Chapter 43: ►

“_The Real Significance_”

The big single-barrel XLR-99 rocket engine designed to blast the X-15 on its ultimate mission to the fringes of space arrived in California in April, 1960, about a year and a half behind schedule. It was shipped to Edwards and bolted to the ground-test stand. During May the North American and Reaction Motors engineers ran the engine in a series of exhaustive tests. It was a sight to see: that small barrel spewing smoke and flame, thrust almost four times as great as the combined thrusts of the two smaller X-1-type engines then powering the X-15. The rocket-engine noise boomed across the desert for thirty miles.

In late May the first big engine was installed in X-15 number three, the ship we had specifically reserved for this first engine. And in early June X-15 number two, after my ninth and final powered flight in that craft, was torn down and the two smaller engines removed in preparation for the arrival of the second big engine. Meanwhile, we got set to ground-test the big engine which was installed in number three.

The ground tests of this engine, which has as much power as an Army Redstone missile and almost three times the power of the Navy’s Vanguard missile, were elaborate for Edwards (though stark compared to the blank-check missile operations). We had made some improvements on the ground-test stand. The engineers had built special steel clamps to hold the X-15 to the concrete apron. They had installed underground concrete observation bunkers, which looked like Maginot-Line pillboxes. The telemetry engineers rigged elaborate equipment to transmit a record of everything happening in the X-15 during the engine run to a master console in the NASA administration building. For this big moment in the history of our craft, nothing would be left to chance.

Late in the afternoon of June 8 I arrived at the ground-test area wearing street clothes. X-15 number three, with her powerful new engine, was clamped in place on the stand. She was brimming with Lox and new fuel for the big engine--ammonia, more powerful or “exotic” than the Walc used in the two smaller engines. A thick coating of ice had formed on the fuselage around the Lox tank. Wispy Lox vapor trailed off into the afternoon sky. A snarl of electrical power connections--the umbilical cords--ran from a hole in the concrete to the ship’s side tunnels.

Harry Gallanes, North American’s power-plant test boss, greeted me: “Looks like we’re all set, Scotty.” He and his crews had been working without let-up since dawn. They had pretty much kept to this dawn-to-dusk (sometimes later) schedule since the day the big engine arrived, another manifestation of that curious enthusiasm for things mechanical which seemed to infect all members of the flight-test team.

I climbed into the cockpit and donned a Scott Airpack breathing device similar to the unit skin divers wear underwater. It would supply my oxygen, pumped into the airplane from an external connection. The simple airpack was more comfortable and far less bother than the X-15 full-pressure suit, which I did not need on the ground. I closed the canopy and turned on the nitrogen gas flow, to cool the electronic equipment in the cockpit and to build up a pressure which would block out possible ammonia fumes or other toxicants, should something go wrong during the engine run.

On this ground test--my second in this airplane--we intended to simulate all the events of a real drop from the mother plane with rocket-engine light-off. If all went well, we hoped to make an actual flight a month later, perhaps sooner. Harry Gallanes and his men retired to the bunkers. Gallanes manned the radio circuit as test director. Q. C. Harvey took up his post in the forward bunker. Soon we were well through the countdown. At six minutes to “drop” I turned on the APUs. X-15 number three was completely on her own. It was time for the big test.

A siren whined a warning. The mechanics, protectively dressed in hooded clothing, evacuated to the bunkers. They had been hanging around checking for leaks or other possible malfunctions until the last moment. A group of fire trucks, parked about two hundred yards away, were ready to rush to the rescue, if needed. Otherwise there was no sign of life. Alone in the cockpit I checked the gauges. As we approached the time for engine light-off, three movie cameras, mounted outside and aimed at the rear of the X-15, began to roll. Inside the cockpit I turned on the data recorders.

I called each step of the engine-start procedure on the radio, pausing briefly after each item on the check-list.

“Master switch coming on NOW.”

“Prime.”

“Pre-cool.”

“Pump idle.”

“Igniter idle.”

I then moved the main engine throttle from its stowed position to the engine-start position. The engine is designed to light-off at half-thrust. When I moved the throttle, in effect opening the main fuel and Lox lines, the engine cracked to life with a tremendous roar. The ship vibrated powerfully in her steel mounts. The engine ran smoothly as designed. Slowly I opened the throttle to full power. The noise was terrific.

