Composite inflatable antennas for small - Satellites and backup communication

There is an ever-growing need for deployment of large space structures with large apertures for applications such as communication relays. There is also rapid growth in small spacecraft such as CubeSats and Small-Sats for deep space science missions but are limited by their size and how much they can communicate back to Earth. In addition, there is a growing need to have backup communication systems on large satellites that will have minimal mass, volume and power footprint. There are several competing technologies for deployment of space structures such as interlinked deployable mechanisms and inflatables. Interlinked deployable mechanisms contain mechanisms with many hundreds of moving parts that dependent on each-other for successful deployment. Inflatables are relatively simple and offer the best stowage and mass footprint. They can use green (non-toxic) sublimates to inflate and be rigidized using UV curing. These inflatables offer the highest volume to mass stowage ratios, while providing a rigid product in space. The system is also puncture resistant to micro-meteorites. However, challenges remain with composite inflatable in achieving high-quality finished surface required for a x-band or Ka-band communication antenna. Our work is focusing on composite inflatables that combines different materials, such as inflatables containing modular bladders with soft and rigid materials, miniature sensors and actuators to form a structure. Composite inflatables are born out of the size, rigidity limitations and precision limitations of conventional inflatables. The advantage of a composite inflatable is it is modular, smart, has strength and rigidity properties of a solid, but is mostly gas. Each module can be independently adjusted to fine-tune the overall shape and perform corrections to varying environmental conditions. Our research is focused on developing Ka-band inflatable antenna for CubeSats that range in size from 1 to 3 m and can be stowed in a 1 to 1.5 U package. The technology will utilize composite inflatables that produce a smooth wrinkle free surface, a parabolic shape, modular structure to withstand local punctures and sufficient rigidity under varying in-space conditions. Inflatables offer the lowest mass, lowest stowage volume design yet. Our studies have shown inflatable achieving up to a 10-fold mass and volume savings compared to conventional structures. Advancement of this technology offers advantage in producing ultra-low cost communication constellation satellites. Our work combines use of analytical tools, high-fidelity simulations with laboratory experiments and demonstrations in a thermal vacuum chamber. In this work, we will for the first time apply analytical structural design principles and high-fidelity structural simulation tools to show how a composite inflatable for Ka-band antenna will take shape. This will be complemented with simulations of the resultant antenna radiation pattern. Our work will then proceed to outline plans for laboratory development and testing of a 2-m Ka-inflatable antenna.