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Korea’s first step toward lunar exploration

The Lunar Exploration Project, the Korean Hope Project

Lunar Exploration

The lunar exploration competition has begun, and it’s unprecedented in scope.

Ever since mankind’s first Moon landing with Apollo 11 in 1969, once again, the U.S. is pushing ahead with the Artemis program, a manned Moon landing program. Developed countries or regions in aerospace such as the EU, China, Japan, and India as well as private start-ups are engaged in space exploration such as lunar exploration in the New Space era marked by a challenging mindset, innovation, and new opportunities as of late. Developed countries in aerospace are recognizing the Moon as an area of undeveloped and unlimited potential, unlike the lunar exploration of the past, and are in the process of being at the forefront of space development through lunar exploration. Developed countries in aerospace are transitioning their space development sights from a focus on Earth to the Moon and Mars based on developed space technologies, and are securing more advanced space technologies through space exploration. The U.S. has held its status as a leading country in space development through space exploration and maintains a strong interest in the field of science, national security, and economy. Our regional neighbors such as Japan, China, and India are also actively progressing forward in the exploration of the Moon, comets, and Mars. Through lunar exploration, they are seeking the development of high-tech space technologies such as flight and control technology to the Moon, technology to enter lunar orbit, Moon-landing technology, sample-collection and return-to-Earth technology, lunar exploration rover operation in an extreme space environment, nuclear batteries, and space Internet. Meanwhile, they are even anticipating space industrialization to accelerate and creation of new jobs. The reason why the world’s sights are on the Moon once again is that they can secure natural resources from the Moon along with the possibility of utilizing the satellite as a stopover site for the deep space exploration of Mars, etc. With manned and unmanned explorations, the presence of rare resources like water, Helium 3(He3), Uranium, and rare earth elements on the Moon have been confirmed. As of now, the only countries which have succeeded in unmanned lunar landings are the U.S., the former Soviet Union, and China, and the six countries or region which have succeeded in lunar orbiter exploration include Japan, China, India, the EU & U.S. and the former Soviet Union. Thus, if we do not commence space exploration ourselves, we would lag further behind in space development with other countries.

Korea’s first step toward lunar exploration

Based on the accumulated capacity for space technologies, Korea is also planning its space exploration, and the lunar exploration is one of the plans. For the first step of this plan, Korea launched the first lunar orbiter, Danuri, on August 5, 2022. And then Korea will make its first landing onto the Moon by 2023 by its own space launch vehicle. Korea Aerospace Research Institute (KARI) launched the first lunar orbiter, Danuri(KPLO, Korea Pathfinder Lunar Orbiter), which will be the first step for ensuring & verifying its capability of space exploration. Lunar exploration will enhance the space technologies of Korea, increase the value of Korea, and stimulates pride as Korean.

01Development of Danuri (KPLO)

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Heading to the Moon in August 2022

Danuri(KPLO, Korea Pathfinder Lunar Orbiter), the first Korean lunar probe, is an unmanned lunar probe expected to carry out the mission of lunar observation while flying at an altitude of 100km over the Moon. This project taking place under a cooperative system in which the Korea Aerospace Research Institute (KARI) oversees the system, main body of the orbiter, and ground station; and Korean universities and research institutes, and NASA support the payloads, deep space communication, and navigation technology. The test lunar orbiter (KPLO) consists of the main body with a width, length, and height of 1.82m, 2.14m, and 2.29m, respectively, and six payloads. The major project details of the test lunar orbiter involve the development of the main body and payloads of the test lunar orbiter, construction of a deep-space ground station, phase 2 preceding research, and international collaboration with NASA. The project is carried out with the cooperative system in which KARI oversees the system, main body, and ground station with the participation of 6 major Korean research institutes and NASA of the U.S.. It is equipped with NASA payloads and carrying out missions such as orbiter tracking, communication support, deep-space navigation service support, etc.

Technologies needed for Moon & deep-space exploration secured

The lunar orbit exploration through a test lunar orbiter (KPLO, Korea Pathfinder Lunar Orbiter) requires space probe design and production technology to endure missions in an extreme lunar environment, navigation, and control technology for a precise flight to the Moon, and lunar orbit entry technology. KARI aims to secure deep-space communication technologies such as establishing a large deep-space antenna capable of tracking and communicating with the orbiter to overcome signal sensitivity deterioration due to the distance between the Earth and Moon; technology for developing an orbiter applying a light-weight design, large capacity propulsion system technology; and technology for navigation to the Moon. NASA of the U.S. is supporting deep-space communication and navigation technology. KARI has achieved weight reduction (from over 80 to 50kg) of electronic units including the onboard computer, power controller, power distributor, mounted data processor, and harness of the test lunar orbiter by applying a lightweight design and has reduced the power consumption (110W→ 65W) of the signal/power distribution system. The institute has also localized the 30N class (4 units) large-capacity high-thrust propulsion system needed for entry into lunar orbit. This contrasts with the existing satellite altitude control thruster which was 5N class. KARI has also developed a Deep space antenna system (35 metres) to extend communication range to the moon.

