Mercury Atlas 4

Spacecraft:
S/C-8A
Launch Vehicle:
Atlas 88-D
Launched:
13 Sep 1961

⇑ Mission List ⇑

Designation: Mercury A O(U)-1
Description: 1st Mercury Atlas unmanned orbital

Decay Date: 1961-09-13.
USAF Sat Cat: 183.
COSPAR: 1961-A-Alpha-1.
Apogee: 248 km (154 mi).
Perigee: 156 km (96 mi).
Inclination: 32.8000 deg.
Period: 88.40 min.

Mercury-Atlas 4 (MA-4) was launched from Cape Canaveral with special vibration and noise instrumentation and a mechanical crewman simulator aboard in addition to the normal spacecraft equipment. This was the first Mercury spacecraft to attain an earth orbit. The orbital apogee was 123 nautical miles and the perigee was 86 nautical miles. After one orbit, the spacecraft's orbital timing device triggered the retrograde rockets, and the spacecraft splashed in the Atlantic Ocean 161 miles east of Bermuda. Recovery was made by the USS Decatur. During the flight, only three slight deviations were noted - a small leak in the oxygen system; loss of voice contact over Australia; and the failure of an inverter in the environmental control system. Overall, the flight was highly successful: the Atlas booster performed well and demonstrated that it was ready for the manned flight, the spacecraft systems operated well, and the Mercury global tracking network and telemetry operated in an excellent manner and was ready to support manned orbital flight.

The program insignia shown above is post factum.

References:
Grimwood, James M. 1963. Project Mercury: A Chronology. NASA SP-4001.
Encyclopedia Astronautica.
Wikipedia.