We measure the moment of inertia of the spacecraft both before and after sample acquisition. It turns out that this technique has a measurement uncertainty of 90 grams (3-sigma). Therefore, our sample collector (TAGSAM) is required to pick up 150 grams of material. Under optimum conditions, TAGSAM can pick up two kilograms of material. We have the capability to attempt sample collection three times. However, we hope to get enough sample on the first attempt. The second two are backup options in case the first attempt does not pick up enough material.
The primary objective of OSIRIS-REx is to return pristine carbonaceous material from the early Solar System. Spectral analysis of Bennu suggests that it is similar on composition to the very rare CI and CM carbonaceous chondrite meteorites. These rocks are rich in organic compounds and water-bearing minerals like clays. We hope to find organic molecules that may have led to the origin of life on Earth and inform the likelihood that life may have originated elsewhere in our solar system. The team’s sample analysis objectives are distributed among five broad categories, based on analytical techniques. These are: mineralogy & petrology, elemental & isotopic composition, organic chemistry, spectral properties, and thermal properties. We use a wide variety of techniques including NanoSIMS, transmission electron microscopy, electron microprobe analysis, mass spectroscopy, gas and liquid chromatography, synchrotron particle accelerators, thermal conductivity analyzers, and laboratory spectrometers.