Presentation Information
[PPS03-P05]Feasibility Study on Applying the Ames Stereo Pipeline for Asteroid Shape Reconstruction at Hayabusa2# Flyby Observation of Asteroid Torifune
*Tanagi Atsuya1, Naru Hirata1 (1.The university of Aizu)
Keywords:
Asteroid shape model,Flyby,Torifune,ASP
In July 2026, the asteroid explorer Hayabusa2 will conduct a flyby observation of asteroid (98943) Torifune as part of its extended mission. A flyby observation is a method in which the spacecraft conducts observations as it passes by a target body. The observable period is extremely short, and opportunities to capture high-resolution images are limited. Furthermore, it is impossible to observe the entire surface of the target body; only the hemisphere on the side where the spacecraft passes can be observed. Additionally, although the relative position of the spacecraft with respect to the target body is roughly known, constraining it with high precision is difficult.
In asteroid exploration, the shape model of the target body serves as foundational data for estimating density and is therefore indispensable for scientific analysis. However, reconstructing the asteroid's shape under the aforementioned flyby observation conditions is extremely difficult. Several Structure from Motion (SfM)-based software tools exist for shape reconstruction. These SfM tools can automatically estimate the camera position and attitude at the time of capture if a sufficient number of images are available. However, they lack the functionality to re-optimize these estimations with high precision based on rough information about the spacecraft's position and attitude.
Therefore, in this study, we attempted to reconstruct the asteroid shape utilizing rough spacecraft position information using the Ames Stereo Pipeline (ASP), an open-source software developed by NASA Ames Research Center. While ASP is mainly used to produce Digital Elevation Models for the Moon and other large bodies, there are few examples of its application to asteroid shape reconstruction. ASP is equipped with a Bundle Adjustment (BA) function that optimizes camera position and attitude. Specifically, the predicted spacecraft position information is provided as an initial value, and BA is used to optimize minute attitude errors and geometric inconsistencies during imaging. Through this approach, we demonstrated the potential to estimate high-precision 3D shapes while stabilizing the camera geometry, even for flyby observation data with limited viewpoints.
In asteroid exploration, the shape model of the target body serves as foundational data for estimating density and is therefore indispensable for scientific analysis. However, reconstructing the asteroid's shape under the aforementioned flyby observation conditions is extremely difficult. Several Structure from Motion (SfM)-based software tools exist for shape reconstruction. These SfM tools can automatically estimate the camera position and attitude at the time of capture if a sufficient number of images are available. However, they lack the functionality to re-optimize these estimations with high precision based on rough information about the spacecraft's position and attitude.
Therefore, in this study, we attempted to reconstruct the asteroid shape utilizing rough spacecraft position information using the Ames Stereo Pipeline (ASP), an open-source software developed by NASA Ames Research Center. While ASP is mainly used to produce Digital Elevation Models for the Moon and other large bodies, there are few examples of its application to asteroid shape reconstruction. ASP is equipped with a Bundle Adjustment (BA) function that optimizes camera position and attitude. Specifically, the predicted spacecraft position information is provided as an initial value, and BA is used to optimize minute attitude errors and geometric inconsistencies during imaging. Through this approach, we demonstrated the potential to estimate high-precision 3D shapes while stabilizing the camera geometry, even for flyby observation data with limited viewpoints.