China’s Lunar and Planetary Data System: Preserve and Present Reliable Chang’e Project and Tianwen-1 Scientific Data Sets

Data infrastructure systems such as the National Aeronautics and Space Administration (NASA) Planetary Data System (PDS), European Space Agency (ESA) Planetary Data Archive (PSA)and Japan Aerospace Exploration Agency (JAXA) Data Archive and Transmission System (DARTS) archive large amounts of scientific data obtained through dozens of planetary exploration missions and have made great contributions to studies of lunar and planetary science. Since China started lunar exploration activities in 2007, the Ground Research and Application System (GRAS), one of the five systems developed as part of China’s Lunar Exploration Program (CLEP) and the Planetary Exploration of China (PEC), has gradually established China’s Lunar and Planetary Data System (CLPDS), which involves the archiving, management and long-term preservation of scientific data from China’s lunar and planetary missions; additionally, data are released according to the policies established by the China National Space Administration (CNSA). The scientific data archived by the CLPDS are among the most important achievements of the CLEP and PEC and provide a resource for the international planetary science community. The system plays a key and important role in helping scientists obtain fundamental and original research results, advancing studies of lunar and planetary science in China, and improving China’s international influence in the field of lunar and planetary exploration. This paper, starting from CLEP and PEC mission planning, explains the sources, classification, format and content of the lunar and Mars exploration data archived in the CLPDS. Additionally, the system framework and core functions of the system, such as data archiving, management and release, are described. The system can be used by the international planetary science community to comprehensively understand the data obtained in the CLEP and PEC, help scientists easily access and better use the available data resources, and contribute to fundamental studies of international lunar and planetary science. Moreover, since China has not yet systematically introduced the CLPDS, through this article, international data organizations could learn about this advanced system. Therefore, opportunities for international data cooperation can be created, and the data service capability of the CLPDS can be improved, thus promoting global data sharing and application for all humankind.

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.

Study of the changes of the distribution of spectral properties of S-type asteroidal dynamical families with age: Mean values and Skewness.

<p>Correlations between family-age and the mean value of slope of the spectral distribution, caused by the cumulative effect of cosmic irradiation, have been established for S-type dynamical families by many authors. We noticed that if there is a variety in the primordial surface composition, then the typical timescale that determines the speed of this evolution is bound to have a range of values. Consequently, as the mean value of the color distribution tends to steeper (redder) slopes, a progressive skewness in this distribution should develop. Using SDSS-MOC-4 colors and NEOWISE albedos, we cross-examined the S-type families members as defined by both Nesvorny et al. (2015) and Spotto et al (2015) and retained only members with albedos and colors in the characteristic range of the S-types. We corroborate the color evolution with age and we compare our results with previous estimations. Using only the "true S-type" family members, we also find a significative correlation between some particular skewness-estimation parameters and age. Our results offer additional evidence of the effects of cosmic-radiation on asteroidal surfaces and may provide possible new relations to determine the age of S-type dynamical families. </p> <p><strong>References</strong></p> <p>Nesvorny D.(2015). NASA Planetary Data System, id. EAR-A-VARGBDET-5-NESVORNYFAM-V3.0</p> <p>Spoto, F.; Milani, A.; Knežević, Z. (2015). Asteroid family ages. Icarus, Volume 257, p. 275-289.</p>

Asteroid taxonomy using artificial neural networks

<p>Asteroids are classified into different taxonomic groups according to their spectral reflectance properties in the visual and near-infrared (Vis-NIR) wavelengths. The spectral properties of the asteroid surfaces can be related to the material of the surface. There are a few taxonomic systems for asteroids, the most recent being the so-called Bus-DeMeo taxonomy (B-DM, DeMeo et al., Icarus 202, 2009). Usually, the exact wavelengths used in the taxonomic system are tied up with the particular survey data that was used to create the taxonomy. With the B-DM taxonomy, it is the SMASSII survey extended to near-infrared with the NASA IRTF telescope observations, and the wavelengths are 0.45–2.45 µm.</p> <p>The ESA space observatory Gaia will produce a significant number of low-resolution asteroid spectra over the 0.33–1.05 µm wavelength range in the Data Release 3 and the final data releases. There is an evident need for evaluating the surface properties of these asteroids using the Gaia data. For example, the list of taxonomic classifications for asteroids, maintained in the NASA Planetary Data System, has 2,600 asteroids with some taxonomic class (Neese, C., Ed., NASA Planetary Data System, 2010), but the Gaia data will eventually contain about 100,000 asteroid spectra.</p> <p>There is a plan to provide a new asteroid taxonomy using the Gaia observations (Delbo et al., PSS 73, 2012). However, a link to existing taxonomic systems such as B-DM would be highly valuable. In this work, we study the possibility to use feed-forward artificial neural network for asteroid spectral classification. We show that the classification accuracy can remain on a reasonably good level even if the B-DM classification is done with the neural network that is trained to use only data having wavelengths in the 0.45–1.05 µm range, which is the overlapping region with the Gaia and the original B-DM systems. This tool can provide the B-DM taxonomic classification for all the asteroids with Gaia spectroscopy.</p> <p><strong>Acknowledgements:</strong> Research supported, in part, by the Academy of Finland (project 325805).</p>

