The GEO-CAPE ROIC In-Flight Performance Experiment (GRIFEX) is a 3U CubeSat that will perform engineering assessment of a JPL-developed all digital in-pixel high frame rate Read-Out Integrated Circuit (ROIC). Its high throughput capacity will enable the proposed Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission concept to make hourly high spatial and spectral resolution measurements of rapidly changing atmospheric chemistry and pollution transport with the Panchromatic Fourier Transform Spectrometer (PanFTS) instrument in development.
This technology validation mission, sponsored by NASA's Earth Science Technology Office, will advance the technology required for the future spaceborne measurements of atmospheric composition from GEO, relevant to climate change, as well as future missions that require advanced detectors in support of the Earth Science Decadal Survey.
128 x 128 array JPL designed all digital ROIC
The purpose of the GRIFEX task is to validate detector technology for the Panchromatic Fourier Transform Spectrometer (PanFTS) which is an imaging FTS designed to operate in Geostationary orbit.
The PanFTS engineering model instrument is currently being developed which will incorporate the focal plane assembly (FPA) and signal chain technology validated by the GRIFEX CubeSat flight experiment.
GRIFEX will validate the JPL developed digital FPA and signal chain for the same signal levels expected for PanFTS in geostationary orbit.
The detector technology that will be flown on GRIFEX will support imaging system for the PanFTS instrument necessary for the planned continuous views of a region of Earth from GEO. This vantage point will enable measurements many times day for imaging to study tropospheric chemistry and the coastal oceans.
The GRIFEX CubeSat experiment will help enable development of the future spaceborne GEO-CAPE mission concept by raising the technology readiness level of the detectors and imaging subsystem for PanFTS, a proposed instrument for GEO-CAPE, through spaceborne engineering assessments of the detector performance in the relevant environment.
Fast readout integrated circuits (ROICs) are needed to develop focal plane arrays (FPAs) with many pixels and high frame rates to support future Earth science missions such as GEO-CAPE to provide broad spectral coverage and high resolution.
ESTO's ACT program sponsored the development of an innovative ROIC based on an in-pixel analog-to-digital converter (ADC) design. The 128x128 ROIC, with 60 micron pixels, has a 14-bit ADC in each pixel operating at an unprecedented rate of 14 kHz using only 1.1 W of power producing all digital output.
In this project the ROIC has been hybridized with a silicon PIN diode photosensitive detector array where the device performance will be tested in the space environment through the GRIFEX flight experiment.