Jack Rasher, Ph.D.


On September 15, 1991, Space Shuttle Discovery videotaped several anomalous, glowing objects that floated along and then sharply changed direction, apparently in response to a flash in the lower left portion of the picture. Shortly afterwards two streaks passed through the regions vacated by some of the objects. The film attracted a great deal of attention because of the possibility that the accelerating objects were spacecraft maneuvering out in space away from the Shuttle. Four NASA scientists viewed the videotape and suggested that the objects were ice particles accelerated by the Shuttle's attitude adjustor rockets. Their analysis was qualitative, and did not include any numerical calculations.

This paper is a quantitative, scientific study of the videotape. Starting with a frame-by-frame analysis of the position of the main object, the author would have been able to obtain all three of its velocity components, as well as its location, if it truly were an ice particle. In the process he has developed five separate proofs that the main object could not have been an ice particle near the Shuttle. This and other prosaic explanations can be easily dismissed. The only viable alternative that remains is that it was a spacecraft; and the other objects, since they reacted at the same time as the main one and in similar fashion, were probably spacecraft, too. This paper concludes with a discussion of the implications of these conclusions.

What follows is the main text from a report I have filed with the Fund for UFO Research, which provided partial financial support for this work. For the sake of brevity the author has omitted the appendices, even though there are several references to them in the text. The entire report can be obtained from FUFOR.


On September 15, 1991, between 20:30 and 20:45 Greenwich Mean Time, the TV camera located at the back of Space Shuttle Discovery's cargo bay was trained on the Earth's horizon while the astronauts were occupied with other tasks. A glowing object suddenly appeared just below the horizon and slowly moved from right to left and slightly upward in the picture. Several other glowing objects had been visible before this, and had been moving in various directions. Then a flash of light occurred at what seemed to be the lower left of the screen; and the main object, along with the others, changed direction and accelerated away sharply, as if in response to the flash. Shortly thereafter a streak of light moved through the region vacated by the main flash, and then another streak moved through the right of the screen, where two of the other objects had been. Roughly 65 seconds after the main flash, the TV camera rotated down, showing a fuzzy picture of the side of the cargo bay. It then refocused, turned toward the front of the cargo bay, and stopped broadcasting.

I traced the trajectories of several of the glowing objects, and of the two streaks, by placing a transparency over a 13-inch television set. The results are displayed in figure 1. The air glow is a region above the Earth's surface that ends at an elevation of about sixty miles.

Donald Ratch, a UFO researcher in Maryland, happened to be taping the sequence on NASA Select, a national cable TV channel that broadcasts NASA activities. He thought the sequence quite unusual, and wrote to his congresswoman, Ms. Helen Bentley, requesting that she look into what the glowing objects might have been. In addition, he contacted Vincent DiPietro, a NASA engineer at Goddard Space Flight Center in Greenbelt, Maryland, who also found the videotape interesting enough to write to his congresswoman, Ms. Beverly Byron, asking her to research what the objects might have been.

Ms. Byron sent the tape to George E. Brown, Jr., chair of the Congressional Committee on Science, Space, and Technology, who showed it to several members of his staff. They concluded that the glowing objects were probably ice particles that had been ejected by the Shuttle, and that their sudden change in direction was caused by a blast from the Shuttle's attitude adjustor rockets (which change the orientation, or pitch angle, of the Shuttle as it floats in orbit around the Earth). This would also explain the flash in the lower left part of the picture. Ms. Bentley sent the tape to Martin P. Kress, an assistant administrator for legislative affairs at NASA. He showed it to four NASA scientists, who concurred that the objects were probably ice particles accelerated by the adjustor rockets. To the best of my knowledge, the individuals who suspected ice particles merely watched the videotape, and did no further scientific analysis. Also, it appears from the wording of the letters that these individuals did not comment specifically about the two streaks that went through the picture several seconds after the glowing objects accelerated. It is possible that they meant to include the streaks with the other objects when they spoke of ice particles. Copies of the replies from Congressman Brown and Mr. Kress are included in Appendix K.