The North American X-15 Mach 2.0 speed and 100,000-foot altitude restrictions are still technically in force. If I allowed the big barrel to run full-bore in flight, I would quickly exceed those limits by a great margin and perhaps go hurtling off to the fringes of space. Thus for my big-engine “demonstration” flights we had worked out a system whereby in the air I would shut down the engine periodically and restart it after the speed and altitude fell off. Now simulating my actual flight plan, I pulled the throttle back and shut down the engine. As prescribed, I waited fifteen seconds and then restarted the engine at fifty per cent thrust.

Rocket engines are equipped with special engine safety devices. If these devices “sense” anything abnormal in burning or engine operation, they automatically shut the engine off and “safety” all the electrical circuits. Evidently after my restart one such device “sensed” a vibration. Almost immediately after I moved the throttle to half-thrust, the engine shut down automatically. There was no sign of trouble in the cockpit, so I prepared to restart the engine once again.

To restart the engine after an automatic shut-down, the pilot must push a special switch which “unsafeties” the engine, or in effect resets all the circuits the automatic device has closed down. If these can be reset, the engine is again ready for start. Beginning the restart procedure, I put the throttle in the stowed position and pressed the reset switch.

It was like pushing the plunger on a dynamite detonator. X-15 number three blew up with incredible force. The rear section of the airplane, from the trailing edge of the wing aft, was instantaneously demolished. The front section of the airplane, including the cockpit and the pilot, hurtled twenty feet across the concrete ramp at indescribable speed, the shortest and fastest rocket ride in history, subjecting me to an acceleration force of maybe fifty G’s. Fortunately, my head was reclining in the headrest on the seat; otherwise my neck might have been broken.

Nine hundred gallons of ammonia and sixty gallons of hydrogen peroxide, a total of 16,000 pounds of powerful liquid, had ignited simultaneously. I knew, of course, that there had been a tremendous explosion, but I had no way of knowing precisely what happened. All I could think of was the possibility of a second explosion that might hurl my part of the airplane halfway across Edwards and through the main hangar and workshop. In the cockpit I moved swiftly to do what I could to prevent this. I turned off the APUs and all external power supply and shifted from external oxygen to X-15 oxygen supply. Then I braced my feet on the instrument panel and put my arms across my face, waiting. There was no panic, no fear. I was concerned primarily for the safety of the other people--those outside--and I thanked God that He had given us the time to install the concrete pillbox bunkers, which were being used tonight for only the second time.

Half a minute later I watched a mass of red approaching the X-15. It was the fire truck. Its hoses pumped a great spray of water over the ship, smothering the fire still raging in the shattered rear section. A few seconds later I saw Art Semone and another mechanic hunched outside the cockpit. They were trying to pull the canopy handle to let me out. At that point I would have preferred to remain inside the cockpit, one of the safest places in the world in the event of fire. But I could see that no amount of hand-signaling would dissuade Semone, and rather than expose him to possible danger I helped open the canopy and leaped out.

Semone must have thought I was injured. When I jumped from the cockpit, he caught me in mid-air and tried to carry me out of the smoke and flames. I whopped him on the shoulder to let him know I was all right and then we all ran quickly to a spot about a hundred feet distant and I checked the bunkers. Everyone, it seemed, had survived, and for this I was very grateful. As it turned out, no one, including me, was even slightly injured. I had someone relay that fact to Alice as soon as possible, knowing the news would be on the radio before the fire was out.

* * * * *

The documentation of that explosion, like everything else about the X-15, was first-rate. In fact it was probably one of the best documented airplane accidents in history. Immediately afterwards, Q.C. gathered all of us in a room, and there we recalled in detail all that we could remember while it was still fresh in our minds. These eye-witness accounts, added to the miles of telemetry data and the film strips from the three movie cameras, would enable us to establish the cause of the explosion very quickly. It was not the fault of the engine. A sequence of coincidences, again hidden in the mysteries of Murphy’s Law, had trapped us. We moved rapidly to avert any possibility of a recurrence in X-15 number two, meanwhile accelerating our efforts to install the big engine in that ship. NASA prudently grounded X-15 number one until we could do everything possible to make sure a similar disaster could not happen.

The fate of number three was quickly decided. She would be rebuilt. Some parts--nose, cockpit, wings--might be salvaged. This was obviously a major task requiring more time and money. The destruction of this airplane is simply part of the price man must pay for progress. Measured against the loss of fifty or so Atlas, Titan, and Polaris missiles at Cape Canaveral, each costing more than a single X-15, it was a drop in the bucket, although a painful one because it temporarily reduced our complete air fleet by thirty-three and one-third per cent.

