Irish scientist’s role in comet-chasing Rosetta mission

17 Jan 2014

An artist's impression of the Rosetta spacecraft. Image via ESA - C. Carreau

The Rosetta spacecraft is due to ‘wake up’ next week. Irish scientist Prof Susan McKenna-Lawlor has been working on the comet-bound mission, as Claire O’Connell found out.

Rosetta is the European Space Agency‘s mission to gather information from comet Churyumov-Gerasimenko. The Rosetta spacecraft, which was launched back in March 2004, is currently in hibernation but next Monday it will be awakened and prepared to carry out a programme that will involve comet mapping in August, deploying a Lander called Philae onto the comet’s nucleus in November and escorting the comet around the sun between November 2014 and December 2015.

Comet touchdown

One of the key steps in the Rosetta programme will be to attach the Lander to the surface of comet Churyumov-Gerasimenko itself. “After Rosetta is inserted into an orbit about the comet nucleus, five potential landing sites will be selected for close scrutiny,” explains McKenna-Lawlor, who is Ireland’s representative on the Steering Board of the Lander. “When a final selection has been made, the Lander will be commanded to eject from the spacecraft and unfold its three legs, ready for a gentle touchdown. A harpoon will immediately be fired on landing to anchor the Lander and prevent it escaping from the comet’s extremely weak gravity.”

McKenna-Lawlor, who studied experimental physics at University College Dublin and is a Professor Emeritus at NUI Maynooth, has been director of the company Space Technology Ireland Ltd (STIL) since it was set up in 1986. Since then STIL has built instrumentation launched by ESA, NASA and the Chinese, Indian and Russian Space Agencies.

For Rosetta, the company designed, constructed and tested the onboard Electrical Support System (ESS) processor unit, she explains, and when the Lander is on the comet, this system will play a key role in passing the streams of commands and data between the Rosetta spacecraft and the instruments on the Lander. “Since the success of the Lander depends on the successful acquisition of scientific data from the comet nucleus, the ESS is defined to be mission critical hardware,” says McKenna-Lawlor.

New insights into the solar system

By gathering information from Churyumov-Gerasimenko, it’s hoped that the Rosetta mission will provide important insights into the formation of our solar system. “Comets have a preserved a record of the early history of the solar system some 4.6bn years ago because they spend almost all of their lifetime in a ‘deep freeze’ at about one light year distance from the sun,” says McKenna-Lawlor. “Due to a chance gravitational perturbation a comet can be deflected into the inner solar system and this is the first time that a robotic system will land on such an object and make direct measurements of its properties. It is very exciting to anticipate having such a unique opportunity to study materials that drove the evolution of the solar system and I personally cannot wait for this phase of the mission to begin.”

When mission controllers have established contact with Rosetta after it is awakened on Monday, the Twitter account @ESA_Rosetta will provide updates on the mission. In the meantime, check out the #wakeuprosetta hashtag.

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Dr Claire O’Connell is a scientist-turned-writer with a PhD in cell biology and a master’s in science communication