by Gene Kranz
Lunney chimed in, “Keeping the LM buys time. We don’t have a second chance and if we jettison the LM we cut off a lot of options. Whatever we do, we damned well better do it right.”
I wrapped up the discussion: “We should hold on to the lunar module and go around the Moon and take our chances with the LM power. I believe we will come up with a plan that gets us home.”
Debates among flight directors are not uncommon. We all arrived at the flight director position along different paths. Given a few minutes, the rapid pooling of experience is often the quickest way to firm up our direction. The discussion was brief, intense, and conclusive. I wanted to get every option and opinion out on the table before we selected the return path. The Trench was nervous about pulling off a direct abort so close to the Moon. I knew Lunney would fight to the death for the long return after talking to the troops in the Trench. Controllers clustered about the console as we talked, recognizing a decision was imminent. Bostick and Deiterich were joined by my FIDO, Bill Stoval, from the Trench. Lousma crowded in, representing the crews.
I vividly remembered the EVA flap from Gemini 9, when I left instructions on the console about what to do only to have top management intervene, thus putting us on a risky course. With that in mind I was not about to leave the trajectory plan undefined. We had all the players at the console and I did not want to open the subject to further debate. I looked directly at Kraft. “Chris, I don’t trust the CSM service propulsion system. It’s in the back end, where we had the explosion, and we won’t know if it is good until we try it. Then it may be too late. We need to buy some time to think and to build the come-home procedures. I believe we can find the power. Our only real option is to go around the Moon.”
Kraft had been listening; he looked at Lunney and then nodded. Lunney said, “I agree. The direct abort closes out our options. We should keep the lunar module.”
The Trench had been standing by, faces grim, hoping they would not be told to pull off a direct abort at this late time. When they saw the decision coming down in favor of their preferred option, they smiled for the first time in a long while, nodding in agreement and relief. Through some miracle, a burst of intuition, something we had all seen, heard, or felt now told us, “Don’t use the main engine.” To this day I still can’t explain why I felt so strongly about this option.
We did not have much time to debate, and I was glad that there had been immediate agreement. Many people were unaware of the options, but I believed that the systems controllers thought I had made the wrong decision. They favored the fastest way home, a direct abort.
Missions run on trust. Trust allows the crew and team to make the minutes and seconds count in a crisis. In the scramble to secure the command module, we didn’t have a chance to brief the crew or even get their opinion on the return path. In my mind I knew the crew would fight to hang on to the lunar module. I felt Lousma, as their representative, would speak out if needed. Kraft went up to brief the NASA brass, who had congregated in the viewing room, on our plan to get Apollo 13 home. The Trench returned to their consoles to start developing the return trajectory plan and brief their back room. The systems guys would have to find a way back with what we had.
Fifty-three minutes after the explosion, the plan was becoming clear. The retreat to the LM was proceeding, the trajectory path chosen, and the handover to Lunney was accomplished. I signed off in the log at 57:05 mission elapsed time, one hour and ten minutes after the explosion. It had been the longest hour in my life.
When I left the control room the remaining cryo oxygen tank pressure was down to 100 pounds per square inch. Time was running out. In less than two hours the command module would die. The situation was not yet stable, but the direction was clear. Lunney presided over the retreat to the LM, saving as many of the CSM resources as we could. After transferring the navigation data to the lunar module computer, Glynn, with a resigned shudder, told the crew to turn off the CSM systems and the computer.
Walking down to the data room to meet my team, I thought of the work ahead. We had to put together in a few hours a set of procedures that normally would take weeks to work out. We would operate outside all known design and test boundaries of the space systems.
The White Team (called the Tiger Team by the media) assembled at 10:30 P.M. CDT in the data room on the second floor. The room was large, about thirty by thirty feet and essentially bare. The only furniture was gray government tables, two overhead TV monitors, and a single intercom panel. The controllers used the room occasionally for team meetings, systems troubleshooting, and working sessions with design engineers. When I walked into the data room I was greeted by my augmented flight control team. The controllers’ arms were filled with orange-colored recorder paper. They were kneeling on the floor, the paper strewn all over the place. In pairs, controllers marked the time annotation, measuring the squiggly traces and rapidly scanning for anything that could pinpoint the cause of the explosion. The room was noisy and smoky, the tension in the air palpable. Engineers and program office personnel, as well as key managers from Grumman, the LM designer, and North American, the CSM designer, were sitting on the tables, since there weren’t many chairs. It was a working room, used principally when there was trouble. Since we had no shortage of trouble, everybody knew it was the place to be.
There were three pieces to the puzzle of the return journey. The command module was the reentry vessel; it had the heat shield but very limited electrical power. The lunar module, which would be used as the lifeboat, was designed to support two crewmen for two days on the lunar surface and was our source for power, life support, and propulsion. The third piece was the damaged service module, the true extent of the damage still unknown. With these pieces we had to fly around the Moon, perform maneuvers, support three crewmen for more than four days, and then, at the very last moment, evacuate the crew into the command module. Then we had to separate the pieces so they would follow different trajectories for reentry.
