SunbYte: A framework for low-cost robotic solar telescopes on high altitude balloons

Abstract

The design and usability of a fully autonomous robotic control system (SunbYte-Sheffield University Nova Balloon Lifted Telescope) for solar tracking and observational applications on-board high-altitude balloons is addressed here. The design is based on a six step development plan balancing scientific objectives and practical engineering requirements. The high-altitude solar observational system includes low cost components such as a Cassegrain type telescope, stepper motors, harmonic drives, USB cameras and microprocessors. OpenCV installed from ROS, python and C software were used to collect and compress housekeeping/scientific data, process the signal, and transmit information to the ground-station via the launch vehicle telecommunication link. The SunbYte system allows the brightest spot in the sky to be identified, point towards it with high accuracy and capture that region with the main telescope. This paper gathers and presents the results from three missions: two flights with High-Altitude Student Platform (NASA Balloon Program office and LaSpace), and one flight with German-Swedish programme: REXUS/BEXUS. The system demonstrated the tracking capabilities of the Sun by capturing and analysing a series of tracking images with the location of the Sun at the calibrated centre. Housekeeping sensor data was collected which enabled issues with the thermal performance to be diagnosed. Low temperature reduced the responsiveness of the motor and harmonic drive actuation system. The developed ground-station interface and telecommunication link allowed response to in-flight issues through updates to the tracking parameters during the flight.

SunbYte: an autonomous pointing framework for low-cost robotic solar telescopes on high altitude balloons

“…This was used to conduct high-speed and high-resolution image capture. The demanding processing required led to some issues around thermal management, power consumption and spatial constraints [47].…”

“…The smaller motors also facilitated a minimization of some electronic components. Despite these changes, the same harmonic drives were used as in the SunbYte I mission [47]. On HASP flights, power (2.5 amps at 30 VDC) and telecommunications are provided.…”

“…Figure 5 illustrates the optical setup for SunbYte III. The following section will focus on the tracking results of SunbYte II and III, for more information regarding results and analysis of the SunbYte I mission, please refer to [47].…”

“…SunbYte I was flown on REXUS/BEXUS in 2017, whilst SunbYte II and III were flown on NASA HASP in 2018 and 2019 respectively. The results and analysis of the SunbYte I mission are presented in a separate paper [47]. The main aim of this current paper is to present the lessons learnt through the analysis of the tracking system for SunbYte II and III.…”