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– On the 24th of last month, SpaceX, an American space exploration company run by Elon Musk, succeeded in bringing 143 satellites to space on the Falcon 9 rocket. This is a record that far exceeded 104 small satellites mounted on PSLV rockets launched in India in 2017.
It took about 90 minutes from the rocket launch to the last satellite ejection. It took 30 minutes to send all 143 satellites on board the rocket into space. The first satellite separation began 59 minutes after launch, and Falcon 9 fired 133 satellites in about 17 minutes. After about 15 minutes of orbit correction, the remaining 10 Starlink satellites were separated. All 143 satellites have successfully landed in Solar Synchronous Orbit (SSO). The solar synchronous orbit is an orbit that always maintains a constant angle with respect to the sun at an altitude of 500 to 800 km. Since this orbit always passes through a fixed position of the Earth at a certain time, it is advantageous for analyzing the change of objects over time. 133 external satellites were launched into the solar orbit at an altitude of 500 km. The remaining 10 Starlink satellites were separated at an altitude of 540km after an additional 40km rise through the orbit correction equipment (TOS).
– How could SpaceX mount 143 satellites in one rocket and safely eject it into space orbit? The secret is contained in the’miniaturization’ of the satellite. Ten satellites and 133 small external satellites for the satellite Internet service’Starlink’ promoted by SpaceX were launched this time. The Falcon 9 used by SpaceX is a rocket that also carried a crew dragon capsule carrying an astronaut. However, this time, he was carrying a small satellite, not an astronaut, as a passenger.
Due to its small size, it is also easy to eject the satellite. It’s easy to think of a ballpoint pen. Each satellite was launched inside a small ejection canister. The inside of the injection canister consists of a spring, a partition wall, and a space for the satellite. The principle is that if the separation wall is removed at the moment of ejection, the satellite is separated by the spring force that springs out.
The reason this mission has received worldwide attention is that it put the first button in the’SmallSat Rideshare’ project announced by Musk in 2019. An increasing number of small satellites are being used behind Musk’s introduction of the ride-sharing concept as a’to make money’ business, not a launch for scientific research. As the demand for small satellites increases, the need to send these small satellites into space has increased. The SpaceX ride-sharing service varies depending on the date and orbit, but launches a satellite weighing 485 pounds (about 220 kg) for $1 million (about KRW 1.1 billion). The customer launches the satellite with other customers, but does not have to purchase the entire rocket and only pays the’satellite boarding fee’.
In the meantime, the rocket was launched with medium and large satellites mounted as the’main satellite’. The small satellites were put together and launched. The rocket carried the main satellite into the desired orbit, and the small satellite was left in the surrounding orbit. However, since medium and large satellites are not launched frequently, a launch market for small satellites has been opened. The SpaceX ride-sharing service, which allows small satellites to be placed on a desired date and orbit, is highly likely to be popular, rather than waiting for medium and large satellites that may be launched. Musk tweeted, “We are delighted to provide an orbital service at a low cost,” and announced that the era of making money into space has really opened.
Out of 133 small external satellites launched this time, 120 are known as’Cubesat’. Cubesat is a micro-satellite measuring about 1.3 kg, measuring 10 cm in width, length, and height. It is large enough to hold an adult woman with one hand. Other satellites that participated in Transporter 1 are also small satellites that weigh less than 500 kg. Most of these small satellites perform research activities or test missions for large satellite launches.
The CubeSat satellite itself was created in 1995 at Stanford University for education. Cubesat’s status has changed since various information technology (IT) developments. This is because the appearance of micro-miniature parts and CubeSat performance is comparable to other small satellites. Unlike medium-sized satellites that require tens of billions to hundreds of billions of won from development to launch, CubeSat can launch very cheaply. The development period is also short, about 1 to 2 years. As it is relatively inexpensive, Cubesat is often used for’tweezers missions’ to obtain only necessary data. In fact, US Inter-Orbital Systems is currently selling CubeSat for research for $22,000 (about 24.5 million won) including the launch cost.
Another reason that small satellites have received attention is because of the’cluster satellite technology’. Musk’s Starlink project is a prime example. It is not a single satellite with good performance in charge of all tasks, but a concept in which several small satellites with good’cost performance’ perform simple tasks, respectively. Smaller satellite performance has improved and made possible by miniaturization of components and improvement of IT. The greatest strength of cluster satellite technology is its response time. One large satellite returns over a long period of time, but cluster satellites have many smaller satellites everywhere.
The popularity of small satellites is also revealed in numbers. According to Euro Consult analysis, about 890 small satellites under 500 kg were launched over the 10 years from 2007 to 2016. Euro Consult predicts that between 2017 and 2026, about 6,200 small satellites will be launched, a 7-fold increase. Musk’s imagination of putting tens of thousands of small satellites in low orbit is gradually becoming a reality.
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