The second space age is about to begin. Space shuttle flight one will depart Cape Canaveral for low earth orbit as early as March 14. Its trip will be short—two and a third days. Astronauts John Young and Bob Crippen will take their flagship Columbia around the world 36 times to test its wings. Then a steep descent down onto the Mojave Desert. But at least three dozen space flights will follow, for tours of a week or more. Columbia will be joined by Challenger, Discovery, and Atlantis. By the late 1980s this fleet of orbiters could be making about 50 flights a year.
What is the space shuttle? Most people know that it sometimes rides piggyback on a Boeing 747. Many have heard about its main engines bursting into flame on the test stand, some of its protective tiles falling off, and the other expensive problems that have delayed Columbia’s maiden flight for more than two years. Yet ask someone how the shuttle is going to get to space, or better still what our nine-billion-dollar super machine will do up there, and the answer will likely be a stammer or a shrug. The space shuttle has come of age with an identity crisis.
Basically, the shuttle is a spacefaring cargo ship that can be used over and over again. Not only will it take satellites, military hardware, and people to space, but it will also bring them back. It will replace all other American satellite launching vehicles. If, once in orbit, a satellite fails, the shuttle can retrieve it for servicing. The shuttle will ferry telescopes, earth-scanning cameras, laboratories, and eventually construction equipment into orbit. It will move industry into space. Apollo’s moon-landing program, Skylab, and the missions to the planets were the age of space exploration. The shuttle begins the age of space exploitation.
At times the shuttle also seems to be the beginning of the people’s space program. “I’m convinced that by 1990 people will be going on the shuttle routinely—as on an airplane,” says Robert Freitag, an advanced programs planner at the National Aeronautics and Space Administration.
For the first time women and minorities will be in the astronaut corps. My daughter could well grow up to help build a solar-power space structure as big as Manhattan Island that would convert solar energy to microwave energy and beam it to earth.
Already an unexpectedly high number of student and civic groups, corporations, private individuals, and foreign countries have bought “getaway specials” from NASA. These are canisters in which anyone anywhere can send experiments and inventions into space for as little as $3,000.
Even Hollywood is enthused. Director Steven Spielberg holds a getaway-special reservation but has no idea as yet what to do with it. The China Syndrome screenwriter, Mike Gray, told me that “the space shuttle is the set of the future.” Still others see the shuttle as the first step toward colonies in space and human emigration from earth.
More immediately, astronauts riding the space shuttle will be deploying and servicing elaborate switching stations for telephones and television. Before the end of the century we should be able to make an inexpensive telephone call from a wristwatch telephone via satellite anywhere in the world. Less certain but potentially just as profitable is the prospect of building, with the shuttle’s help, floating factories that take advantage of the unique ultralow gravity of space.
Finally, the shuttle will be a military machine. The Air Force has reserved 13 of its first 44 flights. A new surveillance system will go up. Our next war could be fought between satellites that hunt and destroy each other or even knock out missiles with lasers or high-energy death beams.
For a while the space shuttle will make only test flights. Not until 1982 will it fly its first regular mission, deploying a giant tracking and data-relay satellite. That gives us time to get to know this complex machine.
The shuttle that will spew fireballs and steam across the launchpad at Kennedy Space Center at Cape Canaveral has three main components: an orbiter, external tank, and two solid-rocket boosters, all bolted together. This ungainly configuration will stand 184 feet tall—about half the height of the Apollo lunar launch assembly.
The orbiter, which looks like a small, fat airliner, is the core of the system. It is what goes back and forth between earth and space. The orbiter features work and living quarters for as many as seven people and a 60-foot-long payload bay for stowing cargo. This bay could carry to space the weight equivalent of five adult African elephants.
However, the most obvious component of the shuttle will be the mammoth white bullet-shaped external tank. The external tank carries the enormous volume of liquid hydrogen and oxygen burned by the orbiter’s main engines. In just eight minutes these three ultrahigh-performance engines will consume enough propellant to fill 18 backyard swimming pools.
