Science Results

The objective of the ngRadar project is the design of a high-power, high-frequency, solid-state, multistatic planetary radar system. Proof-of-concept observations were completed in November 2020 and March 2021 using a 700 W, Ku-band, solid-state transmitter built by Raytheon and mounted at the prime focus of the 100-m Green Bank Telescope (GBT). Echoes from select targets were received by the ten 25-m antennas of the Very Long Baseline Array (VLBA), located on St. Croix, United States Virgin Islands, in the east, across the continental United States, and to Mauna Kea, Hawaii, in the west. The 700 W transmitter was refurbished and redeployed on the GBT in October and December 2024 and again in February and April 2026. For additional information, see Publications and Conferences, and stay tuned for further results!

Results of Proof-of-Concept Observations

The image(s) below were formed by transmitting a signal from the GBT to specific sites on the Moon with the echoes received by the VLBA.

Transmitter Power = ~700 W

Transmitter Frequency = Ku band, 13.9 GHz (2.16 cm)

Waveform Bandwidth = 30 MHz, "chirp" (linear frequency modulated) waveform

Range Resolution = 5 m (based on waveform bandwidth)

Transmitter Polarization = Linear

Receiver Polarization = Dual Circular

Receive Site = Individual VLBA antenna

April 2026 Example Results:

ngRadar: Reiner Gamma on the Moon (April 2026) — The Reiner Gamma region imaged with the pilot GBT/VLBA radar system in April 2026. The original image has range resolution of 5 meters based on the transmitted waveform, while this image is about 100 meters per pixel based on five minutes of data. Image Credit: NSF/AUI/NRAO/Raytheon.

Compare the radar image with the optical version seen by Lunar Reconnaissance Orbiter (LRO). No evidence of the bright surface feature is visible in the radar image! This preliminary result was presented at the community-led Small Bodies Assessment Group meeting in June 2026. See the Conferences tab for more information.

Reiner Gamma from LRO Quickmap — Appearance of the region around Reiner Gamma, a magnetic anomaly and lunar "swirl," to an optical camera in lunar orbit. Image Credit: LRO Quickmap.

March 2021 Example Results:

ngRADAR: Tycho Crater on the Moon (March 2021) — Tycho crater on the Moon imaged for ~40 minutes in March 2021 with 5-meter range resolution using the 700 W transmitter on the GBT with echoes received by the Fort Davis antenna of the VLBA. This image has been reduced in size and resampled. See link below for full-size image; additional size options are available. Image Credit: NSF/AUI/NRAO/Raytheon.

PNG Versions: Original Size (18,432x28,109 ; Size Warning: 371 MB) 1/4 Size (4608x7027 ; 22 MB ; resampled) 1/8 Size (2304x3514 ; 5 MB ; resampled)

GBT prototype-VLBA (Ku multistatic) — Linear and polygonal structures are seen on the floor of Tycho crater, where the radar has potentially seen through a thin layer of regolith to expose more of the underlying geology of the region.

Acknowledgments

The National Radio Astronomy Observatory, including Green Bank Observatory and the Very Long Baseline Array, is a facility of the National Science Foundation (NSF) operated under cooperative agreement by Associated Universities, Inc. (AUI). Part of this work was supported by Mid-Scale Research Infrastructure-1 award 2131866 from the NSF to AUI. Image Credit: NSF/AUI/NRAO/Raytheon.

Disclaimer: Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF), the National Aeronautics and Space Administration (NASA), or other funding agencies.