Chapter 17: Horizon scanner

Theme: March to June 1962. Covers the preparation and flight of Scott Carpenter. This flight provided a good example of what the man could do when the automatic equipment failed, but it also raised a number of questions regarding the flight plans and flight monitoring procedures.

“Aurora 7, Aurora 7, this is California Com Tech, California Com Tech. Do you hear? Over.”

In the control center everyone waits anxiously to hear from Scott. Minutes before, as he was leaving Hawaii station he reported a problem with his attitude control system. Now there are less than two minutes to retrofire. If the spacecraft is not in proper attitude at the time the retro rockets are fired, it will not reenter, but will stay in orbit for days while its oxygen supply gradually runs out.

“Hello California Com Tech. You are loud and clear. How me?” Scott is over the California coast, ninety seconds to retrofire.

“Aurora 7, this is Cap Com. Are you in retro attitude?”

An audible whisper of relief ripples through the control center as Scott reports he is in proper attitude for retrofire. However, his auto pilot is not working; he will have to control attitude manually.

This is the most critical maneuver of the flight. There is only one chance. In previous orbital flights the retrofire had always been controlled automatically. Now the auto pilot has failed and man will have his opportunity to show what he can do.

I am not concerned because I have seen Scott control retrofire time after time in the trainer, but I can see that a number of the engineers in the control center are quite disturbed. They have faith in the auto pilot, but they are less convinced of man’s ability.

Thirty seconds before firing the retro rockets, the retro sequence will begin.

“Chris.” Don Arabian, the capsule engineer is calling to flight director Chris Kraft. “Have him try the ASCS (auto pilot) during retro sequence to see if the orientation mode will hold.”

Just before retrofire the auto pilot shifts into a new mode, and Don apparently feels that in this mode it may hold attitude properly even though it has been malfunctioning before. Chris agrees with him, and sends along the order.

“Retro sequence is green.” Scott’s voice reports the beginning of the critical sequence.

“Check ASCS quickly to see if orientation mode will hold.” From the California station Al Shepard relays Chris Kraft’s order.

High above, Scott reaches down to the control panel and flips a switch. Immediately the spacecraft noses down, out of the proper attitude for retrofire. His right hand whips back to turn the switch off while he pulls at the control stick with his left to raise the nose. The seconds rush by. Four, three, two, one, zero.

Scott fights the controls to bring the spacecraft back into proper attitude. It is almost there, tilted slightly to one side, when he feels the kick of the first rocket. Five seconds later the second rocket fires, and in another five, the third. The control stick swings rapidly while Scott counteracts the action of each retro rocket as it tries to twist the spacecraft one way or the other. His eyes move quickly from the periscope between his knees to the swaying instruments on the panel and on up to the view of the horizon through his window. Finally, all three rockets have burned out.

“How did the attitudes hold, Scotty?”

“O.K., I think they held well, Al.”

In the control center there is a brief cheer. Chris is smiling again.

But now there is another concern. During the retrofire, Scott made use of two manual control systems simultaneously for more positive double authority. As a result he used more fuel than expected, and now one tank is empty. Switching to the other, Scott nurses the attitude of the spacecraft carefully, trying to keep it in the proper orientation for reentry.

At the control center the trajectory specialist reports to Chris that the indicated landing point is two hundred miles farther down range than had been expected. Can there be an error in the computer? No, the answer has been checked and double checked.

Before this message can be sent to Scott, he enters the communications blackout period. Once again tension takes over the control room as we wait for the familiar voice to come over the control center loudspeakers and let us know that he has survived the period of peak reentry heating. But we have forgotten that since he is landing two hundred miles farther away, he will be beyond the range of the spacecraft radio when he comes through the blackout. So nothing recognizable comes from our control center speakers.

Scott is completely alone now, carrying on a one-way conversation with the tape recorder, since no one else hears. Smashing through the atmosphere, the surface outside Scott’s window heats to a glowing green. Smoke and flames can be seen trailing backwards. A small yellow ring marks the point where the flow of hot gases around his cabin converges behind the spacecraft. Now the acceleration builds. Three, four, five g’s. His body is nearly seven times its normal weight, over half a ton.

The attitude control fuel is exhausted and the spacecraft begins to oscillate more and more wildly. Scott reaches up and flicks the switch, deploying the drogue chute. Immediately the little white canopy swings out behind him, and the spacecraft straightens up. Now for the main chute. His right hand moves to the safety switch which keeps the main parachute from being deployed inadvertently. Carefully watching the altimeter, he reaches with his left hand for the manual deploy handle, but it is not needed, for now, through the window, he can see the red and white candy-striped cloth waving back and forth above him.

“Aurora 7, Aurora 7, Cape Cap Com. Over.” A thousand miles to the northeast, relayed by down range aircraft, Gus’ voice comes from the Cape. Weak and static-clogged, it is barely intelligible. But one important message gets through. “Your landing point is two hundred miles long. We will jump air rescue people to you in about one hour.”

Finally with a sudden shock, he is back on earth. Three orbits have taken less than five hours, but because he has gone one-hundredth of an orbit too far, it will be nearly five hours more before he arrives at the Grand Turk debriefing site.