Our 20th Century Space Legacy – Part 1: The Evolution of Rocket Technology

I grew up on a steady diet of science fiction where humanity travelled as freely through space as we do on Earth. Our venture into space so far does not reflect the science fiction I read as a young man. Where the 20th century launched us for the first time into and beyond our atmosphere, the 21st to date has largely remained near-Earth orbit experience for humans in space. Human-built robots have been the spacefarers exploring the planets of the Inner and Outer Solar System and with spacecraft launched in the 1970s reaching interstellar space.

Rockets are a Chinese invention with reference to them as useful for both military and celebratory purposes. The Chinese defended themselves against the 13th century Mongol invasion using rockets with little effect. Through trans-Asian trade, rockets were introduced to Europe in the 14th century. Rockets primarily were powered arrows at this time. In the 19th century the British Congreve rockets inspired Francis Scott Key in his writing of “The Star Spangled Banner,” the American national anthem. Rockets were used in whaling to enhance the power and distance harpoons could travel. Rockets attached to safety lines were used to reach ships in distress so that they could be towed to safety. The Katyusha rockets of World War II were the 20th century equivalent of the British Congreve rocket.

But the rockets that were to launch humans into Outer Space did not use the technology inspired originally by Chinese invention. In 1903, Konstantin Tsiolkovsky, a Russian school teacher, proposed liquid propellants as a rocket fuel because of the potential increase in exhaust velocity to drive rockets farther. In his writing Tsiolkovsky laid the theoretical groundwork for the rockets of Robert Goddard, an American, who built the first liquid-fueled rocket and launched it successfully. It didn’t go far but the technology he demonstrated became the basis for Germany’s emergence as the leader in modern rocketry.

Before World War II rocket clubs popped up throughout Europe, Japan and the United States. Rocket hobbyists were popular in Germany inspirted by the writings of Dr. Hermann Oberth, a Hungarian-born German, who wrote about rocket travel beyond Earth. An inspired Werner von Braun in 1930 began experimenting, building and firing liquid-fueled rockets built on Goddard’s designs. Von Braun eventually became the leader of the German rocket program that created the A-4, the rocket known to us as the V-2. The A-4 stood 14 meters in height (46 feet), burned alcohol combined with liquid oxygen, and could launch a  750 kg, (1,650 pound) payload. It had a range of 360 kilometers (225 miles). Several thousand A-4s with attached warheads were constructed and launched against British, French and Belgian targets from 1944 to early 1945 causing considerable destruction.

With the end of World War II both the United States and Soviet Union took an interest in the weapon systems designed by Germany. German scientists, remaining inventory of A-4  rockets, and the engineering tools and technology were spirited out of the country. The race to exploit and enhance this technology for war and science had begun.

Machines Enter Outer Space, Humans Soon Follow

Both the United States and Soviet Union assembled and test-fired the remaining inventory of A-4 rockets. Then they began building their own largely for war purposes. The dream of using rockets to put machines and humans into outer space seemed like an afterthought.

Exploration of near-Earth space soon followed with the launch of Sputnik, in October, 1957, the first artificial satellite placed in orbit. Weighing 84 kilograms (183 lbs.), Sputnik’s launch vehicle was the R-7.  R-7 technology directly evolved from the A-4. It burned kerosene and liquid oxygen. Today’s Russian space program continues to use the R-7.

To get to orbit rocket technology needed to achieve escape velocity. That meant building rockets with more power. More power required a larger amount of fuel. Both the Americans and Soviets approached this by developing multiple-staged rockets. With multiple staging a rocket could achieve orbit without carrying around any extra weight in the form of empty rocket casings. The approach to multi-staging, however differed dramatically. The Americans chose to build multi-stage rockets in a vertical-stack configuration. The Soviets built multi-stage rockets by strapping together each rocket. In the picture below you can see how the two designs differ. In the short-term the Soviet design made it possible to develop heavier lift capacity. The R-7 had three times the thrust and payload capacity of any of the American rockets. With limited thrust and capable of delivering only small payloads American satellite requirements stimulated integrated circuit development and the technology behind modern computing. But at the beginning of the Space Age, this need for light and small was not seen as an advantage.

In space the Soviets surged ahead with heavy launch capacity and a program aimed at being first in all the key categories;

1. First artificial satellite (Sputnik 1) October 4, 1957
2. First animal sent into orbit (Sputnik-2 with the dog, Laika on board) November 2, 1957.
3. First satellite to orbit the Moon (Luna 1) January 2, 1959.
4. First satellite to send photographic images of  70% of the Moon’s far side (Luna 3) October 4, 1959
5. First animals sent into orbit and returned safely to Earth (Sputnik-5 with two dogs, Belka and Strelka on board) August 19, 1960.
6. First human to orbit the Earth and return safely (Yuri Gagarin in Vostok 1) April 12, 1961
7. First human to do multiple orbits of the Earth (Gherman Titov in Vostok 2) August 6, 1961
8. First multi-crew orbital flight (Vladimir Komarov, Konstantin Feoktistov, Boris Yegorov, in Voskhod 1) October 14, 1964.

For the American program the achievements were far more modest, the successful launch of a satellite, Explorer 1, January 31, 1958. Pioneer 4, launched in March 3, 1959, became the first American satellite  to pass the Moon and achieve solar orbit. On May 5, 1961, Alan Shepard became the first American to achieve suborbital flight. And on February 20, 1962, John Glenn became the first American to orbit the Earth.

The components for reasonably reliable rocket technology made these advances possible. All that was left was the imagination and determination of a government to set an achievement goal. That happened when President John F. Kennedy established a goal of landing a human on the Moon before 1970.

In our next blog we will look at the technology that created to achieve the Lunar landing of Neil Armstrong and Edwin Aldrin in Apollo 11.