The launch is now anticipated to take place on Friday after the second postponement in two days.
“Unlucky again,” the Swedish crew member commented on Twitter.
But Fuglesang was not overly disheartened as the setback gave him the chance to have dinner with his family before his flight to the international space station (ISS) which will now occur no earlier than 6.22am on Friday Swedish time.
The first attempt at a launch from Cape Canaveral on Tuesday had been thwarted by adverse weather conditions.
The latest attempt was called off when the fault in the valve emerged after the countdown had begun and as the shuttle’s external tank was being fuelled, according to a statement on Nasa’s website.
Fuglesang and the other six astronauts had not yet boarded the Discovery vessel for what will be the 30th flight to conduct maintenance on the ISS.
Fuglesang is scheduled to make up to three space walks during his stay at the ISS on the mission which has a strong European focus.