I was approaching Hawaii, and my second sunrise in space. Referring to the flight plan, the Canton Capcom prompted me, before LOS, for an update on the balloon experiment: “Which of the five colors was most visible?”
Carpenter reported: “I would say that the day-glow orange is best.”
Capcom replied: “Roger. For your information, the second sunrise should be expected in approximately 3 to 4 minutes.”
“The Surgeon is after me here,” he added, for another blood pressure check. “Is this convenient?” My in-flight duties at sunrise called for vigorous physical activity, so I waved him off:
“Negative. I won’t be able to hold still for it now. I’ve got the sunrise to worry about.”
He let me alone.
Sunrises and sunsets were extremely busy time-blocks during Mercury flights. There were important measurements to make of the airglow and other celestial phenomena and innumerable photographs to take.
John O’Keefe had some solid hypotheses about the “fireflies” John had seen during his flight. But they remained unexplained. Whatever the critters were, they were particularly active, or at least visible, at dawn, adding to the scientist-pilot’s burden. At 02 49 00 I reported the arrival of a beautiful dawn in space: “I’ll record it,” I told the Canton Capcom, “so you can see it.” As a patrol plane pilot, I had trained to serve as the U.S. Navy’s eyes and ears – a militarily indispensable role. In space, as a Mercury astronaut, I was now the eyes and ears for an entire nation. I felt an obligation to record what few would ever have a chance to see.
I was just beginning to go through my crowded schedule of sunrise-related work when Hawaii took over from Canton, announcing, “Hawaii Com Tech. How do you read me?” prompting me for a short report. The Navy has a one-through-five scale for grading the volume and clarity of voice transmissions. An old Navy quip came to mind, “I read you two by two” – a voice-report short-hand for “too loud and too often.” But I reserved the smart answer and said only, “Stand by one. My status is good. My capsule status is good. I want to get some pictures of the sunrise. Over.”
Capcom asked for a fuel consumption report. Carpenter reported that his fuel supplies were 45–62.
The 45–62 figures were the percentages of Aurora 7’s fuel supply. I had less than half my manual fuel supply left; my automatic fuel supplies stood at 62 percent. Not alarmingly low yet, but low enough. Still Kraft, directing the flight from the Cape, later reported that he wasn’t worried: “except for some overexpenditure of hydrogen peroxide fuel,” he wrote in his own postflight analysis of MA-7, “everything had gone perfectly.” I still had 40 percent of my manual fuel, which, “according to the mission rules,” Kraft figured, “ought to be quite enough hydrogen peroxide… to thrust the capsule into the retrofire attitude, hold it, and then to reenter the atmosphere using either the automatic or the manual control system.”
But I myself was running low on water – hadn’t drunk any even after the prompting over Woomera. This was a mistake. I was in good physical condition and could tolerate dehydration, but I still should have been drinking copious amounts of water to compensate for what I was losing through sweat and respiration. Someone, the flight surgeon, directed the Hawaii Capcom to inquire about my water intake:
“Did you drink over Canton? Did you drink any water over Canton?”
Carpenter replied: “That is negative. I will do, shortly.”
The water would have to wait. But Hawaii Capcom persisted: “Roger. Surgeon feels this is advisable.” More cabin and suit temperature readings were asked for and given. It was at this time that Mercury Control, alert to potential problems, had pondered one of my earlier voice reports (at capsule elapsed 02 08 46) about the difficulty I was having, not with the thrusters, but with the ASCS. It directed Hawaii Capcom to have me conduct an ASCS check:
“Aurora 7. This is Capcom. Would like for you to return gyros to normal and see what kind of indication we have: whether or not your window view agrees with your gyros.”
Sixteen seconds passed. I was feverishly working through the sunrise-related scientific work, too busy to drink water, too busy to send a telemetered blood pressure reading, and ground control had just asked me to perform an attitude check. “Roger. Wait one,” I replied.
Mercury Control had chosen an awkward moment to troubleshoot the (intermittently) malfunctioning ASCS. They wanted an attitude check, at dawn, over a featureless ocean while I was busily engaged with the dawn-related work specified in my flight plan. Again, adequate checks for attitude, particularly in yaw, are difficult enough in full daylight over recognizable land terrain, requiring precious minutes of continuous attention to the view of the ground out your periscope and the window. In my postflight report I explained the difficulty.
Manual control of the spacecraft yaw attitude using external references has proven to be more difficult and time-consuming than pitch and roll alignment, particularly as external lighting diminishes… Ground terrain drift provided the best daylight reference in yaw. However, a terrestrial reference at night was useful in controlling yaw attitudes only when sufficiently illuminated by moonlight. In the absence of moonlight, the pilot reported that the only satisfactory yaw reference was a known star complex nearer the orbital plane.
But Mercury Control had requested an attitude check, and I complied, first reporting that I had to get back within “scanner limits,” that is, to an attitude in which the horizon was visible to the pitch horizon scanner. That required more maneuvering, which required more fuel. I was still trying to cram in more observations.
Capcom asked: “Can we get a blood pressure from you, Scott?”
I sent the blood pressure, reported on the transmission, and continued voice reports on the experiments: the behavior of the “fireflies”; the balloon, still shadowing Aurora 7 like a stray animal, was oscillating some. Just before LOS, I reported I was going to “gyros normal. Gyros normal now.” Hawaii Capcom replied: “Roger, TM [telemetry] indicates your-zero pitch.” And then “LOS, Scott, we’ve had LOS.”
Loss of signal. I was moving on to voice contact with Al Shepard, California Capcom, and approaching the start of my final, most perilous circumnavigation of the planet.
Kris Stoever continued:
The pilot of Aurora 7 speeded toward California, where Al Shepard was capcom, in charge of ground communications. Scott first gave Al his short report on fuel, cabin-air temperature, and control mode (“manual, gyros normal, maneuver off”). But then the important issue: the suit steam-exhaust temperatures. They were “still reading,” he told Al dispiritedly, “70 degrees.”
But Al had good news:
“Understand you’re GO for orbit three.”
While the GO business was nice to hear, it was really hot in the cabin, and Scott still had lots of work to do. As it happened, more than the MA-7 cabin temperatures were hot. From all reports, Kraft was full-out fuming as Scott approached the continental United States. The flight director appears to have concluded, erroneously, that the pilot of MA-7 had deliberately ignored his request for an attitude check over Hawaii. Now, in addition to his anxieties about fuel use, Kraft was nursing a grudge about a snub that never took place.