Verne and Wells

However, the true colossi of science fiction belong to the 19th century. French author Jules Verne wrote a series of adventure novels on scientific themes, of which the most influential was From the Earth to the Moon (1865). Verne made a serious attempt to address the problem of launching a spacecraft towards the Moon, opting to propel his heroes and their moonship from a giant cannon, the Columbiad. His understanding of the laws of physics was somewhat awry, though: he didn't realize that the ship's occupants would be crushed by the sudden acceleration as the shell was fired (something that Kepler had taken into account); and he misinterpreted the influence of gravity (see caption, above left). In contrast, Herbert George Wells made little or no attempt at realism in his story of lunar flight. In The First Men in the Moon, written a generation later in 1901, he solved

JULES VERNE

In a prolific career, Verne wrote 54 novels and numerous short stories. He frequently returned to the theme of exploration in unknown environments and to making predictions of the world of the future.

the problem of space travel by having one of his characters invent a material, cavorite, that blocks out the effects of gravity. What's more, when the spacecraft's cavorite coating is complete, it simply shoots into the sky without any apparent propulsion. However, while Verne's story was focused on the human characters and the voyage to the Moon itself, Wells's imagination can be forgiven, since in his case space travel was largely a means to an end. Once on the Moon, the story turns into a political allegory as the travellers encounter a strange alien society. (In his even more influential The War of the Worlds (1898), Wells's Martians seem to use a "space cannon" to fire their ships towards Earth.)

Both Verne's and Wells's errors would have been obvious to anyone well-versed in the physics of the time, but a generation later educated people were still criticizing the pioneers of rocketry and claiming that space travel was impossible - at a time when it was on the verge of becoming a reality. The old geocentric instincts died hard, and there seems to be something about the laws of motion and gravitation that makes them particularly susceptible to misunderstanding.

BIOGRAPHY

r "a,

NIKOLAI KIBALCHICH

mmm

\

Rocket-powered spaceflight was suggested more than once in the 19th century, but the strangest case must surely be the tale of Nikolai Kibalchich (1853-81). In the 1880s, Russia was an absolute monarchy ruled by the Tsar and his noblemen, and the lower classes were seething with the resentment that would eventually lead to the revolution of 1917. Kibalchich, an engineer by training, became involved in a revolutionary group and made grenades used to kill Tsar Alexander II in 1881. While in prison awaiting execution for his role in the assassination, Kibalchich sketched a design for a rocket-powered passenger platform similar to that shown here. He sent it to the government, but after his death it languished in the archives until its rediscovery i in 1917.

Despite these problems, Wells, Verne, and others that followed them helped shape the imaginations of a generation of scientists. Space travel no longer seemed a fantastical dream, but an attainable goal. At least in some circles, one could now discuss the issues seriously and without risk of mockery.

THE MOONSHIP

In this illustration, Mr. Bedford, narrator of The First Men in the Moon, helps Dr. Cavot: to fit panels of gravity-resistant cavoritet onto his ball-shaped spacecraft.

THE MOONSHIP

In this illustration, Mr. Bedford, narrator of The First Men in the Moon, helps Dr. Cavot: to fit panels of gravity-resistant cavoritet onto his ball-shaped spacecraft.

H.G. WELLS

While Jules Verne was primarily Interested in telling scientific adventure stories, H.G. We 11% was a more political writer, frequently using his\noveJsij about the future tgji^^^M his socialist belief

Rocket prophet

Konstantin Tsiolkovskii did more than any other single person to make space travel a reality, developing many of the techniques and principles still used in rocketry today. Yet he spent most of his life as an obscure provincial teacher, winning recognition only in his old age.

While Verne and Wells had made the subject of space exploration acceptable, it was left to other talents to make it achievable, and the greatest of these was undoubtedly Konstantin Eduardovich Tsiolkovskii. Born in 1857 in the Russian town of Izhevskoye, Tsiolkovskii overcame a childhood illness that left him almost entirely deaf, to become one of the greatest practical scientific thinkers of his time.

