Mike Mullane - Riding Rockets

Our seats wiggled and groaned under the stress. I was amazed by the flexibility of the machine. It reminded me of times in my childhood when I would slide down a bumpy, snow-filled arroyo in a cardboard box. Now, as then, I wondered how my cockpit could stay together through all the bouncing and shaking.

“Throttle up.” The air was thinning and the aerodynamic pressure decreasing. The three Rocketdyne beauties at our backs were once again spiraling to full power. What a rush it was to feel the buildup of thrust, just like jamming the throttles of a fighter into the afterburner detents. I suspect every shuttle pilot would have loved to snatch the controls from the autopilot and manually throttle the engines to full power. How many times in your life would you have 1.5 million pounds of thrust wrapped around your fingers?

The prayers flying from the souls of everybody in the cockpit were identical, that God would continue to smile upon the SSMEs. We most feared these engines, and for good cause. There had been many SSME ground-test explosions and premature shutdowns. We were also strapped to two SRBs, each burning nearly 5 tons of propellant per second, but nobody gave a second thought to them. No engineer had ever come to a Monday morning meeting to explain away a SRB ground-test failure. The SRBs had always worked. But even as we scorched the prayer line with our pleas for flawless SSME function, both SRBs were betraying us. A primary O-ring at different joints in each tube had failed to seal as the motors had ignited. Tentacles of flame from the combustion area had wiggled between the segment facings. Like something alive and trapped, the gas had been wild to escape. It had reached the leak points and started to consume the O-ring rubber. The leak on the left-side SRB was bad enough for hot gas to actually get past the primary O-ring. Though we wouldn’t know it until after the Challenger disaster, we had just experienced the first case of what the Thiokol engineers would later define as “blow-by.” Hot gas had penetrated into the space between the primary and backup O-rings. Had our leak continued moments longer, the primary and backup O-rings would have been consumed and history would have recorded the Discovery disaster instead of Challenger. It would have been Zoo Crew’s names etched in an Arlington Cemetery monument. But the leak hadn’t continued. Inexplicably the primary O-rings had resealed.

The clock was approaching T+2 minutes and the Gs rose to 2.5. An invisible hand pushed me deeper into the seat. I reached forward, drew my hand back, then reached forward again. The veterans had warned it was tough to maneuver an arm under G-loads and it was a good idea to practice in case an ascent emergency later required a reach for a switch.

“You see that?” At Hank’s question I was reminded of Judy’s warning about not ending any sentence with the word that. Needless to say, my ears perked up.

Mike replied, “Yeah, it looks like foam from the tank is flaking off.”

Mike and Hank continued a brief discussion about the particles that were racing past the windows, sometimes striking them. There was no concern in their voices and I quickly dismissed their comments. The ET insulation foam was so light I couldn’t imagine it would damage any part of the vehicle. Nineteen years later a briefcase-size chunk of foam ripping from the gas tank would doom Columbia.

“P-C less than fifty.” Hank relayed the message on his computer screen that the chamber pressure inside the SRBs had fallen to less than 50 pounds per square inch. A loud metallic bang shook the cockpit and a flash of fire whipped the windows as the boosters separated from the ET. Both SRBs tumbled away to parachute into the ocean.

The sudden loss of 6 million pounds of thrust accompanied by dead silence caught me by surprise. Had all three of the SSMEs also shut down? I leaned to my left and stared at the engine status lights and for several heartbeats I expected to see them illuminate in a deadly red glow. But the lights remained off, the radios quiet. I swallowed back my heart. Apparently I had been asleep in training when somebody had described SRB separation and the quiet, velvet smoothness that followed. There was nothing wrong with the vehicle. Discovery had put most of the atmosphere behind her. There was no air to grip the machine or rattle us with shock waves. And the SSMEs were as finely tuned as a Rolex. They continued to deliver nearly 1.5 million pounds of thrust 100 feet behind our backs without a whisper of noise or ripple of vibration. The ride became as smooth as a politician’s lie.

Hank’s altitude and velocity tapes scrolled upward as the sky faded to abysmal black. Sunlight was streaming through the windows and yet the sky was utterly dark. It was my first real space experience, something I had never and could never experience as an earthling…simultaneous night and day, simultaneous high noon and deep midnight.

Our various abort windows began to open and close. “ Discovery, you’re two-engine TAL.” We had acquired enough altitude and speed to fly across the Atlantic and land in Senegal, Africa, if one engine failed, a maneuver known as a Transatlantic Landing abort (TAL). NASA had positioned an astronaut at the Dakar international airport to help air traffic control personnel if we declared an abort. He also had our passports and visas. I had a vision of standing in the customs line at the Dakar airport in our shuttle flight suits with our helmets in the crook of our arms while a fez-headed, accented bureaucrat asked, “Anything to declare?” It was something I hoped never to experience.

“ Discovery, you’re negative return.” The Return to Launch Site (RTLS) abort window closed. We were now too far from Florida and headed too fast to the east to be able to return to a landing at KSC. If an engine failed, we were committed to a “straight ahead” abort. That was okay by all of us. Nobody wanted to do a turnaround RTLS abort. It was an unnatural act of physics. If selected, it would pitch the shuttle around in an outside loop to point us toward Florida. But it would take minutes to cancel our several-thousand-miles-per-hour eastward velocity, so we would actually be traveling backward over the Atlantic. Ultimately we would end up as a million-pound helicopter, fifty miles high, with zero forward speed. Then, we would begin the slow acceleration toward our objective, Florida, only two hundred miles away. The experts swore it would work and Mike and Hank had practiced RTLS aborts in the sim about a thousand times, but nobody wanted to be the first to field-test the procedure.

Discovery continued a nominal ascent. Passing about thirty miles altitude, it occurred to me I could die without ever having seen the Earth from space. The shuttle’s nose was so high and I was sitting so far aft in the cockpit I couldn’t see anything of the planet. But there was a window above and just slightly behind my head and since the shuttle flies to orbit upside down, that window did provide a view of the Earth. It was a mighty temptation.

I looked furtively at Steve Hawley. His head was making small jerking motions like Data from Star Trek as he moved his eyes to every display. There wasn’t an electron running in Discovery ’s body that Hawley’s brain wasn’t also processing. With him at my side, I rationalized, I wouldn’t be missed for a moment of sightseeing. Under the mounting G-forces I craned my neck upward and backward until I thought it would break. The contortion worked. I could see the Earth receding below us. Scattered cumulus clouds had been reduced to points of white. The variations in sea depth were evident in different shades of blue. It wasn’t much of a view and I was condemning myself to one hell of a neck ache to capture it, but it was enough for the moment. If God took me now, at least I would have a story to tell while waiting in line for the down escalator to Bible/feminist/post-doc hell.