Electrical power, water, and oxygen were critical. There was no way to stretch the power unless the Trench came up with options to speed up the return after we passed the Moon. The return plan split into two phases: In less than eighteen hours we needed a maneuver plan and procedures to speed up the return journey. Once this was completed we needed the entry plan sixty hours later. Everything else had to fit in between these two critical events. So far all we had done was to buy the time to give the crew a chance; now we had to deliver. I said a prayer for the crew and the teams that had to do the work.
Walking to the front I motioned to three of my controllers saying, “Aldrich, Bill Peters, and Aaron, come on up front where everyone can see you. The rest of you knock it off and find a place to sit.” I had worked many missions with Aldrich and Aaron and knew their capabilities. Peters, the TELMU on Griffin’s gold team, I knew as one of the best analytic minds in flight control if you gave him a bit of coaching. Some of the controllers rolled up their recorder paper and moved to sit on the tables surrounding the room. Others curled up cross-legged and sat on the floor and still others continued to roll out the records, reading the timing marks and placing notations on the edges.
The room was getting crowded and noisy as even more people tried to force their way inside. Quickly scanning the crowd, and then motioning to my White Team controllers, I said, “We have to cut this team down to size and get some order. There is plenty to do and this room is too full to get anything done. I want the White Team to look around the room and if you see anyone that you don’t need, send them back to their consoles.” Several of the controllers, program managers, and spectators left voluntarily, gingerly stepping around the recorder paper strewn on the floor.
I turned to Chuck Stough, my trusted flight planner. “Chuck, you’re the recorder. I want you to get with the Trench and the flight planners and build me a work plan on every decision we need and when we need to do it.” Then I addressed the people remaining in the room.
“Okay, team, we hav
e a hell of a problem. There has been some type of explosion on board the spacecraft. We still don’t know what happened. We are on the long return around the Moon and it is our job to figure out how to get them home.
“From now on the White Team is off-line. Lunney, Griffin, and Windler will sit the console shifts. We will return only for two major events. The first will be a maneuver, if we decide to do one, after we have passed the Moon. The second will be the final reentry. The odds are damned long, but we’re damned good.
“My three leads will be Aldrich, Peters, and Aaron. Make sure everyone, and I mean everyone, knows the mandate I’m giving them. Aldrich will be the master of the integrated checklist for the reentry phase. He will build the checklist for the CSM from the time we start power-up until the crew is on the water.
“John Aaron will develop the checklist strategy and has the spacecraft resources. He will build and control the budgets for the electrical, water, life support, and any other resources to get us home. Whatever he says goes. He has absolute veto authority over any use of our consumables.
“Bill Peters will focus on the lunar module lifeboat. There are probably a lot of things we have not considered and he will lead the effort on how to turn a two-man, two-day spacecraft into one that will last for four days with three men.
“Whatever any of these three ask of you, you will do.
“Now, I’m addressing myself to the program office and design engineers in the room. Aldrich, Aaron, and Peters need numbers, answers to questions, and unlimited access to your resources. They will ask for things you never thought you would be called on to do and to answer questions you never expected to be asked. I want nothing held back, no margins, no reserves. If you don’t have an answer, they need your best judgment and they need it now. Whatever happens we will not second-guess you. Everything goes in the pot.
“My message to everyone is: rely on your own judgment, update your data as you go along. If you are not the right person, step aside and send me someone who is. When you leave this room you will pass no uncertainty to our people. They must become believers if we are to succeed.”
I moved to the blackboard. “Okay, now let’s get down to work and come up with our initial shopping list. Then I want Aldrich, Aaron, and Peters to select a work area and pull their pieces of the job together.”
In real time I used the same brainstorming techniques used in mission rules or training debriefings, thinking out loud so that everyone understood the options, alternatives, risks, and uncertainties of every path. The controllers, engineers, and support team chipped in, correcting me, bringing up new alternatives, and challenging my intended direction. This approach had been perfected over years, but it had to be disciplined, not a free-for-all. The lead controllers and I acted as moderators, sometimes brusquely terminating discussions with “Close it,” or “It’ll take too much,” or “We’ve tried it before, it didn’t work!” Often the response was simply, “Save it for our last-ditch try.”
With a team working in this fashion, not concerned with voicing their opinions freely and without worrying about hurting anyone’s feelings, we saved time. Everyone became a part of the solution. For the next fifteen minutes, we brainstormed out loud. Astronauts and engineers were assigned to teams, rooms selected, and working schedules arranged. The session concluded with a brief update from the Trench on the trajectory options. Then I took a deep breath and concluded the meeting.