"From the moment of using rocket devices a new great era will begin in astronomy."

Konstantin E. Tsiolkovskii, 1896

Fascinated from an early age with airships and balloons, Tsiolkovskii came to believe that a sealed ship of this type might be suitable for space travel. By this time, most scientists had realized that space beyond Earth was a vacuum - balloon-borne experiments had shown that air pressure fell rapidly at high altitudes. Since most propulsion systems relied on the presence of a medium to push against, they would be useless in a vacuum, so how could a spacecraft be propelled and steered?

A high-speed launch from a Verne-style cannon was out of the question. Tsiolkovskii carried out experiments that showed living creatures could survive an acceleration of up to 60m/s (200ft/s) per second (roughly six times the acceleration due to Earth's gravity, or 6g), but not much more. He also worked out the Earth's escape velocity, the speed required to launch an object from the Earth's surface so that it could never be pulled back by the planet's gravity. This turned out to be about 11.2km (7 miles)

THE INVENTOR'S WORKSHOP

While working as a teocher in the town of Kaluga, Tsiolkovskii produced numerous models to demonstrate his ideas, but never attempted to launch a rocket himself.

per second. Clearly any attempt to reach such a speed in a near-instantaneous burst of acceleration would result in a spacecraft's occupants being crushed to death.

The solution, Tsiolkovskii suggested, was a self-contained rocket or "reaction engine", which could produce steady acceleration inside or outside the atmosphere, eventually reaching speeds where a spacecraft could remain in orbit -its tendency to move away from the Earth perfectly balanced against the force of the planet's gravity - or even break free of the Earth altogether to travel across interplanetary space. Tsiolkovskii was not actually the first person to suggest rockets as a means of space travel (that honour goes to the 17th-century French author Savinien Cyrano de Bergerac), but he was the first to treat the idea seriously, publishing a number of detailed scientific papers that reached fruition in The Exploration of Cosmic Space by Means of Reaction Devices (1903).

Among Tsiolkovskii's breakthroughs was the realisation that multi-stage rockets would be more efficient than single-stage ones (see p.23). He was also the first to show how steering vanes, used to deflect the exhaust, could control a rocket's direction in a vacuum. Tsiolkovskii was certain that liquid fuels would be needed to reach space, since black powder (see p.12) was too weak a propellant, and combusted only by reacting with oxygen in the atmosphere. A truly self-contained rocket would have to carry not only fuel, but also a chemical oxidant, in tanks onboard, and the best choice would be liquid hydrogen fuel burning with liquid oxygen. At the time, however, these substances were impossible to manufacture in large amounts.

TECHNOLOGY

HOW ROCKETS WORK

upward movement

■ _ solid fuel downward movement downward movement particles ejected at high velocity reaction causes rocket to move in opposite direction to exhaust combustion particles ejected at high velocity

Rockets rely on the principle of conservation of momentum - the immutable law that says that unless an external force is applied, the momentum of a system (its mass multiplied by its velocity, or speed in a particular direction) must stay the same. So when the exploding fuel inside a typical rocket forces gas out of the exhaust at high speed, the rocket itself must move in the opposite direction in order for the overall momentum to stay the same. Because the rocket has far more mass than the exhaust gas, it accelerates far more slowly than the exhaust. Once it has left the Earth's atmosphere, the rocket can work equally well, if not better, in a vacuum.

GRAND OLD MAN

Tsiolkovskii spent much of his life in relative obscurity. It was only after the 1917 Russian Revolution that his ideas, such as liquid rocket designs (right), received widespread recognition. When he died, in 1935, he was acknowledged as the pioneer of a new science.

GRAND OLD MAN

Tsiolkovskii spent much of his life in relative obscurity. It was only after the 1917 Russian Revolution that his ideas, such as liquid rocket designs (right), received widespread recognition. When he died, in 1935, he was acknowledged as the pioneer of a new science.

0 0

Post a comment