Come Wednesday, Aug. 6, after nearly a decade and a 4 billion-mile journey, the European Space Agency's (ESA) Rosetta spacecraft will have a rendezvous with Comet 67P/Churyumov-Gerasimenko.
If everything goes according to plan, the Rosetta will have the distinction of becoming the first probe ever to orbit the nucleus of a comet. The Comet 67P/Churyumov-Gerasimenko, which is on its 6.5-year orbit of the sun, is said to have a "dark, dusty crust" and is racing through space at nearly 34,175 mph.
The comet is believed to be the size of a mountain, whereas Rosetta is 9 feet high and 7 feet wide. Despite its relatively small size, the probe is said to have the biggest solar array (extending from over 100 feet tip to tip) that was ever sent into space.
Come August 6, the probe will move within 62 miles of Comet 67P/Churyumov-Gerasimenko and will be at the same speed as the comet.
Rosetta was launched in March 2004 and during its journey has managed to pick up one gravity assist from Mars and three from Earth. During its checkered career, the probe has also flown through the asteroid belt two times and was in hibernation for two years to conserve energy.
Inside the Rosetta's cube-like body is another spacecraft - Philae. This is a small robotic lander which the ESA intends to send down on the comet's surface in November 2014, which will also be a first.
"For the first time, we will rendezvous with a comet, for the first time we will escort a comet as it passes through its closet approach to the sun and - the cherry on the top - for the first time, we will deploy a lander," said Matt Taylor, Rosetta project scientist. "The rendezvous is therefore a key milestone in the mission."
The robotic lander will steer its way to the comet. Harpoons will be shot into the comet prior to Philae's docking on the surface. This move has never been attempted ever before. Philae is designed in such a manner that it can last for nearly six months on its own; however, Rosetta will stay nearby and orbit around the comet.
The Rosetta mission intends to demystify comets and will look to explain the chemistry and composition of the ancient molecules they are composed of. The mission is worth $1.3 billion euro (approximately $1.9 billion).