Beams of light sweeping across the sky at night can cause problems for pilots and drivers. It has the potential to be a substantial distraction, and risks disrupting night vision, particularly with multiple beams. This could be risky around airports and could lead to accidents, similar to laser strikes on aircraft. https://www.faa.gov/newsroom/laser-strikes-aircraft-continue-be-dangerously-high
Having thousands of RO satellites in orbit would lead to frequent bright flashes all over the sky for any observer on the ground. Even millisecond flashes of light at night have been shown to disrupt human circadian rhythms. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0022078
Exposure to artificial light at night is linked to increased risks of some types of cancer. https://pmc.ncbi.nlm.nih.gov/articles/PMC5454613/
The costs to astronomy:
Have you noticed how bright the sky is the last few nights with the very bright nearly-full moon? Now imagine a point source 4x brighter, and moving across the sky. That's what they want to do
Astronomy requires dark skies to see faint celestial objects. Due to scattering of light along the beam, anytime an RO satellite is above the horizon, it would disrupt any
ground-based optical astronomy telescopes in the area. https://digitalcommons.usu.edu/smallsat/2025/all2025/98/
Similar to astronomical observing with a full moon in the sky, it would restrict observations to only the very brightest handful of stars and planets. This would cause the vast majority of astronomy research to be impossible while one or more of these satellites is above the horizon.
Directly shining the beam onto a large telescope (anywhere within 5km of a large telescope facility) could damage sensitive research telescope camera equipment, which are calibrated to study faint celestial objects
The costs to ecology:
These are too numerous to even try to list.
All life on Earth – including humans, migrating birds, pollinating insects, plankton in the oceans – depends on the natural day-night cycle of light and darkness. Many hundreds of scientific studies document the importance to ecosystems and agricultural crops of protecting that natural cycle. Bird migrations, pollination, plant growth, and animal behaviors could all be disrupted by reflected sunlight from orbit.
The costs to orbital safety:
“Sunlight as a service” requires huge mirrors in orbit, which would increase the likelihood of collisions between satellites.
Loss of control could lead to tumbling, causing erratic, bright flashes in the sky.
Large reflector cross-sections also mean a much higher collision risk from micrometeorites and non-trackable orbital debris. Using typical rates https://www.sciencedirect.com/science/article/abs/pii/S027311772030644X at 625km altitude (the orbit RO proposes to use), such reflectors could expect hundreds of micrometeorite and debris impacts each year, quickly degrading the reflector and creating more diffuse and larger beams.
There are already solutions right here on Earth to many of the problems “sunlight as a service” purports to solve. This approach is simply a reckless and inefficient use of Earth orbit, a precious and finite resource.
This list of facts was developed by me and a bunch of very concerned astronomers. If you're a journalist interested in writing a news article about this, please look up my university email and contact me, and I'll be happy to chat.
What can you do? The FCC never opened up a comment period on RO's filing for launch, so there's no official way to protest. They may open it up later? Absolutely no info on that.
DarkSky International is working on a petition to be delivered to RO's misguided investors, I will share that as soon as its public.
Most important: tell people about all the downsides of "sunlight as a service." The world needs to know how incredibly bad this idea is.
Batteries! We need batteries, not space mirrors.
This article by two astronomers details many of the points I just talked about and more ways that Reflect Orbital's plan will never be feasible, just detrimental: now in The Conversation Australia, perfect timing: https://theconversation.com/a-us-startup-plans-to-deliver-sunlight-on-demand-after-dark-can-it-work-and-would-we-want-it-to-264323
Adding to this Reflect Orbital thread: @startswithabang@mastodon.social wrote a thorough analysis of all the ways that Reflect Orbital is a terrible idea. Have a read! https://bigthink.com/starts-with-a-bang/true-cost-solar-power-night-reflect-orbital/
Have I mentioned how much I like Nicole Mortillaro? Great article, includes quotes from @JohnBarentine@scicomm.xyz (there were various good reasons why she didn't interview me for this one, but fortunately a lot of other astronomers besides me are really worried about Reflect Orbital's thoughtless plan)
https://www.cbc.ca/news/science/reflect-orbital-space-mirror-9.6947427
Reflect Orbital is stupid and will cause countless problems with no measurable benefits.
New article from Smithsonian Magazine about how stupid Reflect Orbital's plans are: https://www.smithsonianmag.com/science-nature/giant-mirrors-in-space-could-bring-sunlight-after-dark-one-startup-says-and-astronomers-are-concerned-180987781/
Features interviews with me and several of my excellent astronomer colleagues on the American Astronomical Society Committee for the Protection of Astronomy and the Space Environment! Looks like Reflect Orbital has followed SpaceX's lead and stopped responding to journalist inquiries.
I have doubts about whether or not change.org petitions actually do anything. But if you need to do something small right now against space mirrors, a DarkSky International member set up a petition here: https://www.change.org/p/stop-space-mirrors
DarkSky International just posted their position letter on Reflect Orbital. It is direct and to the point:
"Based on current scientific evidence, DarkSky does not see a viable pathway for such systems to align with responsible lighting principles or with our mission to protect natural darkness. These systems would introduce significant ecological, human health, safety, and astronomical risks at a global scale."
Read their letter and add your name here:
https://darksky.org/news/organizational-statement-reflect-orbital/
Prof. Sam Lawler