Science Missions of the Korean Lunar Exploration Program

The Korea Pathfinder Lunar Orbiter (KPLO), which is the Korean first lunar and space exploration spacecraft, will be launched in August 2022 and arrive in a lunar orbit in December 2022. The KPLO will carry out nominal missions while in a lunar polar orbit an ~100-km altitude for one year. The KPLO has five lunar science mission payloads and one technology demonstration payload in order to achieve their own science and technology goals. The science payloads consist of four Korean domestic instruments and one internationally collaborated science instrument for scientific investigations on the lunar surface and in a space environment. The Korean dometstic science instruments are the gamma-ray spectrometer named KGRS, the wide-angle polarimetric camera named PolCam, the fluxgate magnetometer named KMAG, and the high resolution camera named LUTI. The name of the internationally collaborated science instrument is ShandowCam, which was developed by Arizona State University, U.S., and funded and managed by NASA. The science data acquired by the science payloads will be released to the public in order to enhance scientific and educational achievements. The science data acquired by each science instrument will be archived and released through the web sites of the KPDS (KARI Planetary Data System) for the Korean science instruments and the NASA PDS (Planetary Data System) for the internationally collaborated science instrument.

Dust impact signals detected by Cassini RPWS instrument at Saturn

<p>Cassini spacecraft spent at Saturn almost half of the Saturn year. During these 13 years in the Saturn magnetosphere, the RPWS (Radio Plasma Wave Science) instrument recorded more than half a million of waveforms with signatures that can be interpreted as dust impact signals. The RPWS antennas in both dipole and monopole configurations operated with 10 kHz or 80 kHz sampling rates during the mission.<br>We qualitatively and quantitatively analyze the registered waveforms taking into account the spacecraft potential, density of the ambient plasma, magnitude of the Saturn’s magnetic field and its orientation with respect to the spacecraft. The magnetic field orientation is also used for distinguishing between signals resulting from dust impacts and signals produced by solitary waves, which can exhibit similar shapes. The results of analysis are compared with a prediction of the dust impact model that was recently developed on a base of laboratory simulations. The simulations used the reduced model of Cassini that was bombarded with submicron-sized iron grains in the velocity range of 1–40 km/s at the 3 MV dust accelerator operated at the LASP facility of University of Colorado. The model predicts generation of impact signals due to different fractions of collected and escaped electron and ion charges from the impact plasma plume and different timescales of their expansion. The core of the paper is devoted to a discussion of differences between model predictions and observations.</p>

Plasmasphere observations with Cluster data supplemented with data from the Dynamics Explorer-1 and Van Allen Probes missions

<p>Since 2000 the four Cluster spacecraft have crossed the Earth's plasmasphere along a polar orbit every 2.5 days, with various perigee altitudes (from 1.5 to 4 R<sub>E</sub>), different configurations (string of pearls, tetrahedron) and changing separations (from 10 to 100 000 km). The resulting dataset allows different types of inner magnetosphere studies and provides insight in plasmasphere dynamics, including changes in plasmapause position. Plasmaspheric plumes can also be studied on a case-by-case basis, in a statistical manner and in relation with wave activity (EMIC, electromagnetic rising tone, whistler waves).</p><p>Moreover, data from an old mission, Dynamics Explorer-1, have recently become available. In particular, densities and temperatures for many ions (H<sup>+</sup>, He<sup>+</sup>, He<sup>++</sup>, O<sup>+</sup>, and O<sup>++</sup>) have been derived from the RIMS (Retarding Ion Mass Spectrometer) instrument and are available from October 1981 to January 1985. Such composition data, not available from the Cluster satellites, allow in particular to analyze the distributions of those ions in the plasmasphere boundary layer, as a function of magnetic local time and geomagnetic activity.</p><p>Finally, since 2012, the two Van Allen Probes satellites are orbiting the inner magnetosphere in the magnetic equatorial plane and with a low perigee, allowing a crossing of the plasmasphere every 9 hours. The EMFISIS (Electric and Magnetic Field Instrument Suite and Integrated Science) instrument onboard both spacecraft can determine the electron density in a very large density range (up to 3000 cm<sup>-3</sup>) using several methods. This gives a different opportunity to analyze the plasmapause and plasmaspheric plumes from a different perspective.</p>