.

MESSENGER Principal Investigator Sean Solomon says it took high level of dedication for the team to pull this off.

"Many members of the MESSENGER team devoted long hours and weekends to ensure that the project met the goal of releasing all of our Mercury data six months after the flyby. We are delighted to share these historic data with the scientific community and the public, and we hope that their availability will foster interest everywhere in the mysteries of the Sun's closest planetary neighbor."