45. [Mercury Atlas 4] LAUNCH OF THE FIRST U.S. UNMANNED ORBITAL MISSION NASA, 13 September 1961 Printed 1961. Vintage chromogenic print on fibre-based Kodak paper [NASA image S-61-3249]. With Aerospace Corporation credit stamp and "A Kodak Paper" watermark on the reverse (issued by NASA / Aerospace Corporation, Los Angeles, California). 20.3 x 25.4 cm. (8 x 10 in.) Historical context A superb early colour photograph of the launch of Mercury-Atlas 4, the first successful American unmanned orbital mission. This historic flight demonstrated the Atlas rocket's ability to lift the Mercury capsule into orbit, validated the capsule's autonomous systems, and successfully captured images of Earth from space. The spacecraft completed one orbit before returning safely to Earth. Mission facts: Mercury-Atlas 4, launched September 13, 1961. Altitude ranging from approximately 97 statute miles at its perigee to approximately 140 miles. Retrorockets were fired over the coast of California with the recovery of the spacecraft in the Atlantic Ocean approximately 184 statute miles east of Bermuda in its planned primary landing area. The capsule was recovered in excellent condition one hour and 22 minutes after landing. The spacecraft attained a speed of approximately 17,500 miles per hour upon insertion of the spacecraft in orbit. The Atlas launch vehicle and spacecraft measures 93 feet overall. The diameter of the Atlas is about 10 feet and total thrust at lift-off is 320,000 pounds.