South Korea is exploring the moon, with more missions to come

An undated photo provided by the Korea Aerospace Research Institute for final inspections at the Danuri facility in Daejeon, South Korea, prior to shipment to Florida.  (Korea Space Research Institute via The New York Times)

An undated photo provided by the Korea Aerospace Research Institute for final inspections at the Danuri facility in Daejeon, South Korea, prior to shipment to Florida. (Korea Space Research Institute via The New York Times)

South Korea will go to the moon on Thursday. But she doesn’t want to stop there.

“We are also studying the use of the Moon as a forward outpost for space exploration,” Kwon Hyun Joon, director general of aerospace and nuclear energy at the South Korean Ministry of Science, said in a written response to questions. “Although we hope to explore the Moon itself, we also recognize its potential to serve as a base for further exploration of deep space such as Mars and beyond.”

The South Korean lunar spacecraft, called Danuri, was launched on a SpaceX Falcon 9 rocket from Florida, blasting off on a circular but fuel-efficient trajectory that will make it to the moon in mid-December. There, it will begin an orbit 62 miles above the lunar surface. The main mission is scheduled to last for one year.

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Originally known as the Korea Pathfinder Lunar Orbiter, the expedition was named Danuri after becoming the winning entry in a naming contest. It is a combination of Korean words meaning “moon” and “enjoy”.

Danuri will join a spacecraft from NASA, India and China that is currently exploring Earth’s companion. Just like the United Arab Emirates, which blasted off toward Mars on a Japanese rocket in 2020, South Korea is the latest country to have a small but ambitious space program blasting off into Earth’s far-Earth orbit. Also like the Hope orbiter in the United Arab Emirates, the Danuri mission aims to make meaningful scientific contributions to global efforts to explore and understand the solar system.

Kwon said the main goal of the Danuri mission is to develop core technologies such as orbital trajectory design, deep space navigation, a high-thrust system and a 35-meter antenna to communicate with distant spacecraft.

But the scientific payload of the spacecraft is advanced and will help scientists in South Korea and around the world in studying the magnetic field of the moon, measuring the quantities of elements and molecules such as uranium, water and helium-3, and photographing dark craters at the moon’s poles, where the sun never shines. In addition to providing one of the tools, called ShadowCam, NASA has selected nine scientists to participate in Danuri.

The magnetometer is one of its most important scientific tools. The interior of the Moon no longer generates a magnetic field, but did once, and this primordial field is preserved in lava flows that hardened during this epoch.

The early magnetic field appears surprisingly strong — perhaps even twice as strong as Earth’s, said Ian Garrick Bethel, professor of planetary sciences at the University of California, Santa Cruz and a Danuri mission scientist. current magnetic fields.

It’s baffling, said Garrick Bethell, that “such a small iron core could generate such a strong magnetic field.”

He hopes that after the spacecraft’s primary mission is completed for one year, South Korea can choose to move Danuri much closer to the lunar surface, within 12 miles or less, where the magnetometer can get a better look at magnetized rocks.

“Even a few passes at those lower elevations can help constrain how strong these magnetized rocks are,” he said.

Jarek Bethell is also looking to use the magnetometer to study the magnetic fields generated inside the Moon as it is exposed to the solar wind, a stream of charged particles emanating from the Sun.

The high and low strength of the magnetic field in the solar wind causes electric currents to occur in the moon, and these electric currents in turn generate magnetic fields that will be measured by Danuri. The properties of the magnetic field will give hints about the structure and composition of the moon’s interior.

This work also requires combining measurements with those made by two NASA spacecraft, THEMIS-ARTEMIS P1 and P2, which travel around the Moon in highly elliptical orbits, so that they can measure changes in the solar wind while Danuri measures induced magnetic fields near the surface. .

“What we’re learning from that is kind of a global map of internal temperature, potential composition and possibly water content of the deeper parts of the moon,” said Garrick Bethell.

Scientists will use another Danuri instrument, the gamma-ray spectrometer, to measure the amounts of various elements on the moon’s surface. said Naoyuki Yamashita, a New Mexico-based scientist who works for the Planetary Science Institute in Arizona. He is also an associate scientist at Danuri.

Yamashita is interested in radon, which is formed from the decay of uranium. Because radon is a gas, it can travel from the moon’s interior to its surface. (This is the same process that sometimes causes radon gas, which is also radioactive, to build up in basements.)

Yamashita said the amounts of radioactive elements could provide a history that explains when different parts of the moon’s surface cooled and solidified, helping scientists work out which of the lunar lava flows are older or younger.

Kwon said the Korea Aerospace Research Institute, the South Korean equivalent of NASA, will use the Danuri high-resolution camera to explore the lunar surface for potential sites for a robotic landing mission in 2031.

A second camera will measure polarized sunlight bouncing off the moon’s surface, revealing details about the size of the particles that make up the moon’s soil. Since constant bombardment by solar winds, radiation, and micrometeorites break the soil apart, the size of the grains in a crater can give an estimate of its age. (Smaller grains may indicate an old crater.)

The polarized light data will also be used to map the abundance of titanium on the Moon, which could one day be mined for use on Earth.

NASA supplied one of the cameras, the ShadowCam, that’s sensitive enough to capture the few photons bouncing off the terrain into the moon’s permanently dark, shadowed craters.

These craters, located at the moon’s poles, remain forever cold, below minus 300 degrees Fahrenheit, and contain water ice that has accumulated over the ages.

Ice could provide a frigid history of the 4.5-billion-year-old solar system. It can also be a bonus resource for future visiting astronauts. Machines on the Moon can extract and melt ice to save water. This water can then be broken down into oxygen and hydrogen, providing both breathing air for astronauts and rocket propellants for travelers seeking to travel from the Moon to other destinations.

One of the main purposes of ShadowCam is to find ice. But even with Danuri’s sophisticated tools, that can be tricky. Shuai Li, a researcher at the University of Hawaii and an associate scientist at Danuri, thinks the concentrations may be so low that they wouldn’t be brighter than in areas without ice.

“If you don’t look at it carefully, you might not be able to see it,” he told me.

Jean-Pierre Williams, a planetary scientist at the University of California, Los Angeles, and another Danuri mission scientist, hopes to produce detailed maps of crater temperature by combining ShadowCam images with data collected by NASA’s Lunar Reconnaissance Orbiter spacecraft.

NASA’s orbiter, which has been studying the moon since 2009, carries an instrument that records lunar surface temperatures. But these measurements are blurred over a fairly large area, about 900 feet wide. ShadowCam has a resolution of approximately 5 feet per pixel. Thus, ShadowCam images used with computer models may make it possible to derive differences in surface temperatures.

“Using this data we can determine local and seasonal temperatures,” Williams said. This, in turn, could help scientists understand the stability of water ice and carbon dioxide in the crater.

Researchers will have to wait several months for the science to begin. The spacecraft is taking a long, energy-efficient route to the Moon. It first heads toward the sun, then orbits it to catch it in lunar orbit on December 3. 16. This “ballistic trajectory” takes longer but does not require launching a large engine to slow the spacecraft when it reaches the moon.

South Korea has an extensive military missile program, and has placed several communications and Earth observation satellites into low Earth orbit since it was first launched in 1992. It has expanded domestic missile launch capabilities so that future missions do not need to rely on SpaceX, or other countries , to reach space. In June, the Korea Aerospace Research Institute successfully put several satellites into orbit with the second flight of the domestic Nuri rocket.

“We will take on challenging projects such as moon landings and asteroid exploration,” Kwon said.

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