In 2004 the Rosetta space probe and its lander Philae left Earth and began their journey to a distant comet. Now that Philae has landed on the surface safely, scientists are studying the comet remotely to uncover secrets about the origins of our Solar System.
This dark and icy comet called Churyumov-Gerasimenko – or 67P – orbits the Sun every 6.45 years. It has been doing so for billions of years, but now it’s not alone…
The Rosetta space probe has followed comet 67P on its journey. Launched over a decade ago, it has chased the comet through the Solar System and recently caught up with it.
Rosetta uses its Osiris camera to send back amazing pictures like these. On-board instruments such as Miro and Midas sense gases and look at dust coming from the comet to see what it’s made of.
Riding piggyback on Rosetta is the Philae lander. This smaller spacecraft was jettisoned from Rosetta after the voyage and now performs experiments directly on the surface of comet 67P.
Scientists back on Earth will use data from Rosetta and Philae to learn about comets and the early Solar System. Some hope to find clues to the origins of life in comets.
Barbara Cozzoni works at DLR, the German aerospace centre that operates the Philae lander. She makes sure it works correctly and the on-board instruments produce useful data for scientists.
What is your role in the Rosetta mission?
‘I am part of the operations team at the Lander Control Centre. We remotely command the Philae lander. The most important thing for us was to land Philae safely. Now that we have it can start using its instruments. It is my job to work with scientists and ensure that experiments on Philae produce really useful observations for them.’
How is this mission important?
‘This is the first time humankind has ever landed a spacecraft on a comet. So naturally scientists are testing it in every way they can think of. This is why there are so many instruments on Rosetta and Philae. There’s so much to learn about comets. Before landing we didn’t even know how hard or soft its surface would be.’
Why is it difficult to land on a comet?
‘My friends are surprised when I explain the difficulties of landing on a comet. They think it’s like movies where things happen quickly and easily. The biggest challenge we faced was landing on such a strange shape. This made it hard to find a good flat landing site with enough sunlight for Philae’s solar panels, but not so much it would overheat.’
What happened during the landing?
‘Even though I’d finished my shift before the landing, I couldn’t leave the control room. We were all waiting eagerly for touchdown. The atmosphere was a strange mix of excitement and nervous tension. Some instruments like ROMAP were already giving us data about the comet’s magnetic properties. When Philae landed we hardly had time to relax before beginning experiments.’
What happens next?
‘All of Philae’s scientific instruments take turns to measure things and perform different experiments. Drills probe into the surface of the comet, other instruments examine its dust or chemical properties. Philae works with the orbiting Rosetta to see through the comet. They send powerful radio waves to each other, giving a picture of the inside, a bit like an X-ray.’
What inspired you to get involved?
‘I loved space as a teenager and went on to study physics. Later I worked on weather satellites at the European Space Agency. But these all looked down at the Earth and I wanted to look up. So I found this job at DLR working on a pioneering space mission. I love working in my team of friendly and enthusiastic people.’
What’s so important about this comet? I asked some experts…
Ian Wright, Principal Investigator on the Ptolemy instrument, Open University
‘Rosetta scientists think water on Earth may have come from comets. It’s not easy to know for sure as water looks (and probably tastes) the same on Earth as it does in space. But water molecules from different sources can vary. Rosetta has instruments that can measure this on comet 67P. I’m excited we may soon find answers!’
Sue Horne, Head of Space Exploration Programme, UK Space Agency
‘My son just turned 20, which also marks how long I’ve overseen aspects of the challenging Rosetta mission. Many UK companies and scientists helped create 10 of the 21 instruments on Philae. They’ve produced advanced batteries and miniaturised a laboratory instrument to fit the tiny lander. This instrument, Ptolemy, analyses samples from inside the comet brought up by a drill.’
Seth Shostak, Senior Astronomer and Director of the Center for SETI Research
‘If I want to understand more about plants and animals I’d study their ancestors’ fossils. But to learn how life originally began we need to look at life’s building blocks, amino acids. We study comets, which are stuffed with these chemicals, to understand how life began. I hope this gives us insight into whether we might find life on other worlds.’
Elizabeth Howell, freelance space journalist
‘A long time ago we thought comets foretold disaster. But today we know they’re really fascinating little worlds we’re learning to explore. 67P is full of stable minerals and volatile compounds we’re starting to examine. If we can understand how 67P is put together, it could help us better understand the Solar System.’
This article was originally published as an interactive document in the Antenna gallery at the Science Museum.