GOLDEN, Colorado — Finding exploitable water ice at the lunar south pole is high on the agenda of NASA’s Artemis program. If reservoirs of water ice exist in lunar cold traps, also known as or permanently-shadowed regions, future robotic or crewed missions may be able to process it into oxygen and hydrogen — ideal for life support or manufacturing rocket fuel.
But NASA is not alone in the hunt.
China and Russia are eager to probe the south pole for volatile resources, and are collaborating on the International Lunar Research Station to carry out routine scientific exploration, technological verification and utilization of lunar resources.
Now on the books are two Chinese robotic lunar lander missions. China’s Chang’e-7 is scheduled to launch around 2026 and will focus on investigating water ice at the moon’s south pole region. That’s to be followed by Chang’e-8, slated for liftoff around 2028, which would continue south pole exploration and showcase technologies for the construction of future infrastructure on the moon.
Launch preparations
Potentially beating China there is the United States, pending the early Jan. 2025 co-launch of two key spacecraft, the NASA Lunar Trailblazer orbiter and the Intuitive Machines IM-2 mission as part of NASA’s Commercial Lunar Payload Services initiative.
As a NASA Small Innovative Missions for Planetary Exploration (SIMPLEx) program spacecraft, Lunar Trailblazer’s lower-budget scientific mission is considered a secondary but still important ice snooping project. It will be launched with the IM-2, a Nova-C lunar lander dubbed Athena. The IM-2 lander and Lunar Trailblazer moon orbiter will launch together on a SpaceX Falcon 9 rocket.
Intuitive Machines spokesperson Josh Marshall told SpaceNews that they plan on delivering the IM-2 lunar lander to NASA’s Kennedy Space Center in Florida for launch preparations in the 4th quarter of 2024, “with an extended mission window reaching into January.”
“We launch when IM-2 does, which we anticipate is soon,” Lunar Trailblazer principal investigator and Caltech planetary science professor Bethany Ehlmann told SpaceNews.
Top-notch science
The Caltech-led Lunar Trailblazer hardware is successfully through all environmental testing, with final software and operation readiness tests now taking place, Ehlmann told SpaceNews. Still to come is installing final ordinance and shipping to Florida for fueling and integration a few weeks before launch. Lockheed Martin provided the spacecraft and is integrating the flight system, under contract with Caltech.
It’s a been a challenging five years for the team, Ehlmann said, but they now find themselves weeks away from being ready for launch.
“Lunar Trailblazer is a new type of NASA planetary science mission, providing top-notch science at lower-cost than traditional planetary missions by accepting higher risk,” Ehlmann said. “Cost savings include commercial off-the-shelf parts and a single-string system spacecraft.”
Spectral fingerprints
Trailblazer will collect important data about the form, abundance and distribution of water on the moon, answering questions about the water cycle on airless bodies.
When Lunar Trailblazer settles into its lunar orbit and begins its work, it will map the spectral fingerprints – or wavelengths of reflected sunlight – of forms of water over the lunar landscape, and will also record the temperature of the moon’s surface. By observing the same locations at different times of day, Lunar Trailblazer will find out if the amount of water changes over time.
“Trailblazer’s data is key for future missions with boots or wheels on the ground,” Ehlmann said. “Lunar Trailblazer will be the highest spatial resolution infrared compositional and temperature mapping so far,” with the orbiter’s high-resolution data “able to tell those missions to turn left or turn right with our maps navigating them to the water and mineral deposits of highest interest.”
Spacecraft operations are to be performed from Caltech’s Infrared Processing and Analysis Center, and will involve students from Caltech and Pasadena City College, Ehlmann said. “It’s a tremendous opportunity to train the next generation while accomplishing priority science.”
Hop to it
However, researchers don’t know the precise location of water ice on the moon, nor do they know its physical and chemical form, Ben Bussey, chief scientist for Intuitive Machines, said. “So, we do not know how easy it will be to extract. To use the terrestrial mining industry terminology, it is the difference between a ‘resource’ and a ‘reserve.’”
“Ice has the potential to be an important lunar resource,” Bussey added. “However, we do not currently know the information required to determine the nature of that resource.”
If IM-2 successfully touches down, a Micro-Nova Hopper (a propulsive drone funded by NASA) will be deployed to jump across the lunar surface. As it hops around, the drone will supply the first direct surface measurement of hydrogen, a key indicator for the presence of water, using a neutron spectrometer provided by Hungary’s Puli Space Technologies, Bussey explained.
“The hopper will also fly into a permanently shadowed crater, providing surface information from these cold traps for the first time,” Bussey said.
Also onboard IM-2 is the Polar Resources Ice Mining Experiment-1 (PRIME-1), a NASA experiment designed to search for water ice on the moon.
Matter of luck
With some luck, the upcoming array of spacecraft hardware to the moon could discover lunar ice, Norbert Schörghofer, a Planetary Science Institute senior scientist based in Hawaii told SpaceNews.
At optical wavelengths, no ice has been detected in permanently-shadowed regions, so the prospects are not great, Schörghofer said.
The IM-2’s PRIME-1 has a drill and a mass spectrometer, but it is stationary and cannot move. The landing location is too warm for ice to accumulate, “but if ice-rich material was ejected from a nearby crater it might have survived,” said Schörghofer. “It is a gamble.”
For that reason, Schörghofer said, “The Micro-Nova hopper may offer the best chance to find ice, albeit only indirectly.”
Schörghofer said that all three of these low-cost approaches are not comparable to full-fledged lunar science missions such as NASA’s recently cancelled Volatiles Investigating Polar Exploration Rover (VIPER) — or China’s Chang’e-7 lunar lander.
Whether any of the soon-to-fly U.S. moon probes encounter ice is a matter of luck, Schörghofer said. “If not, the next ice-sniffing missions to the lunar south pole will be from other nations, possibly launching in 2026. The race is on,” he said.
Editor’s note: This article originally listed specific dates for the IM-2 launch window, attributed to a Caltech website. That source has been disputed and the sentence deleted from this article.
