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Have you noticed how 3D printing has become a phenomenon? People seem to want to 3D print anything they can now. Maybe the 3D printing craze will collide with the Internet of Things and we’ll get a printed smart fork. While other people are writing about the 50 best things you can make with them and then throw away, I’m going to tell you how NASA hopes to use 3D printing. Spoiler alert, they want to print spacecraft and circuits. NASA has laid out a scientific mission that details exactly how and why they would use printed circuits. They have also reviewed the current technologies that could make that future a reality.
How NASA Missions Can Use Printed Circuits
The final frontier is an extreme environment that requires extraordinary innovation to explore its reaches. NASA has pulled off lots of incredible missions in the past, but as we move further into space travel they’ll need even more advanced tools to complete their missions. Flexible printed circuits are one technology NASA is looking at to help them reach their lofty goals. Their theoretical StANLE mission was planned in order to showcase why printed circuits would be advantageous and how they might look.
The StANLE mission was thought up to illustrate the potential of printed spacecraft. When I first read “printable spacecraft,” I thought they wanted to print a space shuttle. It turns out these vessels would be more like sheets of paper to be used primarily as meteorological stations. These sensor arrays would be jettisoned over a huge area in order to collect things like temperature, pressure, wind speed, radiation, and humidity.
NASA isn’t talking about printing these.
In the past, NASA has used things like rovers to study other planets. A 3D printed system would have several advantages over that kind of mission. Rovers can be quite advanced, but travel slowly and can only take data in one area at a time. They also carry a greater risk of failure since all their components are centralized. A major failure in one system could cause the whole rover to fail. Alternatively, using thousands of discrete sensors over a wide area spreads the risk of failure out over thousands of units while collecting large amounts of data. Flexible circuits themselves also carry several advantages, particularly their low weight and small size. Those two attributes are what would allow this kind of mission to theoretically be successful. NASA compared the weight budget of this mission with a more traditional one (564 kg), which would just have one lander. They found that even with a payload of thousands of circuits, this mission would still fit the same weight budget. With this kind of arrangement, they could deploy thousands of lands over thousands of kilometers, instead of using just one station.
You’re probably wondering what these printable spacecraft would actually look like? It turns out they would look basically like a piece of paper; one big flexible circuit. This PCB would be made up of components like an antenna, microcontroller, analog to digital converter (ADC), battery, solar cells, temperature sensors, radiation sensors, photo sensors, pressure sensors, humidity sensors, and wind sensors. Some of this technology is currently available in a flexible format, but not all of it. That’s why NASA then looked into what printable circuit technologies it would take to make this mission a reality.
Flexible printed circuits will look more like this.
Technology Readiness Levels
NASA develops and utilizes cutting edge technologies. To help organize those efforts they have developed a rating system of technology readiness levels (TRLs). The highest TRL is 9, which means something has been flight proven. A TRL of 1 shows that a technology is only in the beginning research stages. In order to give us a better idea of how viable the StANLE mission is, NASA looked at TRLs of each printable piece. NASA needs these components to be ready by 2020. Since each of them have commercial applications and are currently being researched, it’s likely they’ll make that deadline. I’ll talk to you about one of the parts that is halfway ready, and one that is still in initial research.
One piece of the puzzle that is nearly complete is the temperature sensor. Not only do flexible temperature sensors already existed, printed ones do as well. The sensors NASA is looking at are printed with silver nanoparticle ink, which can last for the duration of the mission. Current top of the line sensors can operate between -263℃ and 27℃ with a resolution of 0.1℃. NASA feels that these attributes meet their requirements for range and sensitivity, so this sensor is well on its way.
Things are not always so simple, though, and other components need more work. The microcontroller could be the hardest piece to make fully printable. Printed microcontrollers do exist, but they’re very slow. A StANLE spacecraft’s microcontroller would need to control read/write to the memory, regulate power, and poll sensors for data. NASA could reduce functionality to meet the technology where it is, but that’s not a great solution. Instead, they hope to use a hybrid of a flexible thin film microprocessor. It won’t be printed, but it would still be flexible and fit in with the overall spacecraft design.
NASA hopes to have this mission ready to go by 2024, which means the technologies involved need to be ready around approximately 2020. I’m not sure if all of these systems will make it, but I hope they do. The theoretical StANLE mission shows how useful printed flexible circuits could be. They could expand the range and reduce the risk of current space missions without adding weight or volume. Now we just need our research labs to keep pumping out printable sensors and other printed PCB components.
This NASA mission clearly shows that the future of circuits will be both printed and flexible. You’re going to need to learn how to use flexible circuits, and also how to design them. Lucky for you great PCB design software like Altium Designer can help with that. Altium Designer has lots of tools that can help you with flexible design.
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