Pilot Workload, Fuel Became A Challenge As He Conducted Experiments And Flew The Spacecraft
By Wes Oleszewski
On the 20th day for February, 1962 John Glenn became the first American to orbit the Earth. Three months later, astronaut Scott Carpenter was prepared to do it again. His project Mercury spacecraft had been christened Aurora 7. Considering the everlasting fame and notoriety that Glenn's flight generated, Scott Carpenter's flight would be known throughout the years mostly for one thing in particular; the fact that his spacecraft overshot the landing point by 250 miles. A few of the people involved in the Aurora 7 mission have, in their autobiographical accounts of the era, attempted to blame Carpenter for the landing overshoot. At least one person has gone as far as to imply that he was incompetent as an astronaut. When you read this article you will likely see things much differently.
In the original project Mercury schedule Glenn's flight, MA-6, and the next flight, MA-7 were to be identical missions lasting three orbits of the Earth. At that time NASA was being extremely careful with its orbital test flight program and its astronauts. The ideal was to get up, fly the vehicle and get back down without any extraneous tasks. In the wake of the success of Glenn's three orbit flight there came a relaxation in that way of thinking and that opened the doors to some new areas of thinking. It was felt that now that we could fly into space it was time to add a large degree of scientific study onto future flights. All of this started to be dumped upon the original pilot assigned to MA-7… Deke Slayton. In his autobiography "Deke!" he said about the push to inject scientific experiments into the flight plan, "… everybody and his brother came out of the woodwork… One damn thing after another. I had my hands full trying to resist it." Fortunately for Slayton this problem
went away about a month after Glenn's flight. It was then that he was removed from flight status due to what was then considered to be a heart irregularity. It would be up to the next pilot to handle the new "science" workload- that pilot turned out to be Scott Carpenter.
No one in NASA management bothered to consider the fact that Mercury had only flown once into orbit as a manned spacecraft. This was a new vehicle in a new place for humans, it was flight test on the highest order and no place to be loaded down with all sorts of experiments. Additionally, unlike Slayton, Scott Carpenter was enthusiastic about adding all of the "science." As it turned out this mixture of a new program, a new spacecraft and a three orbit flight peppered with experiments was an unhealthy combination.
The experiments added into the MA-7 flight included a multicolored balloon released from the spacecraft for observation and photographic purposes, a ground flare visibility experiment, observations of the air glow layer of the atmosphere, a "zero gravity experiment" consisting of three glass balls are small amount of liquid in them, a laundry list of photographic experiments and assorted star sightings and measurements of star brightness as well as personal observations of auto kinesis and spacecraft reaction to movement of arms and legs within the cabin. It's important here to note that prior to John Glenn's flight NASA management was so concerned about his workload that they didn't even want him to take a camera. In fact, Glenn had to go out and buy his own camera to use on the mission. In preparation for the mission, Carpenter had spent 70 hours and 45 minutes in the simulator training for his specific flight and almost none of that time concerned working with the experiments, while at the same
time conducting spacecraft operations.
At 07:45:16 EST on the 24th day of May 1962 the MA-7 flight lifted off from Cape Canaveral. The Atlas booster performed perfectly and Aurora 7 was inserted into the correct orbit. Then at 08:27 into the mission Carpenter reported that he was “ ... beginning to unstow the equipment.” Shortly after that the astronaut fulfilled the first of his non-flying tasks by taking a series of photographs of the expended Atlas booster. By the 16:19 point mission the first hints of a problem that would plague Carpenter throughout the mission appeared. Carpenter reported "I think my attitude is not in agreement with the instruments." What he was seeing was a beginning of a degradation in his ASCS (automatic stabilization and control system). Just 3 minutes later the first signs of the pilot being overloaded began to show. While in contact with the Canary Islands station and receiving a read-up of times for sunset and sunrise, Carpenter was too busy working with his camera and was unable to copy the
numbers. Although he had practiced that moment of flight many times in the simulator, he had never been required to do the task in zero gravity while wearing a pressure suit and gloves and manipulating a camera that had never been designed to be manipulated under those conditions. Further evidence of him beginning to be overloaded came at the next station passage at Kano, Nigeria. When asked if he was doing his gyro caging procedures Carpenter reported, “I am a little behind in the flight plan at this moment. I have been unable at this time to install the MIT film. I finally have it. I'll go through the gyro caging procedures very shortly.” That was at 26 minutes and 37 seconds into the mission, and Carpenter was already falling behind. None of this was actually Carpenter's fault, he reported after the flight that the procedure for caging the gyros, although practiced in the simulator, was not done with live equipment and a visual presentation. He found that procedure, which he had done
often, now ate up valuable time and had a similar difficulty to loading the film in out of the camera with the spacesuit and gloves on. Likewise he found that there was nowhere near enough time to allow for the transition from one activity, or experiment to another. Ultimately Carpenter was forced to stow the camera, forgo the horizon pictures and focus his efforts on the gyro caging procedures. Later on this first orbit he was unable to perform an observation to measure the oscillation of Venus as it came through the horizon. The simple act of removing the equipment and getting it set to go with gloves on cost so much time that by the time he had the equipment set Venus was well above the horizon. As Carpenter focused on the Venus experiment he inadvertently left his automatic and manual thrusters on. In the Mercury capsule this "double authority" consumed fuel at a huge rate. Fortunately Carpenter caught the error relatively quickly, but it still cost him far too much fuel. During his first orbit
Carpenter reported three times that he was behind schedule for flight activities.