There are several other possible explanations for the objects seen in the videotape, in addition to the ice particle theory. Some have suggested that they were tiny particles near the camera lens, instead of ice particles dozens of feet from the Shuttle. Other prosaic explanations might be that they were meteors, satellites, or space junk. Finally, and most spectacularly, they could have been some kind of spacecraft maneuvering in outer space away from the Shuttle. This is a necessary conclusion if none of the other explanations holds up, since the main object clearly accelerated and moved above the Earth's airglow in the videotape. Thus, it would have been an intelligently directed craft that was above the atmosphere; that is, it would have been a spacecraft. Let us look at each of these possibilities in greater detail.

The objects could not have been tiny particles close to the camera lens, since the camera was focused at infinity, as can be seen on the videotape when the camera turns down until the side of the cargo bay is visible. As I mentioned above, the cargo bay was obviously out of focus at first; so any tiny particles near the camera would have been indistinguishable blurs, and would not have been visible.

Also, the glowing objects clearly cannot be meteors, satellites, or space junk, since none of these can change direction. This leaves us with only two alternatives--the objects were either spacecraft maneuvering out in space away from the Shuttle, or ice particles on the order of dozens of feet from the cargo bay. I will now give five separate proofs that the main object in the videotape could not have been an ice particle; and thus must have been some kind of spacecraft. Once that has been established, I will discuss the extraordinary ramifications of these events.


The University of Wisconsin supports a microbiology laboratory in Milwaukee near Lake Michigan. The laboratory, headed by Dr. Rudy Strickler, has research equipment that includes computer software designed to track small living creatures that have been filmed in Lake Michigan. The software uses a 640 by 480 pixel grid that is placed over the picture, and the x  and y coordinates of the creatures are obtained, frame by frame in 1/30th of a second intervals, as they swim though the water. The equipment and software are ideally suited to track the glowing objects in the shuttle videotape. Thanks to a grant from the Fund for UFO Research I was able to hire two students who work for Dr. Strickler, Guy Hussussian anf John Reimer, to track several of the objects. As a result, I ended up with 30 x-y position coordinates per second for the objects over multiple ranges around the main flash, and position coordinates at one second intervals for several seconds before the finer data. I was then able to graph the data, take numerical derivatives, and calculate nonlinear least-square curve fits to obtain the desired results. My methodology is described more thoroughly in the appendices of this report, and to some extent in the main sections as well.


Figure 2a  shows the horizontal position of the main object as a function of time. In figure 2b we see a portion of the data on much smaller vertical and horizontal scales. This is the raw data, extracted frame-by-frame from the videotape taken by the Shuttle. The numbers along the vertical axis are the pixel locations of the main object, increasing from left to right on the videotape. Thus, the line will extend down and to the right as the object moves to the left, and up and to the right as the objects moves back to the right.

Notice that the line stays even at 233 pixels from about one second to 1.5 seconds. This means that the object stops and sits there during this period. We would not expect an ice particle accelerated by an attitude adjustor rocket to do this. The rocket exhaust would exert a continuous force on the ice particle, causing it to slow down, stop only at an exact instant of time (for example, at 1.2 seconds exactly), then immediately start back to the right. It is difficult to conceive of a mechanism by which a rocket exhaust could stop an ice particle and allow it to sit at its location for about half a second, then accelerate back to the right.

The objection could be raised that the "stopping" is actually a viewing angle effect, like when we stand at the edge of a highway and watch a car as it passes by us and drives off into the distance. The further away it gets, the slower it seems to be going. This objection doesn't hold up, for two reasons. First, the object would never actually appear to stop--it only would continue to appear to be going slower and slower. Second (and more significant), the location where the main object would appear to stop due to a viewing angle effect is almost 300 pixels farther to the left than the actual location of the object. This is nearly five times farther to the left of center than where the object actually was, and is actually off the TV screen (the details of the proof are given in Appendix F). The actual location of the main object at the time of the flash and the spot where it would appear to stop due to a viewing angle effect are shown in figure 3. Clearly, the object actually stops.

