Why scientists are worried about plans to put giant mirrors in space

Reflect Orbital wants to provide sunlight after dark using mirrors in orbit.

Slovak researchers have raised the alarm over a controversial project by an American company to put tens of thousands of mirrors in space to beam sunlight to Earth on demand.

Later this year Reflect Orbital will launch a test satellite with a deployable 18-by-18-metre mirror in orbit to test the feasibility of its plans.

But in a new paper researchers from the Slovak Academy of Sciences (SAV), Comenius University (UK) and Princeton University warn that the mirror could end up brightening the night sky up to dozens of kilometres away from where it is intended to shine, even with the “smaller” version of the mirror – the proposed large-scale mirrors will measure 54-by-54 metres.

“The idea has a longer history than one might expect,” lead author Miroslav Kocifaj from SAV’s Institute of Construction and Architecture and Faculty of Mathematics, Physics, and Informatics ( FMFI UK) told The Slovak Spectator.