Early into the second orbit over the Canary Islands station Carpenter was told that mission control was worried about his auto fuel and manual fuel consumption he reported back that he was concerned too and he would try and conserve fuel. As if to add to the workload, telemetry concerning the temperature of Carpenter's suit continued to give ground controllers false indications. Thus at nearly every reporting station the controllers would read up their numbers which Carpenter would debate. At one point they showed a suit temperature of 102° while Carpenter himself sat comfortably in about 74°. Over the Indian Ocean Carpenter figured out that his ASCS system, that he had been relying upon to conserve fuel, was probably acting up and may be costing him additional precious fuel instead.
Shortly after the passing out of range of the Indian Ocean tracking ship, Carpenter deployed a small tethered “balloon” from his spacecraft did some recording on his onboard tape recorder. He was making notes as to his current laundry list of issues- from his suit temperature to his doubts about the ability of the Aurora 7 spacecraft to hold its stability. He also stated quite flatly, “I have gotten badly behind on the flight plan now.”
When Carpenter came into range of the Muchea, Australia tracking station his Capcom was Deke Slayton who passed on and order as well as a stern warning from mission control. "We suggest you go to manual at this point and preserve your auto fuel." Then, following some standard banter about the astronaut’s general condition Slayton warned, "For your information, Cape informs that if we don't stay on manual for quite a spell here, (we) will probably have to end (on) this orbit." What this was in effect saying was that Carpenter’s decision to remain on auto was incorrect. The ASCS was clearly malfunctioning and in doing so draining Aurora 7’s fuel. Fortunately the mission had just moved into a phase where drifting flight was required. Carpenter switched to manual, took his hands off the controls and begin to drift in what Wally Schirra called “chimp mode.”
For almost the complete remainder of his flight Scott Carpenter simply drifted along the orbital path in which he had been inserted. In looking at the fuel consumption charts from the post flight is clear that almost any maneuvering at this point would have run him out of fuel. Aboard Aurora 7 the auto fuel warning light had been on for such a long time that Carpenter actually covered it with a piece of tape to keep it from annoying him.
Passing over Hawaii something cropped up that drew Scott Carpenter's attention- perhaps more than it should have. Back during John Glenn's historic flight he had discovered something he called "fireflies" swirling around his spacecraft. The single observation ignited a debate in the science community as to exactly what these little white objects, officially named "space particles," might be. Some people went as far as to speculate that these so-called fireflies may actually be living creatures. So far, in the mission of Aurora 7 Carpenter had seen only a very few individual particles that seem to drift by. Now as the astronaut moved in the cabin to attempt to cage and test his gyros he suddenly saw a great number of the "fireflies" outside his window. "They definitely look like snowflakes this time." Carpenter reported. He then added that he would attempt to photograph the particles.
