Moon Monday Issue #63

The key scientific difference between Apollo and Artemis? Moon water missions

If there’s going to be one stark difference between scientific investigations of our Moon by Apollo missions and upcoming Artemis ones, it will be the study of water ice and other such volatiles. Lunar samples returned by Apollo astronauts supported a long-held consensus of our cosmic neighbor being extremely dry. Almost four decades later though, technological advances allowed discovering water within lunar volcanic glasses and in apatite mineral samples. Around the same time, ISRO and NASA co-discovered relatively large amounts of water ice on the Moon’s poles. The Moon turned out not to be bone dry after all. These developments, enhanced by more such sample studies and remote orbital measurements, helped rekindle widespread interest in exploring our Moon both from a scientific and resource utility standpoint.

Since then, lunar scientists have been trying to understand exactly how water and other volatiles get produced on the Moon, and then get transported from the equator to its poles where they can get sequestered in permanently shadowed regions for billions of years.

Knowing the exact nature and availability of lunar volatiles is so crucial that even before NASA lands humans on the Moon, a slew of agency-funded robotic missions will take specific measurements to help scientists construct mechanisms governing lunar volatiles.

• The Lunar Flashlight, Lunar IceCube and LunaH-Map CubeSat orbiters will launch on Artemis I. Lunar Flashlight will use near-infrared lasers and a spectrometer to identify locations and states of water ice inside permanently shadowed regions on the Moon’s poles. Lunar IceCube’s infrared spectrometer will map water across the Moon’s surface as well as measure water vapor in the thin lunar exosphere. LunaH-Map will use two neutron spectrometers to map hydrogen—an indicator of water—in the highest resolution to date across the Moon’s south pole over 60 days, both in permanently shadowed regions and on the surface as well as a meter below it.
• A mass spectrometer onboard Astrobotic’s first Moon mission this year will measure water vapor at its landing site of Lacus Mortis at 45° N, and note changes in its amount over time. Related: Russia’s Luna-27 mission to the Moon’s south pole in 2025 will carry a similar instrument.
• NASA is putting a drill and a mass spectrometer onboard Intuitive Machines’ second Moon mission in December 2022 to the Moon’s south pole. The lander will drill up to 1 meter below the surface and analyze the soil for water ice.
• Instruments onboard Masten Space’s 2023 Moon mission will detect water ice and other volatiles such as methane and carbon dioxide to help us better understand the Moon’s polar environment. Aiding the task will be Astrobotic’s MoonRanger rover onboard carrying a NASA-provided neutron spectrometer to detect signs of water ice below the surface.
• NASA’s VIPER rover will explore lunar areas in and around permanently shadowed regions for over 100 days, and use its drill and three instruments to unravel the nature of the Moon’s water ice deposits, assess their resource potential, and determine how accessible they are. This will be the most crucial mission in helping us plan near-future human exploration of the Moon’s poles.
• NASA’s Lunar Trailblazer orbiter will use its two instruments to map the form, abundance, and distribution of water on the Moon, both in permanently shadowed regions and sunlit areas. The mission will also monitor changes in water in sunlit regions over time, and is expected to provide holistic insights on the lunar water cycle. The spacecraft is expected to be ready in October 2022 but its launch is currently scheduled for 2025 as a secondary payload along with NASA’s IMAP mission. The mission team and NASA are looking into earlier launch options.
• As part of the identified science priorities for Artemis III, NASA’s first Artemis human landing mission launching in 2025, the Science Definition Team has expressed the need for having cryogenic sampling capabilities to bring precious volatiles from the Moon’s permanently shadowed regions to Earth for meticulous studies.

A recent review paper on lunar volatiles provides an exhaustive look at everything we know about the Moon’s current volatile inventory, where they come from, how they are likely transported, and how much of it all gets potentially preserved on the poles and below the surface. The paper also mentions specific future measurements by lunar missions, chiefly by VIPER and India’s Chandrayaan 2 orbiter, that could answer many of our questions regarding the Moon’s volatile resource potential.

Some recent results from the Chandrayaan 2 orbiter have already been advancing our knowledge on the matter. Apart from a promising initial result from the orbiter’s dual-frequency radar, the spacecraft’s infrared spectrometer detected even more water on the sunlit Moon last year. Read my past Moon Monday coverage to know its specific importance and how it improves things over SOFIA’s water discovery.

Exploration

NASA’s Artemis I mission to send an uncrewed Orion spacecraft around the Moon and back has been delayed to at least April. NASA says it needs an additional month to complete integrated testing of the fully stacked SLS rocket before the vehicle can be rolled out to the launchpad for a wet dress rehearsal. Based on exactly how this critical final test of fueling, defueling and related procedures goes in late March, NASA will decide the launch date to be either in April or May. The current launch windows available for the same are April 8-23 and May 7-21.

A response to a query put forth to the Lok Sabha—Indian equivalent to the U.S. House of Representatives—reveals that the Chandrayaan 3 Moon landing mission is scheduled for launch in August 2022. ISRO Chief S. Somanath told the Times of India that based on lessons learnt from the Chandrayaan 2 lander’s close but failed landing, Chandrayaan 3 includes software improvements, strengthened legs, and better power and communication systems.

We know so far that the mission consists of a Chandrayaan-2-like lander, and an orbiter to propel the lander to the Moon as well as to relay communications during and after landing. The Chandrayaan 2 orbiter will serve as a backup (and secondary) relay provider. The Chandrayaan 3 lander will carry, among other experiments, a thermal probe and a seismometer to study the Moon’s interior. Being a repeat attempt of Chandrayaan 2’s surface part of the mission, Chandrayaan 3’s landing region is expected to be in a near-polar lunar highland too. As such, its rover will have a pair of spectrometers to determine what the ancient lunar crust is made of.

Masten Space, in partnership with Penn State University and Honeybee Robotics, is working on an intriguing new technology to enable landers, rovers and instruments to survive the frigid lunar night, where temperatures can go well below -180 degrees Celsius. Masten’s NITE system uses exothermic chemical reactions to provide heat and power through the oxidation of metals using leftover spacecraft propellant or mined water. Masten says that compared to other solutions based on batteries and fuel cells, NITE has more than seven times lower mass, a longer lifespan, lunar-dust resistance, and lesser complexity while being over $10 million cheaper. Compared to nuclear-based solutions, Masten says NITE is cheaper, safer and (will be) readily available.

Most interestingly, NITE can allow surface hardware to better explore permanently shadowed regions and even lava tubes. NASA accelerated development of the NITE system with a $2.8 million Tipping Point award in 2020 so that Masten can complete the core technology in 2022.

In August 2021, keen observers noted that the service module of the Chang’e 5 lunar sample return mission moved from near Sun-Earth L1 point, where it was stationed since March 2021, towards the Moon again. After careful observations and modeling, they have now confirmed that the Chang’e 5 service module is in a Distant Retrograde Orbit around the Moon. The orbit’s parameters are similar to that planned for the upcoming NASA’s Artemis I mission. China’s lack of a public statement on the new orbit is curious because this is the first time a spacecraft has entered such a lunar orbit.

More Moon

I wrote an article on NASA’s upcoming CLPS Moon landing missions as part of The Planetary Society’s collection of resource pages on missions and worlds. The CLPS page is intended to be an evergreen resource; notice the plethora of links in there so that people can access more and nuanced information easily.

I’ll be keeping the page up to date as and when major new developments happen so bookmark it maybe?

Everyone, I’m publishing this one-of-a-kind Moon exploration newsletter for free, with no ads. And it will stay that way. If you like my work, support me to keep it going.