Post #3714232

2026-07-10 10:06 UTC

While the FCC has approved a test satellite from Reflect Orbital (which wants to illuminate solar farms at night), the basic physics here seems decisive — on the side of “No, this can’t possibly be a practical thing to do.” From the linked analysis by Michael Brown and Matthew Kenworthy: [Reflect Orbital’s plan is “simple satellites in the right constellation shining on existing solar farms”. And their goal is only 200 watts per square metre – 20% of the midday Sun. Can smaller satellites deliver? If a single 54 metre satellite is 15,000 times fainter than the midday Sun, you would need 3,000 of them to achieve 20% of the midday Sun. That’s a lot of satellites to illuminate one region. Another issue: satellites at a 625km altitude move at 7.5 kilometres per second. So a satellite will be within 1,000km of a given location for no more than 3.5 minutes. This means 3,000 satellites would give you a few minutes of illumination. To provide even an hour, you’d need thousands more. Reflect Orbital isn’t lacking ambition. In one interview, Nowack suggested 250,000 satellites in 600km high orbits. That’s more than all the currently catalogued satellites and large pieces of space junk put together. And yet, that vast constellation would deliver only 20% of the midday Sun to no more than 80 locations at once, based on our calculations above. In practice, even fewer locations would be illuminated due to cloudy weather.] https://theconversation.com/a-us-startup-plans-to-deliver-sunlight-on-demand-after-dark-can-it-work-and-would-we-want-it-to-264323 https://ca.pcmag.com/news/16760/fcc-approves-reflect-orbitals-giant-mirror-satellite-that-astronomers-hate

Replies (6)

@davep@infosec.exchange 2026-07-10 15:24

@gregeganSF@mathstodon.xyz Why not just use your actual sun and battery storage? Eejits.

Open ##3719464
@sohkamyung@mstdn.io 2026-07-10 12:17

@gregeganSF@mathstodon.xyz @startswithabang@mastodon.social also did the calculations and came to this conclusion. "The most unfortunate part of the Reflect Orbital proposal is how unnecessary it is. We already have solutions to all of the problems that it purports to solve, with none of the many significant consequences that an array of giant mirrors would bring to Earth." https://bigthink.com/starts-with-a-bang/true-cost-solar-power-night-reflect-orbital/

Open ##3721086
@darkuncle@infosec.exchange 2026-07-10 18:41

@gregeganSF@mathstodon.xyz Reflect Orbital's whole concept is a non-starter IMO, for so many reasons; however, Overview Energy's approach (collecting solar in geosync orbit, converting to widebeam near infrared and beaming down to existing terrestrial solar farms) seems to have much of the advantages while avoiding many of the drawbacks. https://podcasts.apple.com/us/podcast/space-minds/id1792211045?i=1000772259186 /cc @sundogplanets@mastodon.social who has been consistently educating and leading pushback against Reflect Orbital on Fedi; her efforts are much appreciated.

Open ##3722663
@joost_rekveld@assemblag.es 2026-07-10 10:19

@gregeganSF@mathstodon.xyz It must be that building an empire of solar farms where the sun never sets doesn't absorb enough of the excess money that is sloshing around looking for a purpose ?

Open ##3800735
@natpbs@mathstodon.xyz 2026-07-10 10:24

@gregeganSF@mathstodon.xyz I wonder how much time it would take for a single satellite to generate enough energy by shining on solar farms to compensate for the fuel needed to get it into orbit

Open ##3800736
@acb@mastodon.social 2026-07-10 10:37

@gregeganSF@mathstodon.xyz Maybe they can shine them on the solar panels between railway tracks that they recently tested in Switzerland and synergise two half-baked ideas

Open ##3800743