Seven commemorative covers, each bearing a stamped cachet honoring the X-15 program and signed in ink by an X-15 pilot: Joe Engle, John B. McKay, Robert White, Milt Thompson, Robert Rushworth (two), and William Knight. In fine condition, with a bit of mild toning to a couple of covers. RRAuction COA.
We use cookies on this site to improve your experience. By using this site, you accept our use of cookies. To learn more, please see our Privacy Policy.