If the orbiter itself had to carry all that liquid, it would be far too big. So instead the orbiter will ride on its fuel tank, and then, just before reaching orbit, it will drop the empty tank into the Indian Ocean.
Riding Captive Flame Into Space
Unfortunately, on the ground the fuel in that tank weighs a million and a half pounds. As powerful as they are, the orbiter’s main engines could scarcely budge this load. So a third component is needed, the solid-rocket boosters. Solid rockets, which burn a highly explosive aluminum powder, have long been used by the military. They have tremendous get-up-and-go. One I saw being test-fired in Utah looked as if it were spitting the sun out its tail as it sent a blinding holocaust across the desert.
No man has ridden solid rockets before, largely because they are hard to control. Once ignited, they are on for good. No second thoughts. No throttle back. That has been fine for launching warheads, but not for the subtleties of manned space flight.
On the shuttle the solid rockets are there just for the muscle. Two are bolted onto the external tank, and for two minutes they provide 5.3 million pounds of thrust. That is about what it would take to get 25 fully loaded 747s airborne. Once the solid fuel is exhausted, explosives fire the rockets away, to be recovered by a ship off Florida for reuse.
Finding the Orbital Flyway
So that is the system. One orbiter, one external tank, and two solid-rocket boosters, all taking off at the same moment. Two minutes after launch the solid rockets drop off. A few moments before reaching orbit, the orbiter sheds the external tank. Then it fires up two secondary engines, called the orbital maneuvering system (OMS), which put it in revolution around the earth.
During its orbital flight and later descent, these OMS engines and 44 smaller thrusters placed strategically along the spacecraft enable the orbiter to turn over or to straighten up, to change orbits or to rendezvous and dock. They also make the precise adjustments needed to take the orbiter out of orbit, to bank and swerve it safely through the intense heat of reentry.
In April of 1978, when I first saw the orbiter Columbia taking shape, there was still hope that it would fly the next year. In its huge hangar at the Rockwell Corporation Facility in Palmdale, California, the Columbia looked much like any large aircraft under construction. Its green-coated shell sat amid scaffolding, with men by the score crawling around the sides and in and out of cavities in the fuselage. Men welding. Men wiring and inspecting. Men scratching and often shaking their heads.
All these wires would later be hidden, but at this stage the Columbia was like a body with its skin off and its nerve ends showing. This nervous system is one of the hallmarks of the orbiter.
Nothing as big as the Columbia has ever been put into orbit, and nothing with wings has ever flown anywhere near the 17,500 miles an hour the orbiter must encounter. It is, nevertheless, the orbiter’s brains as much as its brawn that make it the most ambitious flying machine ever built.
From nine minutes before lift-off until just before touchdown, the shuttle flight will be almost totally automated. During critical phases of flight the orbiter’s computers will perform some 325,000 operations a second. These computers are ten times faster than those controlling the Apollo spacecraft, with six times the memory.
The shuttle’s computer system is called “quad-redundant.” Astronaut Deke Slayton explained: “There are four computers, with a fifth as a backup. The four main computers all process the same information. All have to agree. If one disagrees with the other three, it is turned off. If one of the remaining three changes its mind, the majority wins again. If the last two can’t agree, the backup computer is turned on. It decides. It can’t be wrong.”
This redundancy eliminates the need for the scores of mission controllers who kept tab on all the Apollo spacecraft systems and made crucial decisions for the astronauts.
“With the shuttle we are talking about four ground controllers manning a flight versus hundreds on a full-blown Apollo mission,” said flight controller Pete Frank at the Johnson Space Center in Houston.
Instead of ground control, shuttle astronauts will rely largely on three television displays in the cockpit. Two TV screens provide data on trajectory and guidance control. The third handles the orbiter’s electrical, environmental, hydraulic, and many other systems.