Inevitably the newsmen got on my trail. When they called, I was ready with the wisecrack I knew they wanted. “The only casualty,” I said, “was the crease in my trousers. The firemen got them wet when they sprayed the airplane with water.” Too late I realized how this might be interpreted.

“Are you sure it was the firemen?” the reporter asked.

“Yeah, I’m sure,” I said. I pictured the headline:

SPACE SHIP EXPLODES; PILOT WETS PANTS

“Mr. Crossfield,” the reporter went on. “What is the real significance of all this?”

“The _real_ significance?” I asked. “Have you got about ten or fifteen hours, maybe?”

“No,” he said. “I’ve got about two minutes to meet a deadline. Just tell me what’s going to happen now? Where does this leave the program?”

“We’re not sure yet. There will naturally be some investigations. In all probability we’ll accelerate putting the big engine in X-15 number two. A little later we’ll put the big engine in NASA’s X-15 number one.”

“Does this affect your role in the program? Will you still go ahead and make a demonstration flight with the big engine?”

“I don’t know,” I said. “I was only supposed to make one or two low-speed demonstration flights with the big engine and then that was the end of my participation in the project. Bob White and Joe Walker would take it from there. They might change that now. I have no reason to believe there will be any change. There could be. I might not make the big-engine demonstration flights. I honestly don’t know. It’s all very indefinite.”

“Well, thanks. Some day I’d like to talk to you about the real significance. But not now.”

It was always the same: hurry, impatience, no time for thoughtful reflection. Move on quickly to the next story, the next pilot, or missile, or space vehicle, for a bigger and better headline.

“Okay,” I said. “I’ll be seeing you.”

* * * * *

The real significance of the X-15, I hope, has come through in the foregoing pages. It is not just another airplane, another headline. It is another of man’s restless attempts at perfection, and in the aviation world the greatest ever mounted. The X-15 sprang from a deep pool of aeronautical knowledge, the end product of fifty years, and more, of probing this frontier. It was created and built at tremendous cost in terms of money and sweat by some of the most skilled engineers in the free world. As always, we did not achieve our dream of perfection. Only God, I believe, can create the perfect. But in reaching out, we provided some water for man’s never-ending thirst. We learned a great deal. We had set man on his path toward the stars.

Some day, I believe, he will get there. Not so quickly as one might think from reading the newspapers. The speed of this massive scientific effort is like that of the convoy, geared to the pace of the slowest vessel. Thus this daring adventure is regulated not so much by grandiose plans emanating from the increasing layers of scientific administrators in Washington as by the simple function of a valve, an APU unit, or a radio plug. Our tale of adversity with the X-15 is not unique; rather, it is typical of our age. Similar stories, many with fewer points of success, were taking place at the same time in our nation with Atlas, Polaris, Titan, Mercury, Minuteman, a dozen others I cannot recall. Some day, too, perhaps these stories will be written.

In time, our splendid engineers will de-bug the big X-15 engine. I may or may not be allowed to make one or two low-speed flights. Then in the months ahead, depending on the speed of the scientific convoy, Bob White or Joe Walker or perhaps someone else will begin the first, tentative “space” flights in the X-15. They will launch over the designated point in Utah, light off the powerful rocket barrel, and roar heavenward. With God’s help they may reach a speed of 4,000 miles an hour and an altitude of perhaps 100 miles. I hope that many, many pilots will have the opportunity to make these pioneering voyages into space.

Ultimately our work, and the work of the tens of thousands of other engineers in this nation, will be merged to form a more advanced space machine. The bottom of this machine might not look like an Atlas or Saturn. The top might not look like an X-15. But the complete vehicle will be the sum product of all the work of all the engineers in this country. This machine will not rise effortlessly and gracefully from the earth on the first day. Dedicated people such as Charlie Feltz and Harrison Storms must first expend limitless sweat and tears. The machine may crash and explode. So might the second and third, perhaps the fourth and fifth. Congressional committees will investigate, and new layers of scientific administrators will grow atop the old in Washington. But the engineers will prevail in spite of them.

Some day this machine will rise from the face of the earth. It will take man into an orbital path about the earth. It will enable him to build a space station. From there he will shove off to the moon. Then he will go to the nearest planets in our solar system. A hundred years from now, if we have not destroyed our own planet in an ideological war, man may enter the solar system of the nearby stars. He will go there because he must. He is curious and intelligent. He is seeking answers--about himself, his universe, and his God. Because man is a creature of God and the instrument of God, he will not be denied. There will always be another dawn.