The Shuttle—A New Approach to Space
WITH a thunderous roar that shook the earth for miles, the world’s first reusable spaceship, Columbia, blasted off its launchpad at Cape Canaveral, Florida, and rocketed skyward into space. That was on April 12, exactly 20 years after the first manned spaceflight by the Russian cosmonaut Yuri Gagarin. After 54 1/2 hours and 36 earth orbits, the craft blazed through the earth’s searing atmosphere to a landing on a dry lake bed in California, right on time and right on target.
That truly spectacular feat was the outcome of 10 years of development and the expenditure of $10 billion. It was hailed as “ushering a new era in space exploration.” Others described it as “a shot in the arm” for a nation beset with technological self-doubt. Still others greeted it with mixed feelings, saying it “was a tremendous waste of money.”
Why such diverse reactions? As a matter of fact, what is the space shuttle and what is it supposed to do? Is it worth the cost?
Why the Shuttle?
In the past, all spacecraft were sent up by one-shot rockets that later burned up in the atmosphere or fell into the ocean depths. Even the costly spacecrafts themselves usually ended up in museums after just one trip. But with the Space Transport System (STS), the official name of the space shuttle, things are different. The heart of the system is a fleet of orbiters, the first of which is the Columbia, named after the first U.S. ship to sail around the world, in 1790. The space shuttle has been described as a space cargo ship or truck that can make round trips into space over and over again, up to 100 times. This new approach will, in theory, make space flights much more economical.
What Will It Do?
With a payload capacity of 65,000 pounds, the orbiter can carry into space satellites for communications, science and the military, as well as other equipment—telescopes, cameras and even complete laboratories. It can also take up specialists to conduct experiments in space, to study the heavens and the earth, and to service, repair or even retrieve defective equipment. In time, it will be able to open up the possibility of transporting men and materials into orbit to build space stations for harnessing the sun’s energy or for manufacturing in the weightlessness of space. To accomplish all of this the National Aeronautics and Space Administration (NASA) is currently building three more orbiters at $500 million apiece—the Challenger, the Discovery and the Atlantis—so that perhaps 30 to 40 flights a year could be scheduled by the mid-1980’s, and maybe even 50 by 1990.
A Look at the System
The 122-foot, 80-ton orbiter Columbia looks like a bulky delta-winged jet airplane with a 78-foot wingspan. At its tail are three of the most awesome rocket engines ever built. Together they can generate more power than is needed to light the whole state of New York. Yet, minus the nozzles, they are only about five feet tall. Even its fuel pump, the size of an oil drum, has power equal to 28 diesel locomotives. To develop these high-performance engines has literally taxed current technology to its limit, and engine failures have constituted one of the main reasons for the delay of Columbia’s maiden voyage, which was originally scheduled for early 1978.
On the launchpad, the orbiter is fastened to the mammoth 15-story-high external fuel tank, which holds 800 tons of liquefied oxygen and hydrogen. But all of that is burned up by the orbiter’s three main engines in just nine minutes. Still, to lift all that weight into space is more than the three engines can do, powerful as they are. So two solid-fuel booster rockets are added alongside the fuel tank. Looking like two oversized crayons and packed with two million pounds of aluminum powder—the same explosives as those used in fireworks—they provide five times the power of the main engines. They are the largest solid-fuel rockets ever built and the first used in a manned spaceflight.
The Ascent
At blastoff, the orbiter’s main engines ignited first. Seconds later, the booster rockets kicked on with an explosive force and the shuttle began its ascent, slowly at first. In two minutes, the boosters had consumed the last of their fuel supply and were uncoupled from the fuel tank by small charges of explosives. As they fell, three gigantic parachutes opened to ease the splashdown of these $18-million rockets into the ocean below. Two specially built ships, Liberty and Freedom, were waiting in the target area to tow them back to shore to be reused about 20 times, at a cost of $13 million each time.
Nine minutes after lift-off, the fuel in the external tank was spent and the shuttle had reached an altitude of 72 miles. The tank had to be jettisoned at this point so that gravity would pull it back to earth. As the tank fell, the reentry heat burned it to a frazzle and the debris splattered into the Indian Ocean. The $3-million tank is the only part not reused. Recovery would cost more than the tank itself.
Now Columbia was all by itself, coasting. Firing the two yet unused engines of the Orbital Maneuvering System on board took Columbia into a circular orbit 150 miles above the earth.
