Early this morning, after traveling for more than a decade, the Rosetta spacecraft reached orbit around Comet 67P/Churyumov-Gerasimenko after crossing a distance of four billion miles (6.4 billion km). It is the first probe to meet a comet on its journey around the sun.
According to the ESA (European Space Agency), it has taken a decade for the ambitious project to reach the comet known as “Chury”. In the approach, the Rosetta probe has traveled around the sun five times.
It’s a day for champagne.
Chury and its visitor are still 252 million miles from Earth, nearly half way between Jupiter and Mars. Moving at 34,000 miles (55,000 km) per hour, Rosetta and the comet are headed into the inner Solar System.
It takes 23 minutes for messages to reach us from the orbiting probe, signals that register as dips on a graph.
Chury is small (2.2 x 2.5 miles) and has an orbital period of 6.45 years. It rotates once every 12.7 hours. The comet was first observed in 1969 by Klim Ivanovych Churyumov and Svetlana Ivanova Gerasimenko.
The probe’s journey was an arduous one. Three times, Rosetta had to make a gravity-assist flyby of Earth and then one at Mars to get itself on course. In the process, the probe gathered reams of scientific data on two asteroids, Šteins and Lutetia.
Jean-Jacques Dordain, ESA’s Director General has announced:
“Europe’s Rosetta is now the first spacecraft in history to rendezvous with a comet, a major highlight in exploring our origins. Discoveries can start.”
In May, Rosetta began to make a set of complicated and delicate maneuvers which adjusted the probe’s trajectory and speed, bringing it closer to the comet. Given the vast distances involved, any misstep could have sent Rosetta shooting away from its destination.
This space mission has been in the works since the late 1970s and is the result of a multinational scientific partnership. Now, the discoveries lay before Rosetta while Earth watches.
When Rosetta reached a distance of just over 7,000 miles (12,000 km), Chury’s shape made international news. The comet’s nucleus is made up of two segments joined by a neck-like formation, causing the celestial body to look like a rubber duck or a boot.
As of now, Rosetta orbits just 62 miles (100 km) above the surface of Chury. It will get closer. By mid-September, the probe’s narrowing orbit will have allowed ESA to identify a safe site for Rosetta’s Philae lander, currently predicted to deploy November 11th.
The probe will continue traveling with Comet 67P, says Matt Taylor, ESA’s Rosetta project scientist.
“…until its closest approach to the Sun in August 2015 and beyond, watching its behavior from close quarters to give us a unique insight and realtime experience of how a comet works as it hurtles around the Sun.”
Comets are small, icy bodies that travel in orbit within the Solar System; they originate in either the Kuiper Belt or the Oort Cloud, depending on the length of their orbital periods. As they approach the Sun, they give off gas in clouds and tail formations which can sometimes be seen with the naked eye.
Humans have been observing and recording data about comets for millennia. They were once believed to be a bad omen but are now known to consist of dust, rock, and ice that often contains complex organic material which might give us insight into the origins of life on Earth.
There are more than 5,000 known comets within observable range.
Matt Taylor is excited about the Rosetta probe’s success.
“We’re going to ride along with this comet. We’re going to have a ringside seat. It’s going to be an awesome ride. Stay tuned.”
[Image Courtesy Of ESA/Rosetta/MPS]