If something goes wrong—say a heater in a hydrogen tank malfunctions and the pressure of the liquid hydrogen fuel subsequently drops—astronauts will hear a warning tone in their headsets and see a master alarm light flash on. A control-panel light indicating hydrogen pressure also turns on. The astronauts can then use a computer keyboard to call up details of the problem.
“It's a convenience,” says astronaut Vance Brand. “This vehicle is so complicated. There’s far too much data to monitor continuously. This system frees us in orbit for work on our most immediate tasks.”
“Office” With an Awesome View
Except for the three TV screens and some 1,400 switches and circuit breakers, the orbiter cockpit looks much like that of any transport plane. Directly behind the cockpit, though, is a small area with still more control boards and a spectacular view out over the long unpressurized cargo bay. Here work the mission specialists, the people who actually carry out the business of a particular flight. They will be able to watch as they raise the orbiter’s big remote manipulator arm, pick up a satellite stored in the bay, and plunk it overboard.
(The astronaut corps will be broken into two groups. Pilots fly the machine up and back. Mission specialists run the show once in orbit. Later, a third category, the payload specialists, will be added. These will be outside experts: A solar physicist, for instance, may be brought along on a solar astronomy mission.)
The orbiter cabin has two levels. Neither is spacious. Climbing onto the flight deck and into a cockpit seat was a feat of contortion. However, my way was impeded by bulky pilot-ejection seats that will be removed after the shuttle demonstrates several times that it can launch safely.
Beneath the flight deck are the Spartan living quarters, which include three seats, a galley, a washroom, space for either upright sleeping hammocks or berths, stowage, and an airlock exit into the payload bay. About ten people could stand shoulder to shoulder in these living quarters. The decor could be called modern metal file cabinet. As the Columbia’s first commander, John Young, put it, “A seven-day mission with six people is going to be pretty austere.”
The interior of the orbiter may not represent a breakthrough in comfort, but its exterior has certainly pushed technology. One overriding problem in designing a shuttle was how to keep the spacecraft from burning like a meteorite when it reenters the atmosphere. Parts of the orbiter will register temperatures higher than 2500°F.
Earlier spacecraft had chemical heat shields that absorbed the heat, charred, and flaked off. But a shuttle orbiter may have to reenter the atmosphere 100 times or more. It must have a reusable heat shield.
The solution was to cover much of the orbiter’s aluminum skin with tiles made from fibers of 99.7 percent pure silica glass. When they are that pure, silica fibers conduct virtually no heat.
The Stuff to Keep Things Cool
Engineer Ed Law pulled a small glowing cube of this white, plastic-foamlike material from a 2500°F kiln at the Lockheed Missiles and Space Company’s Sunnyvale, California, plant. It had taken more than 30 minutes for the furnace to heat the cube cherry hot. Law picked the cube up by its corners and handed it to me.
“Be careful to touch only the points of the corners,” he said. “A Japanese newsman nearly lost his fingerprints doing this.”
When I took the cube, just a mild warmth radiated into my palms. Three minutes later the cube’s 1700°F interior still glowed. Yet I could touch the cube anywhere on its surface. The heat very near the surface had escaped into the air. That trapped within would take hours to work its way out through the ultrapure silica fibers.
Conversely, the brief intense heat generated by reentry will not be able to get through the orbiter’s tiles: 90 percent of it will be reradiated into the atmosphere.
Some 34,000 of these tiles, coated with a tough reflective sealer, cover the underside and those other parts of the orbiter that will be subjected to severe reentry heating. They look like the pieces of a great black jigsaw puzzle.
Designing and putting that jigsaw puzzle together has been painstaking. The tiles have varying shapes and thicknesses. Many of them have to curve with the contours of the orbiter. A computer tailors and cuts each tile, which is then attached to the orbiter by hand, using a space-age glue that everyone publicly expects—and privately prays—will hold through the rigors of flight. If just one tile from a critical part of the orbiter falls off, the entire spacecraft could be severely damaged.
