Letter to the Editor

The MASCOT landing area on asteroid (162173) Ryugu: Stereo-photogrammetric analysis using images of the ONC onboard the Hayabusa2 spacecraft

¹ German Aerospace Center (DLR), Institute of Planetary Research, 12489 Berlin, Germany
e-mail: Frank.Preusker@dlr.de
² Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo, Japan
³ University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, Japan
⁴ Planetary Exploration Research Center, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba, Japan
⁵ Department of Information Science, Kochi University, 2-5-1 Akebono, Kochi, Japan
⁶ Instituto de Astrofisica de Canarias, University of La Laguna, Santa Cruz de Tenerife, Spain
⁷ Department of Complexity Science and Engineering, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, Japan
⁸ ISAS, JAXA, 3-3-1 Yoshinodai, Chuo, Sagamihara, Kanagawa, Japan
⁹ National Institute of Advanced Industrial Science and Technology, 2-3-26 Aomi, Koto, Tokyo, Japan
¹⁰ Department of Physics, Meiji University, 1-1-1 Higashimita, Tama, Kawasaki, Kanagawa, Japan
¹¹ CAIST/ARC-Space, University of Aizu, Aizu-Wakamatsu, Fukushima, Japan
¹² Department of Planetology, Kobe University, 1-1 Rokkodaicho, Nada, Kobe, Hyogo, Japan

Received: 23 September 2019
Accepted: 3 November 2019

Abstract

A high-resolution 3D surface model, map-projected to a digital terrain model (DTM), and precisely ortho-rectified context images (orthoimages) of MASCOT landing site area are important data sets for the scientific analysis of relevant data that have been acquired with MASCOT’s image camera system MASCam and other instruments (e.g., the radiometer MARA and the magnetometer MASMag). We performed a stereo-photogrammetric (SPG) analysis of 1050 images acquired from the Hayabusa2 Optical Navigation Camera system (ONC) during the asteroid characterization phase and the MASCOT release phase in early October 2018 to construct a photogrammetric control point network of asteroid (162173) Ryugu. We validated existing rotational parameters for Ryugu and improved the camera orientation (position and pointing) of the ONC images to decimeter accuracy using SPG bundle block adjustment. We produced a high-resolution DTM of the entire MASCOT landing site area. Finally, based on this DTM, a set of orthoimages from the highest-resolution ONC images around MASCOT’s final rest position complements the results of this analysis.