Another interesting bit of information, and possibly another proof that the object is not an ice particle, is the following. In Appendix E, I show that the velocity components of the main object before the flash, in the Shuttle's frame of reference and in pixels per second, are vx/r1  = -9.1, vy/r1 = 16.8 ± 1.0, and vz/ r1 = 25.1 ± 1.0, where r1 is the distance to the object as it passes through the horizontal center of the screen. The ratio vz/vy allows us to draw the vector indicating the direction the "ice particle" was moving before the flash, and is shown in the rear view of the Shuttle in figure 4. The force that stops the object would have to be directed toward the Shuttle from out in space. It is difficult to see how an attitude adjustor rocket could do this.

In my description of the events given above, I mentioned that there was a flash of light in the lower left part of the screen. Actually, two separate flashes occurred--a short preflash, and then the main flash. It is of interest to note when the two flashes occurred with respect to the flat line in figures 2a and 2b, the pre-flash started and finished just before the main object stopped, and the main flash began at or just after this time. The pre-flash lasted 150 milliseconds, and the main flash 400 milliseconds. This is another problem for the ice particle theory. The Shuttle has two kinds of attitude adjustor rockets--regular strength for stronger thrusts, and much tinier, vernier rockets for very small changes in orientation. I show in Appendix J that only one of the Shuttle's forty-four adjustor rockets could have supplied the acceleration for the main object, if it really was an ice particle. This rocket was one of the six verniers. The vernier rockets can either fire in 80 millisecond pulses, or continuously for intervals from one to 125 seconds. The durations of the flashes, 150 milliseconds and 400 milliseconds, do not match these numbers. In figure 5 we see the brightness curve for the 400 millisecond pulse, as supplied by Jeff Sainio, MUFON photo analyst. The shape of the curve strongly suggests that there was only one pulse, not a combination of pulses totaling 400 milliseconds. According to Sainio, "....assuming the gamma curve that produced this curve is fairly flat . . . I doubt that persistence distorted this curve much." Sainio made an adjustment for persistence for the curve, as calculated by using lightning previously shown in the videotape. This indicates that the curve is a true representation of the actual brightness of the flash.

A corollary to this proof, and perhaps a separate proof on its own (call it proof la), is the following. I show in Appendix I that if the main object were an ice particle, it was about 65 feet from the vernier rocket that would have done the accelerating. I also show below in section 7 that the exhaust velocity of the vernier along the line leading to the main object would have been about 8450 ft/sec. This means that the exhaust would have reached the main object, and the main object would have had to start accelerating, in a time interval of 65/8450 seconds, or less than 0.008 seconds. The object actually started accelerating nearly a full half second later, or more than sixty times longer than the 0.008 seconds. It is simply not possible for an ice particle to behave in this fashion. The pre-flash and main flash are shown in figure 6. In terms of this figure, the curve for an ice particle would have to start turning upward on the left side of the box that defines the flash, instead of where it actually does start up.

Another approach to the same idea is this. If the exhaust took half a second to reach the "ice particle," then the particle must be about 4200 feet away (roughly half of 8450 ft/sec.) It is hard to imagine that the particle could have drifted that far away, much less that it would still be visible at that range. Yet, another aspect of this idea is given below in proof number five, where the numbers are even more difficult to reconcile with the ice particle explanation.


The second proof that the main object is not an ice particle also proves that the object just below and to the left of it is not. The proof is based on the trajectories of the two objects after the main flash, and is perhaps best illustrated with an analogy.

Suppose two dandelion seeds are floating motionless in the air near my mouth. If I blow on them, they will each move away from my mouth along the lines that connect my mouth to their original positions (see figure 7). To locate my mouth, one only needs to extend these two lines backwards, and my mouth will be at the point where the two lines meet. Similarly, if two ice particles are at rest, and are then blown by an attitude adjustor rocket, we can locate the rocket by drawing lines back along the trajectories of the two particles. If the rocket did the blowing, the lines must meet, and they must meet at the location of the rocket. Recall that in Appendix J, I prove that only one rocket, a vernier, could have accelerated the objects. The two lines, when extended back, would meet at the location of this rocket.

