Even though the Defcon security conference has moved entirely online the year, the US Air Force is going forward with Hack-a-Sat, a months-long competition that culminates with hacking a real orbiting satellite starting on Friday. But another project at Defcon's Aerospace Village this week should have at least as much impact and a potentially much broader reach: an open source satellite communication tool made from about a hundred bucks worth of hardware.
The project, dubbed NyanSat, isn't just a workaround for a remote conference. The goal is to make low-earth-orbit satellite communication technology much more accessible and swap out the massive, specialized transmitters, antennas, and radio dishes that go into satellite ground stations for open source software and an affordable hardware kit. NyanSat ground stations aren't refined or powerful enough to replace the real deal, but their strength lies in their potential ubiquity. With one of the devices up and running, you can point NyanSat's antenna to specific coordinates in the sky and listen for the radio frequency transmissions coming from a satellite that's out there.
"We designed this as a sneaky sidestep to make something inexpensive enough that everyone can have it," says Ang Cui, CEO of the embedded security firm Red Balloon Security, which designed the NyanSat project in partnership with the Air Force and Defense Digital Service. "The innovation here is we're using a cheap IMU—inertial measurement unit—to orient the antenna without having to use expensive motors and controls. It's the same type of instrument used in drones for orientation and navigation. We want to engage as many people as possible with something hands-on and get them interested in DIY space projects."
Out of the box (so to speak), a NyanSat ground station knows its location through GPS and its orientation through the IMU. When you input specific coordinates, it will mechanically move to point its antenna toward them. Red Balloon is also offering an application programming interface that allows you to easily program a moving path, allowing you to choreograph movements so the device follows a satellite as it orbits. From there you can start listening to what satellites are transmitting. For example, you can sync up with the National Oceanic and Atmospheric Administration's weather satellites to essentially livestream high-resolution black and white images of Earth or listen in on what's coming from any coordinates in the sky.
Red Balloon researchers designed a custom motherboard, called Antenny, for NyanSat ground stations. The schematics are open source so anyone can make their own, but the team has been selling the boards and other equipment as a kit for $1. The hardware in the kits costs closer to $100, but Cui says that since Red Balloon isn't paying to send researchers to Defcon this year—and won't be throwing its annual poolside networking event—NyanSat kits are a way to give a gift to the open source community instead. So far Red Balloon has sold about 65 kits and is working to put more of them together in batches of about 50. Cui says his colleagues recently detected a bot someone wrote to automate purchasing the kits as soon as they come back in stock, so there seems to be at least some pent-up demand.
The more NyanSat ground stations are out there, the more they can do together, communicating with known satellites or even probing the more stealthy or unknown objects orbiting Earth. Individual NyanSat base stations don't have to work as part of a collective and share data, but in many ways the devices have more potential as part of community research than as individual instruments. There's already an active Discord channel where people are getting their base stations up and running and discussing ideas for long-term projects.
"Let’s say we have 1,000 of these base stations distributed across North America," says Cui. "If you could shine a radar beam into the sky not knowing if something is there or not, the chances that it's reflected back to you, the sender, would be astronomically small. But if we have thousands of base stations all listening, they could amplify and correlate from whichever station hears the bounce-back to find debris or other objects you wouldn't know are up there."
While the NyanSat project promises an impressively cheap ground station, it isn't the only way to hunt for space debris or undocumented satellites in orbit. Groups of amateur observers have been tracking spy satellites for decades. There's precedent, too, for creating a low-cost, decentralized, open source ground station networks. A project known as SatNOGS, founded in 2014 during the NASA Space App Challenge hackathon, does similar work and has more than 360 deployed ground stations around the world. SatNOGS is run through a larger organization called the Libre Space Foundation. The ground stations cost between $300 and $500 to build. Cui says that he hopes the NyanSat and SatNOGS communities will overlap, since all of the software and schematics for both projects are open source and could augment each other.
"Although indeed there seem to be some similarities, there are many differences regarding the scope of our respective projects," says Pierros Papadeas, director of operations for the Libre Space Foundation. "That said, we would wholeheartedly welcome as many open source projects and implementations of any part of the full satellite communications technology stack, since it could only mean more collaboration opportunities and a chance to broaden the open source space ecosystem. We can't wait to get our hands into a NyanSat kit and hack it to run SatNOGS client."
In addition to the low-cost ground stations, the Red Balloon researchers also collected equipment to build a mobile, military-grade ground station that can serve as a sort of queen bee for the NyanSat hive. The device is a weather-sealed, military spec antenna station designed to mount on a Humvee for satellite communication—the kind of thing that would come in handy in a disaster zone. The ground station transmits on a microwave frequency band reserved for satellite communication called the Ku band, and unscheduled transmissions from a ground station of its power would be illegal, as regulated by the Federal Communications Commission. But the researchers will run a livestream during Defcon showing the ground station's parts and how it's constructed to offer a deeper understanding of what goes into a high-precision and accuracy ground station—very different than the cheap components in a NyanSat ground station. Participants will also be able to control the station remotely, with limitations on transmitting, and listen in on satellite transmissions with more range and clarity.
"Pretty amazing what you can buy in mint condition for $1,600 from liquidators in New Jersey," Cui says.
Or a lot less, if all you're after is a little low-key community satellite tracking from NyanSat.