Subsidiary question: Imagine a sphere 10cm in diameter in low venusian orbit. Slow it down a little in order to deorbit it. What's the density of the sphere, in order to touch the ground at 0 vertical m/s, before climbing up again in the venusian sky because it's less dense than venusian atmosphere? (regarding pressure gradient, aerodynamic drag, high speed winds effects on trajectory, and other things i forget.(see images below))(rough approximations and thoughts are welcome)
Pressure on surface of Venus is 90 times greater than Earth's sea level pressure.
Are there studies about some sort of "low & variable density buoyancy braking lander" designed with removable onionlike heatshields -or a single deflatable heatshield- which would provide control over the density -and therefore the speed- of the whole lander during the descent?
The idea is about bringing multipurpose to parts, in order to minimise the number of parts. Aerobraking starts in high altitude, and stops on the floor, Buoyancybrake should start at a precise altitude, and stop at surface level, 0 m/s vertical speed, with the separation of the last low density, buoyant-heatshielding onionskin layer.
The less onionskins layers needed in the descent, (of low density high temperature resistant & thermical insulant, some sort of aerogel(?)) the better.
links towards atmospheric plots: