Laser measurement aids rocket launch

The 164-ft-long FPE raises the rocket vertically, aligns it, and transfers it onto the launch table. Operation is somewhat like a drawbridge, with more than two dozen precision interfaces requiring tolerances of less than 800 mm. The Laser Tracker is accurate to within 10 mm, ± 0.8 mm/m, and works at a range to 230 ft.

During construction of the FPE, the Laser Tracker was set up on the launch pad to measure and locate the interfaces. It projected a beam that locked onto a handheld retroreflective target, which the operator moved over the surface being measured. The beam reflected off the target and retraced its path back to the Tracker to measure distance. Angular encoders measure the orientation of the Tracker's two mechanical axes. Together, the distance and angular measurements provided the exact three-dimensional location of the target. Measurement data, as well as 3D graphics created from the data, are displayed on a PC or laptop connected to the Tracker.

The Laser Tracker helped pinpoint the exact three-dimensional location of the fixed pad erector components at the Cape Canaveral launch pad.

A Boeing Delta IV rocket blasts off from Cape Canaveral, Fla.