A Reconfiguration Strategy for Distributed Electronic Systems on ISS

verfasst von

Tim Oberschulte, Jakob Frederik Marten, Thijs Jan Wendrich, Matthias Raudonis, Holger Christoph Blume

Abstract

The Bose Einstein Condensate and Cold Atom Laboratory (BECCAL) is a physics experiment facility designed to research ultracold atoms in microgravity. It is planned to operate on the International Space Station (ISS) for several years, following the MAIUS sounding rocket missions. The large setup spans over five EXPRESS rack lockers and includes the main physics package, the laser system, and the control electronics. Within the ultra-high vacuum physics package, Bose Einstein condensates are generated using laser cooling and trapped in magneto-optical traps. Sensors and actuators distributed throughout the experiment are controlled by a control computer over a fiber-optical network.

Most of the electronics in BECCAL are custom FPGA-based boards, organized in a tree network topology. Communication from the control computer is routed through this precision timing network to the endpoints. These endpoints consist of stacked boards controlled by a master over a bus system, which has already been flight-proven in the MAIUS missions. Most of the boards contain an FPGA or a microcontroller to control peripherals, gather sensor data, and communicate with the bus.

The radiation environment in low Earth orbit consists of protons trapped in the Van Allen radiation belt and sporadic heavy intergalactic cosmic rays. Since BECCAL contains more than 100 FPGAs, using radiation-hardened devices is not feasible; instead, commercial off-the-shelf (COTS) devices are used. The radiation causes soft errors in the electronic components that must be handled. We demonstrate how error-detection architectures are employed into the FPGA fabrics, which report errors to the control computer via the network.

In this work, we present our strategy to recover the electronic system during operation in orbit. This includes the detection of radiation-induced errors and the subsequent notification of the control computer. Subsequently, reconfiguration of the FPGAs and microcontrollers is required. In our network, each node can reprogram all their following nodes via a JTAG interface. The stacked boards require a different solution, as JTAG typically operates in a chain through multiple devices and is incompatible with the bus infrastructure inherited from MAIUS. We have designed an improved bus structure that can reprogram FPGAs and microcontrollers and also communicate through a single interface. We show that this can be achieved with a small amount of additional hardware to the existing designs.

Organisationseinheit(en)

Fachgebiet Architekturen und Systeme
Institut für Quantenoptik

Externe Organisation(en)

Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)

Typ

Poster

Publikationsdatum

2024

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja