16:30 〜 16:45
[PPS04-05] Test Flights and Altitude Control Demonstration of a Prototype Venus Aerobot
キーワード：Venus, Aerobot, Balloon, Atmosphere
The clouds of Venus offer a unique extraterrestrial environment: ample sunlight, Earth-like temperatures and pressures, and strong zonal winds that can carry an in situ aerial platform around the planet in just a few Earth days. This cloud layer is key to moderating the solar radiative balance of the planet, the transport of materials between the atmosphere and the ground, and the interactions (physical, chemical, and possibly biological) between atmospheric constituents. The two VeGa balloon flights in 1985, launched by the Soviet Union, successfully flew for almost two Earth days in the Venus clouds using superpressure balloons, a balloon type that nominally has a relatively fixed buoyancy and provides access to only a single altitude.
JPL is pursuing the technologies required to design a buoyant “aerobot” (aerial robotic balloon), with a lifetime of weeks to months, to perform targeted science in the Venus clouds. Because of the extremely strong and consistent zonal winds on Venus, any aerobot is expected to circumnavigate the planet passively every 5 to 7 Earth days. In contrast to its VeGa predecessors, the JPL aerobot is a controllable variable-altitude balloon—providing access to a broad altitude range over the course of the flight, and a commensurately increased science return.
The objective of this work is to develop the variable-altitude Venus technology for an aerobot mission proposal; see accompanying Phantom mission and science abstracts. The architecture consists of two balloons: an outer, metallized Teflon-coated unpressurized balloon (which protects against sulfuric acid aerosols and sunlight), and an inner, Vectran-reinforced pressurized balloon that serves acts as a helium reservoir. Transferring helium between the inner and outer balloons modulates the buoyancy and altitude. For Venus, an aerobot of 12–15 m diameter is necessary for a carrying capacity of 100–200 kg, consistent with a major scientific investigation of and from the cloud layer with an instrument payload of ~20 kg, with a 10 km-tall altitude-control capability nominally from 52 km to 62 km.
We will discuss the subscale prototype fabrication and test flight efforts pursued as a collaboration between JPL and Near Space Corporation. Two prototypes have been built so far at approximately 1:3 scale to the Venus design points, with a third prototype in progress. These prototypes are of increasingly higher fidelity, with balloon envelopes and seams capable of withstanding the challenging environmental conditions encountered in the Venus cloud layer—including high temperatures (~100°C), high-pressure loads (~30 kPa), sulfuric-acid clouds (94% concentration), and solar radiative heating (2300 W/m2). We will report on two recent test flights of these prototypes on Earth (see image) at atmospheric densities equivalent to 54–55 km above the Venus surface, as well as the results of coupon-level testing of balloon materials and the application of these results to the performance at full scale on Venus.
Acknowledgement: This research was funded by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
JPL is pursuing the technologies required to design a buoyant “aerobot” (aerial robotic balloon), with a lifetime of weeks to months, to perform targeted science in the Venus clouds. Because of the extremely strong and consistent zonal winds on Venus, any aerobot is expected to circumnavigate the planet passively every 5 to 7 Earth days. In contrast to its VeGa predecessors, the JPL aerobot is a controllable variable-altitude balloon—providing access to a broad altitude range over the course of the flight, and a commensurately increased science return.
The objective of this work is to develop the variable-altitude Venus technology for an aerobot mission proposal; see accompanying Phantom mission and science abstracts. The architecture consists of two balloons: an outer, metallized Teflon-coated unpressurized balloon (which protects against sulfuric acid aerosols and sunlight), and an inner, Vectran-reinforced pressurized balloon that serves acts as a helium reservoir. Transferring helium between the inner and outer balloons modulates the buoyancy and altitude. For Venus, an aerobot of 12–15 m diameter is necessary for a carrying capacity of 100–200 kg, consistent with a major scientific investigation of and from the cloud layer with an instrument payload of ~20 kg, with a 10 km-tall altitude-control capability nominally from 52 km to 62 km.
We will discuss the subscale prototype fabrication and test flight efforts pursued as a collaboration between JPL and Near Space Corporation. Two prototypes have been built so far at approximately 1:3 scale to the Venus design points, with a third prototype in progress. These prototypes are of increasingly higher fidelity, with balloon envelopes and seams capable of withstanding the challenging environmental conditions encountered in the Venus cloud layer—including high temperatures (~100°C), high-pressure loads (~30 kPa), sulfuric-acid clouds (94% concentration), and solar radiative heating (2300 W/m2). We will report on two recent test flights of these prototypes on Earth (see image) at atmospheric densities equivalent to 54–55 km above the Venus surface, as well as the results of coupon-level testing of balloon materials and the application of these results to the performance at full scale on Venus.
Acknowledgement: This research was funded by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.