Collection of four limited edition covers with ink notations made by Ken Havekotte using a Fisher Space Pen flown on Apollo 13: one with a KSC launch date postmark, numbered 22/28, with the writing: "This ink, from an ALSEP/Fisher Space Pen, flew to the Moon onboard the Apollo 13 Command Module #109 S/C from April 11-17, 1970"; and a set of three Apollo 13 covers honoring specific dates during the mission, numbered 28/55, each notated, "This ink flown to the Moon onboard Apollo 13!" Also includes a certificate of authenticity signed in the same ink. In overall fine condition. From the collection of aerospace memorabilia specialist Ken Havekotte.