Space “bullet” Punctures ISS Solar Array

Either a space rock or man-made debris punctured a small hole in the International Space Station’s solar array as photographed yesterday by astronaut Chris Hadfield. Credit: NASA

“Bullet hole – a small stone from the universe went through our solar array,” tweeted space station Commander Chris Hadfield yesterday. “Glad it missed the hull.”

Chris Hadfield, a Canadian astronaut and current commander of the International Space Station (ISS), stays in touch with earthlings through his Twitter feed. He posts impressions and observations of Earth from space as well as frequent photos. Click image to follow his feed.

Hadfield photographed the small puncture in the array caused by either a tiny meteoroid or a piece of man-made space junk. There’s plenty of both to go around. Earth gets peppered by over 40 tons of asteroid dust and grit every day.

Man-made orbital debris from decades of rocket launches plus a considerable amount of additional space trash from two anti-satellite tests (in 1985 by the U.S. and 2007 by China)  and a 2009 collision of an Iridium communications satellite and Russian military satellite orbit Earth across a wide spread of altitudes.

Illustration showing the growth in the number of satellites in Earth orbit from the dawn of the space age to 2009. More than 95% of the material now being tracked is debris, ie. non-functioning satellites, rocket stages, etc. Click to read the full report. Credit: NASA

Some 20,000 pieces of debris larger than 2 inches (5 cm) are tracked by NORAD radar and at least 500,000 pieces 1/2-inch (1 cm) and larger occupy low Earth orbit between 99 and 1,200 miles high. It’s here where the space station circles the planet at over 17,000 mph 250 miles overhead.

For perspective, a marble-sized object moving with a relative speed of 10,500 mph (17,000 km) to a satellite or ISS would deliver as much energy as a small hand grenade.

STS-35 Space Shuttle window pit from orbital debris impact. Credit: NASA

The space station proper is protected by its hull from small hits by millimeter-sized objects. Presumably this “bullet” was small enough to not pose a danger. Had it struck Earth’s atmosphere, the bit of debris would have burned completely as a meteor. In orbit, the “skin” that protects astronauts is thin in comparison.

You can read more about orbital debris and how NASA deals with it HERE and HERE.

2 Responses

  1. RC

    In the first picture (which shows the hole in the array), how is the background white? Is it a very large area of clouds, or some type of digital trickery to help show the hole in the array?

    1. astrobob

      Definitely clouds. I lightened the original image up just a bit but you can see white clouds at top (they’re out of focus and soft because the focus is on the array) and blue-colored ocean at bottom right.

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