American manned Mars expedition. Study 1964. Unfavorable Manned Planetary - Interplanetary Roundtrip Expedition profiles were studied under NASA Huntsville contracts to General Dynamics and Douglas in June 1963.
Status: Study 1964.
The studies looked at manned Mars missions at unfavorable mission opportunities (e.g. 1975, 1977). Convair concluded that only conjunction class long-duration 800-1000 day missions were feasible at such opportunities.