alt

Modern reproduction with modern embroidery and nice detail. 

This is probably a commemorative contractor patch. I am not sure if it is "IGA" or "LGA". Modern embroidery style. 

An alternate version of the common ALT program patch. This version appears original while there are some modern reproductions.

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. 

Lion Brothers version. One of the most highly-sought LB patches. Easily recognized by the larger "USA" on the wing as well as cloth back.

The nine-month-long ALT program was conducted from February through November 1977 at the Dryden Flight Research Facility and demonstrated that the orbiter could fly in the atmosphere and land like an airplane, except without power-gliding flight. Two NASA astronaut crews-Fred Haise and Gordon Fullerton and Joe Engle and Dick Truly-took turns flying the 150,000-pound spacecraft to free-flight landings.