This proceedings, ""Space 98"", includes papers from Space 98: The Sixth International Conference and Exposition on Engineering, Construction, and Operations in Space; and Robotics 98: The Third International Conference and Exposition/Demonstration on Robotics for Challenging Environments convened in Albuquerque, New Mexico, from April 26-30, 1998. The theme of the Space 98 conference was constructed in space as demonstrated by the continuing activities with the International Space Station. This theme is also part of Developing Resources of Greater Earth for Humankind. ""Greater Earth"" is a concept that refers to the resources available on Earth, in space between the Earth and the Moon, and on the Moon, Mars, and near-earth asteroids. Space resources include solar energy, vacuum, temperature differentials, and orbital position. Lunar resources include stable sites for observatories, mineral resources, shielding materials, and sites for bases. ""Space 98"" covers such topics as: access to space and future activities worldwide; dynamics and control of space structures; space tourism; commercialization and commercial projects in space; international space station; Mir Orbital Station; simulation of space, lunar, and martian environments, gravity, and soil on earth; siting and constructing of extraterrestrial bases; characterization, mining, and use of in situ materials of the Moon, Mars, and asteroids in concrete and other forms; and habitats and controlled ecological life support systems. The purpose of this proceedings is to encourage and stimulate planning, positive and productive interactions, and development of needed technologies and expertise for exploration of space.