New images offer wealth of shuttle insight

Shortly after the big piece came off the tank, the camera spotted a more alarming event — a bright flare emerging from behind the shuttle, probably on its aft structure. Was this a fuel tank rupture or an impact on the invisible side of the vehicle? This kind of flare had never before been seen, and it got the attention of observers both inside and outside of NASA.

This turned out to be an "ordinary" event as well, however. The flare occurred at the precise time that the shuttle ignited its auxiliary propulsion system to give a small extra boost into space. This is a fairly new procedure, and the only other shuttle flight with an external camera had seen its lens contaminated by thrusters from the solid rocket booster separation — so it couldn’t have seen the flare even if it occurred on that flight.

NASA also released images taken from ground cameras just as the shuttle cleared the launch tower, confirming eyewitness accounts of white dots coming off the nose. These weren’t feathers (although another image showed a bird actually being rammed by the ascending tank), but scraps of paper installed over the nozzles of steering thrusters to keep rainwater out.

These deliberately had been modified to tear off early, because earlier designs had held on until nearly supersonic speeds and when they ultimately tore loose, they rammed the cabin front windowsills so violently that they sometimes jammed fragments up under the outer glass layer. The addition of mini-parachutes had been announced by NASA shortly before the shuttle launch, and it was speculated at the time that they would show up almost immediately after launch as falling white dots.

Once the shuttle main engines shut down, and with the video link unbelievably still hanging in there, small particles could be noticed drifting away from the vehicle. At least two of them moved in straight lines and suddenly swerved back towards the tail.

A moment’s thought — and some back-of-the-envelope calculations — showed why this surprise should have been predictable. Even at 18,000 mph, the shuttle was still just at the upper edge of the atmosphere. With an altitude of 55 miles, it was legally not even in "outer space." The very thin air was enough, at such very high speeds, to create an aerodynamic push with the strength of a light breeze back on Earth.

The thin air also, astonishingly, manifested itself as flickering glows along the leading edge of the shuttle as it pulled off the tank. What we were seeing — what we had never seen before —was the angry glow of ionized gasses torn apart by high-speed impact with the spaceship. Such glowing plasma envelops spacecraft falling back into the atmosphere, and it should have been expected to be visible on the way up through the same air layers, but it still caught me by surprise.

The more we open our eyes, on shuttle flights and elsewhere in space, the more surprises we experience. But these results should hardly be reason for excessive worry. Keeping new eyes closed, and opting not to look, has always worried me a lot more.

James Oberg, space analyst for NBC News, spent 22 years at the Johnson Space Center as a Mission Control operator and an orbital designer.

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