The Mammoth Book of Space Exploration and Disasters

A simple and elegant explanation: day had become night. I was still getting accustomed to moving 17,500 miles per hour.

My flight plan at this point consisted mostly of photography. I had crossed the terminator, which is the dividing line between the dark and sunlit sides of the earth, which caused the light levels to change very rapidly. It was exceedingly important that I photograph the changing light levels. To myself, I read off a lot of camera F-stop and exposure values and was thinking aloud about my next capcom.

Carpenter reported: “It’s getting darker. Let me see. Muchea contact sometime – Oh, look at that sun! F11.”

No one was listening, so I reported to the tape: “It’s quite dark. I didn’t begin to get time to dark adapt… cabin lights are going to red at this time. Oh, man, a beautiful, beautiful red, like in John’s pictures. Going to fly by wire.”

A mysterious red light had cascaded through the window just as I went into a new control mode, as specified in the flight plan. It reminded me of the pictures John had taken through his red filter. But mine was only the reflection of the red cabin lights. “That’s too bad.” I was disappointed.

But then I was visited by Venus.

Carpenter reported: “I have Venus now approaching the horizon. It’s about 30 degrees up. It’s just coming into view. Bright and unblinking. I can see some other stars down below Venus. Going back to ASCS at this time. Bright, bright blue horizon band as the sun gets lower and lower – the horizon band still glows. It looks like five times the diameter of the sun.”

The sun completely disappeared at this point in my flight, and I reported the exact time – 00 4734 elapsed – and my total incredulity.

Carpenter reported: “It’s now nearly dark and I can’t believe where I am.”

My wonder gave way to surprise just a minute later, when I saw how much fuel I had already used.

Carpenter reported: “Oh, dear, I’ve used too much fuel.”

“Oh, dear” – a Noxon expression. Over Australia, I would have voice contact with two different capcoms – the first with Deke Slayton at Muchea, the second at Woomera. Over Muchea, Deke and I talked about our Australian friends, John Whettler in particular, who had been a Spitfire pilot during World War II. Then I said “Break, Break,” which is voice communication procedure meaning “change of subject.” We talked about cloud cover, too heavy for me to see the lights in Perth turned on for my encouragement. Deke consulted the flight plan and saw it was time to send some telemetered blood pressure readings. Then some arcane navigational matters – how to determine attitudes, yaw, pitch, and roll – on the dark side.

Carpenter reported: “You’ll be interested to know that I have no moon, now. The horizon is clearly visible from my present position; that’s at 00 54 44 [capsule] elapsed. I believe the horizon on the dark side with no moon is very good for pitch and roll. The stars are adequate for yaw in, maybe, two minutes of tracking. Over.”

In 1962 we didn’t know what was visible on the horizon, on the dark side without moonlight. So Deke and I were discussing how one might establish attitude control under such unfavorable conditions. I relayed what reliable visual references I had out the window or periscope. In the absence of valid attitude instrument readings during retrofire, the pilot can use such external visual references, manually establishing proper retroattitude control with the control stick. Pitch attitude can be established and controlled easily, with reference to the scribe mark etched in the capsule window. Accomplishing the proper yaw attitude, however, is neither easy nor quick.

Attitude changes are also hard to see in the absence of a good daytime horizon. At night, when geographic features are less visible, you can establish a zero yaw attitude by using the star navigation charts, a simplified form of a slide rule. The charts show exactly what star should be in the center of the window at any point in the orbit – by keeping that star at the very center of your window you know you’re maintaining zero yaw. But there are troubles even here, for the pilot requires good “dark adaption” (or a dark-adapted eye) to see the stars, and dark adaption was difficult during the early flights because of the many light leaks in the cabin. The backup measures (“backup” here meaning human) were absolutely critical to have in place at retrofire – in the event of attitude instrument failure.

Deke and I discussed suit temperature, which like the cabin was hotter than I liked. He suggested a different setting, which I tried. Then Woomera capcom hailed me, and I replied: “Hello, Woomera capcom, Aurora 7. Do you read?” while still in voice contact with Deke, at Muchea. “Roger, this is Woomera,” came the capcom’s voice. “Reading you loud and clear. How me?” Deke was confused. He couldn’t hear Woomera and thought to correct me.