Conceptual Design of Crew Exploration Lander for Asteroid Ceres and Saturn Moons Rhea and Iapetus

Abstract

The Spaceship Discovery design was presented at the AIAA Space 2006 and 2009 Joint Propulsion Conferences and is cited in this paper’s references. This conceptual architecture for human solar system exploration has been updated to include a new Design Reference Mission 4 (DRM 4) to Ceres, the largest asteroid in the main asteroid belt between Mars and Jupiter. A future DRM 8 is in work to explore Rhea and Iapetus, the two largest airless moons of Saturn, which also orbit outside of Saturn’s rings. Lander Module 4 (LM4) is a crew exploration lander that is designed to land on Ceres, Rhea, and Iapetus. The objective of this paper is to describe the LM4. This lander provides two-way transportation for a nominal two-person crew between a 100 km parking orbit and the surface, and life support for a surface stay of up to 30 days. It can carry three crew members, with reduced payload, for rescue missions. The single-stage LM4 combines the functionalities of lander, shielded habitat, and surface rover into one vehicle. To reduce development cost, the LM4 features a geometrical layout, structural concept, landing gear, and subsystems that are common to those of the other Spaceship Discovery landers, the LM1 Moon Lander, for Jupiter moons Ganymede and Callisto and Earth’s Moon, and the LM2 and LM3 Mars Landers. These landers were presented at the AIAA 2008 and 2009 Joint Propulsion Conferences and are cited in this paper’s references. The LM4 utilizes only vacuum propulsive braking and incorporates technologies from recent NASA Altair lunar lander concept definition studies. It utilizes LH2/LO2 propellants for descent and ascent, and storable monomethyl hydrazine/ nitrogen tetroxide (MMH/NTO) propellants for the reaction control system (RCS). The design incorporates a layer of water inside the crew pressure cabin wall to shield the crew from the interplanetary radiation environment. Design requirements are presented for landing missions to Rhea, Iapetus, and Ceres. Mission requirements for the Saturn moon Rhea mission were the most stressing to the design and sized the vehicle. Propellant can be offloaded to perform the less stressing missions to Iapetus and Ceres. Design requirements, mass properties, configuration layouts, performance data, and mission profiles are presented for the LM4 crew lander vehicle. This lander design is a proposed solution to land humans on the Saturn moons Rhea and Iapetus and the asteroid Ceres. It is based on reliable and proven technology. The LM4 design and operations concept stress safety and redundancy and feature abort and rescue capabilities. Its design incorporates many features in common with the Spaceship Discovery LM1, LM2, and LM3 landers to reduce development cost.