The Moon is a unique platform from and on which to conduct measurements of the early Universe, gravitation, the Sun, and the lunar ionosphere and interior.
The Lunar University Network for Astrophysics Research (LUNAR) and the Center for Lunar Origins and Evolution (CLOE) are teams within the NASA Lunar Science Institute (NLSI) that are addressing the question of how the Moon can be used as a platform to advance important goals in astrophysics.
The LUNAR team has been pursuing two observational approaches: 1) a lunar orbiting spacecraft— the Dark Ages Radio Explorer (DARE) —which is a mission concept that would orbit the lunar farside to determine the moment when the stars turned on; and 2) technology development for future lunar surface telescopes, which could help detect and characterize Earth-like planets orbiting nearby stars. Both approaches leverage the moon as a science platform; FM radio signals are persistently detected here on Earth, and the lunar farside is potentially the only site in the inner solar system for high-precision radio cosmology.
DARE will use the highly-redshifted hyperfine 21 cm transition from neutral hydrogen to track the formation of the first luminous objects by their impact on the intergalactic medium during the end of the Dark Ages and during Cosmic Dawn. The science instrument is composed of a low frequency radiometer, a receiver, and a digital spectrometer. The various sub-systems have been constructed and are in the process of system integration. After check-out, the system will be deployed and tested at the Murchison Radio Observatory in Western Australia—one of the most radio quiet locations on the planet.
The Lunar Radio Telescope Array (LRTA) is a concept for a telescope located on the far side of the Moon where it is protected from radio frequency interference (RFI). It would detect magnetically generated radio emissions to provide insights into the interior structure of planets— information likely to be difficult to obtain by other means.
Furthermore, the Lunar Laser Ranging (LLR) component of the LUNAR team has taken a two-fold approach toward testing theories of gravity. Not only are they continuing precise measurements of the Earth-Moon distance via laser ranging, but they are also leading efforts to develop a next-generation retroreflector package that could be emplaced on the Moon by future missions.
While the three retroflector arrays deployed during Apollo era were an incredible success, the reduced return from the arrays over the years has limited advanced investigation into general relativity. At present, there are a number of stations that can access Apollo 15 arrays but not the Apollo 11 and 14 arrays; the new retroreflectors will have signals that can be accessed by a large number of lunar laser ranging ground stations. A next generation retroreflector would improve precision measurements for gravitational physics and for understanding the lunar interior.
As a classical theory, general relativity and quantum mechanics are fundamentally inconsistent; there must be a breakdown at some level of accuracy in general relativity or a problem with quantum mechanics. A much higher ranging accuracy would improve scientific results in testing the theory of general relativity by more than two orders of magnitude.
The CLOE team is studying the Moon’s cratering record and simulating the early solar system to understand its early evolution. The team is studying the Late Heavy Bombardment (~3.8 billion years ago), as the outer solar system most likely underwent a violent phase when planets scattered off of each other and acquired eccentric orbits. Strikingly, the team is finding not only that the giant planets changed orbital positions with Uranus and Neptune switching places, but that another unknown planet was likely ejected from our solar system and left to travel through interstellar space as a free-floating rogue planet.
By researching lunar formation and extrasolar planetary systems, NLSI teams are addressing key questions posed by the National Research Council. From probing the cosmic dawn and testing the physics of the universe, to understanding new habitable worlds, NLSI teams are leading the way in developing both theoretical and observational tools in the field of astrophysics.
The LUNAR consortium and the CLOE consortium are both funded by the NASA Lunar Science Institute. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
Posted by: Soderman/NLSI Staff
Source: NLSI Teams