Europe’s comet chasing Rosetta spacecraft has finally arrived at its destination after a ten-year journey, providing scientists for the first time in history with a close-up of a comet.
Shortly after 10am BST, the spacecraft has fired its thrusters to match its speed with that of the comet Churyumov–Gerasimenko, also known as 67P, in a manoeuvre carefully watched and steered from the European Space Agency’s (Esa) control centre in Darmstadt, Germany.
The manoeuvre, described by Esa’s Rosetta Flight Director Andrea Accomazzo as leaving a straight highway to enter an unknown town with busy traffic, was successfully concluded at about 10:30 BST.
Rosetta Spacecraft Operations Manager Sylvain Lodiot confirmed the operation was successful and said it went even smoother than expected.
Instead of entering a conventional orbit around the comet, Rosetta will now fly side by side with P67 with only 100 km between them, increasing the distance as the two bodies fly together around the Sun to enable the scientists to scan its surface.
“They are not going directly to orbit around the comet, because they don’t know the physical properties of the comet,” Esa’s flight dynamics expert Frank Budnik explained.
“They need to see the comet fully illuminated by sunlight to measure its characteristics and understand its landmarks.”
Eventually, Rosetta will enter an atypically shaped triangular orbit around the comet, slowly decreasing the distance between them from 100 km to 25-30 km.
While flying around the Sun, Rosetta and its instruments, including the Osiris high definition camera, the two channel VIRTIS instrument and the small radio telescope MIRO, will measure how the comet’s chemistry is changing and reacting in the proximity of the powerful star.
The data will enable the scientists to break down the comet into its individual components, analysing its chemical composition as well as physical and mechanical properties.
The instruments will also help determine the best landing spot for Rosetta’s precious payload, the Philae lander, which is expected to be released from the parent orbiter in November in the first ever attempt to land a manmade object on a comet.
Prior to the deployment of Philae, Rosetta, with its 32m wide solar arrays, will come to within just 2.5km of the nucleus of the 4km in diameter comet.
The scientists believe, Rosetta,named after the famous Rosetta stone which enabled 19th century archaeologists to decode hieroglyphs of ancient Egypt, will provide a direct window into the origins of the solar system, the emergence of water and hopefully of life itself.
The arrival at Churyumov–Gerasimenko, named after two Soviet astronomers who first observed the comet in 1967, marks a critical milestone in the daring space mission.
Rosetta, launched in 2004, has travelled more than 6 billion kilometres during its ten-year journey.
It was put into deep-space hibernation in 2011 and only woken up for the last stretch of its journey in January this year.
During the last months, the teams have activated and tested all Rosetta’s instruments and started acquiring data as the spacecraft drew nearer to its destination.
The excited space community is now awaiting more than a year of ground breaking science before the mission’s scheduled end in December 2015. Even after that, the scientists hope, the wealth of data will keep them busy for years to come.