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The University of Southampton

Carrying out experiments on a distant comet. A Southampton Astronautics researcher’s role in the Rosetta project

Published: 13 February 2015Origin: Engineering
Picture of Dr Roberto Armellin

Lecturer in Astronautics Dr Roberto Armellin watched the TV coverage of the recent Rosetta mission to comet 67P/Churyumov-Gerasimenko with special interest – he had been part of the project at the Politecnico di Milano before moving to Southampton.

In ten years the European Space Agency spacecraft Rosetta travelled 6.8 billion km to reach the tiny rock less than four kilometres long travelling through space at up to 18 km per second. The challenging project involved around 2,000 people from industry, ESA and scientific institutions.

When the lander Philae reached the comet, the thruster and harpoons failed to operate. It bounced on the surface twice and ended up in an unplanned site at an unknown orientation. This prevented solar panels charging the secondary batteries and thus restricted the mission’s range of scientific activities. However, they may operate to some extent in intense sunlight as Rosetta gets closer to the sun later this year.

“I had worked on the drill (known as SD2) on Philae designed to pick up samples from under the surface of the comet, so it was exciting for me to follow the landing,” he explains. “Unfortunately, there were problems in the landing phase. Only one out of the three drill activities took place and it seems that no sample was collected, although the drill appeared to work normally.”

While a postdoctoral student in Italy, Roberto carried out many tests with the drill on various materials such as air concrete, gravel, glass and carbon foams. The drill, both a tool and a scientific instrument, uses less power than a lightbulb (18-30 watts) and works very slowly in the low gravity of a comet. It was designed to drill up to 245 mm into the comet (625 mm full drill extension), extract three core samples and heat them in tiny ovens. Much investigation is underway to understand why no sample was delivered to the ovens, but the best hypothesis is that the landing site did not allow the drill to enter the soil of the comet.

At Southampton, Roberto now works on astrodynamics including the prediction of orbits of space debris and asteroids

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