NASA’s LunaH-Map Mission Ends, Validates Science Instrument Performance

NASA’s LunaH-Map (Lunar Polar Hydrogen Mapper) mission, a briefcase-sized lunar orbiter that launched as a ride share on NASA’s Artemis I mission last year, has ceased operations after successfully demonstrating its neutron spectrometer can detect water and ice at the lunar surface.

The LunaH-Map CubeSat was designed to map ice deposits across the Moon’s South Pole as part of NASA’s SIMPLEx (Small Innovative Missions for Planetary Exploration) program. It performed a flyby of the Moon shortly after its Nov. 16, 2022, launch on the Space Launch System rocket, but challenges with the spacecraft’s thruster valve prevented it from adjusting course to achieve its planned science orbit around the lunar South Pole. This ambitious orbit was designed to take measurements from altitudes as low as 6.2 miles (10 kilometers), including over the permanently shadowed regions of the Moon.

Several technicians in white smocks, masks and head coverings work around a small briefcase-sized piece of hardware.
Mechanical Engineers Joe DuBois and Nathaniel Struebel (AZ Space Technologies) perform a final pre-shipment inspection on the LunaH-Map spacecraft’s star tracker on July 19th, 2021 while the Principal Investigator, Dr. Craig Hardgrove, observes the procedure. Credit: Arizona State University

In late November, the mission team concluded the propulsion system’s valve was partially stuck. The team then embarked on a six-month effort to repeatedly heat the valve in order to free it and allow for ignition. In late May, it was determined these attempts were unsuccessful and mission operations ceased. The spacecraft’s trajectory will evolve into a stable orbit around the Sun, and the LunaH-Map mission and science team will continue to work on data reduction and publishing scientific results.

During the lunar flyby in November, LunaH-Map’s neutron spectrometer, which was developed and built for this mission by Arizona State University in Tempe, collected nearly three hours of data from the Moon’s surface from a distance of about 800 miles (1300 kilometers). The spectrometer’s rate of neutron detections demonstrated that this instrument can function in the lunar environment and identify enrichments of ice as deep as 3.3 feet (one meter) below the soil.

High-energy neutrons are created in nuclear interactions between cosmic rays and the atoms that make up lunar rocks and soils. LunaH-Map’s neutron spectrometer looked for suppressions of the neutron energies that leak out of the Moon. These measurements usually indicate the presence of hydrogen; and generally, where there is hydrogen, there is water. During the lunar flyby, LunaH-Map’s instrument successfully detected neutrons leaking from the Moon and measured the neutron signal increasing as the spacecraft approached the Moon.

“We are thrilled that the LunaH-Map team was able to use this opportunity to demonstrate the capability of its neutron spectrometer in flight, even though the mission could not be completed as planned,” said Lori Glaze, director of the Planetary Science Division at NASA Headquarters in Washington. “SIMPLEx missions are inherently risky, as they are designed to test the bounds of what can be achieved with lower-cost missions.”

A version of this now flight-proven science instrument is scheduled to be integrated onto NASA’s upcoming Lunar-VISE (Lunar Vulkan Imaging and Spectroscopy Explorer) payload to be delivered to the lunar surface on a future flight through NASA’s CLPS (Commercial Lunar Payload Services) initiative.

LunaH-Map is led by Craig Hardgrove at Arizona State University. The mission was selected in the first round of NASA’s SIMPLEx program, which provides opportunities for low-cost, high-risk science missions to ride-share with selected primary missions. These lower cost missions serve as an ideal platform for technical and architecture innovation, contributing to NASA’s science research and technology development objectives.

SIMPLEx mission investigations are managed by the Planetary Missions Program Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama, as part of the Discovery Program at NASA Headquarters in Washington. NASA provided a ride to deep space aboard the Space Launch System rocket for 10 CubeSats, each of which have separate missions from the agency’s Artemis I flight test.

NASA’s LunaH-Map Captures Image of Auriga Constellation

Image shows the constellation Auriga against black space.
This image acquired by NASA’s LunaH-Map star tracker on Nov. 25, 2022, shows part of the constellation of Auriga. The two brightest stars visible, both binary star systems, are Mahasim (top middle) and Menkalinan (bottom left). Credit: NASA/Arizona State University/KinetX

On Nov. 28, NASA’s LunaH-Map spacecraft acquired its first star tracker image, showing the constellation Auriga and its two brightest stars, Menkalinan and Mahasim. The LunaH-Map navigation team used these images to test a new type of autonomous optical navigation software that can be run on the spacecraft’s flight computer. On Dec. 2, LunaH-Map also successfully acquired observations of Mars and Uranus and processed them onboard using the autonomous optical navigation software routines. The test was successful and demonstrated that the autonavigation software could autonomously correct raw images onboard, estimate the inertial camera orientation using visible stars, compute the astrometric centers of planetary targets in the field, and compute offsets relative to the spacecraft state. Each of these measurements are critical to performing autonomous navigation with onboard images, without the intervention from operators on Earth. Optical navigation algorithms like the one demonstrated on LunaH-Map will be important for future small spacecraft to perform operations in deep space, given their minimal communications resources.

LunaH-Map’s star tracker image of the constellation Auriga in false color and increased contrast, with markers indicating the stars chosen by the spacecraft’s autonomous navigation software for attitude determination. Green crosses indicate the star locations predicted by the software and red crosses indicate their actual observed locations in the image. Credit: NASA/Arizona State University/KinetX

The mission team also made several attempts to image the Earth and Moon; however, these images resulted in saturation of the star tracker. In the coming weeks, additional imaging opportunities of the Earth and Moon will be evaluated to help further demonstrate these novel autonavigation capabilities.