We need to modify our analogy somewhat to fit the real situation. As I will show shortly, the second object was at rest in the horizontal direction, but was floating up vertically a tiny bit at the time of the flashes. This corresponds to the second dandelion seed having a slight upward motion when I blow on it. If we can subtract out this upward motion, what is left has been provided by my mouth. So the line must be drawn back in the direction of the final velocity with the original upward component removed.

We now need to look at the velocities of the main and second objects before and after the flashes. Notice that in the previous proof I analyzed only the horizontal velocity component of the main object as seen in the videotape. This is all that is necessary to prove the point, since a zero horizontal component means that both vx and vy were zero for a full half second. An ice particle cannot stop and sit for half a second in these two directions. We now need to establish that the third component was also zero during this time span. This can be done by analyzing the vertical position of the main object as a function of time. The curve is shown in figure 8 over a longer time span, and in close-up in figure 9. (Note that the data is somewhat noisier for this curve. This is due to the fact that the main object did not move upward in the picture very much.) The vertical position remains constant for nearly the same length of time as the horizontal position does. Since vx and vy have already been shown to be zero, the equation for vzo(see Appendix D),

vzo = -d theta/dt = -(vx/r) cos theta cos theta - (vy/r) cos theta sin theta + (vz/r) sin theta, (D5b)

collapses into vzo = vz sin theta = 0. Since theta is a nonzero constant, the only possibility is that vz is also zero. In other words, the main object is completely at rest during this time period.

We now need to establish that the second object is also at rest, or nearly so. In our analysis we do not need to prove that each of the three velocity components were zero. We only need to show that the horizontal and vertical velocities in the videotape were zero. The reason for this is that when an object is moving in a straight line with a constant velocity, it will appear to an observer to be moving in a straight line, no matter what the observer's viewing angle is. Thus, when an object moving with a constant velocity is filmed, the camera will "see" it trace out a straight line in the picture it captures, and the object will also move in a straight line when it is seen on the TV screen. So if we trace this line back on the flat screen, we will see where the object came from; or, if it started from rest, we will see where the push that accelerated it came from.

The horizontal position of the second object is shown in figure 10 , with a close-up in figure 11 . The flash and preflash are shown in the latter figure. The horizontal position clearly did not change for several seconds before the flashes.

The vertical position probably does change slightly, though, as shown in figure 12 . If the object were an ice particle, the adjustor rocket would add to this (tiny) vertical movement when it fired. The amount added, and hence the acceleration provided, can be calculated from the difference in the slopes of the vertical position curves before and after the flash. From the data these slopes were determined to be 0.95 before the flash, and 3.61 after. This means that 100% x (3.61 - 0.95)/3.61 = 74% of the vertical motion after the flash would have been provided by the adjustor rocket. Thus about one-fourth of the upward motion of the second particle needs to be taken out before we trace its trajectory back to the rocket.

In figure 13 we see the two lines we need to compare. The main object's trajectory is simply extended straight back, since it was completely at rest. The adjustor rocket must be somewhere on this line. The second object's added velocity is determined by choosing a point on the trajectory after the flash. We then draw a right triangle connecting the two points with horizontal and vertical legs. Since all of the horizontal motion and three-fourths of the vertical motion would have been added by the adjustor rocket, we draw a line from three-fourths of the way up the vertical leg back through the position at the moment of the flash. The rocket must be located somewhere on this line.

Obviously, the two lines diverge--there is no way that they will ever meet at one point. If they were ice particles accelerated by the one possible vernier rocket, the two lines must meet at one point. This proves that the two objects were not ice particles accelerated by the vernier adjustor rocket.

We can extend our discussion to include the fast and slow objects on the far right in figure 13, although the case isn't as strong, since they were both moving at the time of the main flash. If we assume that these two "ice particles" were so strongly blown by the adjustor rocket that their final trajectories coincide with the directions they were blown in, then we can draw lines straight back from their final paths, and these lines must also meet at the location of the adjustor rocket. The lines obviously diverge much more than the first two did; but our argument is weaker because of our assumption about the strength of the rocket exhaust.


