What are some reasons we put orbiting spacecraft up into the atmosphere?

The orbiting spacecraft are put in the atmosphere to gain information about the weather conditions, for satellite communications, for measuring changes in the atmosphere. These crafts are put in the outer atmosphere, where the atmosphere is very thin and the craft can stay its specified orbit. 

Answer: buoyancy forceexplanation: in simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object, or the density of the fluid multiplied by the submerged volume times the gravitational acceleration, g. this is also known as upthrust.