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Bennu NASA/Goddard/University of Arizona

Avalanche Photodiodes Help Map Asteroid Surface

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.

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