Posted on 02/03/2003 4:43:52 PM PST by Wolfstar
Edited on 04/29/2004 2:02:01 AM PDT by Jim Robinson. [history]
Released Monday morning, a high-speed NASA engineering film shows a piece of debris falling from the large external tank on the space shuttle Columbia's liftoff and hitting the orbiter's left wing. Bear in mind that these are extreme close-ups of a high-speed event. In the top couple of photos, you see only the top of the broken-off piece. Most of it is in the shadows. Depending on which clip you see and how slowly it is run, to the uninitiated person's eye, it can look either like the debris strikes the wing hard enough to pulverize the debris, or the debris strikes a glancing blow and bounces off in the direction of the main and booster engine exhaust.
(Excerpt) Read more at cnn.com ...
Maybe for the same reason a commercial flight has no parachuttes for the passengers. Cost/benefit.
I have seen two different clips (different resolutions) of this exceeding brief incident, and the clips were run at two different ultra slow motion speeds. In one clip, it looks as though the object hits straight into the wing pretty sharply and the object disintegrates. In the other, it looks as though the object hits just a glancing blow and bounces off (intact) towards the exhaust. The point is that, even to my untrained eye, both how hard and where the object hit the wing is open to interpretation.
In any case, I am convinced that it would take a highly educated eye to correctly interpret what we see in that video and stills coming from it. (That's "educated" in the sense of familiarity with the launch vehicle and orbiter.)
That's why I posted the photos, in the hopes that someone more knowledgeable than I might interpret them for us. Too bad many people have chosen to debate the silly notion that Mission Control is, in effect, a bunch of cold-blooded murders.
But I would assume that in the weightlessness of space that an arm could be pretty spindly and light here, but still be functional there.
It's certainly cheaper and doesn't require more than basic electronics to guide it reliably, in addition the arm has no fuel consumption requirements to place it's use into the "time sensitive" category..
I would go with a tublar arm with drive motors and geared friction devices (like a volkswagon bumper jack, simplistic example) for extension and rotation driven by stepper motors, all run by a microcontroller with a camera on the end.
Okay, go ahead and blast me out of the sky now..
(So to speak.. :)
The shuttle may have been moving in excess of 1000 mph, but remember the "brick" started out moving at the same speed. The actual relative speed between the two would actually be very small. The "brick" stopped accelerating when it broke off and only traveled a small distance before hitting the wing.
At what altitude? Yes, I neglected the effect of the wind, but the higher the altitude, the less important that is. At whatever altitude, the object will only take on the air's velocity quickly if it's not very dense. If it's not very dense, it's not going to have all that much energy/momentum when it hits the wing. I think I heard this afternoon, that they were at 80 something seconds when the debris hit the wing, so they were fairly high. High altitude works in favor of it speeding up, relative to the shuttle, less quickly. If they were doing 1000 mph at the time, they were already fairly high
Whatever it was didn't appear to fall from the top of the tank, but rather from the forward attach point.
Sounds about like the density of dense foam insulation. I'm thinking that its that kind-of hard, brittle stuff that turns to dust when you hit it with a baseball bat. At any rate, its quite a bit larger than a laptop computer and much lighter. I don't think this stuff can even break glass if that's what it is.
Someone else raised the doubt that this foam object hitting the wing is the initial cause. I really don't know, but I'm also suspecting that it is a dead-end street. It's the media's cause; not necessarily NASA's.
The best they could have done, I believe, to increase their chances would have been to dump as much weight as possible. Eject science experiments, suits, food, water, anything to reduce the overall shuttle weight... then pray as they returned.
There was no magical alternative path to keep them safe.
They are not like a motor that goes "zizz" when powered.
They are used for precise movement in X-Y tables and such.
Such a thing could probably be made to be even lighter and work even better today, due to "solid state" gyros and accellerometers, along with cheap microprocessors, than it's designers are likely to have ever envisioned. (The "pad" is really a bag that gets filled up with foam just before use, thus not taking up much space when not needed.) As I said before though, it would be one hell of a ride.
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