Small Satellites and Structural Design

Abstract

The cost to orbit for 1 kg of mass, using an Atlas launch vehicle, is currently around $20,000 and represents the high end of the range of launch costs. The latest technology represented by a SpaceX Falcon launcher, an ISRO Polar Satellite Launch Vehicle (PSLV) or a small satellite launcher such as the Electron all are significantly less costly. Nevertheless launch cost even by the most efficient launchers into low Earth orbit (LEO) remains quite expensive. In the case of very large space craft such as a high throughput satellite for telecommunications with mass of 5000–10,000 kg, the savings that might come from a highly efficient structural frame that reduces the overall mass by 100 kg, or alternatively allows the payload to be 100 kg larger, might be worth something like $2 million dollars per satellite launched. Even for small satellites such as a 3 unit cubesatellite, a very light weight, high strength frame that is thermally stable, and is not adversely affected by high radiation levels, clearly has good value. At this size, however, it is more common to use a lower cost material such as aluminum alloy.

Frame designs for small satellite are getting increasingly more sophisticated. It is possible that a primary frame or even a secondary structure such as a solar cell panel to allow the inclusion of an additional heat sensor, star tracker, or other safety feature or capability to be integrated into the harness design.

Some designs might even allow the addition of a passive de-orbit device that allows the small satellite to more quickly deorbit. In short, some design features for primary or secondary structures are optimized by determining and adding features that reduce both the mass and available usable volume of a small satellite.

The addition of new additive manufacturing capabilities to the arsenal of capabilities available to those who design and manufacture small satellites can increase the performance, cost-effectiveness, or safety of a project.

This article addresses all aspects of a small satellite’s design in terms of its mass, strength, volume efficiency, thermal and radiation protective qualities, reliability, and overall structural aspects and efficiency as measured by all of these factors. It analyzes what aspects have been improved over time and what the prospects are for the future to increase structural design and performance. This article analyzes the status and future direction of research related to primary structure related to small satellites. This primary structure is key to a satellite surviving launch and deployment, its operational integrity throughout the spacecraft lifetime up to its end of life. Also considered is the nature and performance of its secondary structures. The structural integrity of these secondary systems are also necessary to support the successful operation of subsystems or components such as solar panels, thermal blankets, radiation shielding, instrument mounts to be properly anchored so as to operate reliably, and so on. Progress is being made on primary and secondary structure design and performance. In many instances, the design of the small satellite and its structural elements are being integrated with essential elements of the spacecraft to reduce mass, increase volume for payload systems, or otherwise increase efficiency. These innovations are sometimes known as multifunctional elements when structures, panels, wiring harnesses, sensors, and other devices are integrated together in the design.