The Complete Guide to Solar Sails

Posted 12 months ago by Kami

Solar sails are a topic that fascinates many people.

The concept of how they work is often confusing to those who have never heard of them before, and it can be difficult to grasp how they could possibly generate thrust without any fuel.

Lucky for you, in this article will answer all your questions from how do solar sails work to what are the advantages and disadvantages of solar sails.

What Are Solar Sails?

Solar sails are large, ultra-thin mirrors that are pushed by the pressure of light photons on their reflective surface.

These types of sails can harness energy from solar winds to move through space using only sunlight.

How Do Solar Sails Work?

Solar sails are pushed by the pressure caused by photons striking them from all directions at once.

When a photon strikes an object with mass it exerts a force on that object in accordance with Newton’s Laws.

This force is so minuscule that it can only be observed when the object in question has an extremely large surface area.

For example, a 100 square meter sail would have to move at about 1000 km/hour before radiation pressure could overcome its inertia and start pushing it forward.

This effect is how do solar sails work! The more photons that hit the sail, the higher amount of thrust generated by this propulsion system.

What Are The Advantages Of Solar Sails?

The advantages of solar sails are enormous.  

They cannot be exhausted, run out of power, or explode as chemical rockets can.

And because they use no fuel at all, once the initial investment has been made in building them, their cost per unit is much lower than similar propulsion systems that require fuel.  

For instance, it costs about $20,000 to launch a one kilogram payload into Earth orbit using chemical rockets.

Solar sails, on the other hand, once the initial investment has been made, it would only cost approximately $100 for that same amount of mass!

While they cannot accelerate objects very fast at first, solar sails work faster and faster with every kilometer they travel.

This means that with enough time, light pressure can eventually propel objects to speeds close to 55 km/s (100,000 mph).

What Are The Disadvantages Of Solar Sails?

While the advantages of solar sails are many, there are a few disadvantages that must be considered.

For instance, it is very difficult to get them started in motion due to their low initial thrust.

In order for this propulsion system to generate any noticeable momentum, it has to travel through space far from the Sun.

It also has to be constructed out of extremely lightweight material in order to have any chance at all of catching enough photons before it gets fully underway.

What Is A Solar Sail Made Of?

Solar sails are typically constructed out of either aluminum coated plastic or mylar.

Although there is some research being done with solar sails that use graphene, this material has not yet been used to construct an actual working sail because it degrades too rapidly when exposed to the harsh environment outside Earth’s atmosphere.

How Fast Could Solar Sails Go?

The velocity that a solar sail can reach is largely dependent on the amount of solar wind it gets, surface area, and the material its made of.

If the sails are made out of graphene, this propulsion system could travel at up to about 18 kilometers per second (55,000 mph).   

That’s fast enough to get from Earth to the moon in just two hours!  

How Far Can Solar Sails Travel?

Solar sails are great at traveling long distances because of how do they work.

Although the thrust generated is minuscule, if the sails were large enough and traveling at high speeds they would eventually reach a considerable velocity.

A solar sail could travel from Earth to Mars in just over 200 days using only light pressure as its engine!

How Big Are Solar Sails?

Solar sails are very large.

The materials used to make them are lightweight, but not so much that they can easily be folded up into a small enough size for rocket travel.  

An average solar sail is typically about 100 meters by 100 meters (330 feet by 330 feet).

What We Can Use The Solar Sail Technology In?

Solar sails aren’t strictly for propulsion though; they can also be used for other purposes.

For example, they can be used to orient themselves towards the sun for thermal management like how do solar sails work.

They could also use their reflective surface as a light collector and power source or even reflect lasers between each other in order to communicate! The possibilities are endless with solar sails.

Additionally, they are perfect for picking up objects and moving them to new orbits, or even placing themselves into orbit without any kind of external force.

Last Words

The new solar sail technology is truly incredible.

Although they are extremely difficult to design and build, once you have them in place there’s almost nothing that can stop them from doing their job!

I hope this article has helped anyone who may be interested in how these amazing propulsion systems function.

Do you have any questions about solar sails?

If so, please share your thoughts with us in the comments section below and stay tuned for more amazing articles from our team at Solar Energy Hackers.

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A passionate solar energy engineer and environmentalist who loves to create content.