[누리호 발사성공]The world’s first nanosatellite flight… What role does Toyosat play?

The 3rd launch of the Nuri was first a success… Checking communication with 8 satellites

The key is whether the mission can be completed normally while maintaining communication.

[서울=뉴시스]Correspondent Yoon Jeong-min = The eight satellites on the Nuri, which was launched on the 25th, were separated from the launch vehicle around 6:37-39 pm and went into initial communication confirmation. Among them, as of 7:00 p.m. on the same day, it has not been confirmed whether one cube satellite was ejected normally, so related researchers are working on additional confirmation. If each research institute and private company that developed the satellite normally completes communication with the satellite, each satellite will perform its original mission for the next six months to two years.

According to the Ministry of Science and ICT and the Korea Aerospace Research Institute on the same day, the Nuri-ho, which was launched this time, was loaded with one main satellite, ‘Next Generation Small Satellite No.

Among them, it was confirmed that the secondary satellite No. 2 received a ‘beacon signal’ from King Sejong Station in Antarctica at 7:07 pm. A beacon signal is a unique identification number periodically sent from a satellite to the ground. The Ministry of Science and ICT plans to check the satellite status in detail through two-way communication with the ground station of the Korea Advanced Institute of Science and Technology (KAIST) in Daejeon from 5:05 am to 7:51 pm on the 26th.

‘Subsatellite No. 2’, the core mission is to acquire earth observation images through X-band imaging radar technology

What mission does each satellite perform? Supervised by and developed by the Korea Advanced Institute of Science and Technology (KAIST) Satellite Research Institute, Cha-Satellite No. 2 promotes missions such as localization of key technologies including imaging radar (SAR), space science research, and space verification of satellite core technologies.

To carry out the mission, the sub-satellite No. 2 was loaded with ‘X-Band Imaging Radar’, a key technology payload, ‘Space Radiation Observer’, a science mission payload, and four satellite core technology verification payloads.

The X-band imaging radar enables ground observation day and night even in bad weather. Since general optical cameras acquire images in the visible light region, it is difficult to observe when affected by clouds or darkness. However, this satellite shoots microwaves to the ground and acquires Earth observation radar images with SAR technology that recognizes landmarks based on signals reflected from the ground and returned, so there is no major problem in carrying out missions even in bad weather.

This radar has a resolution of 5 m, an observation width of 28 to 40 km, and an observation angle of 20 to 35 degrees. According to the research institute, it is possible to distinguish features without a big difference even when compared to the image of an optical camera using visible light.

In addition, the sub-satellite No. 2 is tasked with precisely measuring cosmic radiation for neutrons and charged particles in near-Earth orbit (550 km in the sky) and drawing up a map of cosmic radiation dose. Based on this, it plans to study changes in cosmic radiation during the rising cycle of solar activity, the influence of the space environment, and the neutron weight of near-Earth orbit.

In order to carry out such tasks, Sub-Satellite No. 2 must remain out of sunlight for a mission period of more than two years. SAR payloads must consume a lot of power due to the nature of the technology. Therefore, it is necessary to expose the gas to the sun at all times so that it can continuously generate electricity with solar heat.

The scheduled time for the 3rd launch of Nuri was set at 6:24 pm, about 2 hours later than the 2nd launch. to reach this If Korea launches the Nuri at 6:24 p.m., Secondary Satellite No. 2 will be able to pass through the bridge in the southern hemisphere.

Astronomical Research Institute ‘Toyosat’ launches the world’s first nanosatellite formation flight

Along with Sub-Satellite No. 2, the 7 sub-satellites loaded on the Nuri were selected through a public contest by the government. The government set the goal of turning this launch into an opportunity for the growth of the domestic satellite industry, and loaded satellites with the most realistic and strong public purpose.

The satellites loaded in this way are 4 ‘Toyosat’ of the Korea Astronomical Research Institute, ‘LUMIR-T1’ of private space company Lumir, ‘JAC’ of JUSTEC, and ‘KSAT3U’ of Cairo Space.

Cheonmunyeon’s 4th Toyosaat was the last of the 8 satellites loaded on the Nuri to be ejected from the launch vehicle. 863 seconds after take-off (14 minutes 23 seconds), the separation of Unit 1 began at 6:38 pm last afternoon, and the separation was completed to Unit 4 at 20-second intervals. These satellites are currently trying to communicate with the ground station in Daejeon, and will try to communicate with the Ethiopian and European ground stations over the next 12 hours to confirm the result of the mission.

The biggest feature of Toyosat is that the four nano-satellites fly in formation. During the first three months, these satellites will fly in a north-south direction in a single line to observe temporal changes in space weather. During this period, the distance between satellites, which had been up to 2,000 km due to the speed difference, will be reduced to less than 10 km.

After the vertical flight, the satellite group will observe spatial changes in the space weather through horizontal flight in the east-west direction for another three months. At this time, the distance between satellites, which had been reduced to 10 km, widened to 400 km again. According to the Astronomical Research Institute, Toyosaat is the first in the world to attempt such a formation flight on a nano-satellite.

In addition, Toyosat plans to observe high-energy electrons that generate aurora flickering in a short time of less than one second with a particle detector, and observe ionospheric plasma bubbles that can disrupt satellite communication and GPS signals.

According to the Astronomical Research Institute, the Toyosaat’s expected lifespan is about one year. However, Lee Jae-jin, head of the space science division at the Astronomical Research Institute, said, “Even if it is operated well for just six months, it is expected that we will be able to carry out all our missions.”

Three private cube satellites also go to space… Maintaining communication is key

Cube satellites of private space companies loaded with Toyosat will also perform their own space environment missions. The cube satellite ‘LUMIR-T1’ developed by Lumir plans to measure cosmic radiation in real time and demonstrate whether the error-recovery function for cosmic radiation works normally.

The mission goal of ‘JAC’ developed by JUSTEC is to acquire space verification images of optical payloads and space verification of attitude control systems for the use of earth observation images. The practicality of the space optical observation camera with a resolution of 4 m was verified, and the main components of the platform, such as the self-made Cube Satellite platform and mounted computer, star tracker for attitude control, reaction wheel, magnetic talker, and power meter, were verified to operate properly in outer space. plan.

The Cairo Space Cube Satellite ‘KSAT3U’ is in charge of collecting polarization data on the surface of the Korean Peninsula and providing it to related research departments and academia. In addition, it plans to demonstrate a technology in space that operates automatically when a satellite function fails or the mission ends, so that the satellite enters and disappears in the atmosphere after early departure from orbit.

The Ministry of Science and ICT plans to announce the final success or failure of communication with the 8 satellites at 11 am on the 26th. Although the launch was successful, if these satellites do not perform their functions in space, this launch could be a ‘half success’.

Three of the four cube satellites (Step Cube Lab-2, Rendezvous, and Snuglite-2) that were loaded onto the Nuri during the second launch last year lost communication shortly after launch. Each public institution and private company that developed the satellite plans to try to transmit commands in various ways even if communication with the satellite is lost.

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