Moon Rocks in the Mission Accessible Near-Earth Object Survey Sample

The Mission Accessible Near-Earth Object Survey (MANOS) is focused on identifying and characterizing potential future spacecraft targets and has built a sample of about a thousand NEOs with techniques including light curves, colors, and spectroscopy since its inception a decade ago. The survey’s focus on objects with relatively similar orbits to the Earth (and thus low relative velocities) means that a fraction of the sample is likely lunar ejecta and space junk, as opposed to NEOs with origins in the Main Belt. Separating out these interlopers is critical to ongoing efforts to understand the distribution of properties in the whole (asteroidal) MANOS sample, but also means that we have built a catalog of physical properties for these ’non-traditional’ NEOs. This set of properties can aid in future discrimination of such objects.

We will present on efforts to identify these interloping objects within the sample both through dynamical and physical means, and on the tools we’ve developed to do so that may be of use to others. There is not a simple rule to identify the origins of objects with such Earth-like orbits, and thus care must be taken with each object to avoid misclassifying it. Below a cut-off velocity-at-infinity of 2.5 km/s, our sample has 50 objects, at least 35 of which have at least a partial light curve and 15 of which have visible reflectance spectra. We will compare the rotational and surface properties of the objects in our sample to small NEOs of similar sizes, to reflectance spectra of lunar materials, and to those of (469219) Kamoʻoalewa, which was recently proposed to be lunar ejecta. We will also compare the properties of this sub-sample to those within the entire MANOS catalog, with the larger aim of understanding the diversity of properties for objects with a lunar origin. This will have implications for understanding the compositional breakdown of NEOs on earth-like orbits, which is key information for applications of in situ resource utilization and impact hazard assessment.