Apollo Expeditions to the Moon

CHAPTER 11.2


THE MOST AWESOME SPHERE

COLLINS: Day 4 has a decidedly different feel to it. Instead of nine hours' sleep, I get seven - and fitful ones at that. Despite our concentrated effort to conserve our energy on the way to the Moon, the pressure is overtaking us (or me at least), and I feel that all of us are aware that the honeymoon is over and we are about to lay our little pink bodies on the line. Our first shock comes as we stop our spinning motion and swing ourselves around so as to bring the Moon into view. We have not been able to see the Moon for nearly a day now, and the change is electrifying. The Moon I have known all my life, that two-dimensional small yellow disk in the sky, has gone away somewhere, to be replaced by the most awesome sphere I have ever seen. To begin with it is huge, completely filling our window. Second, it is three-dimensional. The belly of it bulges out toward us in such a pronounced fashion that I almost feel I can reach out and touch it. To add to the dramatic effect, we can see the stars again. We are in the shadow of the Moon now, and the elusive stars have reappeared.

 
Striding confidently toward the transfer van that will carry them to the launch pad, Apollo 11 Commander Armstrong leads Collins and Aldrin past well-wishers at the start of their historic voyage. Since they are suited up with helmets in place, they carry portable breathing and cooling systems until they can plug into the environmental-control systems aboard their spacecraft.

As we ease around on the left side of the Moon, I marvel again at the precision of our path. We have missed hitting the Moon by a paltry 300 nautical miles, at a distance of nearly a quarter of a million miles from Earth, and don't forget that the Moon is a moving target and that we are racing through the sky just ahead of its leading edge. When we launched the other day the Moon was nowhere near where it is now; it was some 40 degrees of are, or nearly 200,000 miles, behind where it is now, and yet those big computers in the basement in Houston didn't even whimper but belched out super-accurate predictions.

As we pass behind the Moon, we have just over eight minutes to go before the burn. We are super-careful now, checking and rechecking each step several times. When the moment finally arrives, the big engine instantly springs into action and reassuringly plasters us back in our seats. The acceleration is only a fraction of one G but it feels good nonetheless. For six minutes we sit there peering intent as hawks at our instrument panel, scanning the important dials and gauges, making sure that the proper thing is being done to us. When the engine shuts down, we discuss the matter with our computer and I read out the results: "Minus one, plus one, plus one." The accuracy of the overall system is phenomenal: out of a total of nearly three thousand feet per second, we have velocity errors in our body axis coordinate system of only a tenth of one foot per second in each of the three directions. That is one accurate burn, and even Neil acknowledges the fact.

During the cruise phase there was less work and less tension, although housekeeping and navigational duties still had to be done. Here Aldrin in the lunar module listens to numbers from Houston.


The TV camera with its monitor taped to it was also fired up when work permitted to send back to Earth imagery of itself and of the Moon, as well as homey details in Columbia. TV imagery was good, though poorer than an later missions.

ALDRIN: The second burn to place us in closer circular orbit of the Moon, the orbit from which Neil and I would separate from the Columbia and continue on to the Moon, was critically important. It had to be made in exactly the right place and for exactly the correct length of time. If we overburned for as little as two seconds we'd be on an impact course for the other side of the Moon. Through a complicated and detailed system of checks and balances, both in Houston and in lunar orbit, plus star checks and detailed platform alignments, two hours after our first lunar orbit we made our second burn, in an atmosphere of nervous and intense concentration. It, too, worked perfectly.