Design and Fabrication of the Cruise Stage Spacecraft for MSL

The Mars Science Laboratory (MSL) is a scientific mission that will deliver a roving science platform to the surface of Mars. In order to accomplish this mission, the rover must be safely transported from the surface of Earth to the surface of Mars. To achieve this, a Launch Vehicle, Cruise Stage, Entry Vehicle, which is comprised of an Aeroshell,Parachute, and Descent Stage must be employed. The Cruise Stage, Descent Stage and Rover are being designed and assembled at the Jet Propulsion Laboratory in Pasadena, California, while the Aeroshell is being designed and built by Lockheed Martin in Denver, Colorado, and the Parachute is being designed and built by Pioneer Aerospace in South Windsor, Connecticut. The primary function of the Cruise stage is to interface to the Launch Vehicle, and provide the structural load path to the Entry Vehicle, during the launch phase of the mission and then to provide power, telecommunications, navigation and propulsion for the 9 month journey from Earth to Mars, and lastly to orient the Entry Vehicle for Mars Atmospheric entry before burning up in the Mars atmosphere. The Cruise Stage design was based on the heritage Cruise Stages from the Mars Pathfinder (MPF) and Mars Exploration Rover (MER) Missions. These spacecrafts were composed of a similar architecture and provided the same functions, However both MPF and MER Cruise Stages were a 2.75 m diameter by 10 cm high spacecraft while the MSL Cruise Stage is 4.40 m diameter by 60 cm high spacecraft. This size is driven by the size of the MSL Rover which will be the largest vehicle delivered to the Mars surface to date. The key challenges in the MSL cruise stage reside in reacting to the loads from a 3400 kg Entry Body, interfacing to a new launch vehicle, meeting the new alignment requirements for GNC, defining the structure configuration and assembly process, and the design and build of the assembly tooling for such a large structure. This paper describes the design and assembly of the Cruise Stage along with how the key challenges were met.