here is Nasa's explanation of the tether footage
tetherSTS-75 'Tether Footage'
Probably the most controversial of all NASA mystery object footage would be the STS-75 'Tether Footage' of 1995. Claims by UFO researchers that the footage shows UFO Discs up to 3 miles in diameter moving BEHIND the broken tether satellite cable caused a stir among researchers around the world. Hundreds of the mystery illuminated objects were captured in this footage. Larger 'discs' move through the field of view while the broken Tether is being video taped by the shuttle crew.
I have undertaken extensive video enhancements and analysis of this particular footage and here are some of my findings;
1. When the NASA camera is zoomed back to wide angle, many small illuminated objects are 'swimming' around in view. They are ALL small 'dots' of light. They are all in focus due to the long depth-of-field of the low light lux of the camera. There are NO large 'discs' in the scene.
2. When the camera zooms into the Tether, the camera zooms THROUGH many of the small objects, meaning they are between the tether and camera. (There could well be some beyond the tether if that whole area of space contains these objects) Here you see the smaller objects actually enlarging into the so called 'UFO Discs'. These are actually now out-of-focus small objects.
3. Now zoomed into the tether, the depth-of-field of the powerful zoom is very narrow. Meaning that focus is critical and anything outside this narrow focus field would be out-of-focus. The larger 'discs' now have notches in their rim. This is an in camera zoom lens feature. Not an actual notch on the object.
4. When some larger 'discs' move from one side of the frame to the other, this notch changes position from top of the 'disc' to the bottom of the 'disc'. This is caused by the convex shape of the lens in the zoom, not rotation of the 'disc'.
5. These out-of-focus 'discs' are called Airy Discs and are a common feature when filming a small illumination if way out-of-focus.
6. When zoomed into the tether and the 'discs' are large, the camera zooms back. The large 'discs' now revert back to small points of light. Where did the large 'discs' go too? They are just the small objects now in focus.
7. The large 'disc' that is said to move BEHIND the top of the tether, in fact moves INFRONT of the tether. Image enhancements show the tether top is partially covered as the 'disc' moves past. Airy Discs are semi-transparent due to the out-of-focus effect, and some of the tether is seen, but is reduced in clarity when seen through the Airy Disc passing INFRONT. As the 'notch' passes the tether, more of the tether is exposed. Tether is again covered as the rest of the 'disc' passes. Further proof of passing INFRONT.
8. What this means is, that the large disc is actually a small out-of-focus object much closer to the camera than the tether. It is not a UFO disc as claimed by many. You do not see any of these 'discs' in a side-on or other angle view, they are all round Airy Discs.
10. The pulsing of the object is less easily explained, unless the object is spinning or actually pulsing.
11. These objects could also be the mysterious "Space Critter". They move in all directions at various speeds. I have not seen any that actually change direction in flight.
12. The most conclusive test during my analysis was when I stabilized the top of the tether. On the video clip, I drew a line from the center of the 'disc' to the now steady top of the tether. When the camera jolted up and down in this section, any variation in movement between the 'disc' and tether would be seen. The principle used is that closer objects move more then distant objects in the field of view. Test this by bending at the knees while video taping a scene containing close and distant objects. The closer object moves more than the distant objects.
The test would show NO movement variation if the large 'disc' was at or behind the tether at the 100 mile distance of the tether. If the 'large disc' was INFRONT of the tether, than some variation in relative movement would be seen. And this is exactly what the test showed. This is proof that the large 'disc' actually moves INFRONT of the tether by quite some distance. Otherwise the movement difference would not have occurred.
If all these objects are space junk or disposed water from the shuttle turned to ice, then NASA should be fined for Space pollution. But I do not consider this to be the case.