Advantages of Flexible Circuits for Space Applications

July 12, 2017 Altium Designer

planets in space
 

 

Sometimes people ask my why space travel is important. The answer seems obvious to me every night when I go to sleep. My pillow is made out of memory foam, which was developed by NASA. Their research efforts for space exploration have led to a host of other important discoveries and gadgets that we all benefit from today. Another useful technology that was originally developed for the aerospace industry is flexible circuits. Rigid flex and fully flexible PCBs have several advantages over traditional PCBs when it comes to flight around and Earth and far above it. Things like reduced weight and volume increased reliability, and more innovative design make flexible circuits a great choice for infinity and beyond. One particular material that highlights all of these advantages is Kapton®.

Lightweight and Low Volume

You might not think weight matters much in regards to space exploration. Everything is essentially weightless up there after all, right? Unfortunately, rockets and their payloads still experience gravity during liftoff. Carrying something from the ground into orbit is one of the most energy intensive parts of the whole process. Flexible circuits have low mass and take up less space than traditional PCBs, making them perfect for aerospace.

 

Flexible circuits are naturally lighter than a normal board. Instead of using a thick rigid substrate they are mounted on a thin film. Substrate weight savings are compounded as layers are added, which can result in up to 75% weight reduction. That may not seem significant, but when you’ve to pay for your own rocket fuel, every ounce matters.

 

Not only are flexible circuits lighter, they’re also smaller. Obviously a thin film takes up less space than a thick substrate, but the main volume savings come from flexibility. Whereas a traditional board needs a set amount of 3D space, a flexible PCB can be squeezed or folded into nooks and crannies. They can also be bent into unique 3D shapes and fill unused space. With enough creativity, you can save up to 60% space when compared to normal boards. Size matters because a larger payload means a larger, and heavier, launch vehicle.

 

Rocket launching
You don’t want to be carrying any extra weight during launch.

 

Reliability

When designing boards for space, reliability is hugely important. NASA launched Voyager One 36 years ago, and it’s still flying. Your circuits need to be pretty trustworthy if they’re going to be flying through space for 36 years. Flexible boards can withstand more dynamic forces than a traditional board, and they eliminate high failure interconnection points.

 

Spacecraft are subjected to all kinds of dynamic forces, primarily during takeoff.  Dynamic forces are the bane of traditional boards, with vibrations causing up to 20% of failures. Flexible and rigid flex boards are made to twist during operation and can flex thousands of times before failing. This will help flexible boards bend instead of break and keep working in harsh conditions.

 

Connections like solder joints, crimps, etc. are a major risk for failure as well. These attachments can also be broken by dynamic forces. Flexible circuits remove this risk by eliminating connections. Most of the connections on flexible boards are made within the substrate. For a connection to fail, the whole PCB would have to fail. Thus, flexible circuits almost entirely remove a point of failure for your board.

 

Satellite orbiting earth
Flexible circuits are perfect for deployable parts.

 

Versatility

The vacuum of space is a daunting place full of difficult challenges. Engineers need versatile components in order to overcome those obstacles. Flexible circuits provide physical adaptability that can allow designers to implement odd shapes and extensible parts on their spacecraft.

 

Sometimes it’s not convenient to jam a large rigid rectangle into a small area in a spacecraft. Flexible circuits can conform to whatever surfaces they’re mounted on. This means they can be mounted wherever they’re needed. Instead of running wires out from a central unit to far-flung sensor arrays, you could mount your circuit right next to the arrays.

 

Flexibility also comes in handy when you want to implement extensible parts. We’ve all seen things like deployable solar arrays on satellites. Just like dynamic forces and vibration can weaken traditional boards, extending and retracting parts can cause wear and tear on conventional wires and PCBs. You would usually be taking a risk by incorporating that kind of apparatus. However, since flexible circuits are made for just that kind of motion, you can use expendable equipment without fear.

 

Kapton®

Flexible circuits are made out of many materials, but one, in particular, is already widely used for space applications. Kapton® is a thin polyimide film that has already been used on multiple space missions for everything from heaters to solar cells.

 

One reason Kapton® is often chosen is because of its light weight. This has made it a primary choice for everything from cable insulation in rockets to heaters on rovers. Kapton® is also used because of its mechanical properties and vibration resistance. These help it keep things like solar panels and optical sensors safe during operation. This material exhibits all of the qualities that make flexible circuits useful for space travel, so it’s no surprise that so many space missions use it.

 

Whether you’re sending all the way to Mars, or somewhere closer like the International Space Station, you want to be sure your payload arrives at its final destination. Flexible circuitry will help minimize your spacecraft’s size and get it off the ground. It will also improve reliability, and give you more options when it comes to design.

 

Now that you understand why you should use flexible circuits, you need some PCB design software to help you make them. Lucky for you, Altium Designer has tools that can make flexible design easy. Altium will help you get your spacecraft off the ground in no time.


Have more questions about flexible circuits? Call an expert at Altium.

About the Author

Altium Designer

PCB Design Tools for Electronics Design and DFM. Information for EDA Leaders.

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