problem to relieve the tension on a team. Controllers always work best under pressure, and they are doing well during today’s final exam.
The radar data smoothly corrects the altitude difference in the computer, and as we watch, we see another program alarm. Aldrin calls, “Same alarm, and it appears to come when we have a 1668 up.” (1668 is the LM computer display of time, landing site range, and altitude.)
Bales quickly responds, “We are Go. Tell him [Aldrin] we will monitor his altitude data. I think that is why he is getting the alarm.” This information is quickly passed to the crew. Above all, we have to prevent a rapid string of these alarms, which will cause the computer to go into an idle mode and abort the landing. With pressure mounting on the team, I get on the loop, “Okay, all flight controllers, hang tight. We should be throttling down soon.”
Today we are gobbling up the alarms as they occur. I mentally thank SimSup for the final training run on program alarms. Throttle-down comes uneventfully. LM systems and trajectory are good, and Duke advises the crew they are looking great. As the crew continue to pitch over to the vertical for the start of the landing phase, they select the steerable antenna to assure continued communications.
We seem to gain strength as the problems mount. Again, I repeat, “Okay, everybody, hang tight… seven and one half minutes.” I run out of breath with that statement. Bales comes on the loop. “The landing radar has fixed everything, the LM velocity is beautiful.” Carlton, the LM CONTROL, has been watching the fuel gauging system, and he selects the fuel quantity measuring probe that will be used for giving the crew and control team voice call-outs on “seconds of fuel remaining.” The voice loop calls are now back to the expected traffic levels, and eight minutes after checking with Bales that the landing radar has updated the computers, I start to close out my final mission rules for landing. We have met all of the mission rule requirements. It is time to make the final landing Go NoGo decision.
After the LM pitches toward the landing attitude the computer automatically completes the braking phase and switches to the final approach program. I know we are long, and the crew is now able to verify that the automatic system approach will take them into a large crater. My console telemetry display indicates the LM is about 7,000 feet above the surface, with a descent rate of 125 feet per second. Armstrong now selects a new landing point in the computer to overfly the crater, and Carlton reports that Armstrong has checked out the manual attitude control.
I start around the loop for the landing Go NoGo. I have met all of my rule criteria, and I am sure that controllers have, too. We are about to hand over the control for the final phase to Armstrong and Aldrin. Soon, we will be spectators just like the rest of the world. The controllers respond crisply and again Bales gives a “Go!” that rings through the room. I continue with my final polling. All controllers are “Go!”
With deliberate emphasis, I say,
The intensity increases and all calls become even swifter. They are emotional, but crisp and shorn of excess verbiage. Controllers now report what they are seeing, and Duke starts to choose data from the controllers to send up to the crew. As the LM passes through 2,000 feet, Duke picks up another alarm, this time a 1202, and he advises the crew we copy. Throughout the descent so far we have not seen any discernible effect of the alarms on LM computer performance.
Aldrin does not bother to respond. The control team has gone to a negative reporting mode as seconds become even more precious. Normal reporting stops and controllers report only NoGo conditions, with the exception of Carlton’s fuel-remaining calls. The room is silent, expectant, listening intently to the crew calls: “700 feet, down [descending] at twenty-one… 540 feet, down at fifteen.” During the descent, Buzz Aldrin, the LM pilot, selected landing data from the computer display and called out the critical data to Neil Armstrong, who was piloting the LM. The reports normally consisted of altitude, rate of descent, and forward velocity, although in many cases only the single most critical element was reported.
Carlton calls out in hushed tones, “Attitude hold.” I acknowledge, “ATT hold,” then silence. The crew is searching for a landing site. Duke, in even more hushed tones, states, “I think we better be quiet from here on, Flight!” I respond, “Rog, the only call-outs from now on will be fuel.” My voice loops become silent, the atmosphere electric as we hang on to each of the crew’s words and wait for Carlton’s call. We are within 500 feet of the surface and continuing the descent. We watch displays that the crew cannot see and listen for sounds yet to be uttered. If anyone so much as clears his throat, twenty other voices shush him.
Reflexively, I reach out and grip the handle on the TV monitor with my left hand and think, Damn close! I continue to keep up with my notations in the log. Again, I feel Tindall stir in his chair as he leans forward to look at the displays. It must be hell to be a spectator today. I have to break through the tension. I run a quick status check, “FIDO, are you happy!” “Go, Flight!” “Guidance, how about you? Are you happy?” “Go, Flight!”
The tempo picks up, the crew call-outs of altitude and descent rate increase in frequency. You can almost feel the crew in
In every training run, we would have put it down by now. It is going to be close, damn close, closer than we ever trained for. The voice loops are silent. Then someone unconsciously keys his mike, and for a few seconds you can hear him breathing, then he unkeys. It is quiet, no discussion at all, and in these last few seconds, I feel that every controller, our instructors, program management, and those in the viewing room are mentally on board the LM, feeling for the surface along with
The crew reports, “250 feet, down at two and a half, nineteen forward.” Still near hovering, I think, but moving forward pretty rapidly. They are over a boulder field trying to find a landing spot. I write in my log, “Here we go,” and advise Carlton, “Okay, Bob, standing by for your call-outs shortly.” The crew continues, “200 feet,” then, “160 feet, five down, nine forward.”
“Low level,” exclaims Carlton on the flight director loop. Propellant in the tanks is now below the point where we can measure it. It is like driving your car on empty. Controllers turn their mental clock on. We have 120 seconds or less to land or abort.
Carlton’s backroom controller, Bob Nance, using a paper chart recorder, is mentally integrating throttle usage by the crew and giving Carlton his best guesstimate of the hover time remaining before the fuel runs out. During training, he got pretty good at it and could hit the empty point within plus or minus ten seconds, but I never dreamed we would still be flying this close to empty and depending on Nance’s eyeballs. I wait for Carlton’s next call.
Armstrong is flying and Aldrin is reporting, “100, three and a half down, nine forward.” As the crew passes seventy-five feet, another call comes from Carlton, “Sixty seconds.” I marvel at his calm voice and wonder if he feels the turmoil I am starting to feel. I mentally integrate the time. At seventy-five feet of altitude with a descent rate of two and a half feet per second, we will have about thirty seconds of fuel remaining at touchdown, assuming Nance’s integration is good. It could be a lot closer!
Duke repeats Carlton’s call on the uplink: “Sixty seconds.” There is no response from the crew. They are too busy. I get the feeling they are going to go for broke. I have had this feeling since they took over manual control. They are the right ones for the job. I cross myself and say, “Please, God.”
Carlton’s voice again penetrates, “Stand by for thirty seconds, thirty seconds.” Duke echoes the time on the uplink. The whole mission is now down to the last thirty seconds, assuming we guessed right on fuel.
It is quiet, damn quiet, the silence so great you could hear a feather hit the floor. All the air seems to have been suddenly sucked out of the control room as each controller gasps and then swallows a gulp of air, then holds it for Carlton’s next call.
The crew report almost brings us to our feet: “Forty feet, picking up some dust, thirty feet, seeing a shadow.” They are going to make it! It is like watching Christopher Columbus wade ashore in the New World. Carlton calls, “Fifteen sec…” then stops.
There is a lengthy pause in all crew communications, then, “Contact light… engine stop… ACA out of detent.” It takes me a second to realize the crew is going through the engine shutdown checklist, just as they did in training. It really sinks in when Carlton, in a droll, almost bored voice says, “Flight, we’ve had shutdown.” Duke
