cautious.
I was scheduled to communicate about something or other for a total of seventy-eight times during the fifteen minutes that I was up. And I had to manage or at least monitor a total of twenty-seven major events in the capsule. This kept me rather busy. But we wanted to get our money’s worth when we planned this flight, and we filled the flight plan and the schedule with all the things we wanted to do and learn. We rigged two movie cameras inside the capsule, for example, one of which was focused on the instrument panel to keep a running record of how the system behaved. The other one was aimed at me to see how I reacted. The scientists used the film to compile a chart of all my eye movements, which they related to the position of the instruments I had to watch as each moment and event transpired. On the basis of this data they later moved a couple of the instruments closer together on the panel so that future pilots would not have to move their eyes so often to keep up with things.
One minute after lift-off the ride did get a little rough. This was where the booster and the capsule passed from sonic to supersonic speed and then immediately went slicing through a zone of maximum dynamic pressure as the forces of speed and air density combined at their peak. The spacecraft started vibrating here. Although my vision was blurred for a few seconds, I had no trouble seeing the instrument panel. I decided not to report this sensation just then. We had known that something like this was going to happen, and if I had sent down a garbled message that it was worse than we had expected and that I was really getting buffeted, I think I might have put everybody on the ground into a state of shock. I did not want to panic anyone into ordering me to leave. And I did not want to leave. So I waited until the vibration stopped and let the Control Centre know indirectly by reporting to Deke that it was “a lot smoother now, a lot smoother”.
The pressure in the cabin held at 5.5 psi, just as it was designed to do. And at two minutes after launch, at an altitude of about 22 miles, the Gs were building up and I was climbing at a speed of 3,200 mph. The ride was fine now, and I made my last transmission before the booster engine cut off: “All Systems are Go.”
The engine cut-off occurred right on schedule, at 2 minutes 22 seconds after lift-off. Nothing abrupt happened, just a delicate and gradual dropping off of the thrust as the fuel flow decreased. I heard a roaring noise as the escape tower blew off. I was glad I would not be needing it any longer. I reported all of these events to Deke, and then I heard a noise as the little rockets fired to separate the capsule from the booster. This was a critical point of the flight, both technically and psychologically. I knew that if the capsule got hung up on the booster, I would have quite a different flight, and I had thought about this possibility quite a lot before lift-off. There is good medical evidence to the effect that I was worried about it again when it was time for the event to take place, for my pulse rate reached its peak here – 138. It started down again right away, however. (About one minute before lift-off my pulse was 90, and Gus told me later that when he and John Glenn saw this on the medical panel in the Control Centre, they figured that my pulse was a good six points lower than Gus thought his was and eight points lower than John’s.) Right after leaving the booster, the capsule and I went weightless together and I could feel the capsule begin its slow, lazy turnaround to get into position for the rest of the flight. It turned 180°, with the bottom end swinging forward now to take up the heat. It had been facing down and backwards. The periscope went back out again at this point, and I was supposed to do three things in order: (1) take over manual control of the capsule, (2) tell the people downstairs how the controls were working, and (3) take a look outside to see what the view was like.
The capsule was travelling at about 5,000 mph, and up to this point it had been on automatic pilot. I switched over to the manual control stick, and tried out the pitch, yaw and roll axes in that order. Each time I moved the stick, the little jets of hydrogen peroxide rushed through the nozzles on the outside of the capsule and pushed it or twisted it the way I wanted it to go. When the nozzles were on at full blast, I could hear them spurting away over the background noise in my headset. I found out that I could easily use the pitch axis to raise or lower the blunt end of the capsule. This movement was very smooth and precise, just as it had been on our ALFA trainer. I fed the yaw axis, and this manoeuvre worked, too. I could make the capsule twist slightly from left to right and back again, just as I wanted it to. Finally I took over control of the roll motion and I was flying Freedom 7 on my own. This was a big moment for me, for it proved that our control system was sound and that it worked under real space-flight conditions.
