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Radio wave Observation at the Lunar Surface of the photoElectron Sheath (ROLSES)


Mission Name: Intuitive Machines 1 (Odysseus)
Principal Investigators:Dr. Jack O. Burns, Jr.
Principal Investigators:Dr. Natchimuthuk Gopalswamy


The primary objective of the Radio wave Observation at the Lunar Surface of the photoElectron Sheath (ROLSES) is to study the photoelectron sheath density and scale height near the lunar surface. The data will help understand the effect of the lunar environment on lunar surface radio observatories. The science objectives for ROLSES are: 1) measure the electron density in the local near-surface plasma via the local electron plasma frequency oscillation; 2) observe solar and planetary radio waves from a lunar surface observatory; 3) detect terrestrial natural auroral and human-made radio emissions; 4) sense interplanetary and lunar dust via grain contacts with the antenna; 5) attempt to measure the Galactic background radiation below 30 MHz; and 6) assess the radio frequency interference (RFI) from the lunar lander.

ROLSES is a low frequency radio receiver system, or radio spectrometer, with two frequency bands, 10 kHz to 1 MHz and 300 kHz to 30 MHz, each with 512 bins, giving a resolution of 1.76 kHz for the low-band and 58.01 kHz for the high-band. Each band will give averaged spectra over 4 seconds. ROLSES has electronics units and four Spiral Tube and Actuator for Controlled Extension / Retraction (STACER) antennas that extend from the walls of the NOVA-C lander. The STACERs are 2.5 meters long and are deployed horizontally, normal to the sides of the lander. Two of the STACERs on opposite sides are mounted at approximately 3 meters above the surface, and the other two, on the perpendicular sides, are mounted at 1 meter height.

Each STACER feeds into a front-end electronics unit, a pre-amp and signal conditioning analog electronics. The signals from each antenna are digitized to 14 bits. The data are processed by a Field Programmable Gate Array yielding time-averaged spectral values, which are transmitted to Earth. Due to the data rate limitation of 17 kbps, the data will be delivered as 4 second averages from two antennas, followed by 4 second averages from the other two antennas, alternating continuously over the 14 Earth-day nominal mission.

The Intuitive Machines 1 Odysseus lander touched down on the Moon on February 22, but tipped over and came to rest at a 30 degree angle to the horizontal. The four STACER antennas were deployed, although the final orientation antennas is not known. The investigators report that data have been received from the instrument.

Alternate Names

  • IntuitiveMachines1(IM1)/LowFrequencyRadioObservationoftheNearSideLunarSurface(ROLSES)


  • Planetary Science: Fields and Particles

Additional Information

Questions and comments about this experiment can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Dr. Natchimuthuk GopalswamyPrincipal InvestigatorNASA Goddard Space Flight
Dr. Jack O. Burns, Jr.Principal InvestigatorNew Mexico State

Selected References

  • Burns, Jack O., et al., Low Radio Frequency Observations from the Moon Enabled by NASA Landed Payload Missions, The Planetary Science Journal, 2:44 (16pp), 2021 April
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