STS number confusing

[cookie8]

The last shuttle mission was STS119 but the current one is STS 125. Could anyone explain to me how these numbers work?

[h0ughy]

i suppose mission numbers are assigned to specific missions - this one obviously got bumped up

[Spanrz]

The number are misson numbers., Yep sure did. This mission was slated to go up before the other one.

STS means "Space Transportation System" and the numbers are the amounts of flights.

The reason was that a couple of months before the mission was going to be launched, the Hubble camera crapped out. It put their service mission schedule up the creek.
So they had to delay servicing it, to work out what repairs they had to do.

Hence why they are mixed up.