The Geopolitics of Space Exploration

By Marcello Spagnulo

This is the tale of the modern Space Age, detailing all the risks, rewards and rivalries that have fueled space exploration over the decades. Jump into a world of ambitious entrepreneurs and determined spacefaring nations, of secret spy satellites and espionage, of all the cooperative and competing interests vying for dominance in ways little known to the public.

Written by an Italian aeronautical engineer with over thirty years of experience in government and private industry, this English translation explains how and why the game has fundamentally evolved and where it is headed next.

Exploring such topics as GPS and cyberspace, the economics of private and public industry and the political motivations of emerging spacefaring powerhouses like China, this book is an engaging foray into the ongoing battle for our terrestrial home through extraterrestrial means.

• Language: English
• Publisher: Springer
• Release date: Apr 2, 2021
• ISBN: 9783030691257

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© The Author(s), under exclusive license to Springer Nature Switzerland AG 2021

M. SpagnuloThe Geopolitics of Space ExplorationSpringer Praxis Bookshttps://doi.org/10.1007/978-3-030-69125-7_1

1. Fundamentals of Astronautics

Marcello Spagnulo¹  

(1)

Rome, Italy

Interestingly, according to modern astronomers, Universe is finite. This is a very comforting thought - particularly for people who can never remember where they have left things.Woody Allen

Most people, unless they have studied aerospace engineering or astrophysics, are not aware of the complicated mathematical laws regulating spaceflight outside the Earth’s atmosphere or between planets in the solar system. Almost everyone has been influenced by science fiction movies, which since the fifties have been showing spaceships as cosmic airplanes capable of performing hypersonic accelerations and breath-taking turns, engaging in duels with laser weapons and firing thousands of light beams into the cosmic void.

These spectacular manoeuvres are impossible to achieve, not just because of current limitations of technology, but because they are simply not allowed by the laws of orbital mechanics. Just go to NASA’s official website and watch the docking of a cargo ship to the ISS; the lack of dynamism in this manoeuvre will be evident. Both approaching space vehicles are flying at an unimaginable speed of 16,700 miles per hour, but despite this, the whole sequence seems slow and even a bit boring.

The following nonmathematical, nontechnical pages have been written to illustrate some aspects of astronautical science in a way that is accessible to anyone.

To keep it simple, consider the similarities and differences between spaceships and airplanes, the only vehicles that most people take to lift themselves off the ground and come closer to the starry sky. The motion of a spaceship differs from that of an airplane in three ways.

First, its speed does not depend on its altitude. Two planes can fly at the same altitude at different speeds. On the contrary, in space, there is a precise relationship between the distance from Earth and speed. Satellites, spaceships or space stations that move in the same orbit – i.e. at the same altitude from the Earth’s surface – always have the same speed. This varies with altitude. The closer to Earth a satellite is orbiting, the higher its speed is and the shorter its travel time around the planet. The relationship between orbit altitude and speed in space is a precise mathematical rule – thus, those fast and reckless spaceship manoeuvres can only be seen in movies.

Second, an airplane flying in the atmosphere travels through the air, which is a compressible fluid, to sustain the wings allowing it to manoeuvre. By moving ailerons¹ on the wings or the tail rudder, an airplane shifts the flow of air around it and thus changes direction, in the same way that a boat manoeuvres in the water with its oars or rudder.

There is no air in space, so a satellite must always use rocket engines to manoeuvre. This has important implications in a space project because, depending on the type of mission, it will be necessary to precisely calculate all the necessary fuel, including a contingency reserve, and fill the tanks before take-off. To date, it is not yet possible to refuel in space or return to Earth to fill up and then take off again, as airplanes do. Moreover, one of the most widely used propellant for spaceships is hydrazine, a nitrogen chemical mixture that is highly toxic and harmful to humans and the environment, so refuelling can only be done on Earth in closed and protected areas.

Third, a flying airplane always encounters air drag, which continuously slows it and tends to bring it down. To avoid this catastrophic event, its engines must always be running, providing the necessary thrust not to crash. This does not happen in space. Satellites go into orbit thanks to a rocket, named launcher, that carries them inside its fairing; the powerful engines of the launcher defy the Earth’s gravity, bringing the payload to the limits of the atmosphere over 90 miles high.

At that point, just like a slingshot, the launcher releases the satellite. The satellite then begins to turn around the Earth with the same speed – about 5 miles per second – provided by the rocket itself. In practice, the spacecraft remains in constant balance between the Earth’s gravity and the centrifugal force, following a curved trajectory parallel to the Earth’s surface. It is attracted by the planet’s gravity, but if the rocket has provided it with the right speed, the spacecraft remains in orbit and never falls back.

It may sound weird, but it works. An astronaut inside the ISS feels weightless – not because there’s no gravity, but because he or she is in a state of perpetual pseudo-fall. In addition, the Moon orbits the Earth and is attracted by its gravity, just like the ISS. It makes a round trip around our planet in 27 days at a speed of 620 miles per hour, in a sort of constant fall towards the Earth – an event that luckily for all of us never happens.

Sir Isaac Newton had the brilliant intuition that the gravitational physics between the Earth and the Moon was the same as that of an apple falling to the ground from a tree, and so he translated the laws of gravity into equations. Spaceships and satellites switch on their engines only when they need to change position or height, i.e. to accelerate or brake. This means that spaceflight mostly happens with lights and engines switched off on rigid highway lanes, following a precalculated path thanks to the mathematical laws discovered by Newton.

