A Small Low-Cost Resistance Based Atomic Oxygen Sensor
- Paper number
IAC-08.C2.6.8
- Author
Prof. Jingyu Tong, Beijing institute of satellite environment engineering, China
- Year
2008
- Abstract
In order to understand the space environment, to update the models which predict both the environment and the environment effects on spacecraft, to define the best techniques for ground-based experiments, it is necessary to develop flight experiments for detecting space environment and its effects and to collect flight experiments data. Beijing institute of spacecraft environment engineering has developed a small, low-cost sensor for detecting atomic oxygen environment and its effects. The sensor bases upon an electrical resistance film which is made of some susceptible conductive materials to atomic oxygen. The resistance film would be eroded in the flight experiment. The atomic oxygen flux and the erodent rate of flight samples could be determined by monitoring in-situ changes in electrical resistance of the sensor. Up to now, suitable atomic oxygen sensing conductive materials include silver, osmium and carbon. Silver has very high atomic oxygen reactivity. But a protective oxide layer would be produced as silver reacts with atomic oxygen. Its atomic oxygen reactivity is non-linear. Silver is not suitable for long-term flight experiment. The carbon reactivity with atomic oxygen is medium and linear. But its electrical resistance has a poor stability in the harsh space environment. Osmium electrical resistance is very stable in the space environment. The volatile OsO4 would be produced as osmium reacts with atomic oxygen. Its atomic oxygen reactivity has good linearity. But its atomic oxygen reactivity is small. Osmium is suitable for long-term flight experiment. This paper introduces an osmium based atomic oxygen sensor. It is made of a quartz plate with dimension of 30mm?20mm?1.5mm plated a 0.47?m thick osmium film. In order to increase the sensitivity of the sensor, the osmium film is etched to an electrical resistance line 0.5mm in width and 200mm in length with laser fine cut. As a result, the electrical resistance would have a larger change after a certain thickness loss of the osmium film. The sensor can measure atomic oxygen flux and fluence. Its operating life is about 1 year in the 400km?500km altitude. The atomic oxygen effects sensor is made of a quartz plate sputtered 20nm silver film. An experiment material film is coated on the silver film. The material film reacts with atomic oxygen and becomes thinner and thinner in the orbit. When the material film is eroded away completely, exposed silver film would be oxidized quickly and its electrical resistance would become large. Then, the eroded time of material film could be determined and the material eroded rate by atomic oxygen could be computed easily.
- Abstract document
- Manuscript document
IAC-08.C2.6.8.pdf (🔒 authorized access only).
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