The idea of a sustained human presence in space has long captured the American imagination. Yet, even as construction of the International Space Station inches forward, massive cost overruns threaten to turn the dream of Americans living in space into a taxpayer nightmare.

The space station recently received a $310 million boost from a House Appropriations Subcommittee, increasing its budget for next year to $1.83 billion. If completed, the station will require an investment of $334 from every taxpayer in the country.

But egregious cost overruns — now estimated at $4.8 billion — have forced NASA to cut back scientific experiments on the space station, giving taxpayers less science for even more money.

The cost overruns are due in part to gross mismanagement at the space agency. An internal NASA memo earlier this year revealed that the agency had underestimated operating costs by $846 million over a four-year period.

NASA has also spent $1 billion on projects  that will likely never be built. In one example, the agency spent 19 months and $97 million on a propulsion module design before rejecting it.

Budget woes are not new to NASA. A 1998 independent review concluded that NASA would exceed the $17.4 billion budget for the station and would have trouble even staying within a revised budget of $26 billion.

NASA's ongoing partnership with Russia further complicates the station's budget picture. Bringing Russia onto the project in 1993 was supposed to save NASA $2 billion, but the U.S. has spent millions combating delays and helping the bankrupt Russian Space Agency keep up its end of the bargain.

Due to the budget overruns, scientific experiments on the station have already been cut by 90 percent. NASA estimates that it takes 2.5 people to operate the station. But cost overruns will limit the crew to three people, leaving only half of one person's time to conduct scientific research.

The House Appropriations Committee has assigned a special team to investigate the overruns in an attempt to get the space station on budget, while allowing the station to become a top of the line scientific research center.

That's a good idea. Space research is an important national investment, but taxpayers should get the science they are paying for, not be forced to foot the bill for NASA's mismanagement.