Four official softcover NASA publications for the first four flights of the Mercury program: Results of the First United States Manned Orbital Space Flight, February 20, 1962; Results of the Second United States Manned Orbital Space Flight, May 24, 1962 (NASA SP-6); Results of the Third United States Manned Orbital Space Flight, October 3, 1962 (NASA SP-12); and Project Mercury Summary, Including Results of the Fourth Manned Orbital Flight, May 15 and 16, 1963 (NASA SP-45). In overall fine condition, with sunning to the spines and ownership notations to covers.
