Scientists at the Green Bank Observatory in West Virginia have used a transmitter with ‘less power than a microwave’ to produce the highest resolution images of the moon ever captured from Earth.
Using the Green Bank Telescope (GBT) and Very Long Baseline Array (VLBA), the team captured high-resolution radar images of the moon, laying the foundation for a next-generation radar system that will allow scientists to study planets, moons and asteroids throughout the solar system. The prototype of the new system, which was used to capture the images, is part of a joint effort by the National Radio Astronomy Observatory (NRAO), Green Bank Observatory (GBO) and Raytheon Intelligence & Space (RIS). The group is designing a new radar system for the GBT, the world’s largest fully steerable radio telescope.
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| The Green Bank Telescope. Image credit: Jay Young |
The team used a low-power radar transmitter designed by RIS with the GBT. The radar transmitter delivers up to 700 watts of output power at 13.9 GHz. The transmitter sent radar waves to the moon’s surface, and the echoes were received by the NRAO’s ten 25m VLBA antennas. The resulting image shows the Tycho crater on the lunar surface with an impressive 5m resolution.
‘It’s pretty amazing what we’ve been able to capture so far, using less power than a common household appliance,’ said Patrick Taylor, radar division head for GBO and NRAO.
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| ‘A Synthetic Aperture Radar image of the Moon’s Tycho Crater, showing 5-meter resolution detail.’ Image credit: Raytheon Technologies. |
The flagship system in the works will be much more powerful, with a 500 kilowatt, Ku-band (13.7 GHz) radar system. It will use the existing VLBA array and a future Next Generation Very Large Array (ngVLA) as its receivers. The proposed high-power system will offer ‘nearly 1,000 times the output power and several times the waveform bandwidth (up to 600 MHz),’ delivering even better resolving performance.
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| Image credit: Raytheon Technologies |
The system will do much more than allow scientists to image and study different celestial bodies, it will also be a critical part of a planetary defense system. The radar system will be able to detect, track and characterize objects that may threaten Earth. During testing, Taylor said the team located a km-sized asteroid more than 2M km from Earth. An asteroid of that size could devastate the planet. The next-generation radar system could detect objects smaller and further away, potentially providing critical information to support NASA’s Double Asteroid Redirection Test (DART) mission.
Concerning astronomy, the GBT’s enhanced radar system will deliver data at higher resolutions and wavelengths than were previously impossible. Between those impressive capabilities and the ability to help defend Earth against potential threats, the next-generation radar system promises to enhance planetary science and planetary defense alike.