Given a "Go" for his third and final orbit, Carpenter's next task was to jettison the "balloon" that he had deployed earlier in his flight. The balloon experiment, which was to investigate visual phenomena in the space environment, simply didn't work out. Using a 30 inch Mylar sphere that was to be inflated to 900 PSI, the experiment required the astronaut to observe panels on the balloon painted orange, white, silver, yellow and phosphorescent. The balloon itself was attached to a 100 foot nylon line. On the other end it was attached to the spacecraft with a "strain gauge." It was hoped that measurements of the balloon’s tension on the capsule could be measured. Additionally it was hoped that the balloon, as it unfolded, would dispense a quantity of 1/4 inch Mylar discs or "confetti" that had been placed into the folds when the balloon was packed. Officially the description of the experiment was described as: "The astronaut will observe the operation from the deployment sequence, through
tethering, to release and separation, and any oscillations or gyrations will be noted. Photography of angular displacement, the various colors, and the confetti dispersion will be provided for correlation with visual responses. The astronaut will orient the spacecraft in order to track the balloon’s trajectory after it is released and photographs during this phase are requested when distances are recorded." Scott Carpenter did not have the camera dexterity or the fuel required to do any of that. The confetti was never observed, the balloon did not fully inflate, and the tether holding the balloon to spacecraft rarely had any tension. Normally the balloon simply floated randomly around out of sight of the spacecraft window and the tether was often so loose that it looped. Carpenter made only one observation of visual acuity saying that orange was the color most easily seen. Then, at the beginning of the third orbit over Cape Canaveral, when he went through the procedure to jettison the balloon it
failed to let go. It remained attached until reentry when it simply “went away.”
Cape Canaveral Capcom queued Carpenter to give them an observation of the Zero-G experiment as he headed out over the Atlantic on the final orbit. The astronaut dutifully gave his observations which Capcom was unable to clearly receive- so it had to have repeated shortly before Aurora 7 passed out of range. Switching to the capsule’s voice record mode, Carpenter went on to describe zero-G, how it affected his eyes and the lack of auto kinesis. Then Carpenter used some of the time on his last pass over the Atlantic Ocean to un-stow and again load the MIT film into his camera. This time he was determined to get the photographs that he had missed on his first orbit. He also took time to talk more about the fireflies and his own spatial orientation. Oddly, there he was on the brink of running out of fuel that would be critical to maintain his proper orientation during reentry, yet Scott Carpenter's greatest concern was cramming to get all of the "science "done. It is very clear that Scott
Carpenter had fully bought into the added science workload and was determined to get as much done as he could.
It should also be mentioned here that an additional load was placed upon Scott Carpenter by his highly dysfunctional spacesuit cooling system that required constant adjustment and readjustment as well as the reporting of that to ground controllers. Additionally the flight surgeons on the ground required a blood pressure procedure at nearly every station. Carpenter's own confidence and attitude, however, remained quite good, when informed by ground controllers that his respiration data, that was previously not being received on the ground, was finally being received he said, "That's very good. I guarantee I'm breathing."
During the remainder of this third and final orbit Carpenter managed to get a respectable portion of the remaining science experiments checked off of this list. Then at 04:19:22 sunrise occurred and he found himself in the same luminous swarm of fireflies for John Glenn had witnessed. He also noticed that if he rapped his hand on the hatch he could stir up thousands of them. Scott Carpenter had solved spaceflight’s newest mystery- the space particles were nothing more than ice crystals clinging to the capsule.
Approaching Hawaii for the final time the absolute most critical portion of Aurora 7’s flight was about to begin; retrofire. Carpenter was instructed to orient the spacecraft and go to ASCS in preparation for the pre-retro sequence. He accomplished that task, but then diverted his attention to the stowage checklist. A moment later he reported to the ground, "… my control mode is automatic and my attitude standby, waiting minute, I have a problem in…" Ground controllers waited 33.5 seconds before Carpenter continued, "I have an ASCS problem here. I think ASCS is not operating properly." Moments later he returned to fly-by-wire controls and reported that his attitudes did not agree. He was 5 minutes from retrofire. He also reported that he was showing a descent rate of about 12 feet per second. Hawaii ground had just enough time to run through the pre-retro checklist with him before he went out of range. Upon contacting the California station Carpenter reported to Alan Shepard, "I
don't have agreement with ASCS in the window Al. I think I'm going to have to go to fly-by-wire and use the window and the scope." Shepard agreed and told Carpenter he had 30 seconds until retrofire.
