Contamination Control

JSC scientist Mike Zolensky took the lead in formulating and implementing the Contamination Control Plan for the STARDUST Mission. This plan was the blueprint for ensuring that the returned samples remained as pristine as possible, so that the maximum may be learned from their studies. It has been almost 30 years since we had to write the last such plan (for Apollo and Luna Missions to the Moon), and so for STARDUST we had to learn all over again how to make and operate a clean spacecraft. The experience we have gained is applied to other sample return missions like Genesis and Hayabusa.

A significant constraint on any sample return is the absolute requirement for a contamination-free sample container. Calculations indicate that for a chondritic composition sample weighing 1 µg, the total permitted contamination levels for inorganic elements on the walls of the sample container vary from 10-9 to 10-16 g. For nanogram-sized grains the requirements are significantly more stringent. Accordingly, smaller-scale techniques such as ion probery, proton induced X-ray emission analysis (PIXE), and resonance ionization mass spectrometry (RIMS) require even more care in contamination control. For organic compounds, contamination control requirements are not only hard to achieve, but currently often difficult to usefully define.

STARDUST spacecraft, indicating principal components. The image shows the aerogel collector deployed, ready to collect dust.