Artemis missions could place most powerful imaging telescope on the moon

Ground-based interferometry on Earth has proven to be a successful method for conducting science by combining light from multiple telescopes into one large telescope. But how can an ultraviolet (UV)/optical interferometer telescope on the Moon deliver enhanced science, and can the Artemis missions help make this a reality? This is what a recently submitted study to the SPIE Astronomical Telescopes + Instrumentation 2024 conference hopes to address when a team of researchers proposes the Artemis-enabled Stellar Imager (AeSI), which, as its name suggests, could potentially be delivered to the lunar surface via NASA’s upcoming Artemis missions. This proposal was recently accepted as a Phase 1 study through NASA’s Innovative Advanced Concepts (NIAC) program and has the potential to develop a revolutionary extremely high angular resolution method for conducting science on other planetary bodies, while also contributing to other missions.

Here, Universe Today discusses this incredible research with Dr. Gioia Rau, an astrophysicist at NASA’s Goddard Space Flight Center and program director at NSF, about the motivation behind this study, key takeaways from this work, next steps as this moves beyond Phase 1, long-term goals for lunar surface locations, and how AeSI can advance our understanding of exoplanet habitability. So, what was the motivation behind this study?

Dr. Rau tells Universe Today“The motivation behind this study is to assess whether we can build and operate a large sparse aperture observatory (interferometer) on the lunar surface in conjunction with the human Artemis program and determine if it can compete with a previously developed free-flyer option. The end goal is to enable the study of our Universe with Ultra High Definition at ultraviolet and optical wavelengths with ~200x the angular resolution of HST! Ultraviolet observations are not available from the Earth’s surface due to the overlying atmosphere and even in the visible, the Earth’s atmosphere limits the ultimate resolution available with ground-based interferometers.”

For the study, the researchers are building on long-standing proposals to place UV/optical interferometers in space, but due to the lack of infrastructure on the lunar surface, scientists have favored using satellites and orbiters, which the researchers call “free-flyers.” For AeSI, the researchers are proposing to build a lunar interferometer using infrastructure delivered to the moon through NASA’s Artemis program with the goal of providing cutting-edge science related to exoplanetary systems, including the surfaces of stars, their interiors, magnetic fields, space weather, and habitability of exoplanets.

To achieve this, AeSI will consist of a 1-kilometer UV/optical imaging interferometer located near the lunar south pole, which is the landing region for the Artemis program, specifically Artemis III. In addition to the improved science, the team is also promoting the scalability of the project, noting that it could potentially include as many as 30 or more elements to serve as a single interferometer. Additionally, the team is addressing several issues that could arise during this endeavor, including lunar dust, seismic activity, and the use of robotic tools to assist with construction. So, what are the key takeaways from this study?

Dr. Rau tells Universe Today“The main conclusions from this study are that the project is feasible, demonstrating that the visionary idea of ​​our PI, Dr. Kenneth Carpenter (NASA/Goddard Space Flight Center), can be realistically developed. The study provides important recommendations for further research and technology development, which will be crucial to advancing the project and addressing the technical challenges and further technology development that are needed.”

As noted, AeSI was approved for a Phase 1 study (less than 4% success rate!) through NASA’s Innovative Advanced Concepts (NIAC) program. NIAC has been successfully advancing technology within the aerospace industry since 1998. Its original name was the NASA Institute for Advanced Concepts, until it closed in 2007. Just two years later, Congress requested that the National Academy of Sciences investigate why it had closed. This made recommendations for the future, which resulted in the current NIAC program in 2011.

Since then, NIAC has contributed to technological advances in nanosatellites, planetary exploration, exoplanet spectroscopy, astrophysics, cosmology, solar science, human space exploration, and many others. These proposals go through three phases, with each phase allowing for more funding and time for the project. What are the next steps if AeSI is a Phase 1 study, since it is a Phase 1 study?

Dr. Rau tells Universe Today“The next steps would involve seeking Phase 2 support from NIAC and exploring additional funding and resources. Phase 2 would focus on further developing and refining the initial 9-month study we conducted in Phase 1. We believe our visionary concept has the potential to revolutionize scientific research and provide a significant opportunity for technology demonstration on the lunar surface, so we sincerely hope to receive further support from NIAC and/or other supporting sources!”

Dr. Rau talks about the long-term goals for AeSI Universe Today“There are several limitations to placing interferometers on the lunar surface, especially optical and UV interferometers! We describe this in more detail in the final report of the NIAC Phase 1 study, which will be public and published early next year. Our project is currently planned to start with a Phase 1 consisting of 15 rovers in an elliptical array configuration with a major axis of 1 km. The observatory will evolve in later phases to an array of ~30 rovers with an improved hub to combine the beams from the larger number of rovers (mirror stations) and will provide extremely high angular resolution of celestial objects such as distant Sun-like stars, active galactic nuclei (AGN), exoplanets, cool evolved stars and more!”

As noted, one of the science goals of AeSI, in addition to the improved science performed on stars, will also be to determine the habitability of exoplanets, which is because NASA has confirmed the existence of over 5,700 exoplanets in our Milky Way galaxy. Of these, nearly 70 are currently designated as being in the “habitable zone” of their host star, with 29 of these being possible terrestrial (rocky) worlds and the remaining 41 being possible “water worlds” or mini-Neptunes. These potentially habitable worlds have been found to orbit both inside and outside the habitable zone, with some orbits taking them both inside and outside the habitable zone during a single orbit. How might AeSI advance our understanding of the habitability of exoplanets?

Dr. Rau tells Universe Today“AeSI will provide a deeper insight into the characteristics of the host stars in distant exoplanetary systems. By analysing these stars more thoroughly, we can gain a better understanding of the conditions that influence the habitability of their surrounding planets. This includes investigating the interactions between planets and their stars, which can have a significant impact on the potential for life on these exoplanets.”

As NASA prepares to return humans to the Moon for the first time since 1972 with the Artemis program, it is important to note the incredible science that can be accomplished with the infrastructure established by Artemis. Therefore, with ground-based interferometry from Earth as a long-established and successful scientific field that has contributed to a better understanding of radio astronomy, solar physics, nebulae, galaxies, and exoplanets, AeSI offers a unique opportunity to perform revolutionary science, imaging distant stars with the highest angular resolution ever, on other planetary bodies while simultaneously testing new technologies.

Dr. Rau concludes by telling Universe Today“AeSI will provide the first ever ultra-high angular resolution images of the Universe in the ultraviolet (UV). This is a huge leap forward for so many aspects of astrophysics, from understanding magnetic activity in stars and its impact on surrounding planets, to detailed studies of exoplanets, space weather, AGN, stellar astrophysics and more! AeSI’s high angular resolution ultraviolet and optical observations will open new frontiers in astrophysics, providing a richer and more detailed view of the most energetic and enigmatic components of the Universe.”

How will AeSI help improve UV/optical interferometry in the coming years and decades? Only time will tell, and this is why we do science!

As always, keep doing science and keep looking up!

Additional links:

SPIE Astronomical Telescopes + Instrumentation 2024