Precise astrometry and diameters of asteroids from occultations – a data set of observations and their interpretation

ABSTRACT Occultations of stars by asteroids have been observed since 1961, increasing from a very small number to now over 500 annually. We have created and regularly maintain a growing data set of more than 5000 observed asteroidal occultations. The data set includes the raw observations, astrometry at the 1 mas level based on centre of mass or figure (not illumination), where possible the asteroid’s diameter to 5 km or better, and fits to shape models, the separation and diameters of asteroidal satellites, and double star discoveries with typical separations being in the tens of mas or less. The data set is published at NASA’s Planetary Data System and is regularly updated. We provide here an overview of the data set, discuss the issues associated with determining the astrometry and diameters, and give examples of what can be derived from the data set. We also compare the occultation diameters of asteroids with the diameters measured by the satellites NEOWISE, AKARI AcuA, and IRAS, and show that the best satellite-determined diameter is a combination of the diameters from all three satellites.

SPICE TOOLS SUPPORTING PLANETARY REMOTE SENSING

NASA's "SPICE"<sup>*</sup> ancillary information system has gradually become the de facto international standard for providing scientists the fundamental observation geometry needed to perform photogrammetry, map making and other kinds of planetary science data analysis. SPICE provides position and orientation ephemerides of both the robotic spacecraft and the target body; target body size and shape data; instrument mounting alignment and field-of-view geometry; reference frame specifications; and underlying time system conversions. <br><br> SPICE comprises not only data, but also a large suite of software, known as the SPICE Toolkit, used to access those data and subsequently compute derived quantities–items such as instrument viewing latitude/longitude, lighting angles, altitude, etc. <br><br> In existence since the days of the Magellan mission to Venus, the SPICE system has continuously grown to better meet the needs of scientists and engineers. For example, originally the SPICE Toolkit was offered only in Fortran 77, but is now available in C, IDL, MATLAB, and Java Native Interface. SPICE calculations were originally available only using APIs (subroutines), but can now be executed using a client-server interface to a geometry engine. Originally SPICE "products" were only available in numeric form, but now SPICE data visualization is also available. <br><br> The SPICE components are free of cost, license and export restrictions. Substantial tutorials and programming lessons help new users learn to employ SPICE calculations in their own programs. The SPICE system is implemented and maintained by the Navigation and Ancillary Information Facility (NAIF)–a component of NASA's Planetary Data System (PDS). <br><br> <sup>*</sup> Spacecraft, Planet, Instrument, Camera-matrix, Events

SPICE TOOLS SUPPORTING PLANETARY REMOTE SENSING

NASA's "SPICE"^* ancillary information system has gradually become the de facto international standard for providing scientists the fundamental observation geometry needed to perform photogrammetry, map making and other kinds of planetary science data analysis. SPICE provides position and orientation ephemerides of both the robotic spacecraft and the target body; target body size and shape data; instrument mounting alignment and field-of-view geometry; reference frame specifications; and underlying time system conversions. <br><br> SPICE comprises not only data, but also a large suite of software, known as the SPICE Toolkit, used to access those data and subsequently compute derived quantities–items such as instrument viewing latitude/longitude, lighting angles, altitude, etc. <br><br> In existence since the days of the Magellan mission to Venus, the SPICE system has continuously grown to better meet the needs of scientists and engineers. For example, originally the SPICE Toolkit was offered only in Fortran 77, but is now available in C, IDL, MATLAB, and Java Native Interface. SPICE calculations were originally available only using APIs (subroutines), but can now be executed using a client-server interface to a geometry engine. Originally SPICE "products" were only available in numeric form, but now SPICE data visualization is also available. <br><br> The SPICE components are free of cost, license and export restrictions. Substantial tutorials and programming lessons help new users learn to employ SPICE calculations in their own programs. The SPICE system is implemented and maintained by the Navigation and Ancillary Information Facility (NAIF)–a component of NASA's Planetary Data System (PDS). <br><br> ^* Spacecraft, Planet, Instrument, Camera-matrix, Events