Satellite Streaks in HETDEX: Spectra, Orbital Identification, and Survey Impact

Abstract We present a spectroscopic database and analysis of satellite streaks in Public Data Release 1 (PDR1) from the Hobby–Eberly Telescope Dark Energy Experiment (HETDEX), covering 6778 observations and ∼90 deg 2 of sky from 2017 January to 2024 July. We detect 527 streaks across 492 observations, a contamination fraction of 7.3% that rises to monthly values above 20% by 2023–2024, although the streaks mask only 0.09% of the survey area. Of the 527 streaks, 475 (90.1%) are identified with a cataloged object using archival two-line elements: 258 (54%) lie in low or medium Earth orbit, and 217 (46%) are geostationary or highly elliptical. Only 35% were launched since 2010; the rest are spent rocket bodies, debris, and older spacecraft. This reflects HETDEX’s sensitivity to faint objects and its 2017–2024 observing baseline. The Hobby–Eberly Telescope’s large 10 m aperture and HETDEX’s ∼6 minute exposures result in similar observed magnitudes for low Earth orbit (LEO) and geostationary Earth orbit (GEO) objects (median g AB = 16.2 ± 1.1 for LEO, 16.7 ± 1.1 for GEO). However, once transit time is corrected for, instantaneous magnitudes differ widely: g inst = 7.4 for LEO versus g inst = 13.0 for GEO objects, a difference of 5.6 mag, while the exposure-averaged magnitudes differ by only 0.5 mag. Normalized to 550 km, the 34 Starlink streaks give g (550 km) = 5.95, consistent with the mean V (550 km) = 5.92 ± 0.04 reported for VisorSat-design spacecraft. The spectra are consistent with reflected sunlight, with modest, signal-to-noise-driven differences in slope. The catalog, spectra, and code are archived on Zenodo (doi: 10.5281/zenodo.22962479 ).