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OSIRIS-REx will return pristine samples of carbonaceous asteroid Bennu. This article describes how pristine was defined based on expectations of Bennu and on a realistic understanding of what is achievable with a constrained schedule and budget, and how that definition flowed to requirements and implementation. To return a pristine sample, the OSIRIS- REx spacecraft sampling hardware was maintained at level 100 A/2 and <180 ng/cm2 of amino acids and hydrazine on the sampler head through precision cleaning, control of materials, and vigilance. Contamination is further characterized via witness material exposed to the spacecraft assembly and testing environment as well as in space. This characterization provided knowledge of the expected background and will be used in conjunction with archived spacecraft components for comparison with the samples when they are delivered to Earth for analysis. Most of all, the cleanliness of the OSIRIS-REx spacecraft was achieved through communication among scientists, engineers, managers, and technicians.Comment: 75 pages, 28 figures, 2 supplements, accepted for publication in Space Science Review

The effect of group success and failure upon interpersonal attraction in cooperating interracial groups was investigated in a 2X2X2 factorially designed experiment. The level of participation in the group's decision making (high or low) and race (black or white) served as the additional independent variables. The 56 military subjects exhibited significantly greater attraction for groupmates under the success as opposed to the failure condition (p < .001). No main effects for the race of the group member being evaluated or the level of participation in decision making were obtained, nor were there interactions among any of the three independent variables. Separate analyses of the attraction ratings given the white and the black groupmates further revealed that whatever elevated or depressed the ratings for one, similarly affected the ratings for the other. A general satisfaction-dissatisfaction interpretation is offered to explain the effect of group success-failure on interpersonal attraction. Implications for the scapegoat hypothesis are discussed.Reviews of the literature on interpersonal and attitudinal outcomes of personal contact with representatives of a disliked group make it clear that these outcomes vary widely, sometimes being positive, sometimes negative, and sometimes absent (

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