Rocket Engines: Nozzles and Pipes
The greatest challenge to the shuttle designers, however, has been the three big main engines on the orbiter. At full power these engines release as much energy as 23 Hoover Dams. Yet the engines weigh only 7,000 pounds each and, minus their nozzles, stand only five feet tall.
I am not sure what I expected to see at a factory that makes rocket-ship engines. Maybe lots of chrome and glitter. Certainly sparkling-clean assembly rooms. But a day at Rockwell’s Rocketdyne plant in Los Angeles showed me that rocket making is a heavy, sometimes grimy, industry. It involves casting and welding thick chunks of metal, firing them in room-size furnaces, and dipping some of their components in great vats of electroplating chemicals. Under construction, these engines looked to me like glorified car motors with nozzles. Except for the intricate plumbing.
More than a thousand tiny tubes, for instance, run up and down the sides of the nozzles. During combustion these tubes siphon off the engine’s frigid hydrogen fuel and use it to cool the nozzle enough to keep it from melting. More tubes then collect the hydrogen and feed it back to power two turbines that jump the pressures within the engine to nearly 700 times that of a typical household pressure cooker.
The engines need to burn hydrogen under those high pressures to get maximum thrust. Such pressures put unprecedented demands on rocket-engine technology. In test firings, turbine blades have fluttered and cracked, bearings and rotating parts have broken down. Sometimes combustion has begun where nobody wanted it.
It has taken the Rocketdyne engineers about a year longer than anticipated to work out the problems. For a while the main engines received most of the blame for the shuttle’s delays.
A Problem With Tiles
Then the thermal tiles proved much trickier to apply than expected. The Columbia had to be ferried from California atop a 747 with only a small number of its tiles in place. Enroute fake tiles, put on to protect parts of the craft from aerodynamic damage on the flight, fell off, ruining some of the real tiles. Later, thousands of tiles had to be removed and rebonded, giving the whole tile program an aura of fiasco. There were also delays in developing the computer programs that are used in the flight simulators that astronauts train in. That meant that even the astronauts could not have been ready on time.
One component that could have made the original date, however, is the huge external tank. “It’s an 80,000-pound balloon,” says one NASA engineer. “It’s a big tin can,” says another. Some tin can. The external tank is actually the backbone of the whole shuttle system. Both the solid rockets and the orbiter are bolted to it, and the overwhelming thrust these five engines produce at launch converges on the struts and beams of the external tank.
“In one spot the tank’s shell may have to be membrane light and right next to it be able to withstand the equivalent of an enormous explosion,” said Joseph Marcus of Martin Marietta, which runs NASA’s Michoud assembly plant near New Orleans. “The tank also has to hold twenty times its weight in propellant, and keep it at hundreds of degrees below zero.”
It takes more than half a mile of welds to put an external tank together. Once assembled, a tank is sprayed with foam insulation. Why insulate the tank? For one thing, the shuttle’s odd shape will cause drag during its ascent, and parts of the tank will get quite hot. Since aluminum loses strength above 350°F, an unprotected tank might fall apart before it separates from the orbiter.
After separation the tank will reenter the atmosphere and disintegrate. Recovering it is not now economical, but eventually a small thruster, which would take the tank on into orbit, could be added. Bright aerospace-industry minds are dreaming up ways to use the discarded tanks. Perhaps several could be the core for a space station. Maybe the aluminum could be recovered to build ferries going from the shuttle’s low earth orbit to construction sites higher up.
What happens for the time being when the external tank breaks up? The question is timely in light of NASA’s problems with the falling debris from the dying Skylab.
“We target where the tank will land,” says Porter Bridwell, one of NASA’s external-tank program managers. “We have selected a site over the Indian Ocean at least 200 miles from land and with low density shipping. We have enough insulation to keep it intact down to 165,000 feet. The debris footprint will be 100 miles wide and 600 miles long.”
How big will the pieces of this 80,000-pound balloon be?
“That’s a good question,” said Bridwell. “It’s a magic art trying to predict that sort of thing. I just don't know.”