Technologies required for Lunar Orbit Exploration

달궤도 탐사 소요기술을 구분지어 세부적으로 설명한 표입니다.
Classification Details
Main body
  • - Main body system
  • - Navigation & guided control (autonomous navigation and altitude control technology, laser or microwave advanced design technology)
  • - Power system
  • - Structure system (light-weight design, propulsion system mounting, propulsion system separation mechanism)
  • - Thermal control (lunar orbit/lunar surface thermal analysis technology, active high-efficiency thermal control technology, electronic unit thermal design for extreme environments)
  • - TC & R (long distance communication)
  • - Propulsion system (propulsion system development)
  • - FSW
Mission/ System
  • - System concept review
  • - System operation concept
  • - Mission analysis (Moon characteristics related to lunar science mission, payload, landing zone selection)
  • - Orbit analysis/optimization
  • - Launch vehicle connection
  • - Total assembly
Payload
  • - Science payload & technology test payload
  • - INL payload
ILN
  • - Communication WG (frequency selection, communication protocol)
Ground station
  • - Development of large antenna
  • - Development of lunar mission operating software
  • - Lunar mission operation
The test lunar orbiter (KPLO) is scheduled for launch on board the U.S. SpaceX’s Falcon 9 launch vehicle in August 2022. After its launch, the test lunar orbiter (KPLO) will shoot toward the Moon using the lunar orbit transfer method (BLT/WSB), which approaches lunar orbit by using the nearby astrophysical gravity of the Sun and Earth. The test lunar orbiter (KPLO) is expected to commence lunar surface filming after going through its initial testing upon entry into lunar orbit. The launch of the test lunar orbiter (KPLO) was originally scheduled in December 2020 but was postponed to August 2022. The total budget is KRW 233.3 billion which is an increase of KRW 35.5 billion from KRW 197.8 billion. Meanwhile, KARI is undergoing the development of deep-space Internet protocol design, landing device design & landing technology development, lunar exploration rover, and nuclear batteries, etc.
  • Total weightApprox. 678kg (1.82m×2.14m×2.29m)
  • Mission lifetimeJanuary 2023 ~ December 2025
  • Operation orbitCircular orbit 100km above the Moon, 90 degree inclination angle
  • Payload6 units
  • Date of launch2022.8.5
KPLO01
KPLO02
KPLO03
KPLO04

02Payloads of the Danuri (KPLO)

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Six payloads developed by Korean research institutes & NASA

Danuri(KPLO) carries a a total of 6 payloads. The orbiter contains 5 payloads developed by Korean universities and research institutes including KARI and 1 payload from NASA. Korean universities and research institutes are developed a high-resolution camera for exploring the proposed landing site for lunar landing module, a polarized camera to analyze the lunar surface particles and spacecraft’s effect, and a lunar magnetic field-measuring instrument to measure the magnetic field intensity around the Moon for studying the cause and process of Moon formation. The Korea Institute of Geoscience & Mineral Resources, which will measure the gamma-ray spectrum for resource exploration of the lunar surface, developed a gamma-ray spectrometer for identifying the elements constituting the lunar surface and its distribution pattern, while KARI is developing a 5m-grade high-resolution camera filming the proposed landing site for the Korean lunar probe.
The polarized camera developed by the Korea Astronomy & Space Science Institute will be used to film the image of the entire lunar surface and capture polarized images of areas except for the polar region. In addition, it will designate the proposed landing site for the lunar probe by using the filmed images and examine the types of materials and particle sizes on the surface of the Moon. Kyunghee University developed the lunar magnetic field measuring instrument, a magnetometer for measuring the magnetic force 100km above the surface of the Moon. The gamma ray spectrometer can identify the ingredients and distribution patterns of elements constituting the lunar surface. It is developed by the Korea Institute of Geoscience & Mineral Resources. The Electronics & Telecommunications Research Institute (ETRI) developed the space Internet test equipment for testing the delay-tolerant network. NASA’s ShadowCam will perform the reflectivity mapping of permanently shadowed regions on the surface of the Moon to find the evidence of water.

