Deployment simulation of very large inflatable tensegrity reflectors

Propulsion, energy collection, communication or habitation in space requires ever larger space structures for the exploration of our solar system and beyond. Due to the payload size restrictions of the current launch vehicles, deployable structures are the way to go to launch very large structures into orbit. This paper therefore presents the design and simulation of a tensegrity based structure with inflatable rigidizable tubes as compression struts. The literature review showed that inflatable structures are most promising for the development of deployable reflectors larger than twenty meters in diameter. Good compression performance and reliability can be achieved by employing rigidisable inflatable tubes. The concept presented in this paper will focus on the development and simulation of a one meter diameter hexagonal reflector substructure that can be easily expanded to larger diameters due to its modular design. The one meter diameter modular approach was chosen to be able to build a full size benchmark model to validate the numerical data in the future. Due to the fact that the tensegrity compression elements are not initiating at one specific location, a passive reaction gas inflation technique is proposed which makes the structure independent of any pumps or other active inflation devices. This paper will discuss the use of inflatable rigidizable elements and their counteraction with the rest of the tensegrity structure. Simulations have been undertaken to capture the deployment behaviour of the inflating tube while getting perturbated by the attached tensegrity tension cables. These simulations showed that the use of inflatable rigidisable struts in tensegrity assemblies can greatly decrease the system mass and stowed volume, especially for very large reflectors compared to conventional approaches