Debris near space station was bigger than reported

* Debris was 5 inches in diameter, not 1/3 of an inch

* Close encounter was with piece of rocket engine from '93

The piece of orbital space junk that forced three astronauts to briefly evacuate the International Space Station on Thursday was bigger than originally reported, NASA officials said on Friday.

The object, identified as a piece of rocket engine that flew in 1993, was about 5 inches (12.7 cm) in diameter, not .35 inches (0.89 cm).

Had it struck one of the pressurized modules aboard the $100 billion space station, the crew would have had only 10 minutes of air, said NASA spokesman Kelly Humphries.

Station commander Michael Fincke and flight engineers Yury Lonchakov and Sandra Magnus slipped inside a Russian Soyuz escape vehicle for about 10 minutes when the potentially destructive space litter came too close for comfort.

Even tiny objects pose a risk to satellites and spacecraft orbiting Earth. Because objects in orbit are moving on different paths, at different inclinations and at speeds of 17,500 miles (28,163 km) per hour and faster, something as small as a grain of sand can impact with the power of a bowling ball moving at 100 mph (160 kph), Humphries said.

NASA had expected the debris to come as close as 2.8 miles (4.5 km) to the station. As of Friday, officials still did not know exactly how close it came.

Radars used to keep track of debris in orbit will first have to get another good fix on its location, said Gene Stansbery, the orbital debris program manager at NASA's Johnson Space Center in Houston.

Stansbery said reports that the object was .009 meters (.35 inches) stemmed from a reference to its cross section, not its overall size. "Whoever put out that blurb misinterpreted that number," Stansbery said.

ADDITIONAL DEBRIS

Station crews have had to take temporary refuge in their escape ships fives times previously for orbital debris issues, said NASA spokesman Kyle Herring.

If time allows, NASA will maneuver the station to avoid coming within 25 meters (82 feet) of a piece of space junk. The path of the debris that flew by the station on Thursday was too uncertain to plot in time, Stansbery said.

With more than 500 additional pieces of debris now in orbit as a result of the crash last month between an Iridium communications satellite and a defunct Russian spacecraft, the U.S. space agency is analyzing new radar maps that can pinpoint objects as small as 0.79 inches (2 cm), Stansbery said.

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