EARTH TO VISIT MARS THIS CHRISTMAS

Earlier this year, three Spacecraft left Earth and began their six month trips to Mars. The European Space Agency launched Mars Express from Kazahstan on June 3rd 2003, and NASA launched Mars Exploration Rover A on June 8th, and Mars Exploration Rover B on June 25th, both from Florida, USA.

MARS EXPRESS
The Mars Express spacecraft is both an orbiter and a lander, similar to NASA's Viking explorers in the 1970s. An orbiter orbits the planet, taking pictures, and analysing the planet from a distance. A lander actually lands on the planet and conducts scientific experiments, often involving analysing soil and rock samples, looking for traces of water (which if found, greatly increases the chances that life exists or once existed on Mars), and also takes pictures of its surrounding landscape, sending them to Earth. The Lander on Mars Express is called Beagle 2 and will be released from Mars Express on 19th December 2003. While Beagle 2 is heading for its landing site on Mars, Mars Express will attempt to place itself into orbit around Mars. Up until three days before 25th December, Mars Express will be heading directly to Mars, as if it is going to collide into it. This is so that its Lander, with no propulsion system of its own, lands exactly where planned. Three days before 25th December, Mars Express' speed will be slowed down from 11 kilometres a second to 9 kilometres a second. This will cause the spacecraft to be captured by Mars' gravity, and keep it in orbit around the planet as a satellite. If the speed is slowed down any more, the spacecraft is likely to float back into space. If the speed is not slowed down enough, Mars Express is likely to collide with Mars. Mars Express' orbit around Mars will be elliptical, meaning that it spins round the planet as if in an oval, going as close as 260 kilometres from the surface and as far away as 11,000 kilometres away. This will be controlled by the spacecrafts propulsion system. Comets and the planet Pluto also have elliptical orbits. 

An artist's impression of Beagle 2 separating from
Mars Express - Copyright European Space Agency

LANDING ON MARS
During its descent, Beagle 2 will be traveling at 20,000 kilometres an hour. Friction in Mars' atmosphere will slow down the Lander's speed. At 1,600 kilometres an hour, two parachutes will be deployed which will slow down the Lander's speed even more. As the Lander comes close to landing, huge gas-filled bags will be released which will soften the landing. Once the Lander has come to a complete halt, the bags will be deflated and Beagle 2 can begin its experiments. 

Missions to Mars have a reputation of failing. The planet is like a space version of the Bermuda Triangle, where spacecraft simply seem to vanish! In fact, two thirds of all missions to Mars have been unsuccessful. In the 1960s and 1970s, just about all of the former Soviet Union's attempts to visit Mars failed. Some spacecraft didn't even leave  Earth, others left Earth but missed Mars, and others stopped responding on their way to Mars. NASA were more successful. They sent their Mariner probes to visit planets in twos (so they would send up Mariner 1 and 2 at about the same time, and two years later, Mariner 3 and 4, again followed two years later by Mariners 5 and 6, then 7 and 8, and then 9 and 10. In most of these missions, one of the two Mariner probes failed in some way. Not all of the Mariner missions were destined for Mars. Some of them visited Venus and Mercury. Mariner 4 succeeded in sending back the first close-up images of Mars' surface. Mariners 6 and 7 followed, and Mariner 9 sent back the first images of Mars' volcanoes, exciting scientists who were getting bored of looking at pictures of rocky surfaces and craters. The Viking probes in 1970s were both successful, sending back the first pictures from the surface of Mars, but even these missions suffered from some technical failures. The next successful mission to Mars came over twenty years later in 1997 when Pathfinder visited Mars, launching its rover, the Sojourner Rover, to explore the planet's surface, just like Mars Express' Beagle 2 will do this December. Beagle 2's experiments, mainly involving soil and rock sample analyses, are expected to last for about 180 Martian Days. I will be keeping you up-to-date with developments and discoveries from this Mars mission on this website. To find out more information, visit the official mission site by the European Space Agency.

MER-A AND MER-B
NASA's Mars Exploration Rovers are expected to land on Mars in January 2004. Both rovers will probe Mars' surface to search for evidence of water. These little robotic tourists will also take photographs of the Martian panorama and send them back to Earth, providing that any passing aliens on the planet don't attempt to spoil NASA's fun.....

MER-A will land in the Gusev Crater. It is believed that this is where there was once a lake on Mars. Equipment on the rover will probe the rocks and soil in this area.

MER-B will be landing on the opposite side of the planet to its sister rover in an iron-rich area called the Meridiani Planum. As well as analysing soil and rocks and taking pictures of the surrounding area, it can also take microscopic images of the surface and grind rocks.

For information about this mission, visit NASA's official website.