Riding Rockets

CHAPTER 6 The Space Shuttle

As we TFNGs gloried in our introduction, we were woefully ignorant of the machine we were going to fly. We knew the space shuttle would be different from NASA’s previous manned rockets, but we had no clue just how different or how the differences would affect the risks to our lives.

Before the space shuttle, every astronaut who had ever launched into space had ridden in capsules on throwaway rockets. The only thing that had ever come back to Earth was the capsule bearing the astronauts. Even these capsules had been tossed aside, placed in museums across America. While the capsules had grown in size to accommodate three men, and the rockets to carry them had grown bigger and more powerful, the basic Spam-in-a-can design, launched with expendable rockets, had been unchanged since Alan Shepard said, “Light this candle,” on the first Mercury-Redstone flight.

We would fly a winged vehicle, half spacecraft and half airplane. It would be vertically launched into space, just as the rockets of yesteryear, but the winged craft would be capable of reentering the atmosphere at twenty-five times the speed of sound and gliding to a landing like a conventional airplane. Thousands of silica tiles glued to the belly of the craft and sheets of carbon bolted to the leading edge of the wings and nose would protect it from the 3,000-degree heat of reentry. After a week or two of maintenance and the installation of another 65,000-pound payload in the cargo bay, it would be ready to launch on another mission.

The space shuttle orbiter (the winged vehicle) would have three liquid-fueled engines at its tail, producing a total thrust of nearly 1.5 million pounds. These would burn liquid hydrogen and liquid oxygen from a massive belly-mounted gas tank or External Tank (ET). Eight and a half minutes after liftoff the empty ET would be jettisoned to burn up in the atmosphere, making it the only part of the “stack” that was not reusable.

As powerful as they were, the three Space Shuttle Main Engines (SSMEs) did not have the muscle to lift the machine into orbit by themselves. The extra thrust of booster rockets would be needed. NASA wanted a reusable liquid-fueled booster system but parachuting a liquid-fueled rocket into salt water posed major reusability issues. It would be akin to driving an automobile into the ocean, pulling it out, and then hoping it started again when you turned the key. Good luck. So the engineers had been faced with designing a system whereby the liquid-fueled boosters could be recovered on land. It quickly became apparent that it would be impossible to parachute such massive pieces of complex machinery to Earth without damaging them and posing a safety hazard to civilian population centers. So the engineers looked at gliding them to a runway landing. One of the earliest space shuttle designs incorporated just such a concept. Like mating dolphins, two winged craft, each manned, would lift off together, belly to belly. One would be a giant liquid-fueled booster/gas tank combination, the other, the orbiter. After lifting the smaller orbiter part of the way to space, the booster would separate and two astronauts would glide it to a landing at the Kennedy Space Center (KSC). The astronauts aboard the orbiter would continue to fly it into space using internal fuel for the final acceleration to orbit velocity.

However, designing and building this manned liquid-fueled booster was going to be very expensive at a time when NASA’s budget was being slashed. The agency had won the race to the moon and Congress was ready to do other things with the billions of dollars NASA had been consuming. In this new budget reality NASA looked for cheaper booster designs and settled on twin reusable Solid-fueled Rocket Boosters (SRBs). These were just steel tubes filled with a propellant of ammonium perclorate and aluminum powder. These ingredients were combined with a chemical “binder,” mixed as a slurry in a large Mixmaster, then poured into the rocket tubes like dough into a bread pan. After curing in an oven, the propellant would solidify to the consistency of hard rubber, thus the name solid rocket booster.

Because they were the essence of simplicity, SRBs were therefore cheap. Also, because after burnout they were just empty tubes, they could be parachuted into salt water and reused. There was just one huge downside to SRBs: They were significantly more dangerous than liquid-fueled engines. The latter can be controlled during operation. Sensors can monitor temperatures and pressures, and if a problem is detected computers can command valves to close, the propellant flow will stop, and the engine will quit, just like turning off the valve to a gas barbecue. Fuel can then be diverted to the remaining engines and the mission can continue. This exact scenario has occurred on two manned space missions. On the launch of Apollo 13 the center engine of the second stage experienced a problem and was commanded off. The remaining four engines burned longer and the mission continued. On a pre-Challenger shuttle mission the center SSME shut down three minutes early. The mission continued on the remaining two SSMEs, burning the fuel that would have been used by the failed engine.

Solid-fueled rocket boosters lack this significant safety advantage. Once ignited, they cannot be turned off and solid propellant cannot flow, so it cannot be diverted to another engine. At the most fundamental level, modern solid rocket boosters are no different from the first rockets launched by the Chinese thousands of years ago—after ignition they have to work because nothing can be done if they don’t. And, typically, when they do not work, the failure mode is catastrophic. The military has a long history of using solid rocket boosters on their unmanned missiles, and whenever they fail, it is almost always without warning and explosively destructive.

The SRB design for the space shuttle was even more dangerous than other solid-fueled rockets because their huge size (150 feet in length, 12 feet in diameter, 1.2 million pounds) required them to be constructed and transported in four propellant-filled segments. At Kennedy Space Center these segments would be bolted together to form the complete rocket. Each segment joint held the potential for a hot gas leak; there were four joints on each booster. Redundant rubber O-rings had to seal the SRB joints or astronauts would die.

