Credit: Concept art by Vladimir Vustyansky

 

Earth’s Moon is being eyed as an on-location locale for operating unique and novel observatories.

The just-concluded NASA Innovative Advanced Concepts (NIAC) symposium was the setting for reviewing several NIAC-backed studies.

Robot deployed wire mesh

One concept outlined at NIAC is the Lunar Crater Radio Telescope (LCRT) on the Far-Side of the Moon, explained by Saptarshi Bandyopadhyay of NASA’s Jet Propulsion Laboratory.

This proposal centered on deploying a wire mesh using wall-climbing robots in a 3 to 5 kilometer diameter crater, with a suitable depth-to-diameter ratio, to form a parabolic reflector with a one kilometer diameter.

A selected crater must have several attributes: No boulders or outcrops; a complete crater rim; and a level surface outside the crater.

Credit: Concept art by Vladimir Vustyansky

Physical shield

“The Moon acts as a physical shield that isolates a far-side lunar-surface telescope from radio interference from sources on the Earth’s surface,” Bandyopadhyay said, “the ionosphere, Earth-orbiting satellites, and the Sun’s radio emission during the lunar night.”

LCRT will be the largest filled-aperture radio telescope in the Solar System; larger than the former Arecibo telescope and China’s Five-hundred-meter Aperture Spherical radio Telescope (FAST), Bandyopadhyay said.

Credit: Saptarshi Bandyopadhyay, et al.

LCRT’s science objective is to track the evolution of the neutral intergalactic medium before and during the formation of the first stars. The concept would observe the universe in, so far unexplored, 10−100m radio wavelengths.

Several key conclusions underscored during the NIAC virtual gathering was the cost of the LCRT, narrowed down to 4 alternatives. These range from an option that costs below $1 billion but has moderate risks, to an option that costs $4-5 billion and could potentially be launched with existing present-day technology.

Credit: Ronald Polidan, et al.

FarView

Another Moon-situated NIAC-supported proposal is the FarView – an observatory fabricated on the Moon as a far side radio observatory.

Ronald Polidan of Lunar Resources, Inc. of Houston, Texas and the University of Colorado Boulder’s Jack Burns launched this new research effort to lay the groundwork for a one-of-a-kind lunar radio astronomy observatory: a network of hundreds of miles of antennas put in place on the far side of the Moon using materials reaped from the lunar surface.

Sparse array

FarView will be a sparse array of roughly 100,000 dipole antennas populating an approximately 20×20 kilometer area of lunar real estate. On-site manufacturing of almost all system elements for the radio array, including power generation and energy storage systems is projected.

The dipole antennas would be placed 60 meters apart in rows to create the observatory.

FarView science is focused upon detailed investigation of the unexplored Cosmic Dark Ages using the highly red shifted hydrogen 21-cm line and identifying the conditions and processes under which the first stars, galaxies, and accreting black holes formed.

Robot lays out an antenna on the lunar surface.
Credit: Lunar Resources

First-of-its-kind

No equivalent observatory exists today. This radio telescope will be the first-of-its-kind at this scale and sensitivity and will open a new window (low frequency radio) into the early universe, analogous to the detection of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the details of the cosmic microwave background (CMB) by Planck, a European Space Agency space-based observatory.

FarView measurements cannot be made from Earth due to Earth-generated radio noise and the ionosphere.

“FarView will be evolvable and long-lived using in-situ manufacturing techniques and occasional system upgrades from Earth. It will be of lower cost and longer lifetime than a complete antenna array launched from Earth,” Polidan pointed out.

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