Space Shuttle1

By 1957 some designers were deep in studies to see how a space shuttle might best be designed. All were agreed that the basic answer was to construct a "space aircraft" with wings of a broad ogival² delta shape rather like those of the Concorde SSI. Joined to it would be the booster; this would comprise two or more large solid rockets. Both would be raised vertically until they were standing on their rocket motors with their noses pointed to the heavens. The orbiter would be joined closely above the booster³ to form a kind of biplane combination. The boosters would carry nothing but propellants and have no crew; the orbiter would be loaded with everything needed for its mission in space. The combined vehicles would lift off together and climb vertically before gradually nosing over at a height of some score of miles at a speed many times that of sound. At a height of 25 miles the orbiter would separate. The booster would burn out, fall into the ocean, and be recovered and then refurbished⁴. The orbi­ter would continue out to its appointed mission in space. From its capacious hold⁶ it could produce large space-stations, lunar labora­tories or any of the many other kinds of hardware needed for space operations. Or, its payload could comprise men and supplies, the re­turn trip being the homeward journey to Earth of crews whose duty on a space or lunar station had been completed.

Although the complete shuttle, comprising both the booster and the orbiter, was planned to cost more than a Saturn Vrocket, the cost per mission would be very much less even if in practice fewer than a hundred missions were realized for each vehicle. The cost of delive­ring a load to the moon or to a future space station was estimated at about one-tenth of its 1972 level. These new flying vehicles will close the gap that once existed between aircraft and space rockets. Tomor­row's space vehicle will not look like a vertical tower but like a large aircraft of rather odd shape. When it returns to Earth, it will be in all respects an atmospheric aircraft, with lift provided by a wing and steering effected by aerodynamic controls.

With the appearance of such craft proposed in the late 1970s man will have completed his initial conquest of the Earth's atmosphere and the surrounding region of the solar system.

The space shuttle, with its prospect of being used a hundred times, will enable men of many nations working together to construct great space stations much nearer to Earth than the Moon and much more useful.

The Radiation Hazard in Space

One of the serious questions was the exposure of humans to radia­tion in space. The Van Allen belts, bands of rapidly moving charged particles circling the earth, had been discovered only a few years earlier, and no one was certain of their extent or the intensity of radia­tion associated with them. Also, solar storms had recently been disco­vered that inundated the space around the sun with charged particles, producing radiation levels that would be lethal for a human in an un­protected state.

This was a difficult question. There was not much knowledge about either the frequency or the intensity of solar storms, and the Van Allen belts had not been explored thoroughly enough to indicate how far they extended. Scientists spent several months, therefore, intensi­vely studying the levels of radiation between the earth and the moon. They were able to establish the upper limit of the intensity of solar storms, and they were able to show that the Apollo Command Module provided shielding thick enough so that the men inside it could sus­tain the entire period of a solar storm.

The Lunar Module (LM) presented a different problem because it had to be built of thin and light material that could not protect the astronauts from solar radiation on the lunar surface. (The space suits also offered practically no protection). They determined how much lead shielding they would have to add to the LM to provide the neces­sary protection, and found that it would have made it too heavy for launching. Finally, they took the advantage of the fact that solar storms build up gradually and that, although the radiation can become intense, it takes an exposure of several hours to do any significant da­mage. The problem then became one of detecting the onset of a solar storm, so they developed a network of sensors aboard the Command Module that would detect a radiation buildup; and they modified the missile plan in such a way, that, if radiation were to build up at a cer­tain rate during the moon walk, the astronauts would enter the LM, take off, return to the Command Module, and abort the remainder of the mission. This was an indirect solution, but one which demonstra­ted that the scientists understood the problem and had a plan to deal with it.