Extended Antenna Outage at Madrid Deep Space Network Complex
August 7, 2006
During a planned downtime for installing upgrades to the 70-meter (230-foot) antenna at the Madrid Deep Space Network Complex, from May 22 to Oct. 1, engineers detected cracks in a large bearing system of the antenna.
The cracks were detected in two bearings in mid-June, which allowed the team to begin the replacement of the bearings while the antenna was already scheduled to be out of service. However, the replacement work will likely last longer than Oct. 1. The current estimate for returning the antenna to service is early January 2007. Four replacement bearings have been procured, and the team is currently planning to complete the replacement as quickly as possible.
The Madrid complex is one of three antenna locations around the world that the Deep Space Network uses for tracking and communicating with interplanetary spacecraft. Like the other complexes in Australia and California, Madrid includes several smaller dish antennas in addition to one 70-meter (230-foot) antenna.
The Deep Space Network has already performed similar inspections of all four bearings at the Canberra, Australia, antenna complex, and at the complex in Goldstone, Calif. These bearings were found to be in good condition.
Smaller antennas can substitute for most of the tracking and communication done with the 70-meter (230-foot) antenna. Additionally, two 34-meter (111-foot) antennas can be combined to work together to increase the performance. Because of heavy demand on the entire Deep Space Network, not all scheduling requests can be met with Madrid's 70-meter (230-foot) antenna out of service. The scheduling office of the Deep Space Network is working with the NASA Headquarters Science Mission Directorate to set priorities with flight projects that use the network so that coverage can be scheduled for all top-priority times.
The elevation bearings bear the 1.9-million-kilogram (4.1-million-pound) weight of the 70-meter (230-foot) dish. A set of four bearings supports the antenna's weight and allow the antenna to tilt up and down.
