The last big event we attended was the AAS (American Astronomical Society) meeting January 2020 in Honolulu, where we exhibited our Viewpoint satellite model. Of course, it was a few months later that Covid-19 started to affect the world. We stopped going to conferences, and stopped all in-person meetings. It feels like life now is slowly getting back to normal, at least here in the USA. We have attended two conferences in the last few months, an SPIE conference in San Diego and the Space Tech Expo in Long Beach.
Although the pandemic slowed things down, it hasn't stopped us from continuing work on our Viewpoint satellite. All design work is done on computers these days, and we've adjusted to remote work and remote collaboration. As long as we have fast Internet connections, we can still work with our aerospace partners. We have been working on various project proposals with our aerospace partners for customers interested in our Viewpoint satellite. We did have a change in mindset -- we initially wanted to build our own constellation of imaging satellites, but now we are perfectly willing to sell our satellite to outside customers who want to buy one (or more than one).
One potential customer was interested in a constellation of Viewpoint satellites, and we talked to them during most of 2020. Unfortunately, their country's economy was hit hard by the pandemic, and everything stopped by the end of 2020. Discussions have started with a new potential customer, also for a constellation of Viewpoint satellites. We hope that discussions will continue in a few months.
As a result of our customer discussions, we feel strongly that our Viewpoint satellite has the right features. Because it is easily extendable, we have added two cameras which were not part of our smaller Waypoint imaging satellite. So far, the customers have been looking for Earth observation satellites, so we've made sure that the Viewpoint satellite is an excellent multi-purpose imaging satellite. Our earlier Waypoint satellite had a large 48 megapixel imager, for instance, but in the Viewpoint satellite, we've changed to a 152 megapixel imager. In fact, the design now has two of the 152 megapixel imagers, one of them a monochrome imager and the other one with on-chip RGB color filters. We added a moving mirror to allow long strip mode Earth imaging, allowing the Viewpoint to image about a million square kilometers a day, either in monochrome or in color.
We also upgraded the low noise UV capable imager from 10 megapixels to 37 megapixels. And we added a new 1.3 megapixel short wave IR (SWIR) camera that can sense SWIR out to a wavelength of 1.7 microns.
We have ensured that the Viewpoint satellite uses export approved components and has export approved capabilities. The 50 cm diameter mirror is the largest telescope mirror that can be export approved for Earth observation. We have also restricted the hyperspectral camera to 39 spectral bands, while providing very high resolution (1.5 meter) to conform with export regulations. (For more than 39 bands, the resolution would have to be degraded 30 meters.) Finally, we have removed the control moment gyros and will be using standard momentum wheels.
The title of this posting is "3D Printed Satellites". In addition to all the improvements we've made to the Viewpoint satellite, we've also decided to 3D print large amounts of the satellite. We'll be doing this for cost reasons and for improved performance. We couldn't find the perfect 3D printer, so we invented our own.
There aren't many choices for types of 3D printers that can print out parts for a satellite. Resin type 3D printers can't print strong engineering grade plastics. Metal 3D printers are very expensive and can't print very large parts. Filament based 3D printers can print large parts, can print with engineering grade plastics that won't outgas, but we want to print large parts with a mix of metals and plastics all in the same part. Such a 3D printer doesn't exist.
We've been working on just such a 3D printer. It will be able to print a mix of metals, not just one metal. It will also be able to print a mix of plastics. And it will also be able to print ceramics. It will be able to print all these types of materials all in the same part. We see that such a 3D printer can be used to print strong structural components, light and strong light baffles and other large optical support components, and many others.
One key to building this "omni-material" 3D printer is to have a laser controller that modulates the laser power very precisely, able to adjust the power as the laser beam moves over the 3D printed material so that a consistent amount of power is delivered even as the laser beam is accelerating, decelerating, or changing directions.
In the picture above, we have a fiber coupled 30 watt laser diode module. The laser is about 40% efficient at best, so circuitry must deliver up to 75 watts of electrical power. The laser driver circuitry is similar to the laser driver we have developed for our optical communications. Since we don't have to worry about operating in space (at least not this version!), we can use water cooling to keep the laser diode cool. We've finished assembling our first laser control board prototype, and will be testing soon, right after we finish programming the FPGA and writing some software.