The role of chemistry in space exploration

Background

Space exploration is without a doubt one of the most intriguing areas of science. As humans, we have a natural tendency to investigate everything around us – with space, the main question we want to answer is if there is life beyond us on Earth. Astronomers use advanced telescopes to help look for celestial objects and therefore study their structures, to get closer in finding a solution to this question.

However, astronomers do have to communicate with other scientists in doing so. After all, the field of science is all about collaboration. One example is theoretical physicists studying observed data and, as the name suggests, come up with theories using computational methods for other scientists to examine experimentally. In this article, we will acknowledge the importance of chemistry in space exploration, from not only studying celestial bodies but also to life support technology for astronauts and more.

Examples of chemistry applications

1)     Portable life support systems

To survive in space requires advanced and well-designed life support systems due to being exposed to extreme temperatures and conditions. Portable life support systems (PLSS) are devices connected to an astronaut’s spacesuit that supplies oxygen as well as removal of carbon dioxide (CO2). The famous apollo lunar landing missions had clever PLSS – they utilised lithium hydroxide to remove CO­2 and liquid cooling garments, which used any water to remove heat from breathing air. However, these systems are large and quite bulky, so hopefully we can see chemistry help us design even more smart PLSS in the future.

2)     Solid rocket propulsion systems

Chemical propellants in rockets eject reaction mass at high velocities and pressure using a source of fuel and oxidiser, causing thrust in the engine. Simply put, thrust is a strong force that causes an object to move – in this case, a rocket launching into space. Advancements in propellant chemistry has allowed greater space exploration to take place due to more efficient and reliable systems.

3)     Absorption spectroscopy

Electromagnetic radiation is energy travelling at the speed of light (approx. 3.0 x 108 m/s!) that can interact with matter. This radiation consists of different wavelengths and frequencies, with longer wavelengths possessing shorter frequencies and vice versa. Each molecule has unique absorption wavelength(s) – this means that if specific wavelengths of radiation ‘hits’ a substance, electrons in the ground state will become excited and can jump up to higher energy states. A line appears in the absorption spectrum for every excited electron (see Figure 1).

As a result, spectroscopic analysis of newly discovered planets or moons can give us information on the different elements that are present. It should also be noted that the excited electrons will relax back down to the ground state and emit a photon, allowing us to observe emission spectra as well. In the emission spectra, the lines would be in the exact same place as those in the absorption, but coloured in a black background (see Figure 2).

Fun fact: There are six essential elements needed for life – carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. In 2023, scientists concluded that Saturn’s moon Enceladus has all these which indicates that life could be present here!

1)     Space medicine

Whilst many people are fascinated by the idea of going to space, it is definitely not an easy task as the body undergoes more stress and changes than one can imagine. For example, barotrauma is when tissues filled with air space due to differences in pressure between the body and ambient atmosphere becomes injured. Another example is weakening of the immune system, as researchers has been found that pre-existing T cells in the body were not able to fight off infection well.

However, the field of space medicine is growing and making sure discomforts like those above are prevented where possible. Space medicine researchers have developed ‘countermeasures’ for astronauts to follow, such as special exercises that maintain bone/muscle mass as well as diets. Being in space is isolating which can cause mental health problems, so early-on counselling and therapy is also being provided to prevent this.

To conclude

Overall, chemistry plays a vital role in the field of space exploration. It allows us to go beyond just analysis of celestial objects as demonstrated in this article. Typically, when we hear the word ‘chemistry’ we often just think of its applications in the medical field or environment, but its versatility should be celebrated more often.

By Harsimran Kaur

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