The second unmanned lunar lander 'Athena' of the American space company Intuitive Machines landed on July 7 at 2:31 a.m. (Korean time) in the lunar south pole region of Mons Mouton. It successfully landed on the moon again, one year after Intuitive Machines' first lunar lander 'Odysseus' arrived at the moon on February 24 last year.
Odysseus and Athena encountered issues during the landing process, failing to land properly. However, Steve Altemus, CEO of Intuitive Machines, noted, "If we are operating the spacecraft on the moon a week after sending it to Florida, that alone can be declared a success," emphasizing the achievement.
Before Athena arrived on the moon, another American space company, Firefly's lunar lander 'Blue Ghost,' safely landed on the lunar northern hemisphere, known as Mare Crisium, on July 2. Blue Ghost landed with precision, and all onboard payloads are functioning normally. With private space corporations' lunar landers arriving and successfully starting their missions at four-day intervals, evaluations suggest a new era of private lunar exploration has begun.
◇Signal interference resolved through collaboration among corporations
After the landing of Athena, CEO Altemus introduced an intriguing incident during a briefing. When Athena entered lunar orbit, one of the radios communicating with Earth detected signal interference. The interference occurred because the frequency band used by Firefly's Blue Ghost, which landed on the moon four days earlier, was close to Athena's frequency band.
Intuitive Machines immediately collaborated with Firefly to confirm whether the frequency signal interference would pose problems for Athena's landing, concluding it was safe before proceeding with the landing. Tim Crain, CTO of Intuitive Machines, said, "Firefly understood the importance of humanity sending a lander to the moon and willingly collaborated, giving us a sense of community spirit."
Firefly's Blue Ghost also set a record as the first in lunar history to receive signals from the Global Navigation Satellite System (GNSS). What we refer to as the Global Positioning System (GPS) is a type of GNSS. GPS determines precise locations based on the time taken to receive artificial signals from the ground.
The idea of using GPS in space has been discussed for over a decade. Some GPS signals transmitted by satellites travel beyond Earth into space, and the National Aeronautics and Space Administration (NASA) announced in 2020 that it could receive GPS signals on the lunar surface through experiments.
While the sensitivity of the signal is only one-thousandth of that received on Earth, it is said that with the proper equipment, it is possible to verify locations on the lunar surface using GPS. Blue Ghost confirmed this potential by equipping a signal-receiving device called 'LuGRE.' This device, created by the Italian Space Agency, operated normally after Blue Ghost landed on the moon and successfully received GNSS signals.
Previously, lunar landers sent by humanity could not use GPS and went through complex processes to verify their locations. Engineers tracked locations by combining signals from Earth tracking stations with onboard sensor signals of lunar landers. This required the lunar lander to face the Earth tracking station.
However, confirming that GNSS signal reception is possible on the moon suggests that, similar to cars, ships, and aircraft on Earth, GPS could be easily used to verify locations on the lunar surface. In the future, spacecraft orbiting the moon or surface landers and rovers equipped with satellite signal receivers will be able to use GPS navigation anywhere on the moon.
Kevin Coglins, who oversees the Space Communications and Navigation program at NASA, stated, "The ability to receive GNSS signals on the moon represents an exciting advancement for the development of lunar exploration navigation," adding that there are plans to actively utilize this capability in future lunar exploration missions.
◇Japan to retry lunar landing in June, South Korea also targeting lunar exploration market
The private sector's lunar exploration is not entirely successful. Israel's SpaceIL developed the lunar lander 'Beresheet,' which attempted a lunar landing in 2019 but crashed and exploded on the lunar surface. Failures also occurred last year, with Japan's space company iSpace attempting a landing in April 2024 but failing, and in January 2024, the American space company Astrobotics' lunar lander also failed to land.
Japan's iSpace will make another attempt at a lunar landing this year. The lunar lander 'Resilience,' developed by iSpace, was launched towards the moon aboard SpaceX's rocket on January 15. This rocket also carried Blue Ghost, which had previously successfully landed on the moon. This is the first instance of two lunar landers being carried by a single rocket. NASA even designated it the 'Double Moon Mission.'
Resilience was launched alongside Blue Ghost but chose a different route to save fuel instead of heading directly to the moon. After advancing to a point about 1 million kilometers away from Earth, it is set to accelerate toward the moon using Earth's gravity. This has delayed the landing timing, and Resilience is expected to attempt a lunar landing around June 5.
South Korea, under the leadership of the Korea National Aerospace Administration (KARI), is preparing for lunar exploration, aiming for 2032. However, there are also corporations preparing to enter the lunar exploration market even ahead of that. Intergravity Technologies, founded by former Korea Aerospace Research Institute employees, is a prime example. This company is working on developing an orbital transport vessel that connects Earth's orbit with the lunar orbit. They are also developing a hopper that moves by jumping on the lunar surface instead of rolling.
Lee Gi-joo, CEO of Intergravity, stated, "We aim to complete the development of the orbital transport vessel by the second quarter of 2026 and carry out launches in 2027, gradually securing transportation services between Earth, the moon, and deep space to showcase our technological prowess on the international stage."