Eärendil-1: bright or blight?, Pg2

Key Highlights:

• On July 9, the U.S. Federal Communications Commission (FCC) authorized Reflect Orbital to launch Eärendil-1, a test satellite.
• The satellite is designed to deploy a large, steerable mirror to reflect sunlight towards specific spots on Earth at night.
• Reflect Orbital aims to extend usable hours for solar panels and provide light for critical operations like emergency missions.
• The American Astronomical Society (AAS) raised concerns about potential skyglow and disruption to optical astronomy.
• The FCC granted a limited two-year license, imposing conditions for coordination with NASA and other agencies to protect astronomy.

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Detailed Insights:

• Eärendil-1 will operate in a non-geostationary orbit at an altitude of approximately 625 km with an 88° inclination.
• The satellite's core technology is a "deployable, highly specular thin-film reflector" that is motorized and steerable.
• The FCC ruled that while it regulates radiofrequency interference and orbital debris, the visual impact of reflected sunlight is outside its statutory authority.
• Conditions for approval include coordinating with the U.S. National Science Foundation and the National Telecommunications and Information Administration.
• The satellite must also adhere to specific duty cycles and conjunction angles to prevent interference with other space missions.

Key Concepts Involved:

• Non-geostationary orbit: An orbit where a satellite does not remain fixed relative to a point on Earth's surface.
• Skyglow: Artificial brightening of the night sky due to light pollution, impacting astronomical observations.
• Orbital debris: Non-functional, human-made objects in orbit around Earth, posing collision risks.
• Radiofrequency interference: Unwanted signals that disrupt the reception of desired radio communications.