Solar Array Drive Assemblies (SADA) are primarily used to rotate and position solar panels on satellites. The systems consist of a Solar Array Drive Mechanism (SADM) and electronics which are commercially available as standalone components or as a complete SADA solution.
In this article we give a brief overview of what SADAs are and how they operate, followed by an overview of systems available on the global marketplace for space.
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Introduction
Surface-mounted solar cells and stationary solar arrays have long been used for power generation in satellites. But as the industry has grown, the development of more demanding payloads and advancements in propulsion systems are pushing power requirements higher.
In addition, with the miniaturization of satellite platforms and sub-systems, optimizing every component for Size, Weight, Power, and Cost (SWaP-C) is a significant challenge. In some cases conventional solar arrays are no longer adequate or, at least, optimal for modern, agile, and multi-functional satellites.
This is leading many engineers to consider deployable solar arrays, which can offer access to higher levels of power once in position on orbit. Such arrays have several components and in this article we take a closer look at one of the most important – the Solar Array Drive Assembly.
About Solar Array Drive Assemblies
Solar Array Drive Assemblies, or SADAs, are an integration of mechanical and electrical components used for rotating the solar panels on the satellite. The mechanical actuator drive system of the SADA rotates the solar arrays based on sun tracking information, while the electrical component of the SADA provides a pathway for power transfer from the arrays to the satellite.
A SADA mainly consists of Solar Array Drive Mechanism (SADM) and Solar Array Drive Electronics (SADE). While several companies sell a full SADA solution, many others have also made SADM and SADE available as standalone products.
A SADA is used to position the solar arrays towards the sun (or in another required direction) and transfer the generated power from solar panels to the satellite bus. For this function, SADA utilizes a combination of onboard computer/electronics (which is a part of the SADE) and motors as well as actuators (which is a part of the SADM).
The SADM forms the complete mechanical structure of SADA helping the spacecraft to achieve flexibility to rotate and position the solar arrays as per the mission requirements. On the other hand, the SADE ensures the smooth commanding of these mechanical components.
Optimal positioning of the solar arrays with respect to the position of the sun maximizes the acquired sunlight and increases the power output for the same given area of the panel – so potentiometers are used for position feedback. SADAs can also help reduce the mass and size requirements of solar arrays significantly.
Important SADA engineering parameters
Some of the key specifications commonly identified for commercial SADA products are:
- Power transfer capacity via slip rings/capsules,
- Actuator power consumption,
- Angular rotation (in terms of output torque/step size with the unit in Nm, or output step angle with the unit in degrees), and
- Mass and size.
The power transfer range, and therefore consumption, varies significantly based on the size of the satellite for which the SADA is designed and the circuit lines used.
Twist capsules or slip ring modules enable power and signal transfer within the system to ensure precise control. For noise-free limited rotation ranges and power transfer requirements, a twist capsule is used, and for continuous rotation, slip rings are preferred. Multiple slip-ring modules or hybrid slip-ring and twist capsule configurations are also available in the commercial market.
The operating environments and applications of SADAs include Low Earth Orbiting (LEO) missions, Geostationary (GEO) satellite operations, Antenna Pointing Mechanisms (APM) for LEO data downlink antennas, powering inter-satellite links, and supporting interplanetary missions.
Solar Array Drive Assemblies and related equipment on the global market
In the section below you can see an overview of various SADAs and associated equipment, subsystems, and accompanying devices available on the global market.
Please note that this list will be updated when new products are added to the global marketplace for space – so please check back for more or sign up for our mailing list to get all the updates.
You can click on any of the links or images below to find out more about each of the SADA products, or you can submit a generic request for a system to meet your mission needs by simply sharing your required system specifications with us (for free!)
The COMAT SADM 200 is a plug & play Solar Array Drive Mechanism for small satellites to optimize onboard power generation.
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The DHV Technology MicroSADA-10 is designed for 6U and 12U CubeSats. It is customizable to include Solar Array Drive Mechanisms (SADM) and Solar Array Drive Electronics (SADE) modules in one single device. It is designed for platforms with a height of 10 mm.
The DHV Technology MicroSADA-18 is designed for 6U and 12U CubeSats. It is customizable to include Solar Array Drive Mechanisms (SADM) and Solar Array Drive Electronics (SADE) modules in one single device. It is designed for platforms with a height of 18 mm.
The Revolv Space SARA is an autonomous & fail-safe Solar Array Drive Mechanism for smallsats, including actuation system, electronics, & sun sensors.
The Honeybee Robotics Micro-Sat SADA is a hybrid stepper actuator designed for space applications. It offers a fine pointing system for several space applications. The unit can be configured to accommodate power transfer for solar array pointing or gimbal applications.
The Honeybee Robotics Small Sat SADA is a solar array drive actuator designed for space applications. It is designed to accomodate small satellite spacecrafts. The unit consists of a continuous rotation with slip ring for power transfer.
The Kongsberg KARMA-4 is a second generation (SG) Solar Array Drive Mechanism (SADM) designed for space applications. It consists of two main subsystems - the driveline with motor/gear and the rotary solar power and signal transfer unit. The product is mainly suitable to use in Low Earth Orbit (LEO) missions.
The Kongsberg KARMA-4 is a third generation (TG) Solar Array Drive Mechanism (SADM) designed for space applications. It is customizable to meet the mission requirements and can be delivered with a slip ring or a twist capsule for the transfer of power and signals. The product is mainly suitable to use in Low Earth Orbit (LEO) and Geostationary Earth Orbit (GEO) missions.
The Kongsberg KARMA-5 is a second generation (SG) Solar Array Drive Mechanism (SADM) designed for space applications. It consists of the mechanism with structural interfaces, a drive line and position sensor, and a slip ring for rotary power and signal transfer. The product is mainly suitable for earth observation and science missions.
The Kongsberg KARMA-5 is a third generation (TG) Solar Array Drive Mechanism (SADM) designed for space applications. It can be configured with one, two, three, or four slip ring modules depending on power requirements. KARMA-5 TG SADM also consists of a PCB-based Slip Ring providing a compact design and enabling a wide power range. The product is mainly suitable for Geostationary Earth Orbit (GEO) missions.
The Thales Alenia Space Solar Arrays, Deployment, and Mechanism Solutions are designed to meet customer demands for space and satellite missions. Under these custom solutions, Thales Alenia Space provides solar arrays as well as associated deployment and drive mechanisms for LEO, MEO, and GEO satellites. The solar array solutions vary from 140W to 23kW; providing customers with a more flexible approach to meeting the mission requirements.
The IMT SRL µSADA is a solar array drive assembly suitable for nano and small satellite to increase the available power energy. The system has six solar panels, three in each wing which increases the active area required for power generation. The system features a Hold Down and Release Mechanism (HDRM) with a simultaneous/sequential burn strategy.
References and further reading
- Development of a Solar Array Drive Assembly for CubeSat, Passaretti and Hayes [PDF]
- Bi-Axial Solar Array Drive Mechanism: Design, Build and Environmental Testing, Scheidegger, Ferris, and Phillips [PDF]
- Integrated modelling of microvibrations induced by Solar Array Drive Mechanism for worst-case end-to-end analysis and robust disturbance estimation, Sanfedino, Alazard, Preda, and Oddenino
- Eurostar Neo Solar Array Drive Mechanism Completes Qualification Testing