Frequently asked questions

Satcat compiles publicly available data from the following providers:

• TLE data provided by the U.S. government - Website
• Space weather timeseries data provided by Celestrak - Website
• Space weather conditions data provided by NOAA - Website
• Supplementary TLE data provided by Mike McCant - Website
• Launch vehicle data from GCAT (J. McDowell) - Website
• Brightness magnitude and RCS values provided by Mike McCant - Website

Payloads

Payloads are satellites, spacecraft, or rockets with specialized instruments for diverse scientific and technological missions. There are several different types of payloads, each serving a different mission purpose:

• Communications satellites, such as Starlink satellites, which are used to transmit internet, radio, television, and other data
• Space stations, like the International Space Station (ISS) or Chinese Space Station, which serve as habitable research laboratories
• Scientific research satellites, such as the Hubble Space Telescope
• Earth observation satellites, which collect data about Earth’s surface and atmosphere
• Navigation satellites, like GPS, which provide global or regional positioning systems
• Miniaturized satellites, like CubeSats, are used for educational purposes, technology demonstrations, and research experiments
• Military satellites, which are used for defense purposes

Analyst objects

Analyst objects are objects on Earth’s orbit with insufficient fidelity to be published in the public satellite catalog. This can be due to infrequent tracking, cross-tagging (observation association with closely-spaced objects), or inability to associate the object with a known launch.

Debris objects

Debris objects in space refer to the collection of defunct objects orbiting the Earth. Examples of debris include non-operational satellites, rocket bodies, and fragments generated from explosions, collisions, or faulty payload assembly.

Unknown objects

Unknown objects in Earth's orbit typically refer to objects that have been detected orbiting the Earth but have not yet been identified or cataloged. These objects could be anything from previously untracked satellites, spent rocket stages, debris from satellite collisions, or even natural meteoroids temporarily captured by Earth's gravity.