Table of Contents
CubeSat Solar Sail Deployment
SummaryStraight out of science fiction like Star Wars, a solar sail is a thin sheet of reflective material which uses the sun's light to propel small spacecraft. This technology eliminates the need for traditional propellant fuels which are costly, heavy, and limited. This works well for CubeSats, tiny satellites made for scientific experiments. In 2015, Bill Nye's Planetary Society launched a solar sail CubeSat with a $1.2 million Kickstarter campaign.
The aim of this project is to design and build a deployment mechanism for a solar sail contained within a CubeSat. Ultimately this device will be integrated into an RIT Space Exploration (SPEX) satellite. Their goal is to test solar sail propulsion for both orbiting and high-speed space travel. The desired outcome of this project is a repeatable and remote sail deployment system which meets all the specifications of CubeSat regulations, does not compromise stability, and minimizes weight and volume.
This exhibit will include a video of the full size sail deployment, as well as a live tabletop demonstration. Visitors can also examine 3D printed models and a display of a portion of the sail. Look for the big shiny sheet and come talk to our friendly student exhibitors about the future of space travel!
Initial Design Phases
Identifying ConstraintsThe first phases of the project consisted of determining the exact project goals and researching what had been done before by other projects. Initially, the RIT Space Exploration (SPEX) club leaders and faculty adviser were interviewed to determine the specific customer needs. These needs were identified and developed into engineering specifications and constraints for our project throughout the design process. These were all met and are listed below.
- Meet CubeSat Regulations
- Withstand the force from solar pressure and air drag
- Deployment can be started remotely
- Reliably deploy a sail from a CubeSat
- Know deployment progress
- Leave room for sail control mechanism in the future
- Avoid destabilizing the CubeSat
These were the primary targets of the project, but there were also secondary objectives. These "nice to have" features listed below were not mandatory, but if possible were to be included. Throughout the course of the project, the team managed to achieve all of these goals in addition to the primary goals.
- Sail can also be partially retracted
- Remain open source
- Easy to manufacture
Comparison to Similar ProjectsOnce the project requirements were defined, research was carried out on similar projects. Solar sail deployments from CubeSats are not common, and only 6 similar projects were discovered. We used information from these projects to compare to our ideas from brainstorming. The important details of these projects and what they look like can be seen below. More details on the key takeaways from this benchmarking can be found here.
Brainstorming and Concept GenerationOnce the project constraints were identified and research into existing technology was completed, brainstorming design ideas began. Many different design ideas were considered using different technologies. Once a large number of potential concepts were created, the potential designs were narrowed down to 4 which were considered to be the best concepts. Designs were eliminated based on their complexity, inability to meet the goals of the project, or violation of the CubeSat standards. The remaining 4 designs were then analyzed in depth with consideration given to their relative performance in each needed task. The four concepts selected for this are shown below. Concept 1 (Pink) was selected for the project design after analysis.
PrototypingOnce the design concept was selected, detailed design began. This included meeting with the member of SPEX to confirm the team's design ideas did not violate the CubeSat standards. Each individual component of the initial design was then discussed and modeled using 3D CAD software. These components were then created using a 3D printer to allow immediate testing of the concepts and to detect any major issues that would arise with the design. This was intended to prevent major issues with the final machined components, which would take much more time and effort to modify. The assembly of the CAD components was then completed, and the 3D printed components were combined into a prototype of the CubeSat frame.
A variety of tests were then conducted with the printed frame. Although the dimensions of various components did not exactly match those of their CAD models, the printed prototype was useful in determining several design issues. The largest of these were with the components that the booms deployed from, which were changed from curved to straight. Based on information learned from this process, the designs of the individual parts were changed and new ones were printed and replaced old components. Additionally, the prototype frame was used for some preliminary tests of fitting the solar sails within the CubeSat, as well as rough force and torque estimates needed to determine an appropriate motor to use. Once this testing was complete, the parts were finalized and drawn for machining.
More information on the individual parts and printed components can be found under Prototyping.
Preliminary Analysis and TestingBefore actual construction began, analysis of many of the important design choices was made to ensure they met the project engineering specifications. As progress continued, these evolved into analysis based on design changes and finished components. Many of these tests were conducted at various points during the project. Brief descriptions of the conducted tests in each phase of the project (approximately 4 week periods) and links to them are listed below.
Meeting engineering specifications and sail construction:Here a variety of key constraints were tested to ensure the design was feasible. This is where having enough space for the sail, having low enough mass to be launched, the possibility of losing of control of the satellite from the moment created by sail deployment, and the details of the initial sail design analyses can be found.
Sail construction and sensor testing:Here important choices in the construction of the initial solar sail that would be used for deployment testing is described. This includes how we decided to connect smaller pieces together, testing of the best way to fold the sail so it would fit within the CubeSat, how we decided to attach the sail to the CubeSat and booms, and analysis of the sensors used to track deployment.
Final design and component analysis:Here testing of the moment resulting from deployment to ensure the satellite would not destabilize and burn up in the atmosphere was conducted. Importantly, a final design of the CubeSat itself and the mechanism that would deploy the sail is discussed here. The actual construction of the initial full size sail quadrant is described and analyzed here, along with testing the folding of the sail and subsequent takeaways. This also contains analysis on the force from solar pressure and air drag, as well as suitable ranges of operation for the CubeSat.
Final Design Process and ResultsThe process of acquiring the final machined components of the design took place over a period of several weeks, and each was inspected for tolerances and compliance to drawings. As each component was received, it replaced its respective 3D printed component and was tested. Ultimately, all of the components were received and tested. Once this occurred, all of the final components were tested. Numerous issues arose which were addressed, and then more problems appeared. These were dealt with as they arose, and the process of combating the initial problems can be seen underneath the risk assessment denoting the team's most pressing concerns. Additional problems and their solutions continued to arise throughout the design and testing process. Finally, the design reached a state where it could meet all of the customer needs, and that is what you see here today.
There is much more detail about the information presented here, as well as other tests, risks, and design details not discussed on this page located throughout this website that can be accessed through the links at the bottom of this webpage.