CubeSat: The Ultra-small but Ultra-efficient Artificial Satellite

It would be a mistake to think that all the bright spots in the night sky were stars. In fact, many satellites are floating above the sky. In particular, there are hundreds of “CubeSat” satellites which are much smaller than ordinary satellites. Three more of these CubeSat satellites, being made in Korea, are set to be launched in the next 100 days. In commemoration of the launch of Korea’s three ultra-small satellites, including the SNUSAT from Seoul National University and the VisionCube from the Korea Aerospace University, SKT plans to look further into space development in Korea, the details of the CubeSat satellites, and what they mean for the future of society.

The Age of Ultra-small Satellites

Previous Space Developments and Limitations in Korea

Korea started to develop their aerospace field relatively later than other developed countries. Space development became worldwide as the first satellite was launched by the Soviet Union in 1957. About forty years later, in 1996, the Korean government established its national aeronautics development plan and the fundamental plan for aerospace industry development in 1999. Despite its late start, Korea reached a remarkable level of technology development in a short period of time thanks to the high level of aerospace-related technology such as machinery and electronics. In particular, Korea managed to gain independent satellite information such as weather and ocean observations. Despite the development of its first space-launch-vehicle, Naro-1, in cooperation with Russia in 2013, Korea still lacks the core technology for launching space vehicles and the budget for space development.

Naro-1 Preparing for Launch/ The Korea Herald

According to the Korea Aerospace Research Institute (KARI), the total amount of budget spent in the space industry was $596 million by the South Korean government and \31 trillion by enterprises and universities in 2015, which hold only 0.7% and 0.8% of the world space market respectively. Hyundai Research Institute, a private research institution, claimed that the space industry in Korea is still in its infancy. Although limits do exist in Korea’s space-related developments, the field is gradually being developed in Korea, especially as the interest in CubeSat continuously grows.

What is CubeSat?
CubeSat is an elongated, miniaturized, box-shaped artificial satellite. It is mainly characterized by its simple design. The length of a normal massive satellite launched from the Earth’s atmosphere ranges from between 1.5 to 138 meters whereas the basic size of a CubeSat is 10cm in width, length, and height (with a volume of 1L). This standard size is called one unit. It is possible to combine several standardized units into various shapes and sizes. The box design makes a robust structure, which is suitable for protecting various components of the satellite from air pressure during the launch.

CubeSats were developed in 1999 by professors from California Polytechnic State University and Stanford University, and have been evolved in an open source project which allows anyone to read source code while maintaining the rights of the developer. It was initially made to help graduate students design, test and operate real satellites. CubeSats, however, are now being commercialized in the satellite industry. According to KARI, from 2000 to 2017, the number of CubeSats launched from around the world was about 750, and half of them were for commercial use. For example, Planet, a representative CubeSat company, sells Earth observation videos, which are recorded by more than 100 CubeSats satellites consisting of three units, and Spire, an American venture company, tracks 75,000 ships around the world with 40 CubeSats.

Various Units of CubeSat/ radiusspace.com

The Double-sidedness of CubeSats
The Limitations of CubeSats
Although they developed quickly, CubeSats currently have two major limitations which need to be solved. Above all, a CubeSat performs relatively poorly when compared to the previous massive artificial satellites. It cannot execute many functions because its inside is too narrow to load many types of equipment. A CubeSat also has no place to store a jet device which is necessary for performing missions, so it cannot move by itself as a large satellite is able to do. That is, it isunable to modify its orbit as massive arti­cial satellites can.
In addition, CubeSats are burdened with the danger of becoming space debris. Excessive numbers of CubeSats are continually revolving in the Earth’s atmosphere, and there is a huge risk of colliding with large spacecraft. There are regulations to make CubeSats fall to Earth when they reach the end of their lives which is normally within 25 years. These regulations, however, are not mandatory, so they are not programmed in many CubeSats. Moreover, if one side of a CubeSat receives sunlight concentratively, the remaining battery or fuel may explode, making the CubeSat a potential cosmic bomb in space. In order to solve these problems, KARI plans to build an algorithm for automatically recognizing and tracking the target object in space and apply it to the satellites to lessen space debris. When space debris’ images are detected, a cleaning satellite is programmed to catch the matching space waste nearby. CubeSats with a size of 30cm in length are the current candidates for cleaning satellite debris.

