000126161 001__ 126161
000126161 005__ 20190316234327.0
000126161 037__ $$aREP_WORK
000126161 245__ $$aLow Cost Earth Sensor Based on Oxygen Airglow (AIRES)
000126161 269__ $$a2008
000126161 260__ $$c2008
000126161 336__ $$aReports
000126161 500__ $$aFinal report of ESA contract ESA-ESTEC 20267/06/NL/JA
000126161 520__ $$aThis project has demonstrated the feasibility of a low-cost Earth sensor based on imaging oxygen airglow, allowing 0.4° accuracy from GEO under any illumination condition. Available Earth Sensor (ES) are based on the measurement of the earth’s infrared radiation to determine the vector to the Earth’s centre. These designs provide excellent accuracies over a large field of view, but are often heavy, large, require cooling or temperature stabilization and are power hungry. In addition, the sensor concept for a LEO or GEO application ES differs significantly. We have developed a novel ES concept for applications where milli-degree accuracy is not required, but where low-cost is essential and lower (about 1 – 5°) accuracy is acceptable. Such a sensor could be used in new scenarios and to improve spacecraft reliability by providing a low-cost back-up sensor. Our Earth Sensor concept is based on imaging atmospheric oxygen emission at 762 nm using highly sensitive detectors. In both night-time and daytime there is continuous emission at 762 nm due to oxygen recombination. Low-noise active pixel sensors (APS) or low-light detector based on arrays of single photon avalanche diodes (SPAD) enables the ES to operate at night and day, over a wide temperature range, with a very compact optical system (aperture of 8 mm, focal length of 11 mm) and no scanning elements. A modular design allows designing similar instruments using the same wavelength band, the same detector technology, the same optics, the same power and data interfaces and similar algorithms for GEO and LEO applications, thus reducing the development cost. We have developed an Earth appearance model at 762 nm, which was used as input for the mechanical, optical and electric design of the Earth Sensor (conceptual design). In order to achieve a low-cost solution, simplicity and reduction of part count was a driving factor in the design trade-offs. Total mass for the GEO design is 845 g with a mean power consumption of 4 W. Algorithms were developed to determine the vector to the Earth from the images. A breadboard was built to display a simulated picture of the Earth under varying conditions, image those pictures at different temperatures with a radiation tolerant APS (LCMS), and verify the correct operation of the algorithms. In addition to the conceptual design and breadboard level demonstration of key technologies, a novel detector chip was designed and fabricated: a radiation-tolerant array of single photon avalanche photodiodes (SPAD) build using conventional 0.35 μm CMOS technology. The chip was tested under proton and gamma irradiation, and operated with only minor changes in dark current after 30 krad TID. Having shown the feasibility of such an Earth Sensor, this work concluded with a development plan to lead to a flight model.
000126161 6531_ $$aEarth Sensor
000126161 6531_ $$aOxygen airglow
000126161 6531_ $$aLEO
000126161 6531_ $$aGEO
000126161 6531_ $$aSPAD
000126161 6531_ $$aSPAD radiation hardening
000126161 700__ $$aScheidegger, N
000126161 700__ $$0240376$$g162368$$aShea, H
000126161 700__ $$g146991$$aCharbon, E$$0240305
000126161 700__ $$aRugi-Grond, E
000126161 8564_ $$zURL
000126161 8564_ $$uhttps://infoscience.epfl.ch/record/126161/files/AIRES%20Final%20report.pdf$$zn/a$$s4911441
000126161 8564_ $$uhttps://infoscience.epfl.ch/record/126161/files/Executive%20summary%20AIRES.pdf$$zn/a$$s748385
000126161 909C0 $$xU10955$$0252107$$pLMTS
000126161 909CO $$qGLOBAL_SET$$pSTI$$ooai:infoscience.tind.io:126161$$preport
000126161 937__ $$aLMTS-REPORT-2008-001
000126161 973__ $$sPUBLISHED$$aEPFL
000126161 980__ $$aREPORT