International Space Station

The ISS is enthusiastically supported by many people who are interested in space travel for its own sake and by those scientists who hope to fly their own experiments on the platform. However, it has long been heavily criticized by a majority of the scientific community for delivering too little science for the dollar and thus, in effect, diverting money from more effective research. Some scientists argue that the bulk of the research planned for the ISS addresses technical questions that are peripheral, rather than fundamental. For example, Science, the journal of the American Association for the Advancement of Science, complained in 1998 that the ISS's "greatest impact will be felt in the small community already studying problems related to spaceflight—a vital research area only if we assume that increasing numbers of people will someday travel, or even live, outside of normal Earth gravity." In other words, the ISS is an ultimately romantic project that puts astronauts in space in order to figure out how to put more astronauts in space.

The claim that the ISS has little to offer science was boosted by Russia's conveyance to the ISS of two private space tourists—officially designated Space Flight Participants—in 2001 and 2002, over loud protests from other ISS participant nations. Two wealthy men, one American and the other South African, paid $20 million apiece to the cash-strapped Russian government in exchange for a trip to the ISS.

Even before the loss of the space shuttle Columbia in February 2003, funding for completion of the ISS was in doubt. Both the United States Congress and the governments of the European Union have long been skeptical of the ISS's costs, and NASA was under such political pressure that it admitted it could not guarantee that the station will ever be grown beyond the "core complete" stage, with long-term living quarters for only three astronauts. Three astronauts, however, are not enough to tend the scores of experiments for which the ISS's racks have room, so if the ISS is not expanded much of the science potential already constructed will go to waste. Critics of the ISS argued that continued support for the ISS amounted to throwing good money after bad; supporters of the ISS counter-argued that ISS research is essential for make an eventual trip to Mars and that human space-travel projects generate valuable technological spinoffs.

The Columbia disaster of early 2003 has, as of this writing, made the ISS's future murkier. Although Russian rockets can supply many of the ISS's needs and ferry astronauts back and forth to it, only the space shuttle's cargo hold is large enough to carry many of the components planned for the ISS. Another, more urgent factor is that the ISS loses orbital altitude steadily due to friction with the outer fringes of the earth's atmosphere. Small rockets attached to the station regularly restore its altitude. The fuel for these rockets has been delivered via space shuttle, but after the Columbia disaster, a long delay seemed certain before frequent shuttle flights could be resumed, and Russian spacecraft have not been designed to deliver sufficient fuel. Engineers in both Russia and the United States have proposed alternate solutions, but as of March 2003 no firm course of action had been approved.