Mercury-Atlas 5
Mission type | Test flight |
---|---|
Operator | NASA |
Harvard designation | 1961 Alpha Iota 1 |
COSPAR ID | 1961-033A |
SATCAT no. | 208 |
Mission duration | 3 hours, 20 minutes, 59 seconds |
Distance travelled | 81,902 kilometers (50,892 mi) |
Orbits completed | 2 |
Spacecraft properties | |
Spacecraft | McDonnell Aircraft |
Launch mass | 1,331 kilograms (2,934 lb) |
Crew | |
Crew size | 1 |
Members | Enos |
Callsign | Mercury-Atlas 5 |
Start of mission | |
Launch date | November 29, 1961, 15:07:57 | UTC
Rocket | LC-14 |
End of mission | |
Recovered by | USS Stormes |
Landing date | November 29, 1961, 18:28:56 | UTC
Orbital parameters | |
Reference system | Geocentric |
Regime | Low Earth |
Perigee altitude | 158 kilometers (85 nmi) |
Apogee altitude | 237 kilometers (128 nmi) |
Inclination | 32.5 degrees |
Period | 88.44 min |
Epoch | November 29, 1961[1] |
On the Mercury-Atlas 5 flight Enos became the first chimpanzee, and third primate, to orbit the Earth Project Mercury Mercury-Atlas series |
Mercury-Atlas 5 was an American
History
By November 1961, the
The NASA Public Affairs Office issued a press release prior to the flight, stating "The men in charge of Project Mercury have insisted on orbiting the
Launch and orbit
The flight used Mercury
MA-4's successful flight in September had renewed confidence in the Atlas's reliability, and although an Atlas E test carrying a monkey was lost in a launch failure that November, NASA officials assured the public that it was a different model of booster than the Atlas D used for the Mercury program and that that accident had no relevance here. Although MA-4 had performed well, there was still some concern about high vibration levels during the first 20 seconds of liftoff, so the autopilot on MA-5's booster was modified slightly to correct this problem.
Atlas 93D arrived at CCAS on August 12 and was erected on LC-14 October 6. Prelaunch preparation proceeded relatively smoothly, with a number of minor repairs, including a potentially serious problem with the vernier engines not being bolted in place tightly, which could have resulted in damage to the airframe during launch.
The Range Safety system on Atlas 93D was modified so that a manual cutoff command could be sent to the sustainer engine. This was to prevent the capsule from being accidentally boosted into a higher than planned orbit if engine over-acceleration occurred.
A more compact all-solid state telemetry unit replaced the bulky vacuum tube-based package used previously.
Atlas 93D was the second D-series Atlas to contain the new SMRD (Spin Motor Rotation Detection System), designed to ensure proper gyroscope operation prior to launch.
MA-5 was planned as a close approximation of the upcoming MA-6 crewed orbital mission. Mercury-Atlas 5 would be launched from
Spacecraft #9 had originally been intended to fly on MA-4, but Spacecraft #8 was used instead after having been recycled from the failed MA-3 launch. #9 was the second of the "Mark II" Mercury capsules with a larger square window and explosive bolt hatch, while the older "Mark I" capsule had small port windows and a heavy locking mechanism. Gus Grissom's flight on MR-4 had used a Mark II capsule, but it was necessary to test it on a proper orbital mission to ensure that the large window could handle the much higher heat of reentry there.
On October 29, 1961, three chimpanzees and 12 medical specialists moved into quarters at the Cape to prepare for the flight. The name given to Enos, the chimpanzee selected to fly the MA-5 mission, in Hebrew means "man". Enos's backups were (in order of possible call-up) Duane, Jim, Rocky, and Ham (the Mercury-Redstone 2 veteran). Enos was from Cameroon, Africa (originally called Chimp # 81), and was purchased by the USAF on April 3, 1960. He was about 5 years old at the time of flight and weighed just under 40 pounds (18 kilograms).
On November 29, 1961, about five hours before launch, Enos and his
The turnaround and
At the end of the first orbit, ground controllers noticed the
As the MA-5 passed over the
Problems
As the MA-5 capsule reached the Canton Island station, Mercury Control realized that the attitude control system was malfunctioning. A metal chip in a fuel supply line had caused one of the clockwise roll thrusters to fail. The failed thruster allowed the spacecraft to drift from its normal attitude. This drift caused the automatic stabilization and control system to correct the spacecraft attitude. The spacecraft would swing back into the normal 34° orbital attitude, and the sequence would start again. The spacecraft repeated this drift and correction process nine times before retrofire. It did it once more between retrofire and the receipt of the 0.05 g (0.49 m/s²) light telemetry signal. The remaining thrusters used 9.5 pounds (4.3 kg) of fuel to keep the spacecraft properly aligned during the second orbit. Each loss of attitude cost over 1 pound (0.45 kg) of fuel as compared with the entire first orbit consumption of only 1.5 pounds (0.68 kg).
In addition to the attitude control problems, the environmental control system started having problems during the second orbit. The couch-suit circuit temperature rapidly rose from 65 to 80 °F (18 to 27 °C). This was an indication that the heat exchanger was freezing. The rise in suit temperature caused Enos' body temperature to rise to 99 °F (37 °C), then to 100 °F (38 °C). The medical observers began to worry about the chimpanzee's condition. At 100.5 °F (38.1 °C), his body temperature stabilized. This indicated that the environmental system had started to function again. The cooling system seemed to correct itself, but the attitude problems continued.
As the spacecraft neared Hawaii on its second orbit, medical monitors were willing to let Enos continue the flight for a third orbit. However, the engineering team were concerned about the stuck thruster causing high fuel consumption, so they advised terminating the flight before the capsule ran out of attitude control gas.
There was one more attitude control excursion early in reentry; after that, the rest of reentry and recovery were uneventful. The destroyers
Post-landing
The spacecraft and Enos were both found to have survived the mission in good condition, although the chimpanzee had removed all of the medical electrodes and the urine collection device from his body.
On November 4, 1962, Enos died of dysentery caused by shigellosis, which was resistant to antibiotics of the time. He had been under constant observation for two months before his death. Pathologists at Holloman reported that they found no symptom that could be attributed or related to his space flight a year before.
The Mercury spacecraft and Atlas booster had now been qualified to carry a human into orbit.
See also
- Monkeys and apes in space
- Animals in space
- Splashdown
References
- ^ McDowell, Jonathan. "SATCAT". Jonathan's Space Pages. Retrieved March 23, 2014.
- ^ Swenson Jr., Loyd S.; Grimwood, James M.; Alexander, Charles C. (1989). Woods, David; Gamble, Chris (eds.). This New Ocean: A History of Project Mercury. NASA. SP-4201. Archived from the original on July 13, 2009. Retrieved August 12, 2009.
- ^ "Mercury spacecraft #9 display page on A Field Guide to American Spacecraft website". Archived from the original on May 3, 2009.
This article incorporates public domain material from websites or documents of the