Excelitas Technologies' avalanche photodiode enables surface mapping of Bennu asteroid
An avalanche photodiode (APD) made by Excelitas Technologies (Waltham, MA) is the main detector for the laser altimeter carried by NASA's OSIRIS-REx spacecraft to the asteroid Bennu. The instrument is being used to help select the location on Bennu where OSIRIS-REx will come in contact with the asteroid to collect samples to be returned to earth (and is being used to scientifically characterize the asteroid as well). Maps created by the OSIRIS-REx Laser Altimeter (OLA) contain precise information on Bennu's topography.
The Excelitas team has congratulated NASA, the Canadian Space Agency, the OLA Science Team led by Michael Daly (York University, OLA Instrument Scientist), and MDA (a business unit of Maxar) for the final assembly helping enable the space mission's notable success. On April 5, 2019, NASA released a three-dimensional view of Bennu, created on the spacecraft by the OLA. In February, OLA made more than 11 million measurements of the distance between OSIRIS-REx and Bennu's surface as the spacecraft flew less than 2 km above the surface, the closest orbit ever achieved by spacecraft.
"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.
When sample sites are selected after about sixteen months of comprehensive surface mapping, the spacecraft will deploy a robotic arm to reach out (without landing) and collect at least a 2.1-ounce sample that will be brought back to Earth for study in 2023. NASA's website says the mission "will help scientists investigate how planets formed and how life began, as well as improve our understanding of asteroids that could impact Earth."
Excelitas says the APD used for OLA is its C30954EH, a 0.8 mm active diameter silicon photodiode that has high quantum efficiency at the YAG-wavelength (1064 nm), fast response time, and wide operating temperature range. The standard product was successfully qualified for the extensive requirements of a deep-space probe. Excelitas has a long heritage of designing and producing YAG-enhanced APDs used in several space surveying missions.
The company is exhibiting at SPIE Defense + Commercial Sensing in the Baltimore Convention Center, April 16-18, 2019 (Booth 438). Attendees can visit Excelitas' booth to learn more, and to discuss their requirements for optical LiDAR payloads and other mission-critical optoelectronics and advanced electronic systems.
Source: http://www.excelitas.com/Pages/News_Events/Press_Release4_9_2019.aspx
John Wallace | Senior Technical Editor (1998-2022)
John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.