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# 5 major scientific discoveries that make it possible to send Danish Andreas Mogensen on a space mission

In 2015, Andreas Mogensen became the first Danish astronaut in space when he spent 10 days on the International Space Station. Now he is going again – this time for six months.

By Mikkel Linnemann Johansson, , 8/25/2023

On Saturday 26 August 2023 at 9:27 Danish time four international astronauts depart on a six-month space mission. The Danish astronaut Andreas Mogensen is a crew member and who will pilot the SpaceX vessel from the Kennedy Space Center in Florida to the International Space Station, ISS, which orbits the earth at approx. 400 kilometers altitude.

Here, until February 2024, they will carry out experiments and data collection in connection with a large number of Danish and international research projects from universities and companies.

However, this is only possible today because physicists and other researchers have made a large number of scientific discoveries over many hundreds of years - down here on Earth.

Learn 5 of the most significant discoveries that make space travel possible right here.

## #1 - Newton

We start with an old familiar example from 1687, when the British physicist and mathematician Isaac Newton publishes his book Principia and describes the three laws about the forces that affect the movements of an object as well as universal gravitation.

- For the International Space Station, it is gravity that means it can remain in a circular orbit around the Earth, just as the moon remains in its orbit around the Earth. And there is speed! In fact, the space station circles the earth 16 times in a day.

This is what we are told by Professor Mads Toudal Frandsen, who teaches the physics students at the University of Southern Denmark in Odense and researches dark matter.

- Even though several hundred years have passed since Newton made his discoveries, it is still his understanding of gravity that is the starting point for the calculations that are the basis for sending a space station into orbit around the Earth and for sending the astronauts to the space station and back home , he explains.

## #2 – Tsiolkovslij's Rocket Equation

When you talk about space travel, you also talk about great distances. Therefore, even tiny deviations from the route to the destination can lead to missing the target by huge margins.- Here Russian Konstantin Tsiolkovslij's rocket equation from 1903 is also absolutely crucial for Andreas Mogensen to be able to steer himself and his three space traveling colleagues to the ISS. The equation takes into account the change in the vessel's total mass - or weight - during the journey. As more and more rocket fuel is burned off to create propulsion, the total mass of the craft decreases. Therefore, gradually less and less force must be used to influence the direction and speed of the SpaceX vessel, explains Mads Toudal Frandsen.

- Without this equation, it would simply not be possible to calculate the optimal path to follow in order to reach the space station safely, he says.

### From basic research to space travel

When Newton discovered gravity, he had no idea what his work with the laws of physics would lead to. The same applies to Tsiolkovslij, Becquerel, Einstein and today's physicists who are doing research in universities today in a search for a better understanding of the universe and the natural laws that make it all fit together.

– It is a condition when working with basic research that you cannot say with certainty what the new knowledge can be used for, says Mads Toudal Frandsen, who himself researches dark matter.

– But when we look at history, it is confirmed time and time again that the very basic knowledge that comes out of physics research can lead to fantastic and incredible technologies and help change our world, he says.

## #3 - Quantum mechanics and solar cells

A space station uses a lot of energy, which you cannot simply transport from Earth and 400 km into space. It would be far too heavy, cumbersome and expensive.

Therefore, it is necessary to be able to generate its own power on the International Space Station. But when there is no atmosphere, wind energy is not an option. On the other hand, there is plenty of sunlight that can be converted into electricity using solar panels.

- Here we have to thank for the knowledge we have about quantum mechanics and the photoelectric effect, says Mads Toudal Frandsen.

- In fact, we have to go all the way back to 1839, when the French physicist Alexandre-Edmond Becquerel first discovered that certain materials generate a small electric current when exposed to sunlight, he explains.

A lot has happened since then, and with quantum mechanics it has been possible to optimize solar cells, so that today they are much more efficient and can therefore be used on the space station.

- But the discovery in 1839 is the basis for the development of solar cells, says Mads Toudal Frandsen.

## #4 - The understanding of cosmic radiation

Cosmic radiation mainly consists of electrically charged particles from outer space. Down here on Earth, the atmosphere has absorbed much of the energy from the cosmic radiation, but the further you move into the atmosphere, the more intense – and dangerous – the cosmic radiation becomes.

- When we get out to the International Space Station, the cosmic radiation is very powerful because there is no atmosphere to weaken it. Therefore, it requires that the astronauts are well protected against the radiation, says Mads Toudal Frandsen.

In addition to the constant cosmic radiation, there can be solar storms, which are a discharge of particles from the sun.

- They are what we see as auroras when they hit the Earth's magnetic field at the poles, he explains.

Although the atmosphere protects us from the solar storms, at times they can be powerful enough to cause disruptions to electronics on Earth. For example, a particularly strong solar storm in 1989 led to a nine-hour power failure in Canada.

- On a spacecraft such as the SpaceX Dragon or the International Space Station, such disturbances in the electronic systems would be fatal, but because we understand cosmic radiation and solar storms today, we can design vessels and space stations so that they are protected against this threat, says Mads Toudal Frandsen.

## #5 – Einstein's general theory of relativity

Einstein's theory of relativity is important for communication between spacecraft and Earth. With this theory, you can take into account that both the strength of gravity and the speed between two objects affect how time passes. The weaker gravity in space affects time differently than the stronger gravity on Earth does. The stronger the gravity, the slower time passes.

- And that affects the accuracy of the signals we send back and forth between the Earth, the SpaceX vessel and the ISS when we have to communicate with each other, says Mads Toudal Frandsen.

The communication between Earth and the space station is carried by electromagnetic waves. But the length of the waves is affected by the speed of the sender. Therefore, a signal does not have the same frequency when it is received on Earth as it did when it was sent from the space station.

- This is taken into account so that Andreas Mogensen and the other astronauts can communicate with their colleagues - and families - down on Earth, says Mads Toudal Frandsen.

##### Meet the researcher

Mads Toudal Frandsen is a professor of Physics at the Department of Physics, Chemistry and Pharmacy.

Editing was completed: 25.08.2023