Declining volume on space programs partially offset increased revenue in military and unmanned aircraft systems at Northrop Grumman’s Aerospace Systems sector, which reported $2.586 billion in revenue during the 2012 third quarter, up 5.3 percent from the same period last year, Northrop Grumman reported Oct. 24.

Northrop Grumman said the cancellation of the U.S. Air Force’s Defense Weather Satellite System and reduced volume on classified programs was behind the decrease in space-related sales. Company officials were not more specific, either in a press release or a conference call with analysts.

Operating income for Northrop Grumman Aerospace Systems was $288 million for the three-month period ending Sept. 30, down 2.4 percent from the same period last year. Los Angeles-based Aerospace Systems is prime contractor on NASA’s James Webb Space Telescope and a major subcontractor on the Air Force’s Advanced Extremely High Frequency satellite communications system.

At Northrop Grumman’s Baltimore-based Electronic Systems sector, space-related work was a growth factor, partially offsetting a decline in combat avionics and postal automation programs, the company said. Electronic Systems reported sales for the quarter of $1.707 billion, down 10 percent from the same period last year.

Operating income for the sector, whose major unclassified programs include sensors for missile warning satellites, was $279 million for the period, a nearly 10 percent decrease compared with the 2011 third quarter.