cost of space transport is directly related to the delta-v, or change in velocity required to move from the mining sites to the manufacturing plants. Bringing material to Earth orbit from bodies such as Near-Earth asteroids, Phobos, Deimos or the lunar surface requires far less delta-v than launching from Earth itself, despite the greater distances involved. This makes these places economically attractive as sources of raw materials. See also Acid leaching Asteroid mining In situ resource utilization ISS manufacturing Self-replication Space-based economy Space colonization Space elevator Spacelab Varda Space Industries References Further reading Andrew H. Cutler, Metallurgical Properties of Lunar and Asteroidal Steels, 7th Princeton/AIAA/SSI Conference, 1985. David Gump, Space Enterprise: Beyond NASA, Praeger Publishers, 1990, . T. A. Heppenheimer, Colonies in Space, 1977, Stackpole Books, . Lewis, J., Matthews, M.S., and Guerrieri, M.L., Editors, 1993, Resources of Near-Earth Space, University of Arizona Press, 1993. . External links PERMANENT — near-term space resource utilization Space Studies Institute SKYLAB: A Guidebook (see Chapter 5, section 4) Spacehab Wake Shield Facility program v:Lunar Boom Town A role playing study group at Wikiversity where participants plan and study future space ventures.