Rosetta and the Leonids

Very few comets have been observed at close quarters by spacecraft, so most of what we know about these primitive planetary building blocks comes from ground observations.

However, by studying comet dust that enters Earth's atmosphere and creates the shooting stars, scientists can learn a lot about these mysterious cosmic snowballs. This information can then be used to predict what the Rosetta spacecraft will encounter when it arrives at Comet Wirtanen in 2011.

"Our studies of the Leonids should tell us about the porosity of the particles that cause the Leonid shower," said Koschny. "This will help us to calculate the density of their parent comet, Tempel-Tuttle, and to improve our understanding of comets in general."

In addition, by examining the composition of the meteors (looking at their chemical makeup by studying their chemical fingerprints) scientists can speculate on what the comet will be like close-up. Studying the density and intensity of the Leonids helps in understanding how the comet behaves. This is an important factor in selecting the landing site for the Rosetta Lander.

"When Rosetta becomes the first spacecraft to go into orbit around the nucleus of Comet Wirtanen and to release a lander onto its surface, we want to have a good idea about what to expect," said Koschny. "Our observations of the dust from Tempel-Tuttle, which is similar in many ways to Wirtanen, should be a great help."

As part of their Australian adventure the team will also be testing a prototype instrument called the Mutual Impedance probe (or MI for short). But, rather than looking at the skys, the MI probe focuses firmly on the ground. The dry conditions are an ideal testing ground for the probe, which is similar to the SESAME instrument currently being developed for Rosetta. Both of these instruments have been developed to examine the surface layers of an object, a comet or planet for example, by measuring the electrical properties of these objects. By studying these electrical signals, scientists can learn about the composition of the surface layers, and may even discover the presence of water. The results of these tests will help the Rosetta team better understand the data which will come from Rosetta.