  An effective method for detailed observation of the Solar System planets is
the use of vehicles that can perform flight in their atmospheres, with the most
promising of them being Flyers (aircraft for other planets atmospheres).
Besides the advantage of probing the atmosphere directly, they have the ability
to fly on selected direction and altitude, making them suitable for collecting
information over large areas. Equipping the Flyer with nuclear propulsion will
allow it to conduct flight for months without the need of combustible fuel or
oxidizer to be carried on board. Among the planets of the Solar System and
their satellites, Jupiter is a viable target for exploration, since it features
thick atmosphere suitable for aerodynamic flight, there is no solid surface
that can be contaminated after end of the mission, and the atmospheric data for
designing a Flyer is readily available. This paper proposes a mathematical
model for evaluating the thrust, the lift and the maximum allowable mass for
horizontal steady flight as functions of the altitude and different heat
chamber temperatures.
