Ask Ethan: why don't we send trash to the sun?

Original author: Ethan Siegel
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The Solar Orbiter satellite is a great way to study the Sun, but there are many risks and costs associated with launching hazardous waste on the Sun.

For tens of thousands of years, people have practically no effect on our planet and the environment. Only a few million people, distributed throughout the globe, even taking into account fires, wars and garbage, can poison only a small part of the world for a short period of time. But with the increase in the number of people and our technical capabilities, our ability to damage and destroy the biosphere also grew. Now we have more than 7 billion, and managing the environment today is more difficult than ever - and just as important. And since we went into space, shouldn't we send the most dangerous and long-term pollutants - nuclear waste, hazardous waste, indestructible plastic, etc. - in the sun? This is what our reader asks:
I argued with people for years, arguing that sending radioactive waste or space debris to the sun would be too expensive and impossible. According to my unprofessional understanding of orbital mechanics, it seems to me that we will first have to speed up the waste so that it leaves the orbit of the Earth, and then slow it down so that it "falls on the Sun." I know that this is possible because we sent probes to Venus, but I cannot visualize it. Could you help me?

Firstly, of course, it is physically possible. But whether we can do it and whether we should do it are two different questions. Let's start with what is necessary for the implementation of such an enterprise.


Soyuz rocket put up for position on March 24, 2009 at the Baikonur Cosmodrome

We do not fall from the Earth and do not fly into space because the gravitational attraction of the Earth draws us to the center of the earth at such a distance from the center that we are at the surface. There is a certain amount of energy that keeps us on the leash of our world (gravitational potential energy), and for our position with you, we can calculate two important, key speeds. The speed of a stable circular orbit for our distance from the center of the Earth, at which we can move around the planet without touching the surface, and the escape speed, which will allow us to escape from the gravitational attraction of the Earth and go into interplanetary space. In the case of the Earth, we will need to move at a speed of 7.9 km / s to enter orbit, and at a speed of 11.2 km / s in order to break out of gravitational attraction.


Therefore, in order to launch a rocket into the Earth’s orbit, we need to invest in it as much energy as it takes to accelerate to this speed, and this is very much. But still, mankind has been doing this since the 1950s, and when you enter orbit, you will find something surprising that, in general, was known in advance: you are part of a system moving in orbit around the Sun at an enormous speed . The earth moves around the sun at a speed of about 30 km / s, so everything that you put into orbit will also move around the sun at about the same speed. If you need to launch something in the Sun, you need to somehow lose 30 km / s speed. On the other hand, we are already 150 million km from the Sun. If we wanted to completely leave the solar system,



Since it takes so much energy and lifting power to go out into space, we are trying to enable the Universe to do as much work as possible for us. And this means that it is necessary to use gravitational maneuvers - to use the gravitational properties of the planet - to get to the planets of the solar system, lying both inside and outside the Earth’s orbit. As each planet moves around the Sun, two important bodies participate in our experiment, and the spaceship will be the third. A spaceship can perform a gravitational maneuver in two ways:

1. You can direct the ship so that it passes behind the planet, then flies in front of it and, thanks to the sling effect, is again behind it.
2. You can direct the ship so that it passes in front of the planet in its orbit, then flies behind it and, thanks to the sling effect, again faces it.



In the first case, the planet drags the ship, and the ship drags the planet so that the planet accelerates slightly with respect to the Sun, its gravitational connection with it weakens, and the ship loses much in speed (due to the fact that its mass is much less) , and strengthens the gravitational connection with the Sun, moving into an orbit with low energy. In the second case, everything works in the opposite way: the planet loses speed, is more strongly associated with the Sun, the ship significantly increases in speed and enters an orbit with high energy.



In the first scenario, we visit the inner part of the solar system: Venus, Mercury and even the Sun itself, and in the second - we reach the outer planets. That's how New Horizons got to Pluto, and Voyager probes left the solar system altogether!


So it’s technically possible to send garbage to the sun. But this idea has many drawbacks:

• The likelihood of a failed launch.
• Extremely high cost.
• It will be easier to bring it out of the solar system than to direct it toward the sun.

The Soyuz launch vehicle has the most successful launch history in the world; 97% of 1000 launches were successful. But even an indicator of 2-3% can be disastrous if we talk about loading the rocket with hazardous waste that you want to remove from the planet. Imagine that they are distributed in the ocean, in the atmosphere, on populated land, in commercial, industrial or residential quarters. This will not end with anything good for humanity.


Separation of the Soyuz-2.1a rocket on April 19, 2013 with a spaceshipBion-M No. 1 The

maximum load of the Union is 7 tons. Suppose we want to get rid of all nuclear waste. About 60,000 tons of hazardous waste is now stored in the United States, and a quarter of all the world's nuclear plants operate in the country. This is approximately 34,000 missile-filled missiles, even though an inexpensive missile launch costs $ 100 million. Even if we reduce the failure rate to an unrealistic value of 0.1%, that would mean about 34 missiles, or a quarter million kilograms. The waste will be randomly distributed over the Earth and released into the environment. 2014 Antares


unmanned rocket explosion

Perhaps when we have a reliable and working space elevator, this option will be worth considering. But until then, the cost and confidence that someday a catastrophe will surely happen means that the launch of waste in the sun is best left to science fiction. And we need to come up with our own way to deal with our waste.

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