High Quality Content by WIKIPEDIA articles! The VS-40 is a Brazilian sounding rocket using solid fuel, stabilized aerodynamically, distributed between the first stage (4,200 kg) and the second stage (810 kg).A sounding rocket, sometimes called a research rocket, is an instrument-carrying rocket designed to take measurements and perform scientific experiments during its sub-orbital flight. The origin of the term comes from nautical vocabulary, where to sound is to throw a weighted line from a ship into the water, to gauge the water's depth. Sounding in the rocket context is equivalent to taking a measurement.