In this blog post, we will look at how small but powerful nanosatellites have changed space observation and how revolutionary they have been in terms of cost and technology.
Humans have always observed their surroundings. From these observations, we have gained new knowledge, which we have used to develop civilization and improve our quality of life. The scope of human observation extends beyond the Earth we live on to the universe surrounding it, including the movements of the stars, the sun, and the moon. These observations have deepened our understanding of natural phenomena and led to innovative developments in various fields such as agriculture, navigation, and architecture. However, compared to the Earth, the universe is so vast that observing it is much more difficult than observing the Earth’s surface environment. For this reason, good observation tools are necessary to observe space. In the past, Galileo observed space with a telescope he built, but today, we observe space with artificial satellites, which are much more valuable tools than telescopes.
However, because space is so vast, many people may think that artificial satellites used to observe space must be large. My classmates and I, who are studying mechanical and aerospace engineering, also had this idea until we took an introductory course on aerospace engineering. However, there are small artificial satellites called “nanosatellites,” which seem small and incongruous with the vastness of space. What are these nanosatellites, and how do they observe space?
A satellite is a celestial body that revolves around a planet due to gravitational forces, and an artificial satellite is a satellite that has been artificially launched by humans. These artificial satellites are generally classified according to their size, and their functions also vary. Depending on their size, artificial satellites are classified into large satellites (1,000 kg or more), medium satellites (500 to 1,000 kg), small satellites (100 to 500 kg), and nanosatellites, which will be explained in this article. Large satellites are mostly used for communications, weather, and military purposes, while medium satellites are used as practical Earth observation satellites for technology verification. Small satellites are mostly satellites that orbit in low Earth orbit and are also used for lunar and planetary exploration.
So, what are nanosatellites? Although there are no clear standards for nanosatellites, they are generally defined as satellites weighing less than 10 kg. Due to their small size, nanosatellites have many advantages and functions that utilize these advantages. The biggest advantage is that they are inexpensive. It costs between $100 million and $300 million to launch a typical satellite. Considering that South Korea’s budget for the space industry in 2023 is approximately $450 million, launching a satellite comes with a huge economic burden. However, in the case of nanosatellites, the cost of launching one is only about $1 million to $3 million. In other words, you can launch many more nanosatellites for the price of launching one conventional satellite.
In science, when observing facts or finding evidence to support a claim, the more data there is, the more reliable it is. Therefore, the ability to launch nanosatellites multiple times at a low cost has the advantage of increasing the reliability of nanosatellite observations. For example, the main mission of nanosatellites is to investigate the thermosphere, which is the upper layer of the atmosphere, specifically the lower thermosphere at an altitude of 90 to 300 km. When observing the atmosphere, artificial satellites generate heat due to friction with the air, regardless of their size, and this causes them to burn up after a certain amount of time. Therefore, by using inexpensive nanosatellites instead of expensive conventional satellites, it is possible to obtain a larger amount of data more economically.
In addition, because they are inexpensive, there is less risk of failure compared to conventional satellites, which is advantageous for developing and verifying technology. For example, suppose you have developed a technology that can be applied to other satellites. Because of gravity on Earth, it is impossible to determine whether this technology can be used in a weightless environment. In this case, you can use an inexpensive nanosatellite to install the technology on board and launch it into space to verify its effectiveness. In addition, nanosatellites are small and lightweight, so their structure is not complicated and they are easy to assemble. Currently, nanosatellite parts are already sold in kit form, making them easily accessible not only to experts but also to non-experts. Taking advantage of these advantages, when it is difficult to obtain data from conventional satellites, it is possible to obtain data using nanosatellites.
One of the most representative nanosatellites is CubeSat. CubeSat is a satellite with a length, width, and height of about 10 cm. Currently, many countries around the world, including the United States, Germany, and Japan, are using CubeSat extensively and are focusing on its development because of its small size and low cost, which allow it to be used for various space experiments. One example is the space weather observation CubeSat program promoted by the US Air Force. The space weather observation CubeSat program is a program led by the United States to observe space weather using two CubeSats, as space weather (the top of the atmosphere) has become increasingly important due to the large number of spacecraft traveling through space and artificial satellites orbiting the Earth in modern times. In addition to the US Air Force, CubeSats are also actively used in research at various universities, including Arizona, Stanford, and MIT. The CubeSat XI-IV program at the University of Tokyo in Japan is a successful program in which the CubeSat launched in 2003 is still alive and functioning properly. Currently, Korea Aerospace University and Kyung Hee University are conducting research on CubeSats, or nanosatellites.
In modern times, the aerospace industry is becoming increasingly important worldwide, and most developed countries are investing heavily in it. In this era where space is so important, nanosatellites, which are economical and convenient for observing space, will become even more popular in the future. The purpose of this article is to convey to the general public living in this era the importance of nanosatellites in the modern space age and provide a basic explanation of what they are.
