The Suess-Urey (S-U) mission has been proposed as a NASA Discovery mission to return samples of matter from the Sun to the Earth for isotopic and chemical analyses in terrestrial laboratories to provide a major improvement in our knowledge of the average chemical and isotopic composition of the solar system. The S-U spacecraft and sample return capsule will be placed in a halo orbit around the L1 Sun-Earth libration point for two years to collect solar wind ions which implant into large passive collectors made of ultra-pure materials. Constant Spacecraft-Sun-Earth geometries enable simple spin stabilized attitude control, simple passive thermal control, and a fixed medium gain antenna. Low data requirements and the safety of a Sun-pointed spinner, result in extremely low mission operations costs. 相似文献
To investigate changes in spatial orientation ability and walking performance following space flight, 7 astronaut subjects were asked pre- and post-flight to perform a goal directed locomotion paradigm which consisted of walking a triangular path with and without vision. This new paradigm, involving inputs from different sensory systems, allows quantification of several critical parameters, like orientation performance, walking velocities and postural stability, in a natural walking task. The paper presented here mainly focusses on spatial orientation performance quantified by the errors in walking the previously seen path without vision. Errors in length and reaching the corners did not change significantly from pre- to post-flight, while absolute angular errors slightly increased post-flight. The significant decrease in walking velocity and a change in head-trunk coordination while walking around the corners of the path observed post-flight may suggest that during re-adaptation to gravity the mechanisms which are necessary to perform the task have to be re-accomplished. 相似文献
We evaluated the influence of prolonged weightlessness on the performance of visual tasks in the course of the Russian-French missions ANTARES, Post-ANTARES and ALTAIR aboard the MIR station. Eight cosmonauts were subjects in two experiments executed pre-flight, in-flight and post-flight sessions.
In the first experiment, cosmonauts performed a task of symmetry detection in 2-D polygons. The results indicate that this detection is locked in a head retinal reference frame rather than in an environmentally defined one as meridional orientations of symmetry axis (vertical and horizontal) elicited faster response times than oblique ones. However, in weightlessness the saliency of a retinally vertical axis of symmetry is no longer significantly different from an horizontal axis. In the second experiment, cosmonauts performed a mental rotation task in which they judged whether two 3-D objects presented in different orientations were identical. Performance on this task is basically identical in weightlessness and normal gravity. 相似文献