Rosetta Will Approach Earth for the Second Time

The robotic spacecraft Rosetta will approach Earth for the second time to boost up its speed and to correct the trajectory. ESA's comet chaser, the Rosetta spacecraft was launched in 2004 and it intended to study the comet 67P/Churyumov-Gerasimenko. It consists of two main elements, the Rosetta space probe and the Philae lander. Philae is a so-called lander which will be delivered by Rosetta and has the task of detaching from the spacecraft and land itself on the comet's surface and transmit data about the comet's composition.

These programs to study the passing comets have started as a result of the arrival of comet Halley in 1986, when a number of international space probes were launched to study the cometary system.

The spacecraft Rosetta encountered Earth for the first time in March 2005, after which it executed a Mars fly-by in February this year. As a result of the success of the previous fly-by, Rosetta continued its scheduled mission and will make the second swing around the Earth on 13th of November. These swings are critical to the success of the mission, as the spacecraft gathers momentum to push it on its route and give it enough speed to save as much fuel as it is possible and to make eventual trajectory corrections.

It will pass Earth at an altitude of 5301 kilometers, over the Pacific Ocean at a speed of 45.000 km/h.

While the swing-by made around the planet Mars was needed to slow down the spacecraft and modify its trajectory to send it back toward the inner solar system, the second fly-by around the Earth will give it enough energy to reach the outer Solar System through the asteroid belt to observe the Steins asteroid, then fly back to Earth for a third swing to gain even more speed, observe the asteroid 21 Lutetia in 2010, then initiate a so-called Deep-Space Hibernation until the approach on the 67P/Churyumov-Gerasimenko comet in 2014.

The rendez-vous with the comet will take place at a distance of approximately 4 astronomical units away from the Sun.

In the course of this second fly-by, the highest priority will be given to the spacecraft operations, as this manoeuvre is critical for the success of the mission. Rosetta will be under unfavorable solar illumination and temperature conditions during the swing, giving engineers limited slots for the safe use of the instruments. At the same time the orbiter and its companion Philae will be actively used for the calibration of the instruments.

It will first point to Earth to make observations of the atmosphere and magnetosphere and will take pictures of urban regions situated in Asia, Africa and Europe.