Boeing is making a number of unidentified hardware and software fixes to the core stages for the entire Delta IV launch-vehicle family, to prevent the fuel cavitation problem that stopped the Delta IV Heavy achieving its objectives on its maiden flight last year.
However, the Delta IV Medium scheduled to launch the GOES-N meteorological satellite from Cape Canaveral, Florida in late May will not be modified. The GOES-N launch has been delayed since December 2004. Cavitation was not observed on other Delta IV launches.
GOES-N is the first of a series of three 3,100kg (6,830lb) satellites based on Boeing 601 buses built for the US National Oceanic and Atmospheric Administration. It was originally to have flown on the ill-fated Delta III, which suffered two failures out of three flights between 1998 and 2000 and was then cancelled.
Source: Flight International