Mechanism Design & Flight Build of Furled   High Strain Composite Antenna for CubeSats  Bruce Davis*, Ryan VanHalle*, Kevin Cox* and Will Francis*  Abstract  In August of 2016, Roccor was tasked to develop a CubeSat antenna mechanism that deploys four 20 x 5  inch (51 x 13 cm) radial petals from a small, 2U stowed volume. It was determined that High Strain  Composites (HSC) coupled with a copper-beryllium alloy enabled a simplistic furled solution utilizing few  mechanical parts. A two-stage mechanized deployment scheme was developed to first expose the wrapped  petals to the outside of the spacecraft via a hinged joint and then separately trigger a dynamic unfurling of  the petals with a tether. This paper describes the initial trade study and detailed design of this deployment  mechanism as well as the lessons learned during the flight qualification. In May of 2017, Roccor delivered  two, low-cost flight qualified units to the customer after a design, prototype, build and test campaign lasting  a total of nine months. The hardware is slated to fly in late 2018.   Introduction  The emergence of the small satellite platform and subsequent ease of access to space has created high  demand for advanced, yet compact spacecraft systems serving a range of science, commercial and  defense applications. Furthermore, the industry-wide embracement of the CubeSat standard, establishing  both spacecraft form factor and consistent launch requirements, has established investment in off-the-shelf  spacecraft components and high quantity production within the field [1,2]. Across the community, one of  the largest hurdles to developing a successful CubeSat system is the challenge in miniaturizing the  technology to function within the desired form factor. This is especially challenging when designing  deployable structures such as large antennas or solar arrays, where common physical components such  as fastened interfaces, articulated joints and actuators are not efficient in the miniaturized form factor.  Furthermore, structural performance does not often scale linearly in size causing the need to embrace  different architectures at smaller scales to enable a desired deployed stiffness and precision. One such  technology receiving increased attention within the CubeSat community are High Strain Composites [3,4]  (HSC) or materials that deform from one shape to another during deployment. A commonly known high  strain device is a slit-tube, or a deployable “tape-measure” boom that allows the cross section to be flattened  and rolled into a coil reaching a high packaging efficiency [5,6]. Although the metallic slit-tube device has  extensive flight heritage, a controlled deployment requires complex mechanisms to control the strain energy  of the wrapped coil. When fabricating a slit-tube boom with a HSC material, the ability to tune the composite  laminate to control the strain energy of the furled structure offers a new level of simplicity while enabling  adequate control to deploy and retract the device. The use of HSCs offer an improved level of mechanism  simplicity over architectures utilizing traditional moving mechanisms such as rotational joints, springs,  dampers and latches.  In August of 2016, Roccor LLC was approached by an advanced CubeSat payload provider to design a  mechanical system that would house and deploy a series of co-planer RF elements on orbit. This customer  required a rapid system development ranging from early requirements definition to the delivery of multiple  flight units over the course of a nine-month period. To add to the challenge, this effort was bounded by a  relatively small budget, driving the need for mechanism simplicity. These desired elements consisted of  four petals, each measuring roughly 20 in x 5 in (51 cm x 13 cm) in length and height respectively that  would be aligned radially about a central hub. These petals would also need to be folded into a 2U CubeSat  *Roccor, Longmont, CO Proceedings of the 44th Aerospace Mechanisms Symposium, NASA Glenn Research Center, May 16-18, 2018 NASA/CP—2018-219887 337