Postal cover bearing a March 30, 1961, Edwards Air Force Base cancellation and stamped X-15 cachet with the text “Record of 169,600 ft.,” signed over the cachet in blue ink by pilot Walker. Scattered toning, an ink correction to the record, stamped address, and slight irregular adhesion to the signature, otherwise fine condition. Any item signed by Walker is quite scarce, even more so in philatelic material. RR Auction COA.
