The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, is composed of primitive objects preserving information about Solar System formation. In January 2019, the New Horizons spacecraft flew past one of these objects, the 36-kilometer-long contact binary (486958) Arrokoth (provisional designation 2014 MU69). Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters in diameter) within a radius of 8000 kilometers. Arrokoth has a lightly cratered, smooth surface with complex geological features, unlike those on previously visited Solar System bodies. The density of impact craters indicates the surface dates from the formation of the Solar System. The two lobes of the contact binary have closely aligned poles and equators, constraining their accretion mechanism.

The Kuiper Belt is a distant region of the outer Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU69, a cold classical Kuiper Belt object approximately 30 kilometers in diameter. Such objects have never been substantially heated by the Sun and are therefore well preserved since their formation. We describe initial results from these encounter observations. MU69 is a bilobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color or compositional heterogeneity. No evidence for satellites, rings or other dust structures, a gas coma, or solar wind interactions was detected. MU69's origin appears consistent with pebble cloud collapse followed by a low-velocity merger of its two lobes.

We present detailed photometric properties of the Moon at far ultraviolet wavelengths. The far ultraviolet data from the Lunar Reconnaissance Orbiter (LRO) Lyman Alpha Mapping Project (LAMP) instrument were used to derive two Hapke photometric parameters, the single‐scattering albedo, w, and the asymmetry factor, b, in the single‐particle phase function, for selected mare and highland regions. The derived single‐scattering albedo spectra show blue slopes for both regions. Furthermore, the negative values of the asymmetry parameter, for both regions, indicate backscattering from the surface. The derived photometric parameters were used to normalize the observed reflectance and remove the photometric effects, resulting in significant improvement in the quality of the LAMP dayside maps.

The Lyman‐Alpha Mapping Project (LAMP) UV spectrograph on board the Lunar Reconnaissance Orbiter (LRO) performed a campaign to observe the Moon's nanodust exosphere, evidence for which was provided by the Lunar Atmosphere and Dust Environment Explorer (LADEE) Ultraviolet and Visible Spectrometer (UVS) during the 2014 Quadrantid meteoroid stream. These LADEE/UVS observations were consistent with a nanodust exosphere modulated by meteoroid impacts. LRO performed off‐nadir maneuvers around the peak of the 2016 Quadrantids, in order to reproduce, as closely as possible, the active meteoroid environment and observing geometry of LADEE/UVS. We analyzed LAMP spectra to search for sunlight backscattering from nanodust. No brightness enhancement attributable to dust, of any size, was observed. We determine an upper limit for dust column concentration of ~10 5 cm −2 for grains of radius ~25 nm, and an upper limit for dust column mass of ~10 −11 g cm −2 , nearly independent of grain size for radii <100 nm.

Lunar swirls - the enigmatic, magnetically-anomalous regions - are observed for the first time at far-UV (FUV) wavelengths using LRO/LAMP. Swirls in both highlands and mare regions are spectrally relatively red (or less blue) than surrounding terrains, indicating a difference in weathering and/or composition in the swirls vs. non-swirl regions.We compare spectra of the highlands swirl Gerasimovich with mature and immature low-Fe highlands regions as measured by LAMP and show that the swirl itself does not have the spectral characteristics of either the mature or the immature regions. Mature, weathered highlands regions are spectrally blue in the FUV; immature highlands are less blue, especially at wavelengths > similar to 160 nm. In contrast, the Gerasimovich swirl is spectrally red at wavelengths > similar to 160 nm. We also compare Reiner Gamma, a mare swirl, with mature and immature high-Ti mare regions as measured by LAMP. We find that the mature and immature high-Ti mare regions are spectrally indistinguishable while the Reiner Gamma spectra are less blue at wavelengths > similar to 160 nm. We conclude that both swirls (Reiner Gamma and Gerasimovich) are consistent with less mature spectra than the immature terrains studied here, in accordance with the lower amounts of weathering expected in a solar wind standoff scenario. However, the swirl spectra are also consistent with greater abundances of feldspathic material, as we show that anorthite exhibits a characteristic red spectrum at wavelengths > similar to 160 nm. Thus, the LAMP data are also consistent with a model wherein compositional sorting occurs at swirls. (C) 2016 Elsevier Inc. All rights reserved.

The Pluto system was recently explored by NASA's New Horizons spacecraft, making closest approach on 14 July 2015. Pluto's surface displays diverse landforms, terrain ages, albedos, colors, and composition gradients. Evidence is found for a water-ice crust, geologically young surface units, surface ice convection, wind streaks, volatile transport, and glacial flow. Pluto's atmosphere is highly extended, with trace hydrocarbons, a global haze layer, and a surface pressure near 10 microbars. Pluto's diverse surface geology and long-term activity raise fundamental questions about how small planets remain active many billions of years after formation. Pluto's large moon Charon displays tectonics and evidence for a heterogeneous crustal composition, its north pole displays puzzling dark terrain. Small satellites Hydra and Nix have higher albedos than expected.

Greathouse, G. R. Gladstone, S. A. Stern, M. H. Versteeg, M. W. Davis, J. Wm. Parker, D. E. Kaufmann, P. D. Feldman, W. R. Pryor, A. R. Hendrix Johns Hopkins University Applied Physics Laboratory, Laurel, MD, dana.hurley@jhuapl.edu; Southwest Research Institute, San Antonio, TX; Southwest Research Institute, Boulder, CO; Johns Hopkins University, Baltimore, MD 21218; Central Arizona College, Coolidge, AZ; Planetary Science Institute, Los Angeles, CA

REGIONS. G. R. Gladstone, K. D. Retherford, S. A. Stern, A. F. Egan, P. F. Miles, M. H. Versteeg, D. C. Slater, M. W. Davis, J. Wm. Parker, D. E. Kaufmann, T. K. Greathouse, A. J. Steffl, J. Mukherjee, D. Horvath, P. D. Feldman, D. M. Hurley, W. R. Pryor, and A. R. Hendrix, Southwest Research Institute, 6220 Culebra Rd., San Antonio, TX 78238, Southwest Research Institute, 1050 Walnut St., Boulder, CO 80302, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd., Laurel, MD 20723, Central Arizona University, Jet Propulsion Laboratory, Pasadena, CA.

The Lunar Reconnaissance Orbiter (LRO) has been in orbit since July 2009. The Lyman Alpha Mapping Project (LAMP) [1] on board LRO has a primary focus of investigating the lunar poles (see abstracts by Gladstone et al. and Retherford et al., this meeting), searching for water frost in the permanently shadowed regions, as well as studying the lunar atmosphere. LAMP also makes measurements of the dayside lunar surface on each orbit. In this project, we utilize the LAMP dayside data to study the lunar surface and to understand its spectral variations. The canonical method for investigating the surface composition of planetary surfaces is nearinfrared spectroscopy. Here we utilize the ultraviolet wavelength range, shown to be sensitive to weathering effects and also containing diagnostic compositional features. We focus on data in the 110190 nm range.