Photos: Gantry retracted from Atlas 5

An experiment-carrying, reusable mini space shuttle operated by the U.S. Air Force will be boosted into Earth orbit Wednesday atop a United Launch Alliance Atlas 5 rocket.

The United Launch Alliance Atlas 5 rocket was transferred from its assembly building to the pad at Cape Canaveral’s Complex 41 today for Friday’s launch of NASA’s Tracking and Data Relay Satellite-M that directly supports the International Space Station and various science missions.

Forecasters predict a 90% chance of good weather for liftoff of a United Launch Alliance Atlas 5 rocket from Cape Canaveral just after sunset Tuesday with a classified payload for the National Reconnaissance Office, the U.S. government’s spy satellite agency.