NASA/Goddard/University of Arizona
Bennu

Avalanche Photodiodes Help Map Asteroid Surface

April 10, 2019
Avalanche photodiodes were key components in mapping the surface of a near-Earth asteroid.

An avalanche photodiode (APD) from Excelitas Technologies Corp. is the main detector enabling the surface measurements of an asteroid from space. The APD is part of the detection equipment onboard the laser altimeter on NASA’s OSIRIS-Rex spacecraft. The OSIRIS-REx Laser Altimeter (OLA) was used to provide high-resolution mapping details of the near-Earth asteroid Bennu, providing enough data to create 3D topographical maps and help study asteroid space and topography. The spacecraft flew less than 1.2 miles (2 km) above the surface of the asteroid.

A high-resolution laser altimeter was used to provide surface mapping details for the near-Earth asteroid Bennu (Courtesy: NASA, University of Arizona, Canadian Space Agency, York University, and MDA)

“We’re proud and humbled to have provided one component that’s being used in this historic project,” said Eric Desfonds, Excelitas’ Product Line Manager, Sensors – Defense and Aerospace. “Dedicated collaboration between the contributing agencies and technology developers makes great scientific achievements possible, as we are beginning to see in the mission’s early success.” The laser mapping will guide the future selection of asteroid samples by robotic arms to provide more information about asteroids that could impact the Earth. The APD used for the application was the model C30954EH, a silicon photodiode with 0.8-mm active diameter. The APD is designed for high quantum efficiency at the 1064-nm YAG wavelength, with fast response time and wide operating-temperature range.

About the Author

Jack Browne | Technical Contributor

Jack Browne, Technical Contributor, has worked in technical publishing for over 30 years. He managed the content and production of three technical journals while at the American Institute of Physics, including Medical Physics and the Journal of Vacuum Science & Technology. He has been a Publisher and Editor for Penton Media, started the firm’s Wireless Symposium & Exhibition trade show in 1993, and currently serves as Technical Contributor for that company's Microwaves & RF magazine. Browne, who holds a BS in Mathematics from City College of New York and BA degrees in English and Philosophy from Fordham University, is a member of the IEEE.

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