The Intermediate Frequency Modem System (IFMS), developed by BAE Systems AI Labs, enabled the very weak signals from the spacecraft to be decoded on earth, tracking the distance to the craft to within a metre and its speed to within fractions of a millimetre per second. This enabled the European Space Agency (ESA) team on earth to determine its trajectory and issue the correct commands to the Rosetta spacecraft to enter the orbit of comet 67P Churymov-Gerasimenko as it moved through space at 55,000km/h, and to target the Philae probe that successfully landed on the comet in November 2014.
In addition, the IFMS provided a means to send commands over the 500million kilometres through space, and receive the images and scientific data from the craft. The system was an essential component in the Rosetta mission, without which it would be impossible to communicate with the craft.
The IFMS went into service in 2001 and has been in use ever since. A particular challenge in its development was designing a system that could be upgraded and improved over the long lifetime of deep space missions, using hardware that is now 15 years old – meaning the team had to develop very efficient modern algorithms to make the most of the limited processing power of the older equipment.
“You can have a wonderful trajectory model to control a spacecraft, but it is only as good as the input measurements it gets,” explained Nick James, leader of the IFMS team, based in Chelmsford, UK. “Everything the BAE team did to receive and process these signals was on the ground, millions of kilometres away from Rosetta, but we were able to provide the measurements for the ESA team to turn into the correct trajectories.
"It's the spacecraft and the ESA team that quite rightly get the credit for the Rosetta mission but they rely on a lot of engineering going on in the background so it's great for us to get recognition for the work we have done on the IFMS.”
The team will be presented with their award at the Royal Academy of Engineering’s Awards Dinner at the Tower of London on 23 June.
