  A new era of exploration of the low radio frequency Universe from the Moon
will soon be underway with landed payload missions facilitated by NASA's
Commercial Lunar Payload Services (CLPS) program. CLPS landers are scheduled to
deliver two radio science experiments, ROLSES to the nearside and LuSEE to the
farside, beginning in 2021. These instruments would be pathfinders for a 10-km
diameter interferometric array, FARSIDE, composed of 128 pairs of dipole
antennas proposed to be delivered to the lunar surface later in the decade.
ROLSES and LuSEE, operating at frequencies from 100 kHz to a few tens of MHz,
will investigate the plasma environment above the lunar surface and measure the
fidelity of radio spectra on the surface. Both use electrically-short,
spiral-tube deployable antennas and radio spectrometers based upon previous
flight models. ROLSES will measure the photoelectron sheath density to better
understand the charging of the lunar surface via photoionization and impacts
from the solar wind, charged dust, and current anthropogenic radio frequency
interference. LuSEE will measure the local magnetic field and exo-ionospheric
density, interplanetary radio bursts, Jovian and terrestrial natural radio
emission, and the galactic synchrotron spectrum. FARSIDE, and its precursor
risk-reduction six antenna-node array PRIME, would be the first radio
interferometers on the Moon. FARSIDE would break new ground by imaging radio
emission from Coronal Mass Ejections (CME) beyond 2 solar radii, monitor
auroral radiation from the B-fields of Uranus and Neptune (not observed since
Voyager), and detect radio emission from stellar CMEs and the magnetic fields
of nearby potentially habitable exoplanets.