In Appendix I, we see that the actual terminal speed of the "ice particle" would have been 5.5 ± 0.7 ft/sec, and that it would have been 77.7 ± 5.3 feet from the camera when it crossed the horizontal center of the screen. In Appendix B, I also show that an ice particle would have to reach a terminal velocity equal to 98% of the exhaust velocity of the vernier rocket. This velocity is about 8800 feet per second along the central axis of the exhaust. Since vy and vz for the object are 3.0 ± 0.5 and 4.1 ± 0.5 feet per second, respectively (see Appendix I), the object is at a 53.6 degree ± 7.8 degree angle in the y-z plane with this central axis. Thus, the maximum angle in the y-z plane between the object's velocity vector and the central axis of the vernier's exhaust is nearly just over 61 degrees. Figure 14 shows a velocity profile calculated for one of the main adjustor rockets. This figure was taken from a paper on plume impingement modeling delivered in October, 1990, by Don J. Pearson, either at Rockwell International or at Johnson Space Center in Houston (the paper was given to me by James Oberg). Along the central axis the exhaust velocity is 12.165 ft/sec. While at about 61 degrees it is not quite down to 11,800 ft/sec--about 96% of the velocity along the central axis. In other words, there is very little drop-off in speed as the gas expands away from the central axis. This makes sense, since the expansion is into a vacuum, and the gas cannot lose energy by colliding with atmospheric molecules.

If we assume that the vernier rocket plumes behave in a similar fashion, then the vernier's exhaust velocity at the location of the alleged ice particle is about 96% of the 8800 ft/sec along the central axis, or about 8450 ft/sec. So the ice particle should have a terminal velocity of 0.98 x 0.96 x 8800 ft/sec, or about 8300 ft/sec. Quite obviously, the 5.5 ft/sec calculated above is orders of magnitude too small, and so we must conclude for the third time that the object in the videotape could not have been an ice particle near the Shuttle.


The fourth proof is quite brief, and much simpler than the other three. It is also a variation on the corollary given for the first proof. Recall that the main object was at rest for about half a second during the period of the main flash, and then accelerated sharply back up to the right. The time interval from the beginning of the main flash until the main object began to accelerate was about half a second. Presumably this was the time the rocket exhaust was moving through the vacuum up to the "ice particle." In Appendix I, we see that the object would have been 64.0 ± 4.3 feet from the vernier rocket--roughly 65 feet. Thus, the speed of the rocket exhaust would have been approximately v exhaust = 65 feet/0.5 seconds = 130 feet/second. This is also orders of magnitude smaller than the 8300 feet/second needed, and is the fourth proof that the main object could not have been an ice particle.


Another and perhaps better way to locate the alleged ice particle would be the following. We already have seen in Appendix I that the object must be located between the camera and the horizon along a line from the camera through the object as seen on the screen. I have also shown above that the "ice particle" would have to reach a terminal velocity of about 8300 ft/sec. We can calculate where this would be by forming a simple ratio, using values computed in Appendix I:

(8300 ft/sec)/(5.5 ft/sec) = distance/77.7 ft.,

where 77.7 feet is the distance to the object as it passes the horizontal center of the picture. Thus the distance is 117,300 feet, or about 22.2 miles. The situation is illustrated in Figure 15 . The view is from the top, and the Shuttle's nose is pointing toward the top of the page. (The circle indicating the Shuttle is much too large. On this scale the Shuttle would be a dot about 0.01 of an inch in diameter. Similarly, even if the ice particle were as large as a foot in diameter, it would be a dot about 0.0001 inch wide.)

Two problems with the ice particle interpretation immediately surface. First, a (large) particle one foot wide would subtend an angle of less than 0.001 degrees. This is more than an order of magnitude smaller than the limit of resolution of the human eye--the particle would be a point source of reflected light. It is difficult for me to accept the possibility that it would be visible at that distance. And how could the ice particle have drifted that far from the Shuttle?

The second problem is much more serious. Recall that we know the direction the particle moves after the flash. Thus we only need to trace back along this line to locate the necessary position for the attitude adjustor rocket to accelerate the particle in this direction. From the diagram it is clear that the rocket would have to be located nearly fifteen miles below the Shuttle. This is clearly unacceptable, and is yet another proof that the object was not an ice particle.


I also studied the faster object located on the far right side of the videotape. Since it does not stop before or during the flash, its motion requires a more complicated analysis than that used on the main object. In addition, it was moving more slowly than the main object, and so the data are noisier. These two considerations make it more difficult to calculate the expected terminal velocity of the object. But it is enlightening nonetheless to consider one peculiarity about the fast object on the right.

I took numerical derivatives of the data for both the horizontal and vertical positions, with the same intervals as for the main object. Since this object did not stop during the flash, I used the same method from the beginning to the end of the data, from the initial constant velocity through the acceleration period to the final constant terminal velocity. (Once again, if we assume that the object was an ice particle, it must have had constant initial and final velocities.) This process would smear out of the acceleration period somewhat; but since the same method was used for both the horizontal and vertical positions the calculated velocities can be compared and analyzed. The horizontal and vertical velocity curves are shown in figure 16 . The accelerated parts of the curves show that the fast object behaved in a very strange fashion. It actually began decelerating in the horizontal direction about two-tenths of a second before it started accelerating upward. It is very difficult to understand how an ice particle could do this. It is similar to what a person driving a car would do when he makes a right hand turn. The individual would first put on the brakes, slowing down in the direction he is going, and then turn right. But an ice particle, unlike the car, would have to respond immediately in both directions when it is hit by a rocket exhaust. It simply cannot respond to part of the exhaust by slowing down in one direction, then respond to the rest by accelerating upward.


I realize that I have spent a great deal of time proving that the main object in the videotape was not a ice particle (perhaps some would think an excessive amount of time). But I think that it is absolutely necessary that I do so. As I showed above, there are only two possible explanations--that the objects were ice particles near the Shuttle, or that they were spacecraft maneuvering out in space away from the Shuttle. The ice particle theory must be shown to be completely and thoroughly out of the question, because the ramifications are truly extraordinary if the objects really were spacecraft.

First, let us examine the possible accelerations involved. I have not been able to determine from the tape just how far away from the Shuttle the main object was. Since the shuttle was about 355 miles above the Earth when the film was taken, the horizon would be slightly more than 1700 miles away. Obviously the craft was somewhere between the Shuttle and this distance. As shown in Appendix I, we can calculate the terminal velocity of the craft if its distance from the Shuttle is known. We can then make an approximation of its acceleration at this distance by using figure H4 from Appendix H to find a Av/At for the rising part of the curve. I chose At to be one second, which means that Av was nearly 0.9 of the terminal velocity. The results of these calculations for various distances are given in the following table. The accelerations are given in g's and the final velocities in miles per hour. See chart.

Except for the one-mile distance, these numbers are far beyond the capability of any known earthly craft. Even if the ship were as close as 10 miles, the 100 g acceleration would absolutely flatten a human pilot. If it was at the horizon, it was behaving more like Star Trek than Star Wars.

And what were the two streaks that passed through the regions vacated by the main object and two of the other objects on the far right? I admit that I am speculating; but one has to at least wonder whether they were some kind of missiles that were fired at the space craft, and that several of the craft changed directions to avoid being hit. Firing missiles is obviously a hostile act with frightening implications. It implies that whoever fired the missiles considered the craft to be a threat, that they had weapons systems that they felt would be capable of hitting the craft, and that spotting the craft was no surprise.

Let me speculate further. It would seem to me that firing missiles at objects only a mile away from the Shuttle would be very dangerous. If the streaks really were missiles, then I would suspect that the spacecraft were at least ten miles away from the Shuttle, and probably a lot farther. This means that they were accelerating in a manner that we would normally attribute to extraterrestrial craft, and that would be fatal for any human pilot on the Earth.

Another possible interpretation has been suggested by Richard Hoagland. