Session
Science/Mission Payloads Research & Academia
Location
Salt Palace Convention Center, Salt Lake City, UT
Abstract
The Low-frequency CubeSat Radio Instrument (LOCRI) project is intended to study the possibility of observing the fundamental physical processes occurring during the cosmic Dark Ages and Cosmic Dawn using an orbital radio telescope. The Dark Ages are the period of cosmic history between the Cosmic Microwave Background (CMB) ∼380,000 years after the Big Bang, and the formation of the first stars and galaxies, roughly 100-million years later. During this epoch the universe consisted primarily of Dark Matter and neutral hydrogen gas, with no luminous sources emitting visible light. It therefore remains one of the least constrained periods of the universe’s history. Cosmic Dawn is the period that ends the Cosmic Dark Ages, when the first stars and galaxies begin to illuminate and reionize the universe.
The redshifted 21 cm signal is potentially the only means of observing the Dark Ages, and is unobservable from the surface of the Earth due to radio frequency interference and ionospheric distortions. The most radio quiet location near Earth is the lunar farside, and an instrument with the sensitivity to detect the Dark Ages signal will likely need to be located on or in orbit around the moon. However, observing from the lunar surface introduces a number of significant difficulties including thermal, power, and data management, and systematic effects due to the unknown dielectric properties of the lunar regolith. Observing from lunar orbit mitigates these difficulties, making an orbital observatory desirable for cost effectiveness and reduction of systematic uncertainties.
LOCRI will consist of a 3U CubeSat equipped with a two-element dipole array antenna. The antenna and preamplifier electronics will be sky-noise limited over the 0.5 - 125 MHz observing band. Auto- and cross-correlation spectra will be processed onboard the CubeSat, and time averaged observations will be down-linked to a ground station. The CubeSat will rotate during observations to provide full polarization coverage, and the directivity provided by the dipole array antenna will provide angular resolution. This combination of polarization, spectral, and angular information will be crucial for separating the cosmological signal from much stronger foreground components.
LOCRI’s scientific goals are 1) to establish the orbital environment as a viable observatory for low-frequency radio astronomy, 2) to perform the most sensitive observations at 0.5 - 125 MHz made from orbit, 3) to quantify the systematic effects affecting global spectrum measurement, and investigate mitigation methods, and 4) to perform low-frequency measurements of transient events originating from solar system bodies. As part of viability verification, LOCRI will demonstrate the capabilities that will be necessary for a future radio frequency interferometer in lunar orbit. This includes demonstrating low-frequency low-power spectrometer function in orbit, visual-only terrain-relative localization for joint attitude and orbit determination, and high data rate communications between the CubeSat and ground station. The design of LOCRI leverages space-proven technology from the LuSEE-Night instrument and the CMU Argus CubeSat bus to reduce risk and cost. Launch targets 2031, with several months of observing, and delivering approximately 6 GB of science and telemetry data per month.
Document Type
Event
A Low-Frequency CubeSat Radio Instrument for Exploring the Cosmic Dark Ages
Salt Palace Convention Center, Salt Lake City, UT
The Low-frequency CubeSat Radio Instrument (LOCRI) project is intended to study the possibility of observing the fundamental physical processes occurring during the cosmic Dark Ages and Cosmic Dawn using an orbital radio telescope. The Dark Ages are the period of cosmic history between the Cosmic Microwave Background (CMB) ∼380,000 years after the Big Bang, and the formation of the first stars and galaxies, roughly 100-million years later. During this epoch the universe consisted primarily of Dark Matter and neutral hydrogen gas, with no luminous sources emitting visible light. It therefore remains one of the least constrained periods of the universe’s history. Cosmic Dawn is the period that ends the Cosmic Dark Ages, when the first stars and galaxies begin to illuminate and reionize the universe.
The redshifted 21 cm signal is potentially the only means of observing the Dark Ages, and is unobservable from the surface of the Earth due to radio frequency interference and ionospheric distortions. The most radio quiet location near Earth is the lunar farside, and an instrument with the sensitivity to detect the Dark Ages signal will likely need to be located on or in orbit around the moon. However, observing from the lunar surface introduces a number of significant difficulties including thermal, power, and data management, and systematic effects due to the unknown dielectric properties of the lunar regolith. Observing from lunar orbit mitigates these difficulties, making an orbital observatory desirable for cost effectiveness and reduction of systematic uncertainties.
LOCRI will consist of a 3U CubeSat equipped with a two-element dipole array antenna. The antenna and preamplifier electronics will be sky-noise limited over the 0.5 - 125 MHz observing band. Auto- and cross-correlation spectra will be processed onboard the CubeSat, and time averaged observations will be down-linked to a ground station. The CubeSat will rotate during observations to provide full polarization coverage, and the directivity provided by the dipole array antenna will provide angular resolution. This combination of polarization, spectral, and angular information will be crucial for separating the cosmological signal from much stronger foreground components.
LOCRI’s scientific goals are 1) to establish the orbital environment as a viable observatory for low-frequency radio astronomy, 2) to perform the most sensitive observations at 0.5 - 125 MHz made from orbit, 3) to quantify the systematic effects affecting global spectrum measurement, and investigate mitigation methods, and 4) to perform low-frequency measurements of transient events originating from solar system bodies. As part of viability verification, LOCRI will demonstrate the capabilities that will be necessary for a future radio frequency interferometer in lunar orbit. This includes demonstrating low-frequency low-power spectrometer function in orbit, visual-only terrain-relative localization for joint attitude and orbit determination, and high data rate communications between the CubeSat and ground station. The design of LOCRI leverages space-proven technology from the LuSEE-Night instrument and the CMU Argus CubeSat bus to reduce risk and cost. Launch targets 2031, with several months of observing, and delivering approximately 6 GB of science and telemetry data per month.
