12 Months with 67P
Just over 12 months ago the Rosetta space probe completed its historic journey to comet 67P Churyumov - Gerasimenko.
Image Credit: ESA
As the comet approaches perihelion we look at what it has been up to while it has been orbiting the giant dirty snowball.
Eighteen months ago rooms full of scientists and engineers nervously waited around computer monitors across the globe. A decade long mission was approaching its thrilling final act. The first stage in a series of nail-biting moments was a vital phone call. This phone call would not becoming from Earth but instead travelling hundreds of millions of kilometres through the dark void of space. Alone in the darkness, after a long period of hibernation, the Rosetta probe was scheduled to wake-up. It was vital that the probe rebooted and phoned home to Earth. Despite being set on its course nearly 10 years prior there would be vital corrections that would need to be made.
Dialling on time
Much to the relief of the teams working on Rosetta the spacecraft dialled home exactly on time. Despite the relief there were 7 long months to go to ensure the spacecraft was ready for the main element of its mission. Over the next few months a whole suite of diagnostics and calibration exercises were carried out on the spacecraft’s systems. After a long wait everything was done to ensure the spacecraft had the best chance of completing its mission.
The long journey Rosetta had taken was to bring it close, and ultimately, into orbit around Comet 67P/Churyumov – Gerasimenko. Discovered in 1969 this celestial lump of space rock journeys around the Sun every six and a half years. 67P was selected as the target for a European Space Agency exploratory mission.
A spacecraft, Rosetta, would be launched to spend an extended period of time studying the comet and a small lander would be dispatched to sample and investigate the surface of the comet.
Comets have long since been known about, the first being discovered thousands of years ago. They were seen as bad omens often said to foretell the fall of empires and the death of great people. Recent study has revealed that they are infact much more mysterious. As left over remnants of the early solar system they can tell us a great deal of the chemistry that helped formed the Earth.
Image Credit: ESA
These objects can retain this information for billions of years as they are frozen. We find comets at the edges of our solar system. At great distances from the Sun, comets are made up of rock, dust and frozen materials. Frozen and unchanging they can lock away these secrets for untold generations. However on occasion we get an insight into these fascinating objects.
When their orbital paths nudge them closer to the Sun these volatile objects begin vapourise as they heat up, spreading their material through the solar system. This can be seen in the magnificent tails we often associate with comets. Despite their glorious tails, comets appear fairly routine. Giant icy, dust balls of rock cruising through space. Rosetta aimed to change this and discover why these objects are some of the most interesting in the solar system.
As August 2014 approached Rosetta carried out 10 key manoeuvres. This would put the probe on a course that would result in the spacecraft orbiting the comet. Locked in the cosmic dance Rosetta could travel along with 67P held in orbit by the comets gravitational pull. Once in orbit the probe could kick into science mode and use it’s suite of instruments to begin the study of the comet.
Rosetta was equipped with 11 different instruments that would study a whole host of properties. Some of these instruments were dedicated to observing the comet, these would give us detailed views of the composition of the comet, they would allow scientists to investigate the evolution and changes the comet would experience as it approached the Sun and gradually warmed.
The final major objective of Rosetta was to deploy a small lander to the surface of the comet. The lander known as Philae would detach, plummet towards the comet’s surface and then using harpoons anchor itself on the 67P’s surface to begin its science operations. Famously this didn’t quite go to plan. The harpoons failed to fire and Philae bounced, in a tense few hours it was unsure if 67P’s weak gravity would pull the probe back to the surface of the comet. Luckily it did and the lander was able to carry out its planned 60 hours of science gathering before going into hibernation.
Philae was designed to support Rosetta’s study of the object. It was equipped with sensors that could measure the composition of the gases being ejected close to the comets surface. The landers drill discovered that sections of the comet were solid ice, this supported the theory that water on the Earth could have been brought here by comets during the formation of the solar system. Working in conjunction with Rosetta signals were beamed through the comet in an attempt to calculate the density of the comet, this would offer more insights into what it is made of.
Today we celebrate Rosetta’s achievements after spending more than a year in orbit. Today is also a special day for 67P as it approaches Perihelion. This is day of the closest pass of the Sun 67P will make during its orbit. Perihelion passes are often the most dynamic for comets as they are at their warmest. Over the last few days and the next week or so to come we expect to see elevated activity on the tiny frozen world. Already ESA have detected and imaged violent outbursts and more may yet to come.
While some comets fail to survive their Perihelion pass 67P sits far enough away from the Sun that disintegration is unlikely. While still possible Rosetta will remain in orbit to observe proceedings as they go down. As results pour back from Rosetta we will update this blog with any exciting developments. Be sure to keep your eye out as we say, Well done Rosetta!