Delta IV, GPS satellite to make third launch try Monday

The third attempt to launch a new Global Positioning System satellite is set for 11:13 p.m. Monday.

The Air Force scrubbed a second attempt early in the countdown Sunday, saying more time was needed to test the fix for a spacecraft telemetry signal problem that scrubbed Friday's first launch attempt.

An Air Force statement said a "modified approach" to monitoring the telemetry signal needed further validation, but did not detail the modification.

There's an 80 percent chance of favorable weather at Cape Canaveral Air Force Station's Launch Complex 37 during Monday's 18-minute launch window.

After Monday, the GPS mission would need to stand down for shuttle Atlantis' planned return at 8:48 a.m. Wednesday before making another attempt. The next opportunity, if necessary, could come as early as Thursday.

On Sunday, the countdown had just picked up from a planned hold at T minus six hours and 15 minutes when the scrub was announced after 5 p.m., as preparations to fuel the Delta IV were in progress.

The launch had been planned for 11:17 p.m.

The spacecraft, called GPS IIF-1, is the first in a new generation of satellites intended to replenish and modernize the GPS constellation.

The IIF program is trying to overcome several years of delays because of technical problems and design changes that have more than doubled its budget, to $1.6 billion, according to the Government Accountability Office.