Space mission on gravitational waves gets boost from long-term LED study

The Laser Interferometer Space Antenna (LISA) will be the first gravitational wave detector in space, so ensuring its long-term operation is incredibly important. Letson et al. studied 96 commercially available light-emitting diodes (LEDs) for use in LISA’s charge management system, creating models that accurately predicted the device’s performance over LISA’s yearslong operation in space.

The researchers verified that the LEDs studied can perform contactless discharge for the LISA mission, and presented a model that predicts the lifetimes of these devices based on initial measurements of the number of defects within each device.

“A lifetime experiment of this magnitude for deep UV LEDs has never been performed before in the literature,” author Benjamin Letson said. “This paper also shows that large numbers of these devices are negatively affected by high device-to-device variability caused by imperfections in the manufacturing process of these devices.”

The team used a custom test stand and monitoring software to operate UV LEDs in a closely controlled manner for more than 750 days to verify they would satisfy the performance requirements of the LISA mission. Then, the team used regression techniques to develop a model that can estimate the lifetime of an LED along with Monte Carlo simulations to obtain confidence intervals on the devices’ time to failure.

Letson notes more work can be done to improve the model the team has presented. An improved model could help scientists select the best devices for other long-term space missions and diagnose power loss from the devices over time.

Source: “Deep UV AlGaN LED reliability for long duration space missions,” by Benjamin C. Letson, Simon Barke, Peter Wass, Guido Mueller, Fan Ren, Stephen J. Pearton, and John W. Conklin, Journal of Vacuum Science and Technology: A (2022). The article can be accessed at https://doi.org/10.1116/6.0002199 .