In multi-spectral images made by Earth observation satellites that use push-broom scanning, such as those operated by Planet Labs Corp., moving objects can be identified by the appearance of the object at a different locations in each spectral band. The apparent velocity can be measured if the relative acquisition time between images in different spectral bands is known to millisecond accuracy. The images in the Planet Labs archive are mosaics of individual exposures acquired at different times. Thus there is not a unique acquisition time for each spectral band. In an earlier paper, we proposed a method to determine the relative acquisition times from the information in the images themselves. High altitude balloons provide excellent targets to test our proposed method because of their high apparent velocity due to the orbital velocity of the satellite and geometric parallax in images aligned to the level of the ground. We use images of the Chinese balloon that crossed the US in February, 2024 as well as images of an identical balloon over Colombia to test our method. Our proposed method appears to be successful and allows the measurement of the apparent velocity of moving objects from the information available in the archive.
SPHEREx confirms predictions for artificial satellite trail pollution in Low Earth Orbit
NASA Ames Research Center（美国国家航空航天局艾姆斯研究中心）；Bay Area Environmental Research Institute（湾区环境研究所）；IAU Centre for the Protection of the Dark and Quiet Sky（国际天文学联合会暗弱天空保护中心）；Centre de recherche sur les Ions, les Matériaux et la Photonique Université Caen Normandie, ENSICAEN, CNRS, CEA, Normandie Univ, CIMAP UMR6252（卡昂诺曼底大学离子、材料与光子研究中心）；Space Research Centre, Durham University（杜伦大学太空研究中心）；Planet4589 Research（Planet4589 研究）
Peculiar orbital characteristics of Earth quasi-satellite 469219 Kamo`oalewa: implications for the Yarkovsky detection and orbital uncertainty propagation
The impact of electron precipitation on Earth's thermospheric NO production and the drag of LEO satellites
Space Research Institute, Austrian Academy of Sciences（奥地利科学院空间研究所）；Technical University, Graz（格拉茨工业大学）；Institute of Astronomy, Russian Academy of Sciences（俄罗斯科学院天文研究所）；National Center of Physics and Mathematics（国家物理数学中心）；Department of Astrophysics, University of Vienna（维也纳大学天体物理系）；Austrian Space Weather Office, GeoSphere Austria（奥地利空间天气办公室，地球系统奥地利）
