THE CONQUEST OF SPACE: SPACE EXPLORATION & AEROSPACE SCIENCE

✒AstroMuon Kuki🚀🛰

Introduction:

Man, a rational being, has been curious to explore mysteries of nature and this led to many discoveries being made in various part of the world. His incredible lust for knowledge has revolutionized human life and raised the standard of life.As the old Chinese proverb says,the journey of a thousand miles begins with the first step.The journey to the space starts with the very first rocket.
History reveals that scientific revolutions come in waves,often stimulated by advances in physics. In the nineteenth century,the first wave of science and technology was made possible by physicists who created the theory of mechanics and thermodynamics.This enabled engineers to produce the steam engine,leading to the locomotive and the industrial revolution.
In the twentieth century,the second wave was spearheaded by physicists who mastered the laws of electricity and magnetism,which in turn ushered in the electric age.
This made possible the electrification of our cities with the advent of dynamos,generators,TV, radio,and radar.The second wave gave birth to the modern space program,which took us to the moon simultaneously begins Space Age(1951-1958).
In the twenty-first century,the third wave of science has been expressed in high tech,spearheaded by the quantum physicists who invented the transistor and the laser.This made possible the supercomputer,the internet,modern telecommunications and GPS.
In future,we will have to exploit the fourth wave of science by Aerospace technologies. The goal of terraformed Mars exceeds our capability today,but the technologies of the twenty-second century will allow us to turn this bleak,frozen desert into a habitable world.

TSIOLKOVSKY-A LONELY VISIONARY

On his own,he calculated the escape velocity of  the Earth-to be twenty five thousand miles per hour.
In 1903,he published his famous rocket equation,which allows one to determine the maximum velocity of a rocket,given its weight and fuel supply.The equation revealed that the relationship between speed and fuel is exponential.
Normally,one might assume that if you want to double the velocity of a rocket,you simply need to double the amount of fuel.
Instead,the amount of fuel you need rises exponentially with the change in velocity,so that enormous amounts  of fuel are needed to give extra boost in speed.
This exponential made it clear that you would need huge amounts of fuel to leave the Earth.With his formula,Tsiolkovsky-was for the first time able to estimate how much fuel was necessary to go to the moon,long before his vision became reality.
Although Tsiolkovsky was too poor to convert his mathematical equations into actual models,the next step was taken by Robert Goddard,who actually built the prototype that would one day form the basis of space travel.
Tsiolkovsky’s guiding philosphy was,”The Earth is our cradle,but we cannot be in the cradle forever,” and he believed in a philosophy called cosmism,which holds that the future of humanity is to explore outer space.

ROBERT GODDARD-FATHER OF ROCKETRY

Robert Goddard first became interested in science as a child witnessing the electrification of his hometown.Goddard systematically turned this curiosity into a usable scientific tool by introducing three innovations.
First,Goddard experimented with different types of fuels and realized that powered fuel is inefficient.The Chinese had invented gunpowder centuries earlier and used it for rockets,but gunpowder burns unevenly and hence rockets remain mainly toys.
Second,to replace powered fuel with liquid fuel,which could be precisely controlled so that it burns cleanly and steadily.He built a rocket with two tanks,one containing a fuel,such as alcohol,and the other tank containing an oxidizer,such as liquid oxygen.He realised that as the rocket rose into the sky,it’s fuel tanks were gradually depleted.His next innovation was to introduce multi-stage rockets that discarded spent fuel tanks and therefore could shed some dead weight along the way,vastly increasing their range and efficiency.
And third,he introduced gyroscopes.Once a gyroscope is sent spinning,its axis always points in the same direction,even if you rotate it.For example,if the axis points toward the North Star,it will continue to point in that direction if you turn it upside down.This means that a spaceship,if it were to wander in its trajectory,can alter it’s rocket to compensate for this motion and return to its course.Goddard realized he could use gyroscopes to help keep his rockets on target.
In 1926,he made history with the first very successfully launch of  a liquid fueled rocket.It rose 41 feet into the air,flew for 2.5 seconds,and  landed 184 feet in a cabbage patch.

WERNER VON BRAUN

Under Von Braun’s leadership,the scribblings and sketches of Tsiolkovsky’s and the prototypes of Goddard became the Vengeance Weapon 2 rocket,an advanced weapon of war that terrorised London and Antwerp,blowing up entire city blocks.

The V-2 was unbelievably powerful.It dwarfed Goddard’s rockets,making them look like toys.The V-2 stood 46th feet tall and weighed 27,600 pounds.It could travel at a blazing speed of 3,580 miles per hour and it achieved a maximum altitude of about sixty miles.It hits it’s targets at three times the speed of sound,it broke the sound barrier.And it had an operational range of two hundred miles.