The Advantages of CubeSats
Despite their limitations, fortunately, CubeSats do have two main merits as well. The first is their low price. Since CubeSats can be mass-produced, the production cost can be as low as $100 million to $200 million and the launching cost is only about $500 million. CubeSats are known to be economical because only the most basic of equipment is required to collect the necessary information. For instance, to measure temperature, one only needs to attach a thermometer and a communication device to a CubeSat and launch it. In the case of the launch, the normal massive satellites usually require 1:1 corresponding projectiles for each satellite and cost $300 billion to $500 billion for one journey, according to the Ministry of Trade, Industry, and Energy. Since CubeSats’ projectile itself has a standard size, the same projectile can be continuously used, and the mass production of the CubeSat hardware also becomes possible.
Thanks to the low price, studies which were once more difficult, such as the deep investigation of the lower thermosphere, are expected to progress more quickly. If a satellite is floating on the lower thermosphere which is about 90 to 300 kilometers in altitude, it would be easily broken up or burnt due to strong friction with the air. The mission, however, can be carried out with inexpensive CubeSats since the cost would not be prohibitive, even when they are launched dozens or hundreds at a time with some failing.
Moreover, CubeSats are easy to produce. Open source forms for CubeSats are available, so anyone can get a blueprint of a CubeSat to build one. The standard blueprint of a CubeSat is accessible through the website Cubesat.org. Generally, it takes at least five years to develop one massive satellite, but the preparation period of a CubeSat can be shortened to one or two years.

The Future that CubeSats Will Bring

CubeSats in Korea

Two representative space projects using CubeSats are presently on-going in Korea. Firstly, there is the “Lunar Impactor Project” which is a cooperative project between Korea and NASA that has been running since 2012. Its objective is to find the clues of the origin of water on the moon by measuring the high magnetic field craters around the area where ice is buried. The moon was thought to be waterless until Chandra Yan 1 was launched by India in 2008, which showed that there are 600 million tons of ice-like water on the moon. A CubeSat in the project is expected to descend and measure the magnetic field near the surface of the moon depending on the altitude, for the first time in history. There is also the Triplet Ionospheric Observatory, a CubeSat for the Ions, Neutrals, Electrons, Magnetic fields Project (TRIO CINEMA) which has been a cooperative project between Kyung Hee University Korea and the University of California, Berkeley since 2012. Its objective was to investigate the impact of solar wind on the Earth, find out the physical phenomena of the near- earth space, and study the newly discovered neutral particle distribution measurement and changes of the space environment. Three multi-satellite CINEMAs detected energy particles and studied the space environment near the Earth, such as the changes of the Earth’s magnetic field.

The Prospect of CubeSat Development

The CubeSat market is continuously growing every year. According to a market analysis by SpaceWorks, an aerospace engineering company, in 2013, the market of CubeSat production and usage projects to show an average growth rate of about 24% per year from 2014 until 2020. According to NANOSAT, a space industry analysis company, the number of launched satellites increased from 25 in 2012 to 295 in 2017, and the number is expected to increase up to 546 in 2020. The CubeSat field is expected to develop further as several private companies enter the industry. According to SpaceWorks, more than 50% of the existing CubeSats are expected to be developed by private enterprises, not by the government. In 2014, Kickstarter, a crowdfunding site in the United States, had 38 projects in the field of space exploration, and most of them were projects using CubeSats. Space X, a project led by Elon Musk, the founder of Tesla, is launching a new project that will connect the world with telecommunication networks by using 4400 telecom satellites by 2020. Likewise, Google is pushing ahead a plan to provide real-time maps with CubeSats that reflect the changing ground conditions. Furthermore, Korean universities and companies are also jumping into ultra-small satellite development. 19 ultra-small satellites are being developed in Korea and 11 are being launched into space. KARI is currently developing a six unit CubeSat, and students from Yonsei University, Korea Aerospace University and Kyung Hee University, who have participated in a Cube Satellite contest, have also established a small satellite venture company.

The Number of Ultra-small Satellites Launched/ SpaceWorks
The Growing Market of CubeSat/ NANOSAT

The massive artificial satellite project was one of the projects that required a huge budget and labor force at a time when Korea had a low budget and poor investment in this field compared to other countries such as the US. However, various studies became possible with relatively small investment thanks to the development of CubeSats. SKT looks forward to Korea’s further achievements in the space industry by maximizing the advantages of CubeSats while minimizing their drawbacks.

조예진  aarg1004@naver.com

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