Satellite megaconstellations will threaten space-based astronomy Authors: Alejandro S. Borlaff, Pamela M. Marcum, Steve B. Howell. Contact: a.s.borlaff@nasa.gov Nature - Publication date: December 3rd, 2025. DOI: 10.1038/s41586-025-09759-5Article: https://www.nature.com/articles/s41586-025-09759-5 This repository contains the results from a series of simulations of satellitetrails in space telescopes. In particular, the properties listed contain theposition, velocity, and surface brightness of satellite trails, as well as theproperties related to the observers, Hubble Space Telescope, SPHEREx,Xuntian, and ARRAKIHS (Future F-class ESA mission). In addition to the science data (described below) the repository contains three media resources (outreach media images and videos). simulated_satellite_trails_cover_Borlaff_2025.png md5:920dc67bb73f493d2ab4389d3fd27767 A simulated image representing the projected contamination by satellite trails in one of the future space telescopes. The stripes of light reflected from artificial telecommunication satellites outshine the otherwise pristine image of two galaxies interacting in the background, hindering the potential discoveries that might lie below. Credit: NASA / Borlaff, Marcum, Howell (Nature, 2025) growth_out.mp4 md5:01353d5b8f07e3898e73fa434d96ecf9 Historic increase of the number of active satellites in orbit since 1958 to 2040. Credit: NASA / Borlaff, Marcum, Howell (Nature, 2025) orbit_clutter_v4.mp4 md5:377c008e00e644b12b7f041881a32500 Structure of proposed satellite telecommunication constellations in Low Earth Orbit from 1958 to 2037 (predicted). The altitude of satellites is compared to the orbits of Hubble Space Telescope, Xuntian Space Telescope (CSST), SPHEREx, and proposed ARRAKIHS mission. Credit: NASA / Borlaff, Marcum, Howell (Nature, 2025) Science data: The repository contains all the data produced on the article. These are organized in two folders with 4 files each, one per telescope. . |-TRAILS | |-HST_sat_trails.csv | |-ARRAKIHS_sat_trails.csv | |-SPHEREx_sat_trails.csv | |-CSST_sat_trails.csv | |- ntrails_vs_nsats_table.csv |-SPECTRA | |-SPHEREx_trail_flux.fits | |-HST_trail_flux.fits | |-ARRAKIHS_trail_flux.fits | |-CSST_trail_flux.fits | |- mu_vs_wave.csv |-ReadMe.txt TRAILS contains five astropy csv tables, containing the properties of thesatellite trail observations, divided by telescope and exposure(track_id / nsats), and the average properties per number of satellites (ntrails_vs_nsats_table.csv)Consult the header on each table for more details about the columns. SPECTRA contains four multiextension FITS files, containing the spectralenergy distribution of the satellite trails as a function of wavelength, and the average properties per wavelength (mu_vs_wave.csv).The structure of the FITS files is: 0 INFO no-data 01 WAVELENGTH float64 100 # Contains the wavelength for the spectra (in m)2 TOTAL_FLUX float64 NTRAILSx100 # Total surface brightness for each trail [Axis 0: Trail, Axis 1: Wavelength]3 EARTHSHINE float64 NTRAILSx100 # Surface brightness produced by Earthshine [Axis 0: Trail, Axis 1: Wavelength]4 MOONSHINE float64 NTRAILSx100 # Surface brightness produced by Moonshine [Axis 0: Trail, Axis 1: Wavelength]5 SUNSHINE float64 NTRAILSx100 # Surface brightness produced by Sunshine [Axis 0: Trail, Axis 1: Wavelength]6 THERMAL_SUN float64 NTRAILSx100 # Surface brightness produced by Earth reflected thermal emission [Axis 0: Trail, Axis 1: Wavelength]7 THERMAL_SAT float64 NTRAILSx100 # Surface brightness produced by Thermal satellite emission [Axis 0: Trail, Axis 1: Wavelength] See also: DOI: 10.1038/s41586-025-09759-5Article: https://www.nature.com/articles/s41586-025-09759-5