The USS Discovery is one of the most recognizable spaceship designs in all science fiction.  Roughly the size of a nuclear submarine, the USS Discovery was the greatest achievement in human space technology.  Employing powerful nuclear engines, the engineering section of the ship was separated from the living area to protect the crew.  Built in orbit, the Discovery diverted from her original mission to investigate the mystery around Jupiter.

The Discovery was initially conceived as a prototype cargo hauler that was rapidly converted for deep space exploration.  Both Arthur Clarke and Stanley Kubrick liked the concept of interchangeable cargo containers strapped along the hull.  This remained, even when the Discovery changed from a commercial hauler to a government exploration vessel.
 

The ship’s size was best demonstrated during the repair sequences where the antenna can be compared to the astronaut.
 

A central sequence that clearly illustrates that the Discovery is a ship in space occurs early in the third act, when astronaut David Bowman jogs along the central ring of the living area.  Hibernation pods are interspersed with computer screens and scientific equipment.
 

The lower section of the sphere contains the landing bay where three exploration pods are contained in front of three separate doors.  Kubrick never fully resolved what he wanted the pods to be used for.  Designed for repairs, they didn’t contain enough fuel to allow them to land and lift off again from a planetary surface.  If used strictly for repairs, the script never gave any explanation as to why the crew needed three of them.  When the Discovery was a cargo carrier, the design worked well, since multiple pods were needed to load and offload cargo.  As an exploration vessel, the ship wouldn’t require them.  Consequently, having three pods appears to be a waste of valuable space and fuel.  In the end, the bay and pods became both an icon and unresolved conflict for Kubrick. 
 

The central shaft of the ship was a long, sectionalized tunnel.  Its interior lighting gave it an almost other-worldly, high-tech feel.