While NASA's Deep Space Network, an aging array of giant antennas used to communicate with spacecraft beyond low Earth orbit, is handling its current workload, upgrades are sorely needed before many more new missions are launched, according a U.S. Government Accountability Office (GAO) report due to be released May 22.

The 29-page reports says the Deep Space Network has a "deteriorating infrastructure and a limited capacity to serve additional missions. Systems infrastructure, which has been marked by extensive deferred maintenance, is aging and likely to become increasingly fragile and subject to breakdown at a time when demand is anticipated to increase. The potential exists for the loss of scientific data that would be difficult, if not impossible to replace."

A copy of the report, "NASA's Deep Space Network: Current Management Structure is not Conducive to Effectively Matching Resources with Future Requirements," was provided to Space News by an aide to U.S. Rep. Mark Udall (D-Colo.), who asked the GAO last year to undertake the study. In a written statement, Udall, the ranking Democrat on the House Science space and aeronautics subcommittee, called the report "a wake up call that a vital national asset is at risk - one that will be critical to the success both of NASA's future deep space science missions as well as the President's Vision for Space Exploration."

The Deep Space Network was established in 1959 and today consists of 70-meter and smaller communications antennas located at three major sites around the world -- Goldstone, Calif., Canberra, Australia, and Madrid, Spain. The network, which is managed by the Pasadena, Calif.-based Jet Propulsion Laboratory, supports on average of 35 to 40 missions per year. That number is expected to double by 2020, according to the GAO report, as new missions are launched and existing missions operate longer than planned. As a result, the report says, "new customers find they must compete for this limited capacity, not just with each other, but also with legacy missions extended past their lifetimes, such as NASA's Voyager, that nonetheless return valuable science." Voyager was launched in 1977 but remains in service and continues to require Deep Space Network services.

Illustrating the report are photographs GAO officials took of a corroded dish antenna, deteriorating roadways and a leaky building at the Goldstone facility, the only Deep Space Network location the GAO officials visited in the course of their 11-month investigation, which concluded in April. According to the report, NASA has "consistently deferred about $30 million in [Deep Space Network] maintenance projects each year" since 2002. The report says roadway, water and electrical projects often are repeatedly put off as the need for new repairs to mission critical systems crop up unexpectedly.

Many parts of the Deep Space Network's infrastructure are "showing their age" and proving increasingly prone to equipment breakdowns and other disruptions that have caused the loss of science data during routine mission operations and critical events. Goldstone, which has some of the oldest equipment in the systems, is down an average of 16 hours a week for routine maintenance associated with aging, according to the report.

The GAO report details several recent instances where maintenance issues were implicated in communications drop outs that resulted in loss of mission coverage or scientific data. For example, during a critical event for the Deep Impact mission on July 4, 2005, corrosion on the 70-meter dish in Madrid caused an unexpected disruption in service that forced program managers to shift to back up antennas, forcing other users off the system for a period. At Goldstone in October 2005 multiple antennas went down for several hours due to a power disruption traced back to a corroded power line, resulting in an unquantified loss of scientific data. A failed network server in November 2005 caused the Stardust, Mars Reconnaissance Orbiter, Mars Odyssey and Mars Global Surveyor missions to lose a total of 241 minutes of coverage during the disruption.

The report also found that "[The Deep Space Network's] future utility is also in question because NASA currently has no mechanism in place to match funding for space communications assets with program requirements, such as infrastructure and technology development needs, from an agency wide perspective." The report says NASA needs to do a better job coordinating the investments that its various programs make in communications capabilities to avoid expenditures that "undercut broader agency goals." It cites as an example the Solar Dynamic Observatory mission, a Goddard Space Flight Center-led program that invested in its own communications antennas in recognition that the Deep Space Network could not provide the services it needs. "Such duplication undermines the original intent of [The Deep Space Network] to be an efficient, single network for NASA's deep space communications on Earth," the report says.

NASA largely concurred with the GAO's findings and recommendations and said it already had a plan in place for identifying all near-term and long-term Deep Space Network requirements. NASA Deputy Administrator Shana Dale, in a written response included in the GAO report, said NASA shares the GAO's concerns about the future capacity and capabilities of the Deep Space Network but was concerned that the report may create the "wrong impression" that the Deep Space Network is not currently meeting mission demands. "In fact, NASA has never lost a mission due to issues associated with the Deep Space Network," Dale wrote. "More importantly, no mission has been unable to meet its mission requirements due to a lack of capability in the [Deep Space Network]."