A Delta 4 rocket is poised for blastoff this afternoon from south Vandenberg Air Force Base, where crews this morning retracted the mobile service tower from its place protecting the rocket.
The team is counting down to a liftoff at 4:12 p.m. today from Space Launch Complex-6 on South Base.
Mother Nature appears ready to cooperate with the liftoff attempt - launch weather officers are calling for just a 40 percent likelihood that conditions will force a postponement.
Liftoff has been delayed since Thursday so that crews could analyze a potential problem that they has since been resolved.
The United Launch Alliance rocket will carry a top-secret satellite for the National Reconnaissance Office.