NASA’s upcoming Artemis II mission is slated to return astronauts to the Moon no sooner than April 2026. Astronauts were last on the Moon in 1972 during the Apollo 17 mission.
Artemis II will utilise NASA’s Space Launch System, which is an extremely powerful rocket that will enable human space exploration beyond Earth’s atmosphere. The crew of four will travel in an Orion spacecraft, which the agency launched around the Moon and successfully returned during the Artemis I mission.
But before Artemis II, NASA will send two missions to scout the surface of the lunar South Pole for resources that could sustain human space travel and enable new scientific discoveries.
Planetary geologists like me are interested in data from Lunar Trailblazer, one of these two scouting missions. The data from this mission will help us understand how water forms and behaves on rocky planets and moons.
PRIME-1, or the Polar Resources Ice Mining Experiment, will be mounted on a lunar lander. It is scheduled for launch in January 2025.
Aboard the lander are two instruments: The Regolith and Ice Drill for Exploring New Terrain, TRIDENT, and the Mass Spectrometer for Observing Lunar Operations, MSOLO. TRIDENT will dig down up to 3 feet and extract samples of lunar soil, and MSOLO will evaluate the soil’s chemical composition and water content.
Joining the lunar mining experiment is Lunar Trailblazer, a satellite launching on the same Falcon 9 rocket.
Think of this setup as a multimillion-dollar satellite Uber pool, or a rideshare where multiple missions share a rocket and minimise fuel usage while escaping Earth’s gravitational pull.
Bethany Ehlmann, a planetary scientist, is the principal investigator of Lunar Trailblazer and is leading an operating team of scientists and students from Caltech’s campus. Trailblazer is a NASA Small, Innovative Mission for Planetary Exploration, or SIMPLEx.
These missions intend to provide practical operations experience at a lower cost. Each SIMPLEx mission is capped at a budget of US $55 million – Trailblazer is slightly over budget at $80 million. Even over budget, this mission will cost around a quarter of a typical robotic mission from NASA’s Discovery Program. Discovery Program missions typically cost around $300 million, with a maximum budget of $500 million.
Decades of research and development into small satellites, or SmallSats, opened the possibility for Trailblazer. SmallSats take highly specific measurements and complement data sourced from other instruments.
Multiple SmallSats working together in a constellation can take various measurements simultaneously for a high-resolution view of the Earth’s or Moon’s surface.
SIMPLEx missions can use these SmallSats. Because they are small and more affordable, they allow researchers to study questions that come with a higher technical risk. Lunar Trailblazer, for example, uses commercial off-the-shelf parts to keep the cost down.
These low-cost, high-risk experimental missions may help geologists further understand the origin of the solar system, as well as what it’s made of and how it has changed over time. Lunar Trailblazer will focus specifically on mapping the Moon.
Scientists have long been fascinated by the surface of our closest celestial neighbour, the Moon. As early as the mid-17th century, astronomers mischaracterised ancient volcanic eruptions as lunar mare, derived from the Latin word for “seas”.
Nearly two centuries later, astronomer William Pickering’s calculations suggested that the Moon had no atmosphere. This led him to conclude the Moon could not have water on its surface, as that water would vaporise.
However, in the 1990s, NASA’s Clementine mission detected water on the Moon. Clementine was the first mission to completely map the surface of the Moon, including the lunar poles. This data detected the presence of ice within permanently shadowed regions on the Moon in low resolution.
Scientists’ first water detection prompted further exploration. NASA launched the Lunar Prospector in 1998 and the Lunar Reconnaissance Orbiter in 2009. The India Space Research Organisation launched its Chandrayaan-1 mission with the Moon Mineralogy Mapper, M3, instrument in 2008. M3, although not designed to detected liquid water, unexpectedly did find it in sunlit areas on the Moon.
These missions collectively provided maps showing how hydrous minerals – minerals containing water molecules in their chemical makeup – and ice water are distributed on the lunar surface, particularly in the cold, dark, permanently shadowed regions.
But how does the temperature and physical state of water on the Moon change from variations in sunlight and crater shadows?
Lunar Trailblazer will host two instruments, the Lunar Thermal Mapper, LTM, and an evolution of the M3 instrument, the High-resolution Volatiles and Minerals Moon Mapper, HVM3.
Lunar Trailblazer may shed light on these theories and help researchers make progress on several other big science questions, including how water behaves on rocky bodies like the Moon and whether future astronauts will be able to use it.
The Conversation
(César León Jr is a Ph.D. student of Planetary Geology, Washington University in St Louis.)
