USB standard for satellites? Slingshot 1 flies into orbit to test one – Root Devices

The testing of new satellites and space technologies has never been done before easy exactly, but it sure could be easier. Slingshot 1, the 12U Cubesat mission that just launched via Virgin Orbit, is an attempt to make building and testing a new satellite as easy as plugging a new keyboard into your computer.

To say it’s a “USB for space” is an understatement…but not a misnomer. The Aerospace Corporation team that designed the new system draws the comparison themselves, noting that the military has tried to create just that many times with Space Plug-and-Play Architecture (SPA), which became Modular Open Network ARCHitecture (MONARCH). . ) and Common Payload Interface Standard (CoPaIS). But the approaches did not take hold, for example the Cubesat standard, which, by the way, was also pioneered by Aerospace.

The goal of Slingshot 1 is to create a standard satellite bus that is as flexible and easy to use as USB or ATX, using open standards, while meeting all the necessary requirements in terms of security, power and so on:

[Slingshot] offers more agility and flexibility in satellite development using plug-and-play modular interfaces. These interfaces take advantage of open source systems to avoid proprietary lock-ins that could halt development, as well as standardized payload interfaces that do not require a custom satellite bus. These interfaces define the power, commands, control, telemetry, and mission data that may be required for the payload. Without a set of common standards, these carrier-to-satellite requirements are driven by different satellite bus manufacturers. Slingshot addresses this uncertainty by reducing the number of requests and complexity in the interface and creating an open UI standard called Handle.

How will it avoid the common pitfall faced by would-be standardizers perpetuated by XKCD: there are now N+1 standards?

Well, leaving aside the rather sorry state of standards in the satellite world, if you can even say it exists at all, the team decided to base the whole thing on Ethernet, which already supports a huge number of networks in the world.

“The foundation of the Handle on Ethernet standard is based on an extensive ecosystem of hardware and software tools developed for this very common interface, essentially taking the most common terrestrial system standard and porting it for satellite use,” said Dan Mabry, senior engineering specialist at Aerospace. “We’ve optimized the network for low power consumption, but still support gigabit-per-second communication between devices, eliminating the need for custom software development to adapt the network for each new application.”

And as he said when Aerospace wrote the Slingshot for its own purposes last year: “Once the payload is attached, it will be immediately recognized and operational, and all transmitted data will reach the spacecraft downwind without any tweaking or software tweaking. on board. In addition, since it is an embedded network, the data of this payload is also visible to all other payloads. Payloads can easily interact in real-time, and distributed smart sensors and processors are connected to the underlying architecture.”

Combine that with a power hub that can intelligently meet different needs, and a modular case that makes the whole thing look like the back of a well-organized gaming PC, and you’ve got a plug and play recipe that really makes things easy for the would-be designer.

Assembled layout of the Slingshot 1 without the outer case.

Hannah Weiher, Slingshot Program Manager, said: “It strives to reduce interface complexity and support a variety of satellite buses and payloads with minimal or no interface customization. Handle was instrumental in streamlining the payload integration process on Slingshot 1, where we had a wide range of payloads with different requirements, and allowed us to integrate the amount of payload we did into a satellite roughly the size of a shoebox.”

Of course, it’s not enough to simply ship a barebones interface—imagine shipping a computer case with nothing inside. To see if it works, you need the stuff attached, and luckily Aerospace has saved a ton of effort and performance since the Slingshot was created in 2019.

  • Handle – Plug-and-play electrical interface module
  • Bender – Built-in Ethernet and network routing
  • t.Spoon – Modular mechanical interface
  • t.Spoon Camera – Plug-and-play camera module
  • t.Spoon processor – Zynq Ultrascale+ embedded processing
  • Starshield – Built-in malware detection
  • CoralReef – Coral tensor processing unit
  • STarfish – Secure ARM Cortex-M33 embedded processing
  • SDR – software defined radio (SDR) downlink
  • Keyspace – Cryptographic services for SmallSats
  • Lasercom – Space/Ground Downlink
  • ROESA – Using IoT protocols to connect cargo
  • Vertigo – A reconfigurable attitude control system
  • Blinker – GPS transponder for space traffic management
  • Hyper – SmallSat thruster with hydrogen peroxide
  • ExoRomper – A test rig for artificial intelligence and machine learning

Some of these are more or less self-explanatory, such as the various t.Spoon components that make up the central mechanical elements that tie the whole thing together. And of course you need a good software defined radio downlink. But a tensor processing unit and machine learning testbed on a satellite? IoT protocols? Cryptographic services?

CG view of the Slingshot expanding to show its components.

When I spoke with the team while visiting Aerospace’s labs a while back, they talked about how a lot of what’s on Slingshot is unprecedented in some ways, but it’s more about adapting normal ground tasks to the extremely formalized and constrained context of a satellite system . hardware and software.

Let’s say you have three or four workloads sharing CPU and storage. How do you ensure that their communications remain secure? The same as on earth, but adapted to the light processing, limited power and strange interface of the spacecraft. Sure, secure processing and communication in space has been done before — but it’s not like there’s a plug and play version where you can just click a checkbox and suddenly your cargo is fully encrypted.

It’s similar to the ExoRomper, which has an externally mounted camera attached to the TPU. There’s been some artificial intelligence in space before, but never a setup where you can say, oh sure, you can add cloud recognition to your satellite, it’s going to use 2 watts, 20 cubic centimeters, and 275 grams. This one in particular is set up to watch the satellite itself, looking at lighting conditions – something that seriously affects heat loads and power handling. Why shouldn’t your satellite have its own satellite to make sure there are no hot spots on the solar cells?

Data will come from Slingshot as it tests its many components and experiments over the coming months. This could be the start of a new modular era for small satellites.

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