WASHINGTON — The most far-reaching effects of the budget crunch to date have hit home in the U.S. military space program, as the Air Force is delaying and revising plans for its next-generation space-object tracking system while preparing to shut down the current system.

The service cited budget constraints in both cases.

According to an Aug. 15 memo, the Air Force now plans to award the full-scale development contract for its next-generation Space Fence in March 2014, more than a year later than previously planned. The service is also revising the funding profile for the project, which as of July 2012 carried an estimated price tag of $2.4 billion, according to the U.S. Government Accountability Office.

Just three days earlier, the Air Force said it expects to save about $14 million a year by shutting down the current space fence, formally known as the Air Force Space Surveillance System (AFSSS). Consisting of a line of very-high-frequency radars stretching across the southern United States, the AFSSS is a key component of the overall U.S. Space Surveillance Network, which includes other ground- and space-based sensor assets.

In an Aug. 12 press release, the service suggested the AFSSS closure would not compromise its overall space surveillance capabilities and touted the capability of the next-generation system. “When combined with the new Joint Space Operations Center’s high performance computing environment, the new Fence will truly represent a quantum leap forward in space situational awareness for the nation,” Gen. William Shelton, commander of Air Force Space Command, said in the press release.

But in the memorandum for industry posted Aug. 15 on the Federal Business Opportunities website, the Air Force said “due to budgetary constraints” the government would amend its original solicitation for the next-generation Space Fence program to reflect a new funding profile and target date for initial operational capability. A new request for proposals is expected to be issued in November 2013 and a new contract award is anticipated the following March, the memo said.

The contract award had been expected in 2012 or early 2013, but in July, Shelton said the project was being held up due to a Pentagon review of its major acquisition programs. Lockheed Martin Mission Systems and Training of Moorestown, N.J., and Raytheon Integrated Defense Systems of Tewksbury, Mass., have developed competing designs for the Space Fence and had been anticipating selection of a winner to build the system in the coming weeks.

In an Aug. 22 email to SpaceNews, Shelton said new capability will not become available until at least fall 2018. Previously the Air Force expected the initial Space Fence site, an S-band radar located on the Kwajalein Atoll in the Pacific, to be operational in late 2017, budget documents show.

“We are looking forward to the award and fielding of the Space Fence, which will provide enhanced capabilities and increased sensitivity, necessary to maintain situational awareness of threats,” Shelton said in the email. “As our reliance on space grows, our need to track and avoid these threats will also increase.”

The new Space Fence is expected to track objects between 1 and 10 centimeters across that previously could not be seen, according to Brian Weeden, technical adviser at the Secure World Foundation, a nonprofit organization dedicated to space sustainability. The current AFSSS tracks about 22,000 objects bigger than 10 centimeters, said Weeden, a former Air Force officer.

With the next-generation system now five years away and the AFSSS slated to be mothballed in September, Space Command is looking at modified operating modes for some of its other space tracking assets, specifically the Perimeter Acquisition Radar Characterization System (PARCS) at Cavalier Air Force Station in North Dakota and the space surveillance radar at Eglin Air Force Base in Florida.

“Eglin and PARCS enhance the report with more precise data measures that AFSSS cannot. This higher-quality data quality will alleviate the decreased coverage volume from AFSSS,” Shelton said in the email. “When we field the new Space Fence, it will bring to operations the best qualities of sensitivity, capacity and coverage. The Space Fence will not only match the capacity of the AFSSS, but also improve the data quality of our network, providing unsurpassed space situational awareness.”

T.S. Kelso, senior research astrodynamicist at the Center for Space Standards & Innovation, a research arm of orbit-modeling software provider AGI, warned about depending too heavily on the Eglin site.

“With Eglin being the only remaining dedicated space surveillance radar, any outages there would effectively leave us blind — relying solely on the collateral missile warning sites, which are also being considered for cutbacks,” Kelso said in an email. “Any decision to close the AFSSS must be made within this larger context. There are no comparable systems operated anywhere else on the planet to take up the slack.”

The Air Force requested $400 million for the Space Fence for 2014. The House Appropriations Committee, in its proposed defense spending bill, suggested $350 million, citing a “one-year schedule delay.”

In July, Bruce Tanner, executive vice president and chief financial officer of Lockheed Martin, said the company expected the Air Force to issue a Space Fence contract during the third quarter of 2013.

In an email Aug. 22, Rashi Ratan, a Lockheed Martin spokeswoman, said, “We know that Space Fence remains a high priority for the Air Force, and Lockheed Martin is committed to meeting their requirements for this important national security program. Our Space Fence solution offers a scalable, affordable system that can detect, track and catalog more than 200,000 orbiting objects, and will greatly enhance the Air Force’s situational awareness of space.”

Mike Nachshen, a spokesman for Raytheon, referred questions to the Air Force.

Mike Gruss covers military space issues, including the U.S. Air Force and Missile Defense Agency, for SpaceNews. He is a graduate of Miami University in Oxford, Ohio.