failure is out of the question.”
Yardley, who had been conferring with Williams, posed the fatal question: “Chris, what happens if it is valid?”
With only a single data point, the discussion was at an impasse.Williams joined in: “If we come in with the retropack attached, what is the worst thing that can happen to us?” (I could imagine Glenn’s reaction, if he only knew: “What’s this
The debate at the console broke off again as Cooper came on the conference loop to offer his impression of the problems reported by Glenn over Australia. Kraft knew the discussions were bothering his controllers on the floor and motioned the entourage to return to their seats. I noted the clock. The mission was half over and the team needed to make a decision in less than two hours. I made one more trip to my McDonnell engineers, who had been on the phone back to the plant in St. Louis. I doubted they would have any answers prior to entry.
Kraft was again seated at his console when I returned. For a few moments, it seemed that everything had settled down. My console was flooded with Teletype messages and I scanned the most recent arrivals first. The message from the Canton site brought me to my feet and I handed it to Kraft. The message said:
ALL
DE CTN
FM CAPCOM
CTN ADVISED S/C NO INDICATIONS LDG BAG DEPLOY.
S/C RESP DID SOMEONE ASK IF THE LDG BAG WAS DOWN?
CTN RESP WE HAVE BEEN ASKED TO MONITOR LDG BAG AND ASK
IF YOU HEARD NOISES WHEN MANEUVERING.
S/C RESPONSE NEG.
Teletype messages between the tracking stations and MCC are always abbreviated and terse to save transmission time. This message was painfully clear. The Canton Island CapCom (CTN) had inadvertently informed Glenn (S/C or spacecraft) of our concerns.
Kraft had staked out his position long ago: “I don’t worry about things I can’t do something about.” But in this case, he was worrying a great deal. The impasse on entry techniques bothered him. Left to his own he would press on with a normal entry, ignoring the alarm, but Yardley and Faget were two damned good engineers arrayed against him. Williams also had flight test savvy. They were all telling him he should take a different path.
Still, Kraft had picked up the scent. He believed he was on the right track and wanted to buy more time. “I want to give John a complete story,” he explained, “and I need more answers.”
Over Hawaii, Glenn was given the Go for the final orbit. After the discussion with Canton, I was surprised John did not mention his conversation with the CapCom. During his last stateside pass, he continued discussing his attitude control problems, and we provided him with a recommendation for backing up the automatic attitude control.
My roommate, Carl Huss, updated the capsule retrosequence clock to the correct retrofire time for the planned end of the mission landing area. The clocks would automatically initiate the retrofire sequence if the spacecraft attitude was correct when the clock timed out. The mission now coasted into the third and final orbit. Under other circumstances, Huss and Tec Roberts would have been delighted. Their tracking data was solid and the planned retrofire times had not changed by even a second during the last orbit. With the decision time now down to less than an hour, I believed we had all the data we were going to get. Kraft and Williams were facing the lonesome task of deciding what to do. John Glenn’s life, the Mercury program, and America’s future in space were in the balance.
Looking back on this episode, and the other Mercury missions, I find it hard to believe that we did so well. The systems operators did not have the benefit of the massive analytical tools available today. The only computing resources available during the mission were used to process radar tracking data. Compared to the present technology, our computers were the equivalent of a rusty adding machine.
A controller lives or dies based on the information he has at his console. If you lack what you need at liftoff, there is little hope that you will get new information that you would trust during a mission. This realization was the most profound impression branded on me from the Glenn mission. During the final orbit I witnessed the agony and the frustration faced by the controllers and engineers wrestling to help Kraft make the best decision.
There was no right decision that day, nothing in black and white. We could only try to obtain the best answer. At that moment, I also realized that learning by doing was the only way a controller could ever become smart enough to succeed in the tough and unforgiving environment of spaceflight operations.
The last orbit was a stalemate. No more data was coming. The best judgment of the engineers was that there was sufficient attitude control for reentry with the retropack attached. The straps would burn off during entry and should not induce any landing position errors. Kraft restated his position: “It is an instrumentation problem. The heat shield is still attached. If we burn a hole in the damned heat shield we are going to kill Glenn!” Williams, rising to the emotion of the decision, chimed in: “Chris, if you’re wrong we are going to kill him, too.”
The engineers cautioned that if we kept the retropack attached, we needed to confirm that all three retros had fired. If one did not, there was a good chance it would detonate during reentry. Kraft did not comment on this last prediction.
Kraft was still holding out until the last moment, so that he had a complete understanding of the final instructions before he radioed up to John Glenn. The mission was turning into a horse race. Kraft wanted answers from one final test to be performed over Hawaii before he turned the discussion to the entry procedures modifications.
At capsule acquisition, the Hawaii CapCom advised Glenn,
Glenn responded, “Negative. In automatic position did not get a light and I’m back in the off position now, over.”
Kraft turned again to Williams. “Walt, this is the best damned data we can get. The test was negative. We should go ahead with the normal reentry sequence.”
Without waiting for a response, Kraft advised Hawaii, “Tell Glenn we will go ahead with the normal reentry sequence.”
Kraft’s instruction to the Hawaii CapCom surprised Williams. Still not satisfied that the test was valid, Walt continued to question the engineers over the telephone. He was getting a mixed input—the design engineers had conflicting feelings. Stormily closing off the final conference call, he said, “If reentry with the retropack is safe, what do we lose by coming in with the pack on?”
While the debate continued, Glenn had now made contact with the California site, and Huss started the countdown to retro sequence. The count was relayed to the capsule at California by Wally Schirra: “Five… four… three… two… one… MARK.”
Glenn responded, “Retro sequence green.”
Thirty seconds later the retros fired and John Glenn was heading back to Earth. All that was needed was the final decision on whether to retain the retropackage to keep the heat shield in place during the reentry. Schirra said, “Attitude looked good, John. Keep your retros on until you pass Texas.”
Glenn asked several times during the pass about the retropack jettison time. Schirra advised him, “You’ll get the final word over Texas.”
Kraft called Schirra: “California, can you confirm that all three retros fired?” Wally: “Affirmative, Chris.”
In his role as the operations director, Williams leaned toward Kraft, and quietly but firmly said, “That settles it, we’re coming in with the pack on.” Kraft nodded. Williams was the boss and the final decision was made.
Chris got on the voice loop to the Texas CapCom: “Tell John to keep the retros on through entry.”
I had anticipated the decision and had a Teletype message with the procedures already at the site. Glenn would have to override the .05G signal, which changed capsule attitude control modes when capsule reentry accelerations were sensed, and he would need to retract the periscope manually. I handed Kraft the message. Alan Shepard, the MCC CapCom, standing in front of Kraft’s console, nodded affirmatively at its content. Kraft then asked the Texas CapCom, “Texas, do you have the message on entry procedures?”
At acquisition, Texas called the capsule. “This is Texas CapCom,
