STS-51I - Unknown maker

  STS-51-I was the 20th mission of NASA's Space Shuttle program and the sixth flight of Space Shuttle Discovery. During the mission, Discovery deployed three communications satellites into orbit. The mission launched from Kennedy Space Center, Florida, on 27 August 1985, and landed at Edwards Air Force Base, California, on 3 September.

I am unsure of the maker of this patch. It appears very similar to the A-B version however, the lettering is thicker. The stitching is exquisite.