Sources tend to disagree on the exact error in yaw that was present during the retro sequence and reentry, but the best figure seems to be 25°. This overall error was a combination of gyro error, ASCS error and the inability of the human eye to precisely align yaw using the Mercury spacecraft window and its periscope. This error, however, was responsible for a large portion of the landing overshoot. Another portion of the overshoot was caused in the mechanical process of triggering the retro rockets. Carpenter reported in his post-flight interview that when the retro countdown reached zero he thought he did not get ignition, so he manually punched all three retro buttons in sequence. The time that it took between his evaluation that he had not gotten retrofire and his ability to react and push the buttons added to the moments it took to ignite the retro rockets all added up to about 3 seconds. That equated to an overshoot of about 20 miles. Carpenter also has commented over the years that he did
not feel that the retro rockets were burning with the strength that John Glenn had described and that too had added to the overshoot. During the actual retrofire Carpenter did report to the ground that there were issues concerning the burn, he said, "okay, I think they held well Al. I think they were good. I can't tell you what was wrong about them because the gyros were not quite right." It is however worth noting that none of the published historical records indicate any anomaly in the strength of the retro rockets burn.
Nearly 10 minutes before Aurora 7 touched the Earth's atmosphere Scott Carpenter ran out of manual control fuel. He now had no choice other than to rely upon this malfunctioning ASCS system during reentry. Just prior to entry interface he reported the fuel was, "… 15 auto, I'm indicating 7 manual but it is empty and ineffective."
During the reentry blackout Carpenter reported into his onboard recorder, "I've got the orange glow. I assume we are in blackout now." He put out a blind call to Gus Grissom at the Cape but got no return. "There goes something tearing away." He continued to describe, "okay. I'm setting in a role rate at this time. Going to AUX damp. I hope we have enough fuel. I get the orange glow at this time. Picking up just a little acceleration now." Throughout the entire reentry phase Carpenter's ASCS kept him alive with a lot of help from Max Faget (pronounced “Fa-jay”). He was the primary designer of the Mercury capsule and with great sense of forethought Max Faget designed the capsule with its center of gravity offset so that at any time in freefall within the atmosphere the capsule would always orient itself blunt end forward. So, even when Aurora 7’s tanks were empty and its thrusters inert it still dropped through the atmosphere in a relatively stable manner. There was, however, a fair
degree of oscillation in the upper atmosphere and in order to dampen that out Carpenter wisely elected to manually deploy the drogue parachute. At the 10,000 foot altitude preset in the spacecraft’s barostats the main parachute deployed, reefed and then fully opened to lower Aurora 7 to a safe splashdown.
On his way down to the splashdown point some 250 miles off target, Carpenter made broken contact with Gus Grissom at Cape Canaveral. There was just enough time for both to understand that his condition was good, his descent normal, and he was way off target. Following splashdown Carpenter did exactly what he was trained to do. He exited the spacecraft through the upper bulkhead, tossed his life-raft into the water, jumped into the ocean, climbed into the raft and waited for the rescue force to come and pick him up. What followed was what Walter Cronkite once described as, "perhaps NASA's greatest blunder in the history of manned spaceflight." From the beginning of blackout until Carpenter himself was recovered nearly 2 hours elapsed and NASA told the news media almost nothing other than the Aurora 7 would likely land much farther downrange than expected. As far as anyone in the news media knew, America had lost its first astronaut.
Of course Scott Carpenter was recovered in terrific condition. He had spent the time sitting in his little yellow life-raft toying with a small fish that was his only company. The news media soon got over NASA's slight and Americans were just happy to have another spaceflight hero.
In conclusion it is pretty easy to see that the primary difficulty with the flight of Aurora 7 was that NASA sent aloft a fairly new type of vehicle on only its second manned orbital mission with a pilot who had been heavily overloaded with tasks other than flying and who had also been ill trained to perform those tasks. Scott Carpenter was overloaded from the first moments of his mission. Thus, who is to blame for any shortcomings in the mission? Chris Kraft in his book "Flight" heavily contends that Carpenter himself was incompetent. In examining the actual flight through historical records rather than self-serving personal whims it becomes clear that Carpenter was indeed competent and that the incompetent persons were actually in NASA management. This can be said because it was NASA management who allowed, what should have been a three orbit test flight, to be infested at the last moments prior to launch by a wide array of "science experiments." NASA management should rightly have frozen the flight
plan and not allowed these extraneous tasks to be injected into the mission.
Now, 50 years later we can look back at those first steps in human spaceflight with a sense of wonder at the courage that it took to climb aboard those tiny spacecraft. The Mercury Seven astronauts were held up as heroes and elevated to a rightful position where they remain to this day. Scott Carpenter did a good job and his flight taught us as much by its shortcomings as by its successes. (All images provided by NASA)