The International Space Station has been a colossal undertaking among five space agencies whose final price tag will likely be in the vicinity of $100 billion dollars. (The U.S. construction costs alone are estimated to be $31 billion.) Just this year the station finally reached its full capacity of six crew members, but it is still under construction—space shuttle Endeavour sits at the ready today to deliver to the ISS pieces of a Japanese experiment module.

But the ISS program manager for NASA is warning that without a change in policy, all that work will go plunging into the ocean in 2016, just six years after the scheduled completion of the station. "In the first quarter of 2016, we'll prep and deorbit the spacecraft," Michael Suffredini told the Washington Post. The ISS's long-term funding from NASA terminates in 2015, the newspaper notes.

Suffredini's public comments may be intended to simply raise the alarm, and indeed, he makes no bones about his position on the issue. "My opinion is it would be a travesty to deorbit this thing," he told the Post. "If we get rid of this darned thing in 2015, we're going to cede our leadership in human exploration." He also says that NASA is looking at what would be needed to keep the station going deep into the 2020s.

So what will the inevitable deorbiting look like, whether or not it comes in 2016? According to a 2000 report by the National Research Council, 80 percent of the debris generated as the station breaks apart will burn up before reaching Earth. The rest will be scattered across a vast ellipse as great as 300 kilometers by 5,370 kilometers, a debris field nearly as large as the land area of Alaska. The eastern Pacific Ocean, the report surmises, provides the least dangerous destination for that debris.

Artist's rendition of a completed ISS: NASA