NASA upgrades Deep Space Network

NASA upgrades Deep Space Network


Keeping track of manned and unmanned space missions is no simple matter. At any time, dozens of spacecraft'including the Mars Odyssey orbiter, Saturn-bound Cassini orbiter and probes into deep space'are surveying the solar system.

A backup server
at the deep-space telecommunications station in Canberra, Australia, makes
sure data from its many antennas isn't lost.
NASA's Deep Space Network monitors these missions. DSN carries radio communications for NASA spacecraft and collects radio astronomy data and radar observations.

To prevent system failures that could cause data loss, NASA's Jet Propulsion Laboratory in Pasadena, Calif., has upgraded the space network with a data replication and failover system to ensure that scientists remain in contact with the agency's spacecraft.

Antennas are situated at deep-space communications facilities in Goldstone, Calif.; Madrid, Spain; and Canberra, Australia. No matter where a ship is, one, more often two, tracking stations know its position and what it is doing, NASA officials said.

'We now have 24-7 availability for our Deep Space Network satellite tracking systems around the world,' said Wei Ti Chen, a software engineer in the configuration management group of JPL's Telecommunications and Mission Operations Directorate.

Space watch

Chen's department helps monitor all of NASA's space programs. Antennas at the three communications facilities provide telemetry reports for operations throughout NASA.

Until recently, each station used a Microsoft Windows NT server with a Microsoft Visual FoxPro database. But this system lacked failover capabilities. When a server went down, technicians at the tracking stations had to manually transcribe antenna readings and transmit them via e-mail to NASA units that needed the data.

'Technicians had to do everything by hand, and that meant that a lot of reporting didn't happen,' Chen said.

One recent server crash caused two days of downtime. If that had happened during a critical operation such as a launch or repair mission, success would have been jeopardized.

Following the recent upgrades, each of the three Deep Space Network tracking stations now has two Compaq Computer Corp. servers running Windows 2000 Advanced Server. One server is the primary machine, the other is a backup. Both servers run Double-Take, a data mirroring and replication application from NSI Software Inc. of Hoboken, N.J. The software captures changes as they occur on the main server and duplicates them in the backup server.

'We now have a Web-based system to create discrepancy reports from antenna data,' Chen said. 'If a discrepancy repeats, we take a closer look to see what hardware or software needs to be repaired or replaced.

'We figured out the best way to provide 100 percent availability within the budget,' Chen said. 'If a server fails, the other one kicks in after a 20- to 30-second delay, and the Deep Space Network continues to function.'

To upgrade its antenna tracking systems further, JPL has switched to a Microsoft SQL Server 2000 database. SQL Server makes it possible to replicate data between sites.


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