“Okay, listen up. When you leave this room, you must leave believing that this crew is coming home. I don’t give a damn about the odds and I don’t give a damn that we’ve never done anything like this before. Flight control will never lose an American in space. You’ve got to believe, your people have got to believe, that this crew is coming home. Now let’s get going!”
In the control room upstairs, Lunney had completed the evacuation of the crew to the LM and was preparing for a small maneuver that would place the spacecraft on a path to return to Earth. After completing the Tiger Team meeting, I went back to the control room to get a status update from Lunney. Glynn was now concerned about powering down the navigation system. He had been advised by astronauts Tom Stafford and Gene Cernan, in the simulators, about the difficulties of performing an alignment while docked, using the LM optics. The navigation platform (gyros) is aligned using stars and a sextantlike device. Sunlight reflecting off the CSM made it difficult to recognize the navigation stars.
The crew’s report that they could not recognize stars due to the cloud of debris surrounding the spacecraft further convinced Lunney that we needed to keep the LM computer and display system powered up until we completed the get-home maneuver. Then we could power down and coast back to Earth. The risk was high, trading electrical power to keep the computer and navigation system on line against the possibility that we might be unable to realign the navigation platform. Without a navigation platform we could not perform the maneuver to accelerate the return to Earth. If we ran out of power, we could not get into position for reentry. We were playing showdown poker; we needed to get a better hand.
I tracked Aaron down and gave him this new complication, telling him that he should make it his number one priority. Aaron said, “I don’t have to run the numbers all out, but I can tell you that if you take this approach, you will have to power down to a survival-level, limited telemetry, a very late power-up for entry, and the possibility that some of the systems may fail due to the cold. It is going to be tough on the crew. Some of the systems may freeze up.”
“John, the best judgment we have,” I replied, “says that we cannot realign the navigation system. I think this is our only option. Get on it!” Aaron’s problem just got a lot tougher. His group set up their camp in the support rooms adjacent to my home base in the data room. John Aaron would not return to the console until the final shift four days later.
The next set of estimates were grim. We were twenty hours short in electrical power and thirty-six hours short in water for the return trip. I kicked myself for overlooking water as the most critical resource. Water is used for cooling LM equipment, for drinking, and for food preparation. I dug rapidly into a “how goes it” sheet Peters had made for me. We had water for about sixty hours available in the LM descent stage and fourteen hours in the ascent. We weren’t even close. I was now grateful for the time we had spent before the mission in the mission rules, flight planning, and procedures meetings developing options and workarounds for all conceivable spacecraft failures. We knew when the chips were down we could use the command module survival water, condensed sweat, and even the crew’s urine in place of the LM water to cool the systems.
There is no such thing as a first team in mission control. All teams must be balanced, equally competent, equally capable of sustaining the effort. Over the next four days the flight control teams would routinely shift every eight hours, with Lunney, Griffin, and Windler steering the return course. But at this moment the battle for the return of Apollo 13 shifted to the back rooms and factories where the components were assembled and tested. We needed their data and we needed it fast. We needed tests in the laboratories and crews in the simulators to prove the procedures we were writing. Engineers hastily recalled from sleep and still rubbing their eyes were given the challenge to get the tests running, dig out the data, bring up the simulators.
My immediate job now centered on developing the procedures for the get-home maneuver using the engine designed for the lunar landing. The maneuver would have to take place two hours after the CSM and LM passed the lowest point of the orbit around the Moon (pericynthion). My next set of decisions involved determining how aggressively to pursue a rapid return to Earth. The most aggressive option would cut twenty-four hours off the return journey and require jettisoning the damaged service module and using all of the LM descent propellants. Several other options were available and there were advocates of each option. Glynn and I kept our powder dry, abstaining from the debate, knowing Kraft would ultimately turn to us for the final decis
ion. Griffin strongly pushed for any option that would get the splashdown point moved from the Indian Ocean to the Pacific, where we had full recovery capability. We vetoed two faster return options as too time-critical, leaving no downstream options. Some folks lobbied to jettison the service module, but since we had not worked out jettison techniques, that was a moot point.
Almost since the instant of the explosion Glynn and I were pretty much in agreement on not using the main engine. We seemed to be running with some intuitive link that surprised our team members. When we needed to synchronize our thinking we would pass messages via runners or a brief phone call or meeting. Kraft was running interference for the flight directors and we agreed to let the NASA managers play with the options and alternatives. During a crisis every boss wants to get in on the act. Letting them think like flight directors for a few hours kept them out of our hair, and prepared them for when we laid the real plan on the table. The flight directors would get together privately, generally in the second-floor viewing room over a cup of coffee, and discuss our positions before we went to management meetings. The last thing we wanted to do was let the brass think there was any real disagreement in our group or uncertainty about our recommendations.