An artist's impression of what MESSENGER may look like when it goes into orbit around Mercury in 2011. The white structure on the left side of the spacecraft is the crucial sunshade. Click on image for full size (42K JPEG) Image courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.

MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) is the name of a spacecraft that will study Mercury; the planet closest to the Sun. MESSENGER is scheduled for launch from Cape Canaveral Air Force Station in Florida in early August 2004. After flying by Mercury three times, the spacecraft will go into orbit around the planet in March 2011. MESSENGER will study Mercury from orbit for about one year.

Only one other spacecraft has ever visited Mercury! Mariner 10 flew past this hot planet three times in 1974 and 1975. Because Mariner 10's flybys were all on the same side of Mercury, it was able to map slightly less than half of the planet's surface. One of the main goals of the MESSENGER mission is to complete the job of mapping the entire surface of Mercury by capturing high resolution images of the planet's surface.

MESSENGER will investigate some of Mercury's other mysteries. Mercury is the densest planet and has a large core relative to the planet's overall size. The spacecraft will measure the planet's gravity and its magnetic field, which will help us learn more about its interior structure. MESSENGER will also explore the composition of the materials on Mercury's surface, which will help us understand the formation and history of this small planet. Strange as it may seem, some scientists think there may be ice on Mercury, hiding from the intense heat of the nearby Sun in the forever shaded bottoms of large craters near the planet's poles. MESSENGER's instruments will tell us whether water ice is really to be found in this most unlikely location.

MESSENGER will follow a roundabout route on its trip to Mercury. In order to save fuel (and to keep the cost of the mission low), the spacecraft will fly past Earth in August 2005 and past Venus twice, in October 2006 and June 2007. Each planetary flyby will help steer MESSENGER's trajectory towards Mercury as the gravity of the planets alters the spacecraft's course. Finally, MESSENGER will fly past Mercury three times (January 2008, October 2008 and September 2009) before settling into orbit around the planet in 2011.

The Sun is about eleven times brighter, and hotter, in the neighborhood of Mercury than it is near Earth. MESSENGER's flight systems and instruments had to be carefully designed and tested to ensure that they could survive the incredible heat. The spacecraft also carries a sunshade to shelter it from the intense sunlight, much as beachgoers use umbrellas to mitigate the heat on a summer afternoon.

This is what an artist thinks MESSENGER will look like in orbit around Mercury. The white sunshade is on the left side of the spacecraft. Click on image for full size (42K JPEG) Image courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.

MESSENGER is a spacecraft that will study Mercury; the planet closest to the Sun. MESSENGER will blast off from Florida in early August 2004. The spacecraft will go into orbit around Mercury in March 2011. It will study Mercury from orbit for about one year.

MESSENGER is only the second spacecraft ever to visit Mercury. The first was Mariner 10. Mariner 10 flew by Mercury three times in 1974 and 1975. Mariner 10 took pictures of about half of Mercury. One of MESSENGER's main goals is to take pictures of the rest of Mercury.

Besides taking pictures, MESSENGER will study the surface and interior of Mercury. It will also measure Mercury's magnetic field. Mercury is very dense and has a large core. Scientists hope this new spacecraft will help us learn why. They think MESSENGER will also help us learn more about the formation of Mercury, and how the planet has changed over time.

Why will MESSENGER take seven years to reach Mercury? NASA needed to keep the cost of the mission low, so they had to use as little fuel as possible. MESSENGER will fly past Earth once, Venus twice, and Mercury three times before it goes into orbit around Mercury. When it flies by planets, the gravity of the planets will help steer MESSENGER in the right direction without using fuel.

Sunshine is very hot near Mercury. MESSENGER has a special sunshade that will keep the spacecraft from getting too hot. The sunshade is like a beach umbrella!

This is what MESSENGER might look like when it gets to Mercury. The white sunshade is on the left side of the spacecraft. Click on image for full size (42K JPEG) Image courtesy NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington.

A new spacecraft is going to the planet Mercury. The spacecraft is called MESSENGER. MESSENGER is only the second spacecraft ever to visit Mercury!

MESSENGER will blast off in August 2004. It will get to Mercury seven years later in 2011. It will take a crazy path on its way to Mercury. It will fly by Earth once, Venus twice, and Mercury three times! Then it will go into orbit around Mercury.

Mariner 10 is the only other spacecraft to visit Mercury. It took pictures of about half of Mercury in the mid 1970's. MESSENGER will take pictures of all of Mercury. It will also study the surface, inside, and magnetic field of Mercury.

Mercury is very hot because it is so close to the Sun. Why won't MESSENGER get fried? The spacecraft has a special sunshade to keep it cool. The sunshade is like the umbrellas people take to the beach for shade!