It was now time to go to the periscope. I had been well briefed on what to expect, and I had some idea of the huge variety of colour and land masses and cloud cover which I would see from a hundred miles up. But no one could be briefed well enough to be completely prepared for the astonishing view that I got. My exclamation back to Deke about the “beautiful sight” was completely spontaneous. It was breathtaking. To the south I could see where the cloud cover stopped at about Fort Lauderdale, and that the weather was clear all the way down past the Florida Keys. To the north I could see up the coast of the Carolinas to where the clouds just obscured Cape Hatteras. Across Florida to the west I could spot Lake Okeechobee and Tampa Bay. Because there were some scattered clouds far beneath me I was not able to see some of the Bahamas that I had been briefed to look for. So I shifted to an open area and identified Andros Island and Bimini. The colours around these ocean islands were brilliantly clear, and I could see sharp variations between the blue of deep water and the light green of the shoal areas near the reefs. It was really stunning.
But I did not just admire the view. I found that I could actually use it to help keep the capsule in the proper attitude. By looking through the periscope and focusing down on Cape Canaveral as the zero reference point for the yaw control axis, I discovered that this system would provide a fine backup in case the instruments and the auto-pilot happened to go out together on some future flight. It was good to know that we could count on handling the capsule this extra way – provided, of course, that we had a clear view and knew exactly what we were looking at. Fortunately, I could look back and see the Cape very clearly. It was a fine reference.
All through this period, the capsule and I remained weightless. And though we had had a lot of free advice on how this would feel – some of it rather dire – the sensation was just what I expected it would be: pleasant and relaxing. It had absolutely no effect on my movements or my efficiency. I was completely comfortable, and it was something of a relief not to feel the pressure and weight of my body against the couch. The ends of my straps floated around a little, and there was some dust drifting around in the cockpit with me. But these were unimportant and peripheral indications that I was at Zero G.
At about 115 miles up – very near the apogee of my flight – Deke Slayton started to give me the countdown for the retro-firing manoeuvre. This had nothing to do directly with my flight from a technical standpoint. I was established on a ballistic path and there was nothing the retro-rockets could do to sway me from it. But we would be using these rockets as brakes on the big orbital flights to start the capsule back towards earth. We wanted to try them on my trip just to see how well they worked. We also wanted to test my reactions to them and check on the pilot’s ability to keep the capsule under control as they went off. I used the manual control stick to tilt the blunt end of the capsule up to an angle of 34° above the horizontal – the correct attitude for getting the most out of the retros on an orbital re-entry. At 5 minutes 14 seconds after launch, the first of the three rockets went off, right on schedule. The other two went off at the prescribed five-second intervals. There was a small upsetting motion as our speed was reduced, and I was pushed back into the couch a bit by the sudden change in Gs. But each time the capsule started to get pushed out of its proper angle by one of the retros going off I found that I could bring it back again with no trouble at all. I was able to stay on top of the flight by using the manual controls, and this was perhaps the most encouraging product of the entire mission.
Another item on my schedule was to throw a switch to try out an ingenious system for controlling the attitude of the capsule in case the automatic pilot went out of action or we were running low on fuel in the manual control system. We have two different ways of controlling the attitude of the capsule – manually with the control stick, or electrically with the auto-pilot. In the manual system the movement of the stick activates valves which squirt the hydrogen peroxide fuel out to move the capsule around and correct its attitude. We can control the magnitude of this correction by the amount of pressure we put on the stick. The auto-pilot works differently. It uses an entirely different set of jets – to give us a backup capability in case one set goes out – and a separate source of fuel. But the automatic jets are not proportional in the force that they exert. This gave the engineers an idea: they created a third possibility, which they call “fly-by-wire”, in which the pilot switches off the automatic pilot, then links up his manual stick with the valves that are normally attached to the automatic system. This gives him a new source of fuel to tap if he is running low, and a little more flexibility in managing the controls. The fly- by-wire mode seemed fine as far as I was concerned, and another test was checked off the list of things we were out to prove.
We were on our way down now and I waited for the package which holds the retro-rockets on the bottom of the capsule to jettison and get out of the way before we began our re-entry. It blew off on schedule and I could
