On January 31, 1977, it was taken by road to Dryden Flight Research Center at Edwards Air Force Base, to begin operational testing.
While at NASA Dryden Enterprise was used by NASA for a variety of ground and flight tests intended to validate aspects of the shuttle program.[9] The initial nine-month testing period was referred to by the acronym ALT, for "Approach and Landing Test". These tests included a maiden "flight" on February 18, 1977, atop a Boeing 747 Shuttle Carrier Aircraft (SCA) to measure structural loads and ground handling and braking characteristics of the mated system. Ground tests of all orbiter subsystems were carried out to verify functionality prior to atmospheric flight.
The mated Enterprise/SCA combination was then subjected to five test flights with Enterprise unmanned and unactivated. The purpose of these test flights was to measure the flight characteristics of the mated combination. These tests were followed with three test flights with Enterprise manned to test the shuttle flight control systems.
There are two versions be low, I suspect the top one is the original. They are very similar. The "G" in the top one has a descending vertical.