In Orbit
In the cockpit, the two pilots have a commanding view of 1,400 switches and relays and three television screens that are tied in with five computers on board. Actually, from nine minutes prior to take off until moments before landing, the computers were flying the shuttle. The system is called “quad-redundant”: the four main computers process the same information and must come up with the same answer. In case of disagreement, they vote and the majority rules. If this cannot resolve the problem, the fifth, or backup, computer is switched on and it decides. Their huge memory banks hold some 134 million bits of information and at crucial points of the flight they perform 325,000 operations a second.
One of the main objectives of the first flight was to test the cargo-bay doors while in space. On the inside of the doors are four radiator panels that must be exposed to space to dissipate the heat produced by all the electronic equipment on board. After that test, and some navigational-system checks, Columbia was ready to return to earth.
Reentry
To prevent the Columbia from experiencing the same thing that happened to the fuel tank on reentry, 70 percent of its external surface is protected by some 31,000 ceramic-coated silica tiles against the 2,500° F temperature caused by atmospheric friction. The challenge of building this reusable heat shield was every bit as great as that of building the three main engines. The tiles, no two of which are alike, were designed and cut by computers and glued on by hand like a giant jigsaw puzzle. The enormous problems encountered during installation and testing of the tiles became another of the major causes for the delay of the project.
As Columbia descended, belly first, to about 80 miles above the earth, the tiles began to turn fiery red-hot, and the flaming glow around the craft cut off all radio communications. For 16 minutes Columbia was alone at this crucial stage of the flight, and the ground control crew held their breath. So did the crowd waiting on the Mojave Desert floor.
Then, suddenly, came the sonic boom—two loud shocks to announce that Columbia had made it through safely and was now coming in for a landing. For about a minute, 10,000 pairs of eyes were glued on the 80-ton shuttle as it glided down at an angle seven times steeper than any airliner coming in for a landing. The landing gear dropped, and seconds later, they hit the dry lake bed at 215 m.p.h. “Welcome home, Columbia! Beautiful, beautiful,” cried the mission control communicator. So ended the first flight of the space shuttle.
Plans are being made to get Columbia ready for its next trip in about six months. Following that will be two seven-day test flights in 1982, which will then complete the experimental phase of the project.
Is It Worth It?
The economical advantage of the STS was based on the projection that the fleet of shuttles would fly about 50 times a year between 1979 and 1990. If only 30 flights a year were made, the cost per flight would be about the same as that of conventional rockets. Currently, the schedule calls for no more than 20 flights a year, and whether there will be more demand remains to be seen. About one third of the flights are booked by the military, and, in fact, it has been said that without the military, the shuttle would have been scuttled long ago. Many fear that it is a military escalation in civilian guise.
Even from a scientific standpoint some are disenchanted. “What’s happened,” said Joseph Veverka, chairman of NASA’s Comet Science Working Group, “is that the space science program in this country has been almost destroyed.” This is because “money to complete [the shuttle] was taken from science projects.” Even NASA is forced into the unglamorous role of space truck driver for other people’s cargo because it has little money left to develop anything else.
While praising the STS as “worthy and productive,” a group of scientists stated in the Bulletin of the American Academy of Arts and Sciences that “no fundamental principles of physics, no short-term biological issues and no questions of sound engineering practice” would be advanced by it. “By contrast,” said Lester R. Brown, director of Worldwatch Institute in Washington, “there are urgent problems being ignored.” He cited examples such as erosion of farmland and national indebtedness.
There is no doubt that the almost flawless first flight of Columbia is a great technological achievement. Because of that, many have the view that the new approach to space opened up by the shuttle will mean a better future for mankind. But, as the optimism generated by the first flight subsides, there will be plenty of opportunity for rethinking and reevaluating this most complicated flying machine ever built by man.
For conversion into metric system: 1 pound = 0.45 kg; 1 ton = 900 kg; 1 foot = 0.3 m; 1 mile = 1.6 km.
[Pictures on page 25]
Space Shuttle
Three main rocket engines can generate power equal to 23 Hoover Dams
Remote manipulator deploys satellites, space labs and other gear
Empty fuel tank, costing $3 million, discarded after 9 minutes
Computers on board perform up to 325,000 operations per second
Rockets slow orbiter to 14,000 m.p.h. for reentry at 40-degree angle
Silica shield withstands reentry heat of 2,500° For more
Booster rockets provide thrust equal to 25 jumbo jets
Touchdown at 200 m.p.h. on specified runway