Abstract
Calibration of CubeSat and other small payloads presents a variety of challenges including greater susceptibility to the space environment, volume constraints on calibration sources and subsystems, and power constraints on electronics. CIRiS (Compact Infrared Radiometer in Space), built by Ball Aerospace, is a multispectral, thermal infrared, radiometric imaging instrument with on-board calibration system, whose small volume (< 8 cm x 20 cm x 20 cm), weight (< 2 kg) and power (< 9.5 W average, including heaters) are compatible with CubeSat spacecraft, or any application with resource constraints. CIRiS has been integrated to a 6U spacecraft bus for an upcoming mission in Low Earth Orbit (LEO). The primary mission objective is demonstration of new technologies for radiometric imaging and calibration from CubeSats or SmallSats. New technologies on CIRiS include two 1/8 inch thick, flat-panel, high emissivity (e> .9965) carbon nanotube (CNT) blackbody sources and a new model of uncooled microbolometer Focal Plane Array (FPA) with less demanding temperature stabilization requirements than previous versions.
Three calibration views are available in space: to 1) deep space 2) an on-board CNT source at a selectable and controlled temperature and 3) an on-board CNT source at the instrument temperature, also controlled. The CIRiS instrument enables on-orbit selection of calibration parameters including source temperatures, viewing sequence, timing and other variables. Variation of these parameters during the mission will enable optimization of radiometric and calibration performance.
A campaign of thermal-vacuum (TVAC) testing has been completed on the integrated CIRiS instrument and spacecraft. TVAC operations and testing included calibration transfer from a NIST traceable source to the two on-board CNT sources, exercise of the instrument through operational and survival temperature ranges, and instrument performance characterization. The instrument was intentionally configured in TVAC to emulate the on-orbit thermal configuration, with temperature gradients and thermal transients at levels indicated by modeling of the on-orbit thermal configuration. Performance characterization included measurements of repeatability, reproducibility and signal drift.
Transfer of Calibration to CubeSat On-board Carbon Nanotube Sources
Calibration of CubeSat and other small payloads presents a variety of challenges including greater susceptibility to the space environment, volume constraints on calibration sources and subsystems, and power constraints on electronics. CIRiS (Compact Infrared Radiometer in Space), built by Ball Aerospace, is a multispectral, thermal infrared, radiometric imaging instrument with on-board calibration system, whose small volume (< 8 cm x 20 cm x 20 cm), weight (< 2 kg) and power (< 9.5 W average, including heaters) are compatible with CubeSat spacecraft, or any application with resource constraints. CIRiS has been integrated to a 6U spacecraft bus for an upcoming mission in Low Earth Orbit (LEO). The primary mission objective is demonstration of new technologies for radiometric imaging and calibration from CubeSats or SmallSats. New technologies on CIRiS include two 1/8 inch thick, flat-panel, high emissivity (e> .9965) carbon nanotube (CNT) blackbody sources and a new model of uncooled microbolometer Focal Plane Array (FPA) with less demanding temperature stabilization requirements than previous versions.
Three calibration views are available in space: to 1) deep space 2) an on-board CNT source at a selectable and controlled temperature and 3) an on-board CNT source at the instrument temperature, also controlled. The CIRiS instrument enables on-orbit selection of calibration parameters including source temperatures, viewing sequence, timing and other variables. Variation of these parameters during the mission will enable optimization of radiometric and calibration performance.
A campaign of thermal-vacuum (TVAC) testing has been completed on the integrated CIRiS instrument and spacecraft. TVAC operations and testing included calibration transfer from a NIST traceable source to the two on-board CNT sources, exercise of the instrument through operational and survival temperature ranges, and instrument performance characterization. The instrument was intentionally configured in TVAC to emulate the on-orbit thermal configuration, with temperature gradients and thermal transients at levels indicated by modeling of the on-orbit thermal configuration. Performance characterization included measurements of repeatability, reproducibility and signal drift.