The V-2 set a number of world records,shattering all past achievements in terms of speed and range for a rocket.It was the first long range guided ballistic missile.It was the first rocket to break the sound barrier.And most impressively,it was the first rocket ever to leave the boundary atmosphere and enter outer space.

SPUTNIK AGE

After the first  Vanguard missile rise four feet into the air,then drop back down four feet,tip over,and destroy its own launchpad in huge,blinding expansion.The second Vanguard launch few months later also failed.In order to regain Russia reputation or sealed its government in Space race,Von Braun was ordered to quickly launch a satellite,Explorer 1,using the Juno 1 Missile.

Sputnik 1 was the first artificial Earth satellite. The Soviet Union launched it into an elliptical low Earth orbit on 4 October 1957.

1957:Sputnik 2 carried the first animal,a dog named Laika,into orbit.

1957:Lunik 1 was the first rocket to fly past the moon

1959:Lunik 2 was the first to hit the moon.

1959:Lunik  3was the first rocket to photograph the backside of the moon.

1960:Sputnik 5 had the first animals returned safely from space.

1961:Venera 1 was the first probe to fly past Venus.

The Russian Space Program reached its crowning achievement when Yuri Gagarin safely orbited the Earth in 1961.
Note:Since space is premium,astronauts have historically been small people.Yuri Gagarin,for example,was only five feet two inches tall.He was the first person to go in Space.

APOLLO MISSION

First,there was  the one manned craft called Mercury,and then the two manned Gemini,and finally the three- manned Apollo.
Two types of Apollo Mission:Manned Mission and Unmanned Mission.
Manned Mission:Apollo 7 to Apollo 17(only Apollo 13 failed the mission)
Apollo 11 was the spaceflight that landed the first two people on the Moon. Commander Neil Armstrong and lunar module pilot Buzz Aldrin, both American, landed the Apollo Lunar Module Eagle on July 20, 1969.
Unmanned Mission:Apollo 18 to Apollo 20.

Not only that, plethora space missions from various governments and private company are coming up in the future.

SPECIFIC IMPULSE AND ENGINE EFFICIENCY

Engineers sometimes speak of "Specific Impulse, " which enables us to rank the efficiency of various engine designs. "Specific Impulse" is defined as the change in momentum per unit mass of propellant. Hence the more efficient the engine, the less fuel is necessary to boost a rocket into space. Momentum, in turn, is the product of the forces acting over a period of time. Chemical rockets,although they have very large thrust, operate for only a few minutes, and hence have a very low specific impulse. Ion engines, because they can operate for years, can have high specific impulse with very low thrust. Specific impulse is measured in seconds. A typical chemical rocket might have a specific impulse of 400-500 seconds. The specific impulse of the Space shuttle engine is 453 seconds(The highest specific impulse ever achieved for a chemical rocket was 542 seconds, using a propellant mixture of hydrogen, lithium, and fluorine). The thruster for the Smart 1 ion engine had a specific impulse of 1,640 seconds. And the nuclear rocket attained a specific impulse of 850 seconds.

The maximum possible specific impulse would be a rocket that could attain the speed of light. It would have a specific impulse of about 30 million. Following is a table showing the specific impulses of different kinds of rocket engines and some are going to be used in the future. This is likely to change the future of aerospace sector.

TYPES OF ROCKET
(SPECIFIC IMPULSE)

Solid fuel rocket
(250)
Liquid fuel rocket
(450)
Ion Engine
(3,000)
VASIMR plasma engine
(1,000 to 30,000)
Nuclear fission rocket
(800 to 1,000)
Nuclear fusion rocket
(2,500 to 200,000)
Nuclear pulsed rocket
(10,000 to 1 million)
Antimatter rocket
(1 million to 10 million)

(In principle, laser sails and ram-jets engines, because they contain no rocket propellant at all, have infinite specific impulse, although they have problems of their own)

Conclusion:

Egyptians, Babylonians, Mayan and ancient people considered space as habitat to Gods. However, due to the advancement of aerospace technology space is now considered as a place. Space travel is no Sunday picnic anymore!

Ref:The Future of Humanity, Michio Kaku.
A Brief History of Humankind, Yuval Noah Harari.
Astrophysics for people in hurry, Neil de grass Tyson.
Physics of Impossible, Michio Kaku.
Parallel worlds, Michio Kaku.
UC3CM edx lectures,
NASA website, ISRO website,
Wikipedia.