Space reflectors also known as space mirrors, a form of solar radiation management [SRM], are sun shields positioned in space to reduce the amount of solar energy reaching the earth.

Space reflector is an idea that has been in constant development. The earth absorbs up to 70% of the solar rays that are emitted from the sun. The absorption of heat causes the earth the release infrared radiation that is trapped in the atmospheric layers by greenhouse gases which in turn increases the overall heat of the earth resulting in global warming.

Scientists & researchers have been trying to come up with novel solutions to combat global warming. Space Reflectors are one of the solutions that have been proposed for this global problem. Space reflectors can be placed between the sun & the earth can help deflect some of the solar radiation from the earth which will help decrease and cool off the overall temperature of the Earth. 

A space reflector which would consist of one large space mirror or a fleet of smaller mirrors was proposed to be kept in Lagrange point L1. The L1 point is a region where the gravitational forces between the sun & the earth cancel each other, allowing any object to stay in place.

Space reflectors are expected to block out approximately 1.8% of solar rays from coming to earth, however, the adverse effects that Space mirrors might have on earth are still unknown and the complexity of deploying and maintaining space reflectors is still being evaluated.

Deployment Logistics

The deployment & maintenance of a fleet of small space reflectors that can create a shade of around 100,000 km in space would include factors such as construction, transportation, energy & ground support operations. 

The deployment of either one large space reflector or a fleet of smaller reflectors will also contribute to millions of space debris parts orbiting around the earth. Most debris would be small however depending on their speed, such debris will be catastrophic for operational satellites if they were to collide. Additionally, if a very large space mirror is to be deployed, its massive surface area will also pose as a target for other space debris from other decommissioned spacecraft & satellites that might orbit around. Hence, the maneuvering of hundreds of space mirrors or a large space mirror will prove to be very difficult to sustain due to space debris and the humungous size of the mirror

High Expenditure & Maintainance

The estimated cost of constructing and sending a fleet of space reflectors to space is around 750 billion dollars. Even if the space mirror can achieve a 50-year lifecycle, the annual maintenance cost would be around 100 billion dollars. Furthermore, if an individual satellite is required to be replaced at the end of its lifecycle, the cost of the entire replacement operation would be around 5 trillion dollars

Unintended Climate Changes

The direct reflection of solar energy away from earth by the space reflectors will have certain adverse effects on Earth’s climate. As per the function of solar reflectors, due to the deflection of solar radiation, the earth will cool down, however, this will result in unpredictable weather patterns. An overall sudden drop in the global temperature will increase the intensity of droughts and flood due to the disturbance in the hydrological cycle which determine the continuous flow of water on, above, and below the surface of the earth. Furthermore, the change in temperature and climate will also affect the cultivation of crops negatively, further hindering our food sources.

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