Riding Rockets

Discoverywas now a 100-ton glider. She had no engines for atmospheric flight. We began the long fall toward Edwards AFB, California, twelve thousand miles distant. We were coming to America. On the way,Discovery would be enveloped in a 3,000-degree fireball and at the end of the glide Hank would get only one chance at landing. In spite of these daunting realities I didn’t fear reentry as I had feared ascent. There were no SSMEs or turbo-pumps to fail and endanger us, and reentry lacked the rock-and-roll violence of ascent. I shouldn’t have been so confident. There were still plenty of ways to die on reentry and landing. The STS-9 crew had almost found one with their hydrazine fire. In 1971, three cosmonauts were killed on reentry when their capsule sprang a leak. They had not been protected with pressure suits and their blood boiled inside their bodies. We were not wearing pressure suits, so a pressure leak would kill us in the same manner. Of course, none of us could see the future, but on February 1, 2003, the STS-107 crew would find death on reentry due to damage sustained toColumbia ’s left-wing heat shield. Foam had shed from the ET during launch and punched a hole in it.Discovery was flying with the identical heat shield and Mike and Hank had seen foam shedding from the tank during our ascent. We could have been falling into the atmosphere with a hole in our wing and been blissfully unaware. No, I shouldn’t have been so confident in a safe trip home.

For the first half hour after the deorbit burn, there was no indication anything had changed. It felt as if we were still in orbit. We had fallen a hundred miles closer to the planet but the air was still so tenuous it had no observable effect. Then a lost M&M candy appeared from a corner and began a very slow fall. It was my first indication we were no longer weightless. The fringes of the atmosphere were finally slowing us.

At 400,000 feet above the Pacific Ocean, atmospheric friction began to heat the air. The glow in the cockpit windows changed from orange to red to white hot. I twisted my head to look upward through the ceiling windows. A vortex of white-hot air streamed away, flickering like a ribbon in the wind. I was seeingDiscovery ’s wake. The superheated air on the belly was wrapping around the vehicle and combining above her to form a wake of plasma. It streamed off into infinity. In spite of the incredible light show, the cockpit was quiet. There was no wind noise, no vibration.

Discoverycompleted several role-reversals to manage her energy. As thin as it was, there was still enough air to produce lift and the autopilot commanded the vehicle into alternating 75-degree banks to use this lift to pull her off centerline. She was standing on alternating wings, skidding into the Earth’s atmosphere like a snowboarder braking to a stop. She was flying a giantS across the Earth, lengthening the distance to the runway, to give her more time to lose altitude. If she had attempted to dive straight ahead we would have been incinerated.

Our computer displays showedDiscovery as a bug tracking down the centerline of a fan of green energy lines. She was flying like a dream. In spite of the fire outside the windows andDiscovery ’s bizarre maneuvers on our instruments, I felt completely secure. The cockpit was as comfortable as a womb.

The Reaction Control System (RCS) thruster lights flashed intermittently to indicate they were firing to hold our attitude. Just a fraction of a degree in error and we would be tumbled out of control. If it happened, the Pacific would swallow our ashes. NASA wouldn’t find a trace of us.

Deeper into the atmosphere the G-forces increased to the maximum of 2. In any other circumstance this would have been a trivial force. A modern fighter can subject its pilot to 9 Gs. But for an astronaut returning from days of weightlessness, the feel of the G-forces was significantly amplified. It seemed as if an elephant were on my shoulders. I was being crushed into my seat. The weight of the helmet made it difficult for me to hold up my head. My vision began to tunnel, as if I were looking through a straw. I knew from my fighter jet experiences tunnel vision was an indication of approaching blackout. The vision area of my brain wasn’t getting enough oxygenated blood. I inflated my anti-G suit to the maximum setting and the air bladders squeezed my belly button nearly to my spine. I simultaneously bore down with my gut muscles, all in an effort to tourniquet my waist. It worked. My vision cleared.