03KPLO’s Lunar Entry Orbit

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Going to the Moon with BLT/WSB method

The orbit for going to the Moon broadly consists of Direct Transfer, 3.5 Phasing Loop Transfer, BLT (Ballastic Lunar Transfer), etc. The Direct Transfer method previously used by the Apollo program requires time within about 5 days. It directly arrives on the Moon after its launch from Earth. The 3.5 Phasing Loop Transfer used by India’s Chandrayaan program is a method of entering lunar orbit after revolving several times around the Earth in a long elliptical orbit. BLT/WSB method entails flying to the L1 Lagrangian point between the Earth and Sun, which was designed to minimize the space probe’s fuel consumption.
After launch, KPLO was separated from the launch vehicle after entering the Transfer Orbit, an elliptical orbit. Subsequently, after making the solar panels face the Sun, the solar panels were fully deployed by automation. Then, the process of raising its orbit by liquid apogee engine (LAE) firing occurred in order to enter the drift orbit from transfer orbit. Once the satellite got into position, the engine fires a total of 5 times and ascends into a circular orbit (drift orbit) from an elliptical one. And then, by using orbit information and the satellite-installed star sensor, it acquired its position facing the Earth, and finally reaches satellite mission altitude.
  • BLT/WSB method A method devised to minimize the fuel consumption of a probe with an orbit that can reduce speed increments (ΔV) by about 25% when the Moon is captured by increasing orbital energy, even though TLI maneuver (provided by launch vehicle) is generally excellent by flying up to L1 Lagrangian point (approx. 1.5 million km) between the Earth and Sun.
KPLO’s Lunar Entry Orbit1
KPLO’s Lunar Entry Orbit2
KPLO’s Lunar Entry Orbit3
KPLO’s Lunar Entry Orbit4

04KPLO Ground Station & Control System

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Developed by exclusive Korean technology through the know-how of operating satellites

In the initial operation of the test lunar orbiter (KPLO), 24-hour communication is made possible with 4 overseas ground stations in Italy, Australia, Chile, and Hawaii via SSC (Swedish Space Corporation)’s network operation center (Esrange). The remote operation with network operation centers of overseas ground stations is performed at KARI’s satellite operation center. After launch and initial operation of the test lunar orbiter (KPLO), the Korean ground station will be operated starting from in-orbit testing (2 weeks after launch). The ground system of the test lunar orbiter (KPLO) will be developed through technologies and expert human resources acquired from operating low orbit satellites. The ground system consists of the transmission/reception subsystem in charge of communication between the satellite & ground and reception & broadcasting of images; real-time operation subsystem for satellite operation and control; control system such as the mission planning subsystem and aerodynamic subsystem; data pretreatment system for real-time reception, processing and distribution of payload images; and integrated monitoring subsystem of the entire ground system.
  • Composition of Ground System Transmission/reception subsystem, control system, data pretreatment system, integrated monitoring subsystem

05The first public release system of Korean space exploration scientific data

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Public release of Danuri’s scientific data starting from January 2024

https://www.kari.re.kr/kpds The spacecraft "Danuri" is on a mission to fly in a polar orbit at an altitude of 100 km above lunar surface, collecting various forms of scientific data on lunar surface and space environment, including images, magnetic fields, gamma rays, and more. The collected lunar scientific data undergoes a process of correction for noise and distortion caused by the electrical and mechanical characteristics of the science payload, and its quality is verified to be usable for actual research. Each institution responsible for developing the scientific payloads goes through a verification and analysis process to achieve the specific goals of scientific research associated with each payload. After approximately one year from the time the data is received at the KPLO Deep-space Ground System, it becomes publicly accessible on the internet for anyone to use.
To facilitate this, the Korea Aerospace Research Institute (KARI) has developed the KARI Planetary Data System (KPDS), the first planetary data system for Korean space exploration. Through KPDS, data acquired by domestically developed scientific payloads such as KMAG, KGRS, LUTI, and PolCam will be made available to the public. Scientific data from the U.S.-developed ShadowCam, integrated into Danuri as an international collaboration payload, will be released through NASA's Planetary Data System (PDS). To download the scientific data from the KPDS website, no membership or login is required. Anyone can freely download the data for non-profit educational and research purposes. However, a specialized knowledge of the characteristics of the scientific payloads and data processing may be necessary for effective utilization of the publicly available scientific data.
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