Source: The Conversation (Au and NZ)
A US startup has booked two Indian rocket launches to test a planned service no company has sold before: sunlight at night.
California-based Reflect Orbital plans to place giant mirrors in low-Earth orbit, and use them to steer reflected sunlight onto selected locations on the ground.
The company wants to sell space-based illumination for a wide range of purposes, from keeping solar farms generating energy after sunset to search-and-rescue operations. Its first orbital demonstrator, Eärendil-1, will carry an 18-by-18-metre reflector.
Using space mirrors to deliver useful illumination will require overcoming formidable engineering challenges. But there’s another pressing question: who will decide where sunlight redirected from space is allowed to hit the ground?
The light does not stop at the edge of the beam
You might think a space mirror could illuminate a customer’s solar farm or a rescue site while leaving everywhere else untouched. That’s not quite how it works, because Earth’s atmosphere doesn’t respect sharp boundaries.
A peer-reviewed scientific study published last August modelled what happens when reflected sunlight passes through our atmosphere. Molecules and aerosols scatter some of the light beam across the surrounding sky. Light reaching the ground is reflected upwards and then scattered again.
This means the light can affect a much wider area than intended. For a proposed future 54-metre mirror, the study’s authors found that the resulting sky glow could remain substantial well beyond the target area. At 14 kilometres from the beam, it could be brighter than a full Moon across most of the sky. Even 34km away, the sky glow towards the beam could still be brighter than under a full moon.
These are predictions from a model, not measurements from real space mirrors. Still, they expose the unresolved regulatory problem: the people affected may not have ordered the light.
That matters to astronomers, of course, but also more broadly. Reflected light affects natural darkness over an area that may be much larger than what the customer is actually paying for.
In response to questions from The Conversation, a spokesperson for Reflect Orbital wrote
Most people and most places will never see this light. Customers will require permits, local authority sign-off and Know Your Customer compliance to receive the service. Every service will require multi-layer approval – and if people do not want the light, they will not receive it.
So who regulates the light?
The first regulatory test has already exposed an important technical gap.
In July, the US Federal Communications Commission (FCC) authorised Reflect Orbital to deploy and operate Eärendil-1. But its licence only addresses radio communications, specifically the use of specified frequencies for satellite telemetry and control.
Astronomers asked the FCC to impose safeguards mitigating optical effects. The commission declined, concluding that astronomy was outside the scope of its rules.
The American Astronomical Society and others have since challenged that decision.
Now India enters the picture
Reflect Orbital’s new deal with India’s Skyroot Aerospace covers two dedicated launches, using the Vikram-1 rocket and the in-development Vikram-1U.
This means India may now have to confront the question the FCC largely sidestepped. A launch from India requires authorisation through the Indian National Space Promotion and Authorisation Centre, IN-SPACe.
Its rules cover launch safety, registration and environmental impacts. They specifically require limitation of negative environmental effects (on Earth or in space), as well as adverse changes to the atmosphere.
As yet there is no publicly available authorisation showing how IN-SPACe would treat deliberately reflected light.
It is unclear what jurisdiction should regulate the space reflector. Reflect Orbital is American. Skyroot and the launch site are Indian. The spacecraft could illuminate territory in a third country. And atmospheric scattering means the effects could extend well beyond the intended target area.
Neither the US nor Indian regulators have so far addressed light from space. That leaves questions extending beyond launch authorisation.
If a commercial operator wants to illuminate a site in another country, do that country’s authorities need to agree? What about a neighbouring community or observatory affected by scattered light? And if the effects cross national borders, which regulator could require a space mirror operator to change its behaviour?
These questions will become much harder if they are left until reflected sunlight becomes a commercial service, rather than an experiment.
From experiment to service
None of this means Reflect Orbital should necessarily be prevented from demonstrating its technology. In fact, Eärendil-1 could provide real data for regulators: measurements of brightness, atmospheric scattering and how accurately reflected light can be controlled.
Reflect Orbital says it will continue to work with astronomers, communities and regulators as it scales up its tests.
In the meantime, governments must decide who gets to turn on the light – and who gets to object when some of it inevitably travels beyond the customer’s fence.
Richard de Grijs is a member of Astronomy Australia Ltd’s Astronomy–Space Coordinating Committee. He is a former Executive Director of the International Space Science Institute–Beijing.
Original source: https://analysis1.mil-osi.com/2026/10/25/an-american-startup-wants-to-sell-sunlight-after-dark-who-gets-a-say/