The MESSENGER spacecraft flew past Mercury on Monday evening in one of three scheduled slow-down fly-bys before it begins orbiting the planet in a few years. The first images (there are going to be a LOT of them) will now begin to appear. This image from a press release out last night, shows the previously hidden face of the planet.

It doesn’t get more impressive that this. People get into this field so they can be part of these kinds of photographs. What you see is the never-before-photographed side of the planet Mercury.

On the upper right is the giant Caloris basin, including its western portions never before seen by spacecraft. Formed by the impact of a large asteroid or comet, Caloris is one of the largest, and perhaps one of the youngest, basins in the Solar System.

When Mariner 10 visited the planet 30 years ago, part of it (slightly more than one half) was hidden from view and never pictured. Thus, since then all maps of Mercury, like the one below, have contained a mysterious, blurry hemisphere on one side. But no more!

The new image was taken using the Mercury Dual Imaging System’s (MDIS) wide field camera, and it shows features down to a size of 6 miles across. It was taken at a distance of 17,000 miles from the planet.

Other images yet to be released from this fly-by, will show the surface in colour and higher resolution.

Read the full press release here.

Today at 1904 GMT, the NASA spacecraft Messenger will make its first approach of Mercury, the inner-most planet of our solar system. This evening’s approach is the first of three between now and 2011, designed to slow down the probe as it readies to begin orbiting the planet.

This will be the first visit to Mercury by any probe since 1975. More than 1,300 images of Mercury will taken during this encounter, so hopefully we can expect some great pictures to be released over the next couple of weeks.

If you want to read more about the MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraf, then you can visit either the general NASA mission page or a more detailed page from the instrumentation team.

This mission is a very exciting one. Mercury remains one of the only planets to have not been fully mapped by probes (you may have seen the bald patch on many globes of the planet). There are a lot of people getting very excited today!