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The Rosetta space probe has moved into its final orbit of comet 67P before it launches a lander to capture pictures and data from the comet's surface.
Rosetta's thruster was fired for 90 seconds last week to achieve the change in position.
The €1.3 billion space probe was launched in March 2004 after 10 years in development and sent on a trajectory to rendezvous with comet 67P in deep space. It arrived at the comet three months ago and has been orbiting it since to map its surface and analyse the gases and dust that come off it. The European Space Agency (ESA) plans to fire the Philae launcher next week on November 12. If successful the lander will drill into the comet and analyse rock samples as well as analyse the comet's surface.
Rosetta is controlled on Earth via a communications system developed in Essex by defence firm BAE Systems known as the Intermediate Frequency Modem System (IFMS). The system is capable of measuring Rosetta’s speed to within fractions of a millimetre per second and its distance to within a metre anywhere in the Solar System.
The probe is moving at speeds of up to 55,000km/h more than 500,000km away. The IFMS is also the means by which all the imagery and data sent back on Earth.
Nick James, lead engineer for the project at BAE Systems' Advanced Technology Centre in Greater Baddow, said: “Approaching, orbiting, and landing on a comet requires delicate and supremely accurate manoeuvres. The target comet is a relatively small object about 4km in diameter, moving at incredible speeds through the solar system.
“To help make any of this possible, what we have done, in layman’s terms, is create a ‘smart phone’ for interplanetary communication that gives the ESA the capability to communicate with and control the Rosetta probe throughout its 10 year mission as it travels more than five times Earth’s distance from the Sun.
“The reliability of our system has also played a key role in the mission’s success. In an age where high-tech can often mean ‘short life’, for example renewing your smartphone every 18 months, IFMS was designed to provide cutting edge performance for decades.”
IFMS was developed in the late 1990's and has been used for other ESA missions such as the Herschel space telescope Mars Express and the Venus Express probes. The system converts analogue signals into digital ones using a combination of a digital filter and software algorithms to reduce background noise. IFMS also features a highly sensitive receiver to pick-up the incredibly weak signals sent back to Earth from the probe, converting them into data that can be used to communicate the probe’s findings.
IFMS utilises triangulation between two ground stations to determine direction. According to BAE Systems it is accurate to a millionth of a degree, the equivalent to the diameter of a 10p coin at 1000km away.
Engineers at BAE Systems are now developing the next generation of IFMS, the Telemetry Telecommand and Control Processor (TTCP) to take the system into future decades.