While a recent telemetry downlink showed an unexpected spacecraft reset, a Deep Space Network (DSN) pass has since indicated that, with the exception of the likely stuck propulsion system valve, the spacecraft is healthy with all subsystems nominal and operating as expected.

NASA’s Jet Propulsion Laboratory and the DSN teams are scheduling a set of tracks for the week of Dec. 5 the team will use to demonstrate a new type of radio ranging technique called Pseudo Noise Differential One Way Ranging (PN DOR). This is a first-time demonstration of PN DOR and will enable better ranging accuracy on future deep space CubeSats as well as larger missions.

The LunaH-Map science team began analysis of the lunar neutron data acquired during the spacecraft’s lunar flyby, including assessing the geometric effects related to the detector, spacecraft and Moon. From the flyby altitudes, the Moon’s epithermal neutron albedo measured by LunaH-Map can be used to derive a bulk hydration of the Moon, which can be compared with previous lunar orbital neutron measurements made by NASA’s Lunar Prospector and Lunar Reconnaissance Orbiter spacecraft. This measurement demonstrated that the instrument can achieve LunaH-Map’s science mission to map ice at the lunar South Pole.

After several whirlwind weeks, the LunaH-Map operations team took the first much-needed break since launch. They are working on a few minor ground system issues and finalizing the procedures and schedules related to the upcoming PN DOR radio ranging test. The team will soon enter an operational cadence with long (multi-day) heating of the propulsion system valve, followed by communications passes to focus on multiple ignition attempts that will, if successful, enable the completion of the LunaH-Map science mission later next year.

NASA’s LunaH-Map Post-Launch Update

After deploying from the Artemis I Space Launch System rocket, NASA’s LunaH-Map spacecraft was powered on and communicating with Earth 5 hours and 33 minutes following launch on Nov. 16. Shortly after deployment, the operations team made first radio contact with the spacecraft and transitioned it out of beacon mode. Over the next 24 hours, the team also successfully commissioned the solar arrays, radio, neutron spectrometer, and various spacecraft bus systems. The neutron spectrometer collected a set of cruise data that indicated the detector is functioning nominally.

On Nov. 17, the team powered on the propulsion system. However, after many ignition attempts, the system was not able to achieve thrust prior to the spacecraft’s planned lunar flyby on Nov. 21. The mission’s original trajectory required that the spacecraft make a propulsive maneuver on Nov. 21 as a step toward its eventual lunar polar orbit. Based on the propulsion data, the team has assessed that the propulsion system valve may be partially stuck.  Heating this valve over many hours may result in freeing it, allowing for ignition. Therefore, the spacecraft has now been instructed to heat the propulsion valve.

If the propulsion system is able to achieve thrust within the next few months, the mission may still recover some or all of LunaH-Map’s original science mission. On the spacecraft’s current path, alternate trajectories are available to achieve lunar orbit – including orbits that could enable low-altitude measurements of the lunar surface. If even more time is needed to heat the valve and ignite the propulsion system, trajectory solutions outside of the Earth-Moon system may exist to fly close to certain asteroids and characterize their hydrogen content.

During the lunar flyby, LunaH-Map’s neutron spectrometer collected neutron data from as close as 810 miles (1,300 kilometers) above the lunar surface. Data from the detector clearly shows neutrons and gamma-rays from the surface of the Moon increasing along the flyby, demonstrating the instrument is operating as expected and could achieve LunaH-Map’s science mission.

After the flyby, LunaH-Map acquired several images of the Moon with its star tracker. In the next few days, the spacecraft will attempt to send these images back to Earth. The mission also plans to conduct an auto-navigation experiment and a radio ranging test with NASA’s Deep Space Network prior to resuming attempts to ignite the propulsion system.

LunaH-Map’s battery charge is functioning well.  The batteries are currently fully charged from the solar arrays.

LunaH-Map is led by Craig Hardgrove at Arizona State University in Tempe. The mission was selected in the first round of NASA’s Small Innovative Missions for Planetary Exploration, or SIMPLEx, program, with a total cost of $13.3 million. SIMPLEx missions provide opportunities for low-cost, high risk science missions that are responsive to requirements for flexibility. These lower cost missions serve as an ideal platform for technical and architecture innovation, contributing to NASA’s science research and technology development objectives. SIMPLEx mission investigations are managed by the Planetary Missions Program Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama as part of the Discovery Program at NASA Headquarters in Washington. NASA provided a ride to deep space aboard the Space Launch System rocket for 10 CubeSats, each of which have separate missions from the agency’s Artemis I flight test.

NASA’s Luna-H Map to Study Moon Water

NASA’s Lunar Polar Hydrogen Mapper (LunaH-Map) CubeSat was launched by the Space Launch System (SLS) rocket for the Artemis I mission on Nov. 17.

LunaH-Map, developed by Arizona State University and sponsored by NASA’s Science Mission Directorate (SMD), will measure the distribution and amount of hydrogen throughout the Moon’s South Pole. If successful, the LunaH-Map spacecraft will produce a high-resolution map of the Moon’s bulk water deposits, unveiling new details about the spatial and depth distribution of potential ice previously identified during a variety of missions. Confirming and mapping these deposits in detail will help NASA understand how the water got there, how much water might be available, and how it could potentially serve as a resource for longer exploration missions on the Moon. The CubeSat’s mission is designed to last around 60 days once science operations begin.