JOHNSON SPACE CENTER, HOUSTON, Sept. 5, 2012  -- A $100 billion space station saved by a simple $3 toothbrush? It was the brainstorm of astronauts Sunita Williams and Akihido Hoshide and NASA engineers on the ground: a tool to clean a bolt that gave them so much trouble during a marathon 8-hour spacewalk last week.

They were trying to replace an electrical switching unit, but on Thursday they couldn't bolt it to the outside of the station.

What to do if there is no hardware store in the neighborhood and the next supply ship is months away? Build it yourself -- so they attached a simple toothbrush to a metal pole and voila! They were able to clean out the bolt's socket today and finish the job. Shades of Apollo 13 -- when engineers threw parts on a table and brainstormed a solution, which saved the crew.

Spacewalking is incredibly difficult -- the astronauts wear space suits that fight every move they make. Williams wrote about last week's spacewalk in her blog.

"You don't just 'go outside,'" she said. "Usually that is the fun and easy part of the entire thing -- suit sizing, tool gathering and preparation, equipment gathering and preparations, studying new procedures, reviewing and talking through how to get us suited and how to get the airlock depressed, reviewing the tasks we will do with each other and with the robotic arm, talking about cleaning up, and then talking thru a plan to get back into the airlock, and any emergencies that can come up -- loss of communications, suit issues, etc.

"Yes, that took a lot of our time leading up to Thursday last week. Even planning when to go to sleep and what to eat are important. Remember, you are in that suit usually about 8 hours for a 6 hour EVA.

"To my surprise, the most intense part for this EVA happened to be outside when we encountered our 'sticky' bolt.

"That resulted in a long EVA, and over 10 hours in the suit. No bathroom and no lunch."

Williams and Hoshide accomplished their major tasks on today's spacewalk, and earned champagne when they got back inside the space station -- but, alas, there is no alcohol on the orbiting outpost.