Low-Altitude Exploration of the Venus Atmosphere by Balloon

The planet Venus represents an exciting target for future exploration by spacecraft. One target of scientific interest is the lower atmosphere, which represents an environment of high temperature and moderate to high atmospheric pressure. This represents a considerable challenge to the technical art of ballooning, but one which may be amenable to solution. Several possible designs for low-altitude balloons are discussed. Conceptual design for three mission examples are analyzed: a conventional balloon operating below the cloud level at an altitude of 25 kilometers, a large rigid -envelope balloon operating near the surface at an altitude of 5 kilometers, and a small, technology demonstrator rigid -envelope balloon operating at 5 kilometers. I. Introduction HE planet Venus, Earth's nearest neighbor, is an interesting target for exploration by spacecraft. It is a planet with a carbon dioxide atmosphere that is over a hundred times more dense than the Earth's atmosphere, with unbroken layers of clouds so that the surface is never visible from space. Many earlier missions have orbited Venus and probed the atmosphere and surface, including orbital missions, atmospheric probes, lander missions, and high-altitude atmospheric balloons. Nevertheless, significant scientific questions exist about the geology, geophysics, and the atmosphere and climate of Venus, and it remains an exceptionally interesting target for future exploration. 1