When one hears of astronauts conducting repairs on the International Space Station (ISS), it usually involves using sophisticated tools. However, such was not the case in the recent fix that scientists believe may have saved the $100 billion USD Station - All that was needed, was some astronaut ingenuity and, a $3 USD toothbrush.

The nightmare for the six astronauts that currently call it home began last week, when one of its four Main Bus Switching Units (MBSU), responsible for capturing and distributing power from the Station's solar arrays, malfunctioned. Repairing it was crucial to the survival of the ISS given that each 220 pound unit is designed to capture 25% of the ISS's daily energy needs.

But the astronauts were not too concerned - After all, this is the kind of stuff they are trained for. On Thursday August 30th, US astronaut Sunita Williams and Japan's Akihiko Hoshide strapped on their sophisticated tools and took off on a Space walk to replace the broken MBSU with a new one. However, after spending eight hours and 17 minutes - the third longest time spent outside the Space Station in its 12-year history, the two returned home, unsuccessful. Their nemesis? Some metal shavings that were stubbornly stuck inside one of the bolt holes, preventing them from connecting the unit securely.

Dejected, the two space travelers, who had not had any meals or bathroom breaks since they donned their Space suit two hours prior to the failed excursion, secured the new unit with the help of temporary straps and returned to the Space Station to try figure out how to fix the problem.

To make matters worse, on Saturday September 1st, one of the ISS's direct switching units failed, bringing down yet another solar array. With the Space Station now running on only 62.5% of its normal power, things did not look good.

Given that there was no way they could receive emergency tools from Earth, the astronauts knew they had to fix the problem by improvising with things they had around them. After brainstorming a little they came up two ingenious ideas - Using a mesh of wires that had been bent backwards and create a brush to draw out all the shavings stuck inside the socket and then cleaning and lubricating the area with a modified toothbrush and some compressed nitrogen.

Armed with their precious cargo fastened to a metal pole, the two set out again on Wednesday September 6th. While it took four hours of painstaking scrubbing, they were able to clean off all the shavings and bolt in the new MBSU unit successfully - The two astronauts and a toothbrush, had saved the day and the lives of the six astronauts! An added bonus? The extra repair time helped Sunita Williams break the record of 39 hours and 46 minutes set by Peggy Whitson in 2007 for the most time spent on space walks by a female astronaut.

In case you are wondering, no astronaut was asked to sacrifice his/her toothbrush (or teeth) to help with this endeavor - The heroic toothbrush was a spare!

Built to provide astronauts a place to conduct experiments on the effects of weightlessness on plants and animals, as well as, human health, the International Space Station is the most expensive and sophisticated skylab ever built but, it is not the first one. That honor goes to Skylab. Launched by the USA in 1973 it was plagued with problems right from the start and had to be finally brought back in 1979. Though the US hoped to launch a second one, it was the former Soviet Union that proved to be successful with Mir, which hosted astronauts from 1989 to 2001. However that too started having issues toward the end and had to be brought down in what was a fiery entry, in March 2001.

The current Space Station is scheduled to last until 2020 after which it could turn into a base camp for astronauts going beyond near Space, to either Mars or an asteroid. Or, it could just languish in the skies as the largest piece of space junk - We sure hope it is one of the former two!

Resources: theatlantic.com, dailymail.co.uk, about.com