US: The launch attempt of the United Launch Alliance Delta IV with the US Air Force’s Global Positioning System IIF SV-1 satellite (GPS IIF SV-1) has been postponed on May 21. Mission managers require additional time to validate the modified approach to monitor the GPS satellite telemetry signal. The Delta IV rocket and GPS IIF SV-1 satellite are safe and secure at this time. The next launch attempt has been set for Monday with a launch window of 11:13-11:31 p.m. EDT. The weather forecast calls for an 80 percent chance of acceptable weather during the launch window.
The first launch effort on May 20 was called off when a problem with ground support equipment was detected during the day.
According to a report published on NASASpaceFlight.com, The GPS IIF programme has already experienced a number of delays – the first launch was originally scheduled for 2006. It is also nearly a billion dollars over budget. In May 2009, the US Government Accountability Office issued a report entitled “Global Positioning System: Significant Challenges in Sustaining and Upgrading Widely Used Capabilities”, which was highly critical of the GPS IIF and GPS IIIA programmes.
The report also showed scepticism that the US Air Force would be able to keep the system above the minimum operational requirement of twenty four spacecraft past this year, as they expect older satellites to begin failing faster than they can be replaced.
For more information, one can read our earlier stories:
Delta IV launch delayed for 24 hours
GPS IIF satellite set for launch May 20
Source: United Launch Alliance