Thunderbirds Are Go

Yuh   Tuesday, August 17, 2004, 23:56 GMT
Can anyone tell me what "Thunderbirds Are Go!" mean? Is "Go" hear a noun or verb??

Dulcinea del Toboso   Wednesday, August 18, 2004, 02:41 GMT
I think it's being used as an adjective, as in the sense of "ready".
Mxsmanic   Wednesday, August 18, 2004, 19:05 GMT
It's an adjective, patterned after the formalized communications of NASA, which used the expression "xxx is go" to indicate "xxx is ready (no errors detected, continue normal procedures," particularly during countdown procedures.