In 1993, Russia reflected sunlight from space. Now, a California startup wants to turn the night sky into a marketplace for on-demand sunlight from orbit

For centuries upon centuries, night came with the Sun and there was nothing to be done about it. Technology is currently changing this paradigm.

There is an aerospace startup in California called Reflect Orbital, whose satellites will reflect sunlight on Earth from space in specific points once the day ends.

The idea sounds quite sci-fi, yet the solution is rather simplistic - just create a huge reflective surface in space and use it to reflect sunlight.


Also Read | No signal underground: Scientists challenge a decades-old idea about how quantum reality breaks down. Schrödinger’s cat has a new problem

To see whether the concept works, the company plans to launch the satellite Eärendil-1, which would have the reflective surface of 18 by 18 metres in size to be unfurled in space and positioned so as to direct sunlight towards the Earth.

The technology will supposedly allow to create what the company calls "sunlight on demand". However, the concept has caused certain concerns among scientists and dark sky enthusiasts.

The problem is that if the concept works, it will mean that soon thousands of satellites will be sent into space to artificially create sunlight in the night.

A giant orbital mirror could put sunlight on the ground

Eärendil-1 will have an intended orbit at an altitude between 600 and 650 kilometres from Earth. After deployment, the reflective materials would be controlled using motors, giving the ability to direct sunlight.

According to the company's projections, the first satellite can provide an illumination zone of around five kilometers. As the satellite orbits around Earth at around 7.5 kilometers per second, the illuminated area would move along with it.

Also Read | Your cells’ tiny power stations may be doing something quantum: scientists find a mysterious vibration that could influence how the body produces energy


The satellite would not illuminate one spot continuously. The firm suggests that illumination would last for about four minutes, after which the satellite would be past the designated point.

The firm mentioned many possible uses of their satellite. Search and rescue missions can have more illumination during night time operations. Outdoor events might benefit from such satellites in providing temporary lighting. Also, solar power stations can benefit from the extended sunlight thanks to reflection.

The technology in itself is not entirely new. In 1993, Russia launched a space mirror called Znamya 2, which was used to reflect sunlight on Earth. The idea of orbital mirrors was also investigated by Americans during the Cold War.

However, what has changed now is the size of the commercial space sector.

Thousands of satellites are already changing the view above us

The mirror concept is arriving at a time when the space around the earth is becoming increasingly crowded.

Jonathan McDowell, an astrophysicist who keeps track of all manmade objects in space, has observed that the active number of satellites has increased from 2,000 in 2018 to more than 16,000 presently.

Satellite constellations have revolutionized both communication and internet access services but have brought along challenges for astronomy.

Telescopes sometimes capture satellite trails and it interferes with the observations of celestial objects such as planets, asteroids and other distant objects. Scientists using the Vera C. Rubin Observatory in Chile have been working on methods to overcome this challenge for many years.

The challenges of increased objects are not limited to astronomy; chances of collision increase with increase in objects and the defunct spacecraft and debris from rockets add up to the number of space debris.

What Reflect Orbital is proposing is a technology which poses an additional threat. It proposes to put in place satellites which do not simply reflect the sunlight which falls on them but are engineered to reflect the sunlight towards the earth.

This raises questions regarding the adequacy of regulations regarding this kind of commercial technology.

Scientists worry the light could spread beyond its target

Reflect Orbital says its satellite would be controllable and that the mirror could be turned away from Earth when illumination is no longer required.

Scientists, however, point out that light does not necessarily remain confined to a narrow beam once it passes through Earth's atmosphere.

Atmospheric molecules can scatter light in different directions. This is the same basic phenomenon responsible for the blue appearance of the daytime sky.

Research by astrophysicist Gaspar Bakos and colleagues examined how reflected light from a proposed Reflect Orbital satellite could appear under different conditions. Their simulations suggested that the illumination could produce a visible glow beyond the intended target.

The potential effects become more significant if the technology expands beyond a single demonstration satellite.

Reflect Orbital has discussed a future network of thousands of mirrors. The company has said it could eventually deploy 5,000 satellites by 2030 and 50,000 by 2035, with larger mirrors than the initial spacecraft.

Such a fleet could introduce substantially more artificial light into the nighttime environment.

Astronomers are concerned because even a relatively small amount of additional light can affect observations at dark-sky locations. Researchers studying wildlife have other questions, particularly because many species depend on predictable cycles of darkness for feeding, migration and reproduction.

Scientists stress that the ecological consequences of intermittent orbital illumination are not yet fully understood.

The bigger question is who regulates a brighter night

The dispute about Reflect Orbital mirrors also brings up another issue related to space regulation.

Space law evolved mostly during the Cold War, well before the commercial plans for extensive satellite constellations emerged. The 1967 Outer Space Treaty states that outer space cannot be appropriated by any nation state and must be used for peaceful purposes, and additional treaties deal with such issues as registration and liability.

However, it is not always easy to enforce it, especially when some commercial activities have environmental consequences which cross national boundaries.

In the US, different government agencies control different aspects of the space activities. Thus, the Federal Aviation Administration regulates launches and reentries, while the Federal Communications Commission licenses commercial satellite operations.

According to some critics, current approval procedures often consider each separate satellite without taking into account the impact caused by thousands of spacecrafts.

In the case of Reflect Orbital, it may raise awareness of this problem since the use of mirrors has an environmental component – adding light where it did not exist.

The company stated that it wants to collaborate with scientists and other parties, as well as create exclusion zones for astronomy and environmentally sensitive areas.

Whether those measures will be sufficient is still an open question.

FAQ

1. What does Reflect Orbital plan to do?

Reflect Orbital is creating a satellite using reflective surfaces that will aim sunlight towards certain regions on Earth after sunset.

2. What are the potential uses of on-demand sunlight?

According to the company, its proposed uses include emergencies that occur during nighttime, outdoor events, and even extending the operational hours of solar energy plants. All of these are still proposals made by the company and not actual services.

3. Is there any chance that orbital mirrors can harm astronomy?

Yes, they can. The reflected sunlight and light scattered by the atmosphere would add extra brightness outside the intended area. This is a problem feared by astronomers.

4. Will Reflect Orbital deploy thousands of mirrors?

The company has said that it plans to create a far greater constellation in the next few years if the technology becomes successful. This means that thousands of satellites could be launched in the next few years.