狈础厂础鈥檚 (DSN) is in the process of being renovated, and not a moment too soon. One of the network鈥檚 ageing radio dishes stopped in its tracks last month, resulting in the loss of important data from the Cassini spacecraft.
DSN antennas in California, Spain and Australia relay signals to and from spacecraft that are beyond near-Earth orbit. Three 70-metre and ten 34-metre dishes now support 36 missions, including the Mars rovers, the Spitzer Space Telescope and the Cassini mission to Saturn.
On 20 April, the 70-metre antenna at the Goldstone Deep Space Communications Complex in California was due to receive data from Cassini鈥檚 fly-by of Saturn鈥檚 moon Titan. As it rotated into position, though, the giant dish became stuck. The mishap was caused by a gouge in its circular guide rail, which has since been fixed.
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This is a rare occurrence, say mission managers, who told 91av that the DSN loses very little data. Three years ago, however, the US Government Accountability Office that the DSN may not be able to meet future demand because of its limited capacity and 鈥渁n ageing, fragile infrastructure鈥�.
Last year NASA began to refurbish its oldest antennas, the 70-metre dishes built in the 1960s, hoping to extend their operation through to 2025. It is checking the mechanical structure to forestall further glitches and to make sure there are no catastrophic collapses, like that of a 90-metre dish at Green Bank, West Virginia, in 1988.
鈥淣ASA is refurbishing the 70-metre dishes built in the 1960s, to extend their operation through to 2025鈥�
Meanwhile, the dishes鈥� electronics are being upgraded to enable them to receive higher frequencies, which allow spacecraft to transmit data at increased rates. DSN programme manager Michael Rodrigues of the Jet Propulsion Laboratory in Pasadena, California, says he is confident that the network will be ready for the James Webb Space Telescope, designed to transmit data at up to 125 megabits per second when it begins operation in 2014.
Even this upgrade won鈥檛 be enough if NASA decides to send astronauts back to the moon. That would probably require building new antennas to handle the increased traffic.
