Mercury-Atlas 7
Mercury-Atlas 7, launched May 24, 1962, was the fourth crewed flight of Project Mercury. The spacecraft, named Aurora 7, was piloted by astronaut Scott Carpenter. He was the sixth human to fly in space. The mission used Mercury spacecraft No. 18 and Atlas launch vehicle No. 107-D.
For the group of astronauts, see Mercury Seven.Mission type
Test flight
1962 Tau 1
295
4 hours, 56 minutes, 5 seconds
122,344 kilometers (76,021 mi)
3
Mercury No.18
1,350.0 kilograms (2,976.2 lb)
1
Aurora 7
May 24, 1962, 12:45:16 UTC
Atlas LV-3B 107-D
May 24, 1962, 17:41:21 UTC
North-east of Puerto Rico, Caribbean Sea
154 kilometers (83 nmi)
259 kilometers (140 nmi)
32.5 degrees
88.63 minutes
May 24, 1962[2]
The flight was for three Earth orbits, essentially a repeat of John Glenn's Mercury-Atlas 6. However, a targeting error during reentry took the spacecraft 250 miles (400 km) off-course, delaying recovery of Carpenter and the spacecraft for an hour. Carpenter was held responsible, at least in part, for the landing error. Carpenter left NASA for the Navy SEALAB program in 1964.
Pilot[edit]
The original pilot selected for Mercury Atlas-7 was to have been Deke Slayton, with Schirra as his back-up. However Slayton was removed from flight status after the discovery of cardiac dysrhythmia during a training run in the g-loading centrifuge. Slayton had chosen the name Delta 7 for the spacecraft, as this would have been the fourth crewed flight and Delta (Δ) is the fourth letter in the Greek alphabet.[3] Instead of using Schirra who was backup, it was decided to give the mission to Carpenter, who was the backup crew for Mercury-Atlas 6, had trained with John Glenn, and was considered the best-prepared astronaut. When Carpenter was given the mission, he renamed it Aurora 7 for the open sky and the dawn, symbolizing the dawn of the new age. The number Seven was also chosen for the Mercury 7 astronauts. In addition, Carpenter's home address in his childhood was the corner of Aurora Ave. and Seventh St. in Boulder, Colorado, although at a talk he gave at the Boulder Theater in 2003, Carpenter admitted that he never made the connection between the Aurora 7 spacecraft and his old address until friends pointed it out to him after he made the flight.[4][5]
Mission highlights[edit]
Preparation[edit]
Mercury spacecraft No. 18 was delivered to Cape Canaveral, Florida on November 15, 1961. While under checkout, the crew changed the periscope and also worked on the drogue parachute to prevent it from firing prematurely as had happened during the previous flight. In addition, a device known as a "low-level commutator" was added, to measure the temperature around the capsule, recording temperature data from 28 positions on the spacecraft.[5]
Atlas vehicle 107D was rolled out of the Convair factory in San Diego, California on February 25, 1962. It was delivered to Cape Canaveral on March 6.[8]
Changes made to Atlas 107D over Glenn's booster were minor. It had been agreed that the insulation blanket in the tank bulkhead was unnecessary and would be removed on subsequent Mercury-Atlas vehicles, although MA-7 would still retain it. The LOX tank skin was thickened still further due to the growing weight of the Mercury capsule as missions grew longer and more ambitious. A meeting of the Flight Safety Review Board on May 16 discussed the 12 Atlas flights since Glenn's launch and any anomalies on them that were of concern. There had been four major Atlas in-flight malfunctions during this stretch, but three were caused by random quality control defects unlikely to be a concern in the much more tightly supervised Mercury program. More concerning was Atlas 11F, which had exploded almost immediately at liftoff on April 9 and the static firing test of Atlas 1F, which exploded at Sycamore Canyon on May 13. The cause of these two mishaps was as yet unclear, but assumed to be the result of rough combustion, an old problem that had destroyed several previous Atlas vehicles. NASA ultimately decided a rough combustion failure was unlikely to be a concern as Mercury-Atlas vehicles had a three-second hold down prior to launcher release and a different engine start sequence than the Atlas F (as it turned out, the failures on 11F and 1F had an entirely different cause). The explosion of the first Atlas-Centaur shortly after liftoff on May 8 was also a momentary source of concern until postflight analysis found that the Centaur and not the Atlas had been at fault.[5]
The temperature sensor installation and the correction of the drogue parachute circuit delayed the launch until May.[5]
A network of ground stations and ships, called the "Mercury network" was arranged around the globe to provide continuous coverage of the spacecraft. On Mercury-Atlas 7, the network consisted of 15 Mercury sites supplemented by several Atlantic Missile Range (AMR) stations, and the Goddard Space Flight Center.[9] CAPCOMs were operating from different stations around the world to communicate with Carpenter. Gus Grissom was the CAPCOM at Cape Canaveral.[10] Alan Shepard was the CAPCOM at California.[1]
Scientific experiments[edit]
The focus of Carpenter's five-hour mission was scientific. The full flight plan included the first study of liquids in weightlessness, Earth photography, and an unsuccessful attempt to observe a flare fired from the ground.
One of the experiments would include releasing a multi-colored balloon that would remain tethered to the capsule, observing the behavior of liquid in a weightless state inside a closed glass bottle, using a special light meter to determine the visibility of a ground flare, making weather photographs with hand-held cameras, and studying the airglow layer - for which Carpenter would receive special training. The tethered balloon was a 30-inch (760 mm) mylar inflatable sphere, which was folded, packaged, and housed with its gas expansion bottle in the antenna canister. The whole balloon package weighed two pounds. Divided into five sections of different colors - uncolored aluminum, yellow, orange, white, and a phosphorescent coating that appeared white by day and blue by night - the balloon was to be cast off near perigee after the first orbital pass to float freely at the end of a 100-foot (30 m) nylon line. The purposes of the balloon experiment were to study the effects of space on the reflection properties of colored surfaces through visual observation and photographic studies and to obtain aerodynamic drag measurements by use of a strain gauge.[5]