Yet another aspect of the design of the space shuttle made the craft significantly more dangerous to fly than anything that had preceded it. It lacked an in-flight escape system. Had the Atlas rocket, which launched John Glenn, or the Saturn V rocket, which lifted Neil Armstrong and his crew, blown up in flight, those astronauts would have likely been saved by their escape systems. On top of the Mercury and Apollo capsules were emergency tractor escape rockets that would fire and pull the capsule away from a failing booster rocket. Parachutes would then automatically deploy to lower the capsule into the water. The astronauts riding in Gemini capsules had the protection of ejection seats at low altitude and a capsule separation/parachute system for protection at higher altitudes.

The shuttle design did accommodate two ejection seats for the commander and pilot positions, but this was a temporary feature intended to protect only the two-man crews that would fly the first four shakedown missions. After these experimental flights validated the shuttle design, NASA would declare the machine operational, remove the two ejection seats, and manifest up to ten astronauts per flight. Such large crews would be necessary to perform the planned satellite deployments and retrievals, spacewalks, and space laboratory research of the shuttle era. These crews would have no in-flight escape system whatsoever. These were the missions TFNGs were destined to fly. We would have no hope of surviving a catastrophic rocket failure, a dubious first in the history of manned spaceflight.

The lack of an escape system aboard operational space shuttles—indeed, the very idea that NASA could even apply the term operational to a spacecraft as complex as the shuttle—was a manifestation of NASA’s post-Apollo hubris. The NASA team responsible for the design of the space shuttle was the same team that had put twelve Americans on the moon and returned them safely to Earth across a quarter million miles of space. The Apollo program represented the greatest engineering achievement in the history of humanity. Nothing else, from the Pyramids to the Manhattan Project, comes remotely close. The men and women who were responsible for the glory of Apollo had to have been affected by their success. While no member of the shuttle design team would have ever made the blasphemous claim, “We’re gods. We can do anything,” the reality was this: The space shuttle itself was such a statement. Mere mortals might not be able to design and safely operate a reusable spacecraft boosted by the world’s largest, segmented, uncontrollable solid-fueled rockets, but gods certainly could.

It would be more than just the unknowns of a new spacecraft that TFNGs would face. NASA’s post-Apollo mission was also uncharted territory. Having vanquished the godless commies in a race to the moon, the new NASA mission was basically a space freight service.

NASA sold Congress on the premise the space shuttle would make flying into space cheap and they had good reason to make such a claim. The most expensive pieces of the system, the boosters and manned orbiter, were reusable. On paper the shuttle looked very good to congressional bean counters. NASA convinced Congress to designate the space shuttle as the national Space Transportation System (STS). The legislation that followed virtually guaranteed that every satellite the country manufactured would be launched into space on the shuttle: every science satellite, every military satellite, and every communication satellite. The expendable rockets that NASA, the Department of Defense (DOD), and the telecommunications industry had been using to launch these satellites—the Deltas, Atlases, and Titans—were headed the way of the dinosaur. They would never be able to compete with the shuttle on a cost basis. NASA would be space’s United Parcel Service.

But this meant that, of all the planned shuttle missions, only a handful of science laboratory missions and satellite repair missions would actually require humans. The majority of missions would be to carry satellites into orbit, something unmanned rockets had been doing just fine for decades. Succinctly put, NASA’s new “launch everything” mission would unnecessarily expose astronauts to death to do the job of unmanned expendable rockets.

As we TFNGs were being introduced, NASA had to have been feeling good. They had a monopoly on the U.S. satellite launch market. They also intended to gain a significant share of the foreign satellite launch market. The four shuttles were going to be cash cows for the agency. But the business model depended on the rapid turnaround of the orbiters. Just as a terrestrial trucking company can’t be making money with vehicles in maintenance, the shuttles wouldn’t be profitable sitting in their hangars. The shuttle fleet had to fly and fly often. NASA intended to rapidly expand the STS flight rate to twenty-plus missions per year. And, even in the wake of post-Apollo cutbacks, rosy predictions said they had the manpower to do it.

The shift from the Apollo program to the shuttle program represented a sea-change for NASA. Everything was different. The agency’s new mission was largely to haul freight. The vehicle doing the trucking would be reusable, something NASA had no prior experience with. The flight rate would require the NASA team to plan dozens of missions simultaneously: building and validating software, training crews, checking out vehicles and payloads. And NASA would have to do this with far less manpower and fewer resources than had been available during Apollo.

I doubt any of the TFNGs standing on that stage fully comprehended the dangers the space shuttle and NASA’s new mission would include. But it wouldn’t have mattered if we had known. If Dr. Kraft had explained exactly what we had just signed up to do—to be some of the first humans to ride uncontrollable solid-fueled rocket boosters, and to do so without the protection of an in-flight escape system, to launch satellites that didn’t really require a manned rocket, on a launch schedule that would stretch manpower and resources to their limits—it wouldn’t have diminished our enthusiasm one iota. For many of us, our life’s quest had been to hear our names read into history as astronauts. We wanted to fly into space. The sooner and the more often (and who gave a shit what was in the cargo bay), the better.