A Far Range Image Processing Method for Autonomous Tracking of an Uncooperative Target
This paper proposes an image processing method for far range rendezvous. A target spacecraft at distances up to $30$~km is tracked from camera images. The method is based on linking bright, connected sets of pixels over sequences of images. Stars and the target spacecraft are identified by using a star catalog and performing motion segmentation. The algorithm is illustrated in detail and 
%the visibility of stars and of the target are analyzed which is a prerequisite to perform far range image processing. Further, 
results of a flight experiment called ARGON are presented. The experiment took place in the extended phase of the PRISMA mission. The image processing method was employed and a successful rendezvous from $30$~km to $3$~km was accomplished using optical navigation.
Noncooperative Rendezvous Using Angles-Only Optical Navigation: System Design and Flight Results
This paper presents system design and on-orbit results from the Advanced Rendezvous Demonstration using Global Positioning System and Optical Navigation (ARGON). ARGON has been conducted during the extended phase of the Prototype Research Instruments and Space Mission Technology Advancement (PRISMA) mission in April 2012. It represents one of the first rendezvous technology experiments using line of sight measurements from optical navigation and was motivated by the new generation of on-orbit-servicing and debris-removal missions which are discussed at national and international level. Its primary goal was to demonstrate the capability of an active servicer spacecraft to safely approach and rendezvous a non-cooperative passive client using angles-only optical navigation in a ground-in-the-loop fashion. To this end, a dedicated flight dynamics system has been developed for routine processing of the camera images collected on-board, for estimation of the relative orbit of the servicer with respect to the cl...
UV-B radiometry and dosimetry for solar measurements.
Biologically effective irradiance or dose of solar UV radiation was determined using a spectroradiometer, two broadband radiometers and two types of passive UV-dosimeters. The absolute erythema irradiance and the actinic irradiance were calculated from the solar spectrum measured with the spectroradiometer. It was demonstrated that the erythema irradiance is proportional to the actinic irradiance of solar radiation. The erythema irradiance was also determined using the two broadband radiometers which utilize a filter transmitting erythema spectra. Personal UV-dosimeters such as polysulphone and CR-39 were used to determine the erythema dose for a selected period of time. These results were used to estimate the accuracy of the broadband radiometers and UV-dosimeters. It was found that the results obtained from the broadband radiometers deviate from the absolute erythema irradiance by less than 20% during clear days between the hours of 11:00 and 13:00 Eastern Standard Time (EST) in Australia. The assessment of the erythema dose using passive dosimeters such as polysulphone and CR-39 could introduce an error as high as 40% if the calibration was not performed before undertaking experimental measurements.