MURI: Multiband Uncooled Radiometer Instrument

Overview

MURI demonstrated a state-of-the-art microbolometer thermal imager that functions without a cryogenic cooler. Launched into low Earth orbit in January 2023, this instrument is one NASA’s smallest space-based radiometers. Whereas traditional radiometers require heavy cryogenic coolers to maintain a constant temperature, MURI’s novel, uncooled microbolometer technology reduced the instrument payload to just 12 pounds, an essential innovation for launching cost-efficient science missions to measure thermal radiation.

Science Area

Measuring infrared radiation is essential for informing models about phenomena like evapotranspiration, climate change, and volcanic activity. From space, infrared imagers can observe these complex systems on a global scale, and by reducing the size, complexity, and cost infrared instruments and the cost of sending them to space, MURI opened the door to a suite of science missions that maximize science return while conserving resources.

Technology

MURI overcame two major technology hurdles to reach space. First, the team overcame image smear by placing their microbolometer on a piezoelectric stage, which moved at the same velocity of the image as the instrument gathered data. Second, the team overcame temperature interference by installing a temperature control loop that keeps the uncooled microbolometer, the telescope, and the telescope housing at a constant temperature for the full duration of the instrument’s 95-minute orbit. In addition, a small periodic thermal calibration paddle located at the optical aperture of the radiometer removes any residual errors caused by temperature.

Advancements

  • Non-cryogenically cooled LWIR instrument reduces instrument payload to just 12 pounds without comprimising performance, reducing the cost of sending space-based radiometers into orbit.
  • Innovative FPA back-scan technique achieves an absolute radiometric accuracy of around 1%, which is considered world-class for longwave infrared radiometers.
  • Mounted bolometer focal plane array moves with the same velocity as the gathered image, eliminating image smear and improving signal-to-noise ratio by a factor of three.

Principal Investigator

Philip Ely serves as the Principal Investigator for MURI. As Director of Engineering at DRS Cypress, Philip has broad experience in the design, fabrication and test of infrared and visible detectors, detector modules and sensors for NASA, DoD and commercial space based imaging applications such as GOES ABI, GOSAT, Advanced Himawari Imager (AHI), GOES HES, CrIS, WISE, NICMOS and several proprietary programs. Phil also had experience with the development of Micro-bolometers for military and commercial imaging applications.

His co-investigators include Raymond Wagoner, Leonardo DRS; and Aaron Gerace, Rochester Institute of Technology.