South Korea explores the Moon, with more missions to come

South Korea explores the Moon, with more missions to come

South Korea set off for the moon on Thursday. But he doesn’t want to stop there.

“We also plan to use the Moon as an outpost for space exploration,” Kwon Hyun-joon, director general of space and nuclear energy at South Korea’s science ministry, said in a response. written to questions. “While we hope to explore the moon itself, we also recognize its potential to serve as a base for further deep space explorations like Mars and beyond.”

The South Korean lunar spacecraft, named Danuri, launched on a SpaceX Falcon 9 rocket from Florida, setting off on a circuitous but fuel-efficient path that will land it on the moon in mid-December. There it will begin an orbit at an altitude of 62 miles above the moon’s surface. The main mission is planned for a period of one year.

Originally known as Korea Pathfinder Lunar Orbiter, the mission was given the name Danuri after becoming the winning entry in a naming contest. It’s a portmanteau of the Korean words for “moon” and “enjoy.”

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

But the spacecraft’s science payload is sophisticated and will help scientists in South Korea and around the world study the moon’s magnetic field, measure its amounts of elements and molecules like uranium, water and helium-3 and to photograph the dark craters at the lunar poles, where the sun never shines. In addition to providing one of the instruments, called ShadowCam, NASA chose nine scientists to participate in Danuri.

One of its most important scientific instruments is a magnetometer. The interior of the moon no longer generates a magnetic field, but it once did, and this primordial field is preserved in lava flows that hardened at this time.

Ian Garrick-Bethell, professor of planetary sciences at the University of California, Santa Cruz and scientist on the Danuri mission, said the initial magnetic field appears to have been surprisingly strong – potentially even twice the strength of Earth. current magnetic field.

Dr Garrick-Bethell said it was baffling that “such a small core of iron could generate such a powerful magnetic field”.

He hopes that after the spacecraft’s year-long primary mission ends, South Korea may choose to move Danuri much closer to the moon’s surface, within 12 miles or less, where the magnetometer could see magnetized rocks better.

“Even a few passes at these low elevations could help limit the magnetizing strength of these rocks,” he said.

Dr. Garrick-Bethell is also looking to use the magnetometer to study the magnetic fields generated in the moon when it is buffeted by the solar wind, a stream of charged particles emanating from the sun.

The rise and fall of magnetic field strength in the solar wind induces electric currents in the moon, and these electric currents in turn generate magnetic fields that will be measured by Danuri. The characteristics of the magnetic field will give clues to 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 that Danuri measures induced magnetic fields closer to the surface.

“What we would learn from that is a sort of global map of the interior temperature and potentially the composition and maybe even the water content of the deep parts of the moon,” Dr Garrick-Bethel said.

Scientists will use another of Danuri’s instruments, a gamma-ray spectrometer, to measure the amounts of different elements on the moon’s surface. The Danuri’s device can pick up a wider spectrum of low-energy gamma rays than similar instruments on previous lunar missions, “and this range is full of new information for detecting elements on the moon,” said Naoyuki Yamashita, a New Mexico-based scientist who works for the Planetary Science Institute in Arizona. He is also a participating scientist on Danuri.

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

The amounts of radioactive elements could provide a story explaining when various parts of the moon’s surface cooled and hardened, Dr Yamashita said, helping scientists determine which of the moon’s lava flows are older or older. youth.

The Korea Aerospace Research Institute, South Korea’s equivalent of NASA, will use Danuri’s high-resolution camera to scout the lunar surface for potential sites for a robotic lander mission in 2031, Kwon said.

A second camera will measure polarized sunlight bouncing off the lunar surface, revealing details about the size of the particles that make up the lunar soil. Because the constant bombardment by the solar wind, radiation, and micrometeorites breaks up the ground, the size of the grains found in a crater could give an estimate of its age. (Smaller grains would suggest an older crater.)

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

NASA provided one of the cameras, a ShadowCam, which is sensitive enough to pick up the few photons that bounce off the ground in the moon’s dark, permanently shadowed craters.

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

The ice could provide a frozen history of the solar system 4.5 billion years old. It could also be an abundance of resources for future visiting astronauts. Machines on the moon could mine and melt ice to provide water. This water could then be broken down into oxygen and hydrogen, which would provide both air for astronauts to breathe and rocket propellants for travelers seeking to travel from the moon to other destinations.

One of ShadowCam’s main purposes is to find the ice. But even with Danuri’s sophisticated instruments, it could be difficult. University of Hawaii researcher and Danuri scientist Shuai Li thinks the concentrations could be so low that they obviously won’t be brighter than areas without ice.

“If you don’t look at it carefully, you might not be able to see it,” Dr Li said.

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

NASA’s orbiter, which has been studying the Moon since 2009, carries an instrument that records lunar surface temperatures. But these measurements are fuzzy over a fairly large area, about 900 feet in diameter. The resolution of a ShadowCam is about 5 feet per pixel. Thus, ShadowCam images used with computer models could help unravel surface temperature variations.

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

Researchers will have to wait several months for the science to begin. The spacecraft takes a long, energy-efficient route to the moon. It first heads towards the sun, then loops around to be captured in lunar orbit on December 16. This “ballistic trajectory” takes longer but does not require large engines to slow the spacecraft as it arrives on the moon.

South Korea has an extensive military missile program and has placed several communications and Earth observation satellites in low Earth orbit since launching its first in 1992. And it has expanded its national rocket-launching capabilities to that future missions don’t need to rely on SpaceX, or other countries, to get to space. In June, the Korea Institute for Aerospace Research successfully placed several satellites into orbit with the second flight of Nuri, its home rocket.

“We will undertake ambitious projects such as lunar landers and asteroid exploration,” Kwon said.

Jin Yu Young contributed reporting from Seoul.

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