The Mammoth Book of Space Exploration and Disasters

John Aaron was the EECOM, the Flight Controller in charge of the Command and Service Module electrical system, and he recalled, “You must remember we did not have a live television view of the launch. I was just looking at control screens which only had data and curves on them. The first thing I realised was we had a major electrical anomaly. But I did recognise a pattern. When we trained for this condition with our simulators it would always read zeros. It so happened that a year before I was monitoring an entry sequence test from the Kennedy Space Center, and the technicians inadvertently got the whole spacecraft being powered by only one battery. I remembered the random pattern that generated on the telemetry system, and for some reason just filed it off to the back of my mind. I did go in the office the next day to reconstruct what happened and found this obscure SCE [Signal Condition Equipment] switch. Few people knew it was there, or what it was for. It was lucky I was the EECOM monitoring the test that night and when it turned out that we had the problem, I happened to be the EECOM on the console. I don’t think any other EECOM would have recognised that random pattern. Our simulators did not train us for it, but I saw it through the procedural screwup. Although the test happened a year before, that pattern was etched in my mind, and I am talking about a pattern of thirty or forty parameters. Instead of reading zeros, one would read six point something, another read eight point something, which were nonsense numbers for a 28 volt power system.”

Aaron quickly called Capcom Jerry Carr on the voice loop to tell the spacecraft, “Flight, try SCE to Aux.” In the spacecraft Bean heard Carr’s instruction, found the Signal Condition Equipment switch, reached across to flip it down to “Auxiliary” which selected an alternate power supply, and order was restored to the television screens.

Aaron recounts, “We now got back live telemetry that was representative of the actual readouts on the spacecraft. We then realised that the fuel cells, the main power source, had been kicked off the line, all three of them, and the whole spacecraft was now being powered by the emergency re-entry batteries in the Command Module, which worked on a lower voltage. They were never designed to carry the full load of the Command and Service Module in a launch configuration. The next call I made was to reset the fuel cells and the voltage was returned to normal.

“I felt quite relieved just to get those guys into low Earth orbit, but I will never forget what Chris Kraft said to me that day, he said, ‘Young man, don’t feel like we have to go to the Moon today, but on the other hand if you and the other systems people here can quickly check this vehicle out and you feel comfortable with how to do that then we’re okay to go, but don’t feel you have to be pressured to go to the Moon today after what happened. We don’t have to go to the Moon today.’

“We then dreamed up a way to do a full vehicle system checkout by improvising and cutting and pasting some of the crew procedures that they already had.”

Nothing serious seemed to have happened, so while still hurtling ever faster up into space, the crew had restored all the systems except the inertial guidance system, and that was set by the 32 minute mark as they shot into the darkness over Africa.

There was some concern that the lightning may have damaged the parachute system in the nose of the Command Module or affected some of the Lunar Module systems at launch, particularly the highly sensitive diodes of the landing radar. With all systems apparently working normally Intrepid homed in to a pinpoint landing on the target, Snowman Crater and the Surveyor III spacecraft, 2,029 kilometres west of the Apollo 11 landing site.

As a panorama of the landing area spread in the window before him, all Conrad could see was a jumbled mass of similar shadows and craters. How could they possibly pick out a particular crater in the time available? Remembering the trouble the experts had locating the Apollo 11 landing point, Conrad felt apprehensive about finding a speck, the Surveyor spacecraft and its particular crater, buried among these thousands of lookalikes.

However their navigation was so accurate the automatic controls were taking them straight to the target area. When Conrad lined up the figures from the computer in the window he recognised the familiar shape of Snowman Crater coming into view. After taking over Program 66 manual control at 122 metres Conrad found he had to sidestep the Surveyor crater. “Hey, there it is. Son of a gun, right down the middle of the road. Hey, it started right for the centre of the crater. Look out there. I can’t believe it… amazing, fantastic,” an incredulous Conrad remembered how he had asked trajectory specialist Dave Reed to target Intrepid for the middle of the crater, not really believing he could do it.