Update August 4: Arianespace has announced that they have set a NET date of August 14th to try again for launch.
Update August 2: The Ariane 5 launch vehicle is being returned to the assembly building to replace the troublesome sensor. A new launch date is expected to be announced on August 3rd, according to Arianespace.
Arianespace scrubbed its launch of the Ariane 5 today. The countdown was proceeding smoothly until just over two minutes when the “board” (a screen showing the different launch systems and weather and their status for launch) showed red for one of the launch systems. Teams paused the countdown and tried to resolve the trouble before the 40+ minute launch window closed but were unable to resolve the issue.
A statement later said that a sensor in the first stage liquid hydrogen tank was to blame. In that same statement, Arianespace said that the next launch opportunity would be at 5:30 EDT on Saturday, August 1st, however, at the time of writing, they have not said whether or not the issue had been resolved and they would be able to launch at the next window. This article will be updated as needed.