Auto-tuned thermal control on stratospheric balloon experiments

TL;DR

This paper discusses the challenges and solutions for thermal control in stratospheric balloon experiments, focusing on optimizing thermal stability and minimizing gradients for high-precision telescopic observations.

Contribution

It introduces a novel approach to thermal management in balloon-borne telescopes, including the development of parameter solvers for design validation and thermal environment control.

Findings

Thermal design validation using parameter solvers.

Implementation of thermal control strategies for stability.

Minimization of thermal gradients to achieve high-resolution imaging.

Abstract

Balloon-borne telescopes present unique thermal design challenges which are a combination of those present for both space and ground telescopes. At altitudes of 35-40 km, convection effects are minimal and difficult to characterize. Radiation and conduction are the predominant heat transfer mechanisms reducing the thermal design options. For long duration flights payload mass is a function of power consumption making it an important optimization parameter. SuperBIT, or the Super-pressure Balloon-borne Imaging Telescope, aims to study weak lensing using a 0.5m modified Dall-Kirkham telescope capable of achieving 0.02" stability and capturing deep exposures from visible to near UV wavelengths. To achieve the theoretical stratospheric diffraction-limited resolution of 0.25", mirror deformation gradients must be kept to within 20nm. The thermal environment must thus be stable on time scales of an hour and the thermal gradients must be minimized on the telescope. SuperBIT plans to implement two types of parameter solvers; one to validate the thermal design and the other to tightly control the thermal environment.