If China’s space station is so expensive, why does it still need to carry six iron balls weighing one ton?

When launching a rocket, all the load must be used on the blade. Therefore, the load must be as light as possible and must not be overloaded.

After all, spacecraft are expensive to build, and every gram of them is worth half a pound of gold.

However, our country's space station carried 6 large iron balls, with a total mass of about 1 ton.

Why do they need to bring a big iron ball when the payload is so tight? Is it because the space station is too light?

6 large iron balls

These six large iron balls are located on the core module "Tianhe" of the Tiangong space station, and are neatly arranged in a circle on the edge of the core module.

There is a saying in the aerospace field: for every 1 kg increase in the weight of the spacecraft, 750 kg of fuel must be added accordingly.

Therefore, when designing a spacecraft, we try to reduce mass as much as possible, which saves both fuel and cost.

However, the combined mass of these six iron balls is about 1 ton, so the additional fuel would be 750 tons.

Are these six iron balls installed to prove that our country's space program is not short of money?

Of course not. Every component on the spacecraft has its function. We cannot just look at the weight of these six iron balls and ignore the role they play in the space station.

These large iron balls have a professional term, called "control torque gyroscope", which means that although they look like balls, they are actually gyroscopes in essence.

It will rotate like a gyroscope and then change the torque of the space station to adjust the posture of the space station.

We all know that the space station cannot maintain one posture forever, it needs to adjust according to various situations.

These six large iron balls are not embedded in the Tianhe, there is a connector between them and the core module.

These six iron balls are evenly distributed. If you need to adjust the direction, you can rotate these six gyroscopes, and the maximum speed can reach 7000 revolutions per second.

If you still have no idea how they work, you can imagine a toy finger spinner that spins quickly in your hand and you feel a force on your fingers.

This is actually the finger gyroscope changing the torque of the human hand, but because it is too small, it is not enough to change the posture of our hand.

So, this is not something that adds weight to the space station, but rather a necessary component.

But each of these components weighs more than 100 kilograms. How to replace them if they break down?

It's very simple. More than 100 kilograms is its weight on Earth. After entering space, it becomes weightless. Astronauts are all strong men, so moving an iron ball of more than 100 kilograms is not a problem at all.

With the help of Tianhe robotic arm, replacement can be achieved.

Big iron ball work

Although the space station will stay in space for a long time, it does not mean that it will not need to adjust its flight trajectory.

Even at special moments, it needs to adjust its orbit.

There are more than 100 million pieces of space junk in space. They vary in size. Some are abandoned satellites, each weighing hundreds of kilograms; some are broken off fragments weighing only a few grams.

Their flying speed is between 2.8 and 7 kilometers per second. At such a speed, a random collision can destroy parts at best, or even completely scrap the space station at worst.

This dangerous situation must have been taken into consideration when the Tiangong space station was designed.

Therefore, it is necessary to have the ability to adjust one's own posture, otherwise one will be hit head-on.

In addition to avoiding danger, the space station also needs to adjust its posture during docking to allow for better docking.

Spacecraft docking can be divided into manual and automatic. No matter which one, these six large iron balls are needed to play a role.

When necessary, the space station will even turn its head to ensure that a part of itself is always facing the earth, so as to better receive or transmit signals from the earth.

When the International Space Station was built, there was no control torque gyro, so reverse thrust was adopted, using the engine to spray in the opposite direction in order to adjust the direction and posture.

The consequence of this is that a lot of fuel is used. According to statistics, the International Space Station requires $1 billion in additional fuel every year, which is mainly used to adjust the space station.

Later, the International Space Station could not afford such a large expenditure, so four control torque gyroscopes were installed on the main cabin of the space station, each weighing more than 270 kilograms.

Because it can be powered by electricity, and the electricity on the space station comes from solar charging panels, this can save a lot of fuel.

Our country learned from this lesson and used control torque gyro from the beginning, which saved a lot of costs.

So, don’t say that installing iron balls is expensive, it actually saves money.

Space station thrusters

Many people believe that a space station is so big that it requires a lot of energy to propel it.

In fact, the thrusters of the Tiangong space station can only push a piece of paper on Earth. Is that surprising? Is that surprising?

This type of thruster is called a Hall thruster, which is the Hall effect that everyone is familiar with in high school.

In layman's terms, the thrusters of the space station do not spray out fire, but a stream of particles. The charged particles are accelerated by electric fields, and they are ejected at extremely high speeds, providing a thrust.

my country's space station weighs more than 60 tons, but its thrusters only have a thrust of 0.32 Newtons.

On Earth, you can only push a piece of paper. But in space, there is no air resistance, and just a slight force can make the space station move forward.

However, Hall thrusters also consume energy, they consume electrical energy and particles.

The electricity mainly comes from solar charging, and the particles come from the gas brought in advance, mainly xenon.

Xenon gas is easily ionized, producing charged particles. As expected, this is the Heavenly Palace, even the drive is xenon gas!

If the xenon gas is consumed, insufficient injection will occur due to insufficient injection particles.

Therefore, a transport rocket that replenishes materials can periodically replenish compressed xenon gas.

Why choose particle thrusters instead of fuel thrusters? This is because there is no oxygen in space. If fuel is used, additional combustion aids need to be carried, which will increase the weight of the vehicle.

The Hall thruster does not have this concern; it only needs to carry enough particles to achieve continuous energy supply.

In addition, the upper limit of the speed of the Hall thruster is higher than that of the fuel. The upper limit speed of the fuel is the first cosmic speed, but the upper limit speed of the Hall thruster can theoretically reach the third cosmic speed or even higher.

To some extent, it is the main force of future aerospace power.

However, the thrust provided by the current Hall thrusters is relatively small, with the largest thruster providing a force of about 3 Newtons. If we want to use it to achieve free flight, we still need to continue our efforts.

The role of the space station

Some people criticized my country's space station as a "face project" that is a waste of money and time and has no practical value.

In fact, each of us is a beneficiary of aerospace technology, but many people have not discovered it.

The vegetables, fruits, and even the trees grown in the Northwest that we eat all contain a mysterious technology—space breeding.

When plant cells are exposed to weightlessness or radiation, they will mutate, changing their original traits and acquiring new traits, such as increased yield, greater drought resistance, and greater cold resistance.

For example, a kind of pepper available on the market has a vitamin content 30% higher than that of ordinary peppers. It is not an ordinary pepper, it is a pepper that has traveled in space!

Many people don’t know that my country’s space breeding has a market size of over 200 billion and has gradually entered everyone’s lives.

It’s a pity that some people eat high-quality vegetables grown in space and make sarcastic remarks about it being a “face-saving project”.

Another function of the space station is to complete space experiments, especially biological experiments.

We know that experiments require large equipment. If it is just an ordinary manned satellite, astronauts will not be able to perform their functions on it, let alone carry large experimental equipment.

The only thing that can do these two things is the space station. Because of the obstruction of Western countries, my country cannot enter the International Space Station. If we don’t have our own space station, then there are some experiments that we will never be able to do.

For example, growing vegetables in space, which everyone is concerned about, cannot be carried out without a space station.

In order not to waste our racial talent for growing vegetables and to grow vegetables towards the stars and the sea, we need a space station.

Therefore, the Tiangong Space Station is not the end of my country's space exploration, it is just a starting point.

In the future, more domestically-made spacecraft will play their respective roles in space.

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