In-Flight Results Using Visual Monitoring Cameras
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This paper provides an introduction to in-orbit visual monitoring of spacecraft, followed by a description of the imaging systems used on the European Space Agency missions TeamSat and XMM-Newton with a presentation of related results. New imaging systems which are under development are introduced and future missions using them are discussed. INTRODUCTION TO SPACECRAFT MONITORING USING VISUAL SYSTEMS The purpose of external spacecraft monitoring is to provide feedback of spacecraft status during deployment of e.g. antennas, instrument booms and solar arrays. The classical approach using indirect information collection from sensors is becoming impractical when spacecraft and space stations grow larger and have more appendices. A new approach has therefore been introduced using visual systems for direct visual confirmation of spacecraft conditions to complement the classical methods. The use of visual monitoring gives additional benefits such as detection of structural deformation, inorbit spacecraft surface damage analysis and failure diagnostics. Since visual information is used for monitoring the spacecraft, the same system can also be used for taking pictures of e.g. separation between launcher and spacecraft or spacecraft and planetary probe. Pictures of the launcher and spacecraft in orbit with Earth in background, are appreciated by the general public and provide the first results from a space mission. Finally, an picture tells more than thousand words, but it also requires more data to be transmitted, making image compression desirable when many images are required. The requirements on visual monitoring smart sensors can be summarised as follows: • Low power, mass, volume and cost • Versatility in interfacing to onboard data handling and communications systems • Image processing such as compression • Radiation hardness or tolerance Current systems basically meet the above requirements, but further optimisations are considered necessary. The objectives of ongoing developments are to produce a single-chip camera suitable for visual monitoring, image gathering on planetary probes, rovers etc., where size and power consumption has to be minimised.