Now, imagine that you are on board the ISS, floating inside the pressurized module and checking the orbital data on the control panel: altitude at 248 miles and speed at 16,700 mph. You feel safe because this means the station is flying nicely and not falling. You receive a phone call from Houston telling you that you have an imperative commitment on Earth and you must return urgently. If you were the guest star of a Hollywood science fiction movie, you would enter the Soyuz capsule attached to the Russian Zvezda module, turn on the retro-rockets by detaching from the station, point the nose of the spacecraft down – it would be difficult to find it because the Soyuz is a sphere, but let’s pretend that you can – and you would accelerate to descend immediately into Earth’s atmosphere.

If you did this in real life and not in a movie you would risk speeding up, missing the angle of return, bouncing on the Earth’s atmosphere and never returning down. If you were really in the Soyuz’s command seat, you’d have to slow down by firing your engines in the opposite direction of flight. That way, the ship would gently go down, deviating its orbit downward until it met the upper layers of the atmosphere, generating enough friction to return to Earth like an incandescent meteorite.

This is the way re-entry from space really works, and it is in fact a dangerous manoeuvre. One of the main risks for astronauts is friction with the atmosphere. The high kinetic energy of the spaceship, traveling at the amazing speed of five miles per second, must be dissipated as heat. The space shuttle slowed down from 16,700 mph to zero in thirty minutes to land safely on Earth. During this time, the friction with the atmosphere created an ionized plasma at 1,800 degrees Fahrenheit, which surrounded the vehicle, making it a sort of burning meteorite in freefall. The re-entry manoeuvre was critical. Unfortunately, in 2003 it was fatal for the Shuttle Columbia, which disintegrated over Texas due to a crack in the heat shield.

Air drag helps slow down the descent speed from space if we want to re-enter the planet. It also prevents us from orbiting close to the Earth’s surface. If there was no atmosphere, we could enter into orbit even a few miles above the ground – a manoeuvre that can be done on the Moon where there is no air. But on Earth as well as any planet with an atmosphere, if you want to go into space you need to climb over 90 miles above the ground where the air particles are rarefied. It is not enough to climb up to that altitude; it is also necessary to be traveling five miles per second in order to defy the Earth’s gravity and not fall back down. At an altitude of 93 miles, gravity is reduced by 90% with respect to its value on ground, and at 248 miles where the ISS is orbiting, by 95%. For this reason, the speed needed for orbital insertion varies with altitude. If you want to reach an orbit close to the Earth, called low Earth orbit (LEO), which lies between 93 and 620 miles, you need to reach a speed of 16,700 mph. A satellite or nuclear warhead travelling on a ballistic missile – basically a space rocket missing the last stage – takes 45 minutes to make half a tour of the Earth.

If the orbital insertion speed is greater than 16,700 mph, then we leave the Earth, and if we are lucky, we find ourselves on an elliptical orbit along which we approach our planet and then slowly move away from it in a perennial back and forth.

Firing powerful engines at a speed of 25,000 mph, we enter an orbit towards the sun and, if we have done the correct calculations, after a three-day trip we reach the Moon. If we want to escape the deadly attraction of our star as we move towards it, we need to have an engine four times more powerful, which at the moment only exists in the movies. So, in space around Earth as well as in the solar system, we do not travel on spaceships with the engine always running. Instead, we move like stones on predefined orbits such as cosmic freeways, thanks to a mathematical system conceived by Sir Isaac Newton in the late seventeenth century.

Now, let’s forget about the deep space for a moment and focus on our planet to better understand how satellites work. In LEO there are satellites taking pictures of any place on Earth; in the politically correct jargon they are called Earth observation satellites. They have onboard telescopic cameras that point to the Earth’s surface for spying or monitoring activities on specific sites on the ground, but if they turn towards the stars and planets, they take astronomical images and do scientific research.

You cannot take a picture of everything from space, since there are limits to photo resolution beyond which images are blurred because of the wavelike nature of light. Then there is the problem of the very short time of overflight. At an altitude of 93 miles, a satellite flies over a territory of 95 miles in about a minute. In that time, it can take pictures of a few sites, not of the entire area. To overcome this, some satellites are launched into higher orbits such as the geostationary one, called GEO, at 22369 miles above the Earth’s surface. Up there, the gravitational attraction is 42 times lower than on the ground and a satellite travels at a speed of 1.9 miles per second, taking 24 hours to make a complete tour of the planet. In practice, it takes the same time as the Earth’s rotation. This means that a geostationary satellite has the same angular speed as the planet, so it always seems fixed from a ground site, even if it actually moves along the orbit.

Two practical advantages derive from this. First, a single satellite at that distance, equal to six times the Earth’s radius, can observe a third of the entire planet. This means that with only three satellites at 120° apart from each other, you can monitor the whole Earth from that orbit. The second great advantage is that ground stations can transmit to those satellites without moving the antennas, which simplifies the entire connection and hardware. This is why weather and telecommunications satellites fly at that altitude; from there, you can constantly monitor the weather over an entire continent or you can transmit TV signals from one point to another on the planet without using any ground repeater. For this reason, geostationary orbit is also highly strategic for the armed forces. From there, satellites provide crucial support for command and control centres and for all military assets on air, land and sea.

However vast space is, geostationary orbit is very crowded because all the satellites are concentrated on a precise strip above the Earth’s equator. If they were elsewhere, their trajectory relative to the surface, named downrange, would not be a motionless point but instead would be moving up and down, making the pointing of antennas much more difficult. This means that hundreds of satellites from different countries are clustered in space above the most strategic areas of the planet, sometimes interfering with each other. There are international rules to manage these orbital slots, just like for airplane take-offs and landings, but often the rule is determined by the law of the strongest, and those who can occupy the best positions in