Slingshot-1 Spacecraft

Advance on-orbit experiments using modular and autonomous technologies on next-generation satellite systems with SatCat5.

Program named Slingshot, which looks to advance on-orbit experiments using modular and autonomous technologies on next-generation satellite systems. In essence, Slingshot looks to simplify the architecture with open standards and plug-and-play interfaces to streamline bus-to-payload, satellite-to-satellite, and space-to-ground communications.

A key feature of the Slingshot platform is the use of SatCat5, an open source mixed-media ethernet switch architecture that enables a variety of devices to communicate on the same network. Unlike other existing standards, such as CAN and SpaceWire, SatCat5 is able to simultaneously provide high throughput and low-power consumption using ethernet technologies and an end-to-end payload development kit.

Slingshot also uses one common bus-to-payload interface, providing a reusable standard that can eliminate the ad-hoc proliferation of complex, dissimilar protocols that have historically bogged down connectivity and driven up costs.

Slated for launch in early 2022, the Slingshot 1 mission aims to prove the feasibility of providing a standard interface for multiple payloads on a single spacecraft flying in low Earth orbit. In addition to providing access to an on-orbit space test environment, the mission will demonstrate the capability of the SatCat5 ethernet standard, which would allow developers to employ commercial tools and open-source code from the extensive ethernet ecosystem.

In a further bid for increased satellite autonomy, the Slingshot 1 mission will also test the functionality of:

• VERTIGO – A modular attitude control system prototype that can enable satellites to point at targets on earth.
• BLINKER – A GPS transponder for space traffic management.
• HYPER – A hydrogen peroxide thruster.
• LASERCOMM – A next-generation space/ground lasercom downlink.

The Blinker v1 on Slingshot-1 demonstrated the concept of a earth bound ground station querying a standalone device appended to a satellite. The 100 KB downloaded each day included GPS fixes taken every 15 minutes. Those GPS fixes were converted into an ephemeris with a position accuracy of 10’s of meters. The satellite attitude was not modified to accommodate either the GPS antenna or the ground antenna – the satellite acted as if Blinker was not there.

However, a tumbling satellite would have been a better example of the robustness of Blinker – that test will have to wait for the decommissioning of the Slingshot-1 later in 2023.

The LED experiment on Blinker v1 demonstrated that 260 lm from a diode with 120° divergence at a range of 500 km is visible as a 10.5 magnitude star. The electrical power to operate the diode subsystem was 6 watts. The test further showed that a modulated signal can be clearly isolated from the background when a fast Fourier transform is done.

Both Slingshot-1 and Blinker v1 are operating nominally as of this writing. The goal of the flight test was to demonstrate Blinker in an operational configuration, and to raise its TRL.

In parallel, development for Blinker v2 is underway. It is a modest effort to fabricate a lower size, weight, and power version achieved by producing a single circuit board with the functions of Blinker v1 efficiently combined. Blinker v3 is a still future iteration that would require a partnership with an electronics manufacturer to further reduce the footprint of Blinker to a size and power that is truly inconsequential to add to going into low earth orbit. The experiment also confirmed the utility of LED payloads for satellite optical tracking and their applicability to Space Traffic Management operations.

• PLATFORM - Blue Canyon

[1]

• CTIM FD
• GPX-2
• Gunsmoke-L
• MISR-B
• NACHOS 2
• Recurve
• Slingshot-1