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 feel it go, but the green light which was supposed to report this event failed to light up on the instrument panel. This was our only signal failure of the mission. I pushed the override button and the light turned green as it was supposed to do. This meant that everything was all right.
Now I began to get the capsule ready for re-entry. Using the control stick, I pointed the blunt end downward at about a 40° angle, and switched the controls back to the auto-pilot so I could be free to take another look through the periscope. The view was still spectacular. The sky was very dark blue; the clouds were a brilliant white. Between me and the clouds was something murky and hazy which I knew to be the refraction of various layers of the atmosphere through which I would soon be passing.
I fell slightly behind in my schedule at this point. I was at about 230,000 feet when I suddenly noticed a relay come on which had been activated by a device that measures a change in gravity of 0.05G. This was the signal that the re-entry phase had begun. I had planned to be on manual control when this happened and run off a few more tests with my hand controls before we penetrated too deeply into the atmosphere. But the G forces had built up before I was ready for them, and I was a few seconds behind. I was fairly busy for a moment running around the cockpit with my hands, changing from the auto-pilot to manual controls, and I managed to get in only a few more corrections in attitude. Then the pressure of the air we were coming into began to overcome the force of the control jets, and it was no longer possible to make the capsule respond. Fortunately, we were in good shape, and I had nothing to worry about so far as the capsule’s attitude was concerned. I knew, however, that the ride down was not one most people would want to try in an amusement park.
In that long plunge back to earth, I was pushed back into the couch with a force of about 11 Gs. This was not as high as the Gs we had all taken during the training programme, and I remember being clear all the way through the re-entry phase. I was able to report the G level with normal voice procedure, and I never reached the point – as I often had on the centrifuge – where I had to exert the maximum amount of effort to speak or even to breathe. All the way down, as the altimeter spun through mile after mile of descent, I kept grunting out “OK, OK, OK,” just to show them back at the Control Centre how I was doing. The periscope had come back in automatically before the re-entry started. And there was nothing for me to do now but just sit there, watching the gauges and waiting for the final act to begin.
All through this period of falling the capsule rolled around very slowly in an anti-clockwise direction, spinning at a rate of about 100 per second around its long axis. This was programmed to even out the heat and it did not bother me. Neither did the sudden rise in temperature as the friction of the air began to build up outside the capsule. The temperature climbed to 1230°F on the outer walls. But it never went above 100° in the cabin or above 82° in my suit. The life support system which Wally had worked – oxygen, water coolers, ventilators and suit – were all working without a hitch. As the G forces began to drop off at about 80,000 feet, I switched back to the auto-pilot again. By the time I had fallen to 30,000 feet the capsule had slowed down to about 300 mph. I knew from talking to Deke that my trajectory looked good and that Freedom 7 was going to land right in the centre of the recovery area. But there were still several things that had to happen before I could stretch out and take it easy. I began to concentrate now on the parachutes. The periscope jutted out again at about 21,000 feet, and the first thing I saw against the sky as I looked through it was the little drogue chute which had popped out to stabilize my fall. So far, so good. Then, at 15,000 feet, a ventilation valve opened up on schedule to let cool fresh air come into the capsule. The main chute was due to break out at 10,000 feet. If it failed to show up on schedule I could switch to a reserve chute of the same size by pulling a ring near the instrument panel. I must admit that my finger was poised right on that ring as we passed through the 10,000-foot mark. But I did not have to pull it. Looking through the periscope, I could see the antenna canister blow free on top of the capsule. Then the drogue chute went floating away, pulling the canister behind it. The canister, in turn, pulled out the bag which held the main chute and pulled it free. And then, all of a sudden, after this beautiful sequence, there it was – the main chute stretching out long and thin. Four seconds later the reefing broke free and the huge orange and white canopy blossomed out above me. It looked wonderful right from the beginning, letting me down at just the right speed.