40 Years Ago: STS-51C, the First Dedicated Department of Defense Shuttle Mission – NASA https://www.nasa.gov/centers-and-facilities/johnson/40-years-ago-sts-51c-the-first-dedicated-department-of-defense-shuttle-mission/
On Jan. 24, 1985, space shuttle Discovery took off from NASA’s Kennedy Space Center (KSC) in Florida on STS-51C, the first space shuttle mission entirely
Both left and right hand SRBs showed this erosion, the most significant of the program