Workers attached the shuttle Atlantis' orange external fuel tank to its solid rocket boosters Monday, accomplishing another key step before the ship's last scheduled blastoff May 14.

A crane lifted the 154-foot-long tank from a test cell into high bay No. 1 inside the Vehicle Assembly Building early Monday.

The day-long process was completed around 6 p.m. EDT Monday as the rust-colored tank was bolted to the shuttle's twin solid rocket boosters stacked atop a mobile launcher platform, a NASA spokesperson said.

Atlantis is scheduled to roll out its hangar at the Kennedy Space Center April 13. After arriving inside the VAB, the orbiter will be hoisted into place and firmly attached to the external tank. Plans call for the fully-assembled shuttle stack to move to launch pad 39A around April 20.

NASA photographer Jack Pfaller took these photos as the external tank was lifted from its test cell to meet the solid rocket boosters inside the VAB.

Photo credit: NASA-KSC

Photo credit: NASA-KSC