SOAREX-8 suborbital experiments 2015 - A new paradigm for small spacecraft communication

In 2015 NASA plans to launch a payload to 280 Km altitude on a sounding rocket from the Wallops Flight Facility. This payload will contain several novel technologies that work together to demonstrate methodologies for space sample return missions and for nanosatellite communications in general. The payload will deploy and test an Exo-Brake, which slows the payload aerodynamically, providing eventual de-orbit and recovery of future ISS samples through a Small Payload Quick Return project. In addition, this flight addresses future Mars mission entry technology, space-to-space communications using the Iridium Short Messaging Service (SMS), GPS tracking, and wireless sensors using the ZigBee protocol. SOAREX-8 is being assembled and tested at Ames Research Center (ARC) and the NASA Engineering and Safety Center (NESC) is funding sensor and communications work. Open source Arduino technology and software are used for system control. The ZigBee modules used are XBee units that connect analog sensors for temperature, air pressure and acceleration measurement wirelessly to the payload telemetry system. Our team is developing methods for power distribution and module mounting, along with software for sensor integration, data assembly and downlink. We have demonstrated relaying telemetry to the ground using the Iridium satellite constellation on a previous flight, but the upcoming flight will be the first time we integrate useful flight test data from a ZigBee wireless sensor network. Wireless sensor data will measure the aerodynamic efficacy of the Exo-Brake permitting further onorbit flight tests of improved designs. The Exo-Brake is 5 m² in area and will be stored in a container and deployed during ascent once the payload is jettisoned from the launch vehicle. We intend to further refine the hardware and continue testing on balloon launches, future sounding rocket flights and on nanosatellite missions. The use of standards-based and opensource hardware/software has allowed for this project to be completed with a very modest budget and a challenging schedule. There is a wealth of hardware and software available for both the Arduino platform and the XBee, all low-cost or open-source. Along with the Exo-Brake hardware and deployment discussion, this paper will describe in detail the system architecture emphasizing the successful use of opensource hardware and software to minimize effort and cost. Testing procedures, radio frequency interference (RFI) mitigation, success criteria and expected results will also be discussed. The use of Iridium short messaging capability for space-to-space links, standards-based wireless sensor networks, and other innovative communications technology are also presented.

1. Introduction

In early 2015 a sounding rocket will loft the SOAREX-8 payload to 280 Km above the Atlantic Ocean from the NASA Wallops Flight Facility (WFF) in Virginia. Upon reaching the ballistic apex, a single payload carrying several sets of experiments will be jettisoned. One of these located at the top of the payload ‘box’, the Exo-Brake, will unfold like Pegasus's wing. It will be a thin five-meter diameter gossamer metal film parachute that will spring from a small tube. The SOAREX-8 flight will deploy the first large Exo-Brake (previous 1/10 scale Exo-brakes have been tested from the ISS through the TechEdSat nano-satellite series), which will stabilize the payload as it re-enters the atmosphere.