Drive Electronics for Satellite Mechanism Management

The Multi-Purpose Drive Electronics (MPDE) is a versatile two-axes stepper motor controller designed for high performance and smooth mechanical operation in satellite applications. It is capable of operating various types of mechanisms such as antenna pointing mechanisms, solar arrays, or thruster pointing mechanisms.

Optimized for low micro-vibration operation, the MPDE is compatible with a wide range of actuators and available for different power bus voltages. This makes it a flexible solution for diverse satellite applications.

The MPDE comprises two electrically identical units intended for cold redundancy operation. Each unit features an isolated DC/DC converter and a control module, controlled via a MIL1553 TC/TM interface. This interface can be replaced to adapt to different satellite platform concepts, enhancing the flexibility of the MPDE.

The main feature of the MPDE is its high flexibility, large degree of autonomy, and high drive performance, accommodating a wide range of drive applications in satellites.

The Core Drive Electronics (CODE) is a compact and lightweight two-axes stepper motor controller, optimized for small volume and low mass. It is capable of operating various types of mechanisms such as antenna pointing mechanisms, solar arrays, or thruster pointing mechanisms, making it a versatile and cost-effective solution for small satellite applications.

Manufactured in a modular way, the CODE allows for independent control of two bipolar stepper motors per module. Two modules can be stacked vertically to form a redundant unit or to increase the number of drive channels, offering flexibility in configuration. The modules are mechanically separated and operated in cold redundancy for enhanced reliability.

Each CODE module contains an isolated DC/DC converter with EMC filters, providing a protected, hardware-adjustable motor drive voltage. This ensures high operational reliability. Each of the two stepper motor interfaces has its own dedicated connector, housing the motor power signals and 7 additional mechanism signals.

These signals are directly routed to the common control connector and can be used for sensors (switches, thermistors) or heaters (up to 115V). The motor control is performed by receiving 3 discrete signals ENABLE/DIRECTION/STEP per motor on the common control connector.

Building on the proven foundation of the CODE unit, the CODE+ introduces a major step forward in capability and flexibility. With a radiation‑tolerant microcontroller and a fully software‑defined architecture, the CODE+ offers greater configurability, more precise monitoring of mechanism behavior, and advanced motor‑control functions—all within the same compact, stackable form factor.

The CODE+ features a dual‑UART command interface and supports module stacking to increase either the number of drive channels or system‑level redundancy. Optional extension boards add capabilities such as signal multiplexing or a MIL‑STD‑1553B communication interface. The unit operates through CCSDS command and telemetry packets and supports in‑orbit software patching.

CODE+ can directly acquire and process a broad range of analog and digital sensor inputs. This allows the electronics to “sense” what the mechanism is doing in real time—e.g., monitoring motor current, position indicators, end‑switches, or temperature signals. This results in smoother, safer, and more accurate mechanism operations.