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NASA

Low Quality Alloy Cause of Shuttle Main Tank Issue 118

BJ_Covert_Action writes "NASA engineers have finally discovered the root cause of the cracks that have been found on space shuttle Discovery's main external tank. The main tank, one of the 'Super Lightweight Tank' models developed by Lockheed-Martin, employs an aluminum-lithium alloy developed by Lockheed-Martin specifically for this application. The new alloy is used in various structural stringers throughout the SLWT design. Unfortunately, the batch of this alloy used in the tank that is currently mated with the Discovery shuttle appears to be of low quality. The alloy used in the stringers has a 'mottled' appearance, compared to the nominal appearance typically used in the main tank stringers (see picture in article). This appearance is indicative of a fracture threshold that is significantly lower than typical. NASA has determined, through testing, that this low grade alloy has only 65% of the fracture strength of the nominal alloy typically used. NASA engineers have devised a potential fix to the problem that they are currently testing to ensure the repair will cause no unintended consequences. NASA plans to have the Discovery shuttle ready to launch again by February 24th, 2011."
Media

1928 Time Traveler Caught On Film? 685

Many of you have submitted a story about Irish filmmaker George Clarke, who claims to have found a person using a cellphone in the "unused footage" section of the DVD The Circus, a Charlie Chaplin movie filmed in 1928. To me the bigger mystery is how someone who appears to be the offspring of Ram-Man and The Penguin got into a movie in the first place, especially if they were talking to a little metal box on set. Watch the video and decide for yourself.
Image

White House Correspondent Tweets His Heart Attack 77

Tommy Christopher, who writes for mediate.com, has reporting in his blood, so much so that he livetweeted every part of his recent heart attack. "I gotta be me. Livetweeting my heart attack. Beat that!" and "This is not like the movies. Most deadpan heart attack evar. Still hurts even after the morphine," were among his updates as he was rushed to the hospital. Christopher is now in stable condition after recovering from emergency surgery.
Earth

New Estimates Say Earth's Oceans Smaller Than Once Believed 263

Velcroman1 writes with this snippet from Fox News: "Using lead weights and depth sounders, scientists have made surprisingly accurate estimates of the ocean's depths in the past. Now, with satellites and radar, researchers have pinned down a more accurate answer to that age-old query: How deep is the ocean? And how big? As long ago as 1888, John Murray dangled lead weights from a rope off a ship to calculate the ocean's volume — the product of area and mean ocean depth. Using satellite data, researchers from the Woods Hole Oceanographic Institute set out to more accurately answer that question — and found out that it's 320 million cubic miles. And despite miles-deep abysses like the Mariana Trench, the ocean's mean depth is just 2.29 miles, thanks to the varied and bumpy ocean floor."

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