Flight Demonstration and Model Validation of a Prototype Variable-Altitude Venus Aerobot

TL;DR

This work tackles the challenge of enabling long-duration, in-situ science in Venus's cloud layer by advancing a variable-altitude aerobot built from Venus-compatible materials. The authors deploy a subscale balloon-in-balloon aerobot and capture two outdoor flights in Earth-like densities to validate a first-principles dynamics model, FLOATS, against flight data and to project Venus performance. Key contributions include a detailed prototype design with a dual-envelope ZP/SP configuration, an instrumentation suite and gas-transfer subsystem for altitude control, and a comprehensive FLOATS model integrating dynamics, shape, aerodynamics, thermodynamics, heat transfer, and atmospheric inputs. The validated FLOATS framework then informs Venus mission planning, illustrating how altitude-control actions coupled with a larger gondola could achieve multi-circumnavigation science campaigns, with practical implications for future aerial platforms in Venus's atmosphere.

Abstract

This paper details a significant milestone towards maturing a buoyant aerial robotic platform, or aerobot, for flight in the Venus clouds. We describe two flights of our subscale altitude-controlled aerobot, fabricated from the materials necessary to survive Venus conditions. During these flights over the Nevada Black Rock desert, the prototype flew at the identical atmospheric densities as 54 to 55 km cloud layer altitudes on Venus. We further describe a first-principle aerobot dynamics model which we validate against the Nevada flight data and subsequently employ to predict the performance of future aerobots on Venus. The aerobot discussed in this paper is under JPL and Aerostar development for an in-situ mission flying multiple circumnavigations of Venus, sampling the chemical and physical properties of the planet's atmosphere and also remotely sensing surface properties.

Figures (18)

• Figure 1: Subscale prototype of JPL's variable-altitude controlled aerobot, made from Venus-compatible materials, in flight over the Black Rock desert in Nevada, USA. Photograph taken July 2022, courtesy Aerostar. © 2022 California Institute of Technology.
• Figure 2: Photo of aerobot at takeoff, with the two balloon chambers (SP and ZP) labeled. Both balloons are made from the materials needed for a Venus mission, and helium is pumped/vented between balloons for altitude control. Photo courtesy NASA/JPL-Caltech, © 2022 California Institute of Technology.
• Figure 3: A: Material stackup of the zero-pressure (ZP) balloon bilaminate. B: Two layers of the super-pressure (SP) balloon. C: Photograph of SP balloon. Modified with permission from izraelevitz2022subscale, ©2021 California Institute of Technology.
• Figure 4: Instrumentation, gas transfer, and communication systems on the aerobot, divided into multiple platforms in different locations. (a) Buoyancy Control Module (BCM) and Gondola hanging below the aerobot. (b) Poppet for flight termination at the aerobot apex. (c) Ground station with stationary instrumentation.
• Figure 6: Clockwise from top left: equipment and aerobot being laid out on tarp prior to inflation (4:53AM); inflated aerobot prior to release (7:24AM); aerobot in free flight (7:33AM); aerobot being deflated after landing (9:28AM). Photographs from Flight 1, courtesy NASA/JPL-Caltech. © 2022 California Institute of Technology.