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jelizondo [soylentnews.org] writes:

SpaceDaily has an interesting report [spacedaily.com] about a person who survived being struck by debris falling from orbit:

At about 3:30 a.m. on January 22, 1997, Lottie Williams was walking with friends in O’Brien Park in the Tulsa area when a bright streak crossed the sky. Roughly half an hour later, something brushed her shoulder. A small, blackened piece of woven material dropped behind her into the grass. It was light, about 15 centimeters long, and sounded metallic when tapped.

A Delta II second stage had reentered over the south-central United States that morning. Large pieces landed along the same path in Texas, including a 250-kilogram stainless-steel propellant tank and a 30-kilogram titanium sphere. Analysis later found that Williams’s fragment was woven glass fabric consistent with insulation used on the stage.

The evidence is strong, although it is not the same as reading a serial number from the fragment. Williams retained the main piece and supplied material for analysis. Its composition, timing and location matched the reentry. The case is consequently described by NASA, the European Space Agency and The Aerospace Corporation as the only verified report of a person being struck by debris that had fallen from orbit. Williams was not injured.

[...]

The lightweight fragment in Oklahoma was not the only material to survive. The main propellant tank landed near Georgetown, Texas, about 45 meters from a farmhouse. The tank weighed more than 250 kilograms. A titanium helium pressurant sphere weighing about 30 kilograms fell farther along the path near Seguin.

Those tanks left no serious doubt about which vehicle had returned. NASA recorded the stage as object 1996-24B, satellite catalog number 23852. Its path ran from the Tulsa region toward central and southern Texas, matching the order in which debris was found.

[...]

Objects in low Earth orbit travel at several kilometers per second, but falling debris does not retain that speed to the ground. Atmospheric drag removes orbital energy, heats the vehicle and breaks it apart. The fragments that remain then continue slowing through denser air.

A broad, lightweight scrap of fabric has a large area for its mass. Drag slows it readily, giving it a much lower terminal velocity than a compact metal tank. That is why Williams felt a tap rather than an impact resembling a projectile. The fragment could have arrived cool as well as slow; recovered debris is not necessarily still glowing when it reaches the ground.

The episode is therefore a poor illustration of what an orbital-speed collision feels like. It is a useful illustration of what the atmosphere does to different materials during the final minutes of reentry.

Williams remains the only person known to have been directly struck by a piece linked to an uncontrolled orbital reentry. She was unharmed, which matters when the anecdote is used to discuss risk. The event demonstrates that contact is possible; it does not show that injury from reentry debris is common.

Original Submission