Radio-wave Observations at the Lunar Surface of the Photoelectron Sheath (ROLSES)¶

IM-1 · landed · NASA payload

A low-frequency radio receiver with four 2.5-meter antennas. It was to measure the density of the thin electron layer just above the surface, and to record radio noise near the Moon: from the Sun, Jupiter, the galaxy, Earth's transmitters and the lander itself.

PI: Natchimuthuk (Nat) Gopalswamy, NASA Goddard. Robert MacDowall (Goddard) proposed ROLSES and was PI through delivery.
Built by: NASA Goddard Space Flight Center (Engineering and Technology Directorate with the Sciences and Exploration Directorate); antennas by Heliospace Inc.; co-investigator at the University of Colorado Boulder (NASA center)


Technology	science instrument (radio and plasma environment)
Moon Base need	DN-011 L, #0103 (The study's reading. NASA does not tie ROLSES to a Moon Base gap. ROLSES measures the surface plasma (DN-011 L) and the radio environment that surface radios must work in (#0103).)
Route onto CLPS	NPLP; NASA-Provided Lunar Payloads, SMD's 2019 request to NASA centers. On the 21 February 2019 list as 'Low-frequency Radio Observations from the Near Side Lunar Surface'. Assigned to Intuitive Machines' first delivery (TO2-IM); NASA's January 2020 manifest lists it.; 2019-02-21
Timeline	first funding 2019 (NPLP selection); earliest public award: Heliospace antenna order signed 2020-08-18; first flight test not in public sources; selected 2019-02-21; launch 2024-02-15; landing 2024-02-22
On the Moon	partly operated
FO	none

Flights before the Moon¶

None found in the public sources.

Heritage hardware¶

design heritage (antennas): The four STACER monopole antennas were built by Heliospace. They use a beryllium-copper spring strip like the STEREO/WAVES antennas, but smaller. This is a flown antenna design from other missions, not an earlier flight of ROLSES.

"made of beryllium copper (Be-Cu) alloy, similar to STEREO/WAVES antennas"
— arxiv.org: 2603.22600, section 3.1

Funding before the lunar flight¶

SMD NASA-Provided Lunar Payloads, supported through NASA's CLPS program (SMD NPLP / CLPS; from 2019): amount not in public sources

"This NPLP is supported by NASA's CLPS program and we thank them for their support throughout ROLSES development."
— arxiv.org: 2603.22600, Acknowledgments

Purchase order to Heliospace Corporation for the flight antennas. Linked by its description ('ROLES PFM antenna', 'STACER flight antennas', as printed) and by the instrument paper, which says Heliospace built the STACER antennas. (NASA purchase order 80NSSC20P1770 (NASA Shared Services Center); signed 2020-08-18; 2020-08-20 to 2021-03-31): $172,010

"PROVIDE ROLES PFM ANTENNA DEVELOPMENT AND PRODUCTION/STACER FLIGHT ANTENNAS"
— USAspending.gov, award 80NSSC20P1770, description; obligated 172010.46

Purchase order to Heliospace Corporation for a ROLSES antenna simulator. Linked by its description. (NASA purchase order 80NSSC20P1831; 2020-08-01 to 2020-11-30): $32,442

"ROLSES ANTENNA SIMULATOR"
— USAspending.gov, award 80NSSC20P1831, description; amount 32441.65

Grant to the University of Colorado for the co-investigator's work. Its title names the instrument. The results paper says it funded ROLSES-1 data analysis, from NASA's Exploration Science Strategy Integration Office. Science-team support, not hardware; it runs to 2028, past IM-1. (NASA grant 80NSSC22K1264; 2022-06-15 to 2028-04-30): $855,652

"LOW FREQUENCY RADIO OBSERVATIONS FROM THE NEAR SIDE LUNAR SURFACE (I.E ROLSES INSTRUMENT)"
— USAspending.gov, award 80NSSC22K1264, description; amount 855652.0

"funded by NASA grant 80NSSC22K1264 from the Exploration Science Strategy Integration Office (ESSIO)"
— arxiv.org: 2503.09842, Acknowledgments

How it got onto CLPS¶

"The Low-frequency Radio Observations from the Near Side Lunar Surface instrument, a radio science instrument, will measure the photoelectron sheath density near the surface."
— NASA Selects Experiments for Possible Lunar Flights in 2019 - NASA

"ROLSES is one of the NASA Provided Lunar Payloads (NPLPs) selected under the CLPS program."
— arxiv.org: 2603.22600, section 1

"Low-frequency Radio Observations for the Near Side Lunar Surface (ROLSES)"
— First Commercial Moon Delivery Assignments to Advance Artemis - NASA, 22 Jan 2020, under Intuitive Machines Payloads

On the Moon¶

In transit, sunlight overheated one antenna's release bolt and the antenna deployed early and was damaged; ROLSES then took about 83 minutes of data in cruise and recorded Earth's radio transmitters. After the tipped landing a second antenna deployed on its own, and the team deployed the other two by command. ROLSES returned only 36 minutes of surface spectra, against 170 to 340 hours planned, with the gain stuck at its lowest. An upgraded ROLSES-2 is to fly in 2028 to complete the original objectives.

"in the inadvertent deployment and damage of the antenna when the lander was about 9600 km from the Moon"
— arxiv.org: 2603.22600, section 1

"only 36 minutes of spectral data was obtained compared to the projected 170 to 340 hours of data"
— arxiv.org: 2603.22600

"managed to collect a small amount of data over fractions of one day during cruise phase and two days on the lunar surface"
— arxiv.org: 2503.09842, abstract

"An upgraded ROLSES-2 is scheduled to go to the Moon in 2028 to complete the original science objectives for ROLSES."
— arxiv.org: 2603.22600

FO's role¶

Grade: none. No FO project, flight or report mentions ROLSES, its Goddard team or its antennas. The study's earlier traceback grade (none found) stands.

"No FO record or report names SCALPSS, ROLSES, LN-1, the retroreflectors"
— earlier finding of this study (not a public source)

Who built it¶

"Lead Development Organization: NASA GSFC"
— TO2-IM Science Payloads - NASA Science

"were responsible for designing, building, and integrating the instrument electronics, software, and integration to the instrument antenna"
— ROLSES Are Red

"former Principal Investigator Robert MacDowall who proposed ROLSES to the NPLP program and oversaw ROLSES instrument development through to its delivery"
— arxiv.org: 2603.22600, Acknowledgments

"antennas designed and built by Heliospace Inc."
— arxiv.org: 2603.22600, section 3.1

"Burns is co-investigator on the radio experiment that flew aboard Odysseus"
— In new experiment, scientists record Earth’s radio waves from the moon

Moon Base need¶

"Measure the plasma environment at the lunar south pole"
— Moon to Mars knowledge base: DN-011 L: In situ lunar surface plasma environment characterization, Description

"Deploy communications systems that can operate in the lunar geological, electromagnetic, and radio frequency environment."
— Moon to Mars knowledge base: Moon Base technology and knowledge challenges, Associated challenges, Surface-to-surface comms

"to determine how natural and human-generated activity near the surface interacts with and could interfere with science conducted there"
— NASA to Study Effects of Radio Noise on Lunar Science - NASA

Open questions¶

ROLSES's development cost under NPLP: not in public sources. The public awards found (Heliospace antennas, the CU Boulder grant) are parts of it at most.
Did a ROLSES prototype or its electronics fly before IM-1 (sounding rocket, balloon or aircraft)? Not in public sources. The paper says the flight antennas could not be deployed in ground tests.
Is the 2019 Heliospace purchase of a 'BeCu STACER' (80NSSC19P2303, USD 18,690) for ROLSES? Its description does not say.