Engineering topics
McNamara, Karen
Publications and source records attributed to McNamara, Karen.
Sample Return: What Happens to the Samples on Earth?
As space agencies throughout the world turn their attention toward human exploration of the Moon, Mars, and the solar system beyond, there has been an increase in the number of robotic sample return missions proposed as precursors to these human endeavors. In reality, however, we, as a global community, have very little experience with robotic sample return missions: 3 of the Russian Luna Missions successfully returned lunar material in the 1970s; 28 years later, in 2004, NASA s Genesis Mission returned material from the solar wind; and in 2006, NASA s Stardust Mission returned material from the Comet Wild2. [Note: The Japanese Hyabusa mission continues in space with the hope of returning material from the asteroid 25143 Itokawa.] We launch many spacecraft to LEO and return them to Earth. We also launch spacecraft beyond LEO to explore the planets, our solar system, and beyond. Some even land on these bodies. But these do not return. So as we begin to contemplate the sample return missions of the future, some common questions arise: "What really happens when the capsule returns?" "Where does it land?" "Who retrieves it and just how do they do that?" "Where does it go after that?" "How do the scientists get the samples?" "Do they keep them?" "Who is in charge?" The questions are nearly endless. The goal of this paper/presentation is to uncover many of the mysteries of the post-return phase of a mission - from the time the return body enters the atmosphere until the mission ends and the samples become part of a long term collection. The discussion will be based largely on the author s own experience with both the Genesis and Stardust missions. Of course, these two missions have a great deal in common, being funded by the same NASA Program (Discovery) and having similar team composition. The intent, however, is to use these missions as examples in order to highlight the general requirements and the challenges in defining and meeting those requirements for the final phase of sample return missions. The choices made by the Genesis and Stardust teams regarding recovery and sample handling will be discussed. These will be compared with the handling of returned lunar samples and the proposed handling of the Hyabusa samples as well. Finally, though none of these recent missions have been restricted within NASA s Planetary Protection Protocol, this is likely to change as missions venture farther from Earth. The implementation of Planetary Protection requirements will vary significantly based on mission scenario, however some of the potential implications of restricted Earth return will be considered.
In-Field Diffuse Ultraviolet Spectroscopy and Imaging of the Stardust Sample Return Capsule
In-field diffuse Ultraviolet (UV) spectroscopy and imaging systems were developed for the purposes of evaluating the surface chemical composition of spacecraft thermal control coatings and materials. The investigation of these systems and the compilation of an associated UV reflectance and luminescence database were conducted using the Stardust Sample Return Capsule (SRC), located at the Johnson Space Center. Spectral responses of the surfaces of the Stardust forebody and aftbody in both reflectance and fluorescence modes were examined post-flight. In this paper, we report on two primary findings of in-field diffuse UV spectroscopy and imaging: (1) deduction of the thermal history of thermal control coatings of the forebody and (2) bond line variations in the aftbody. In the forebody, the thermal history of thermal control coatings may be deduced from the presence of particular semiconducting defect states associated with ZnO, a common emissivity constituent in thermal control coatings. A spatial dependence of this history was mapped for these regions. In the aftbody, luminescing defect states, associated with Si and SiO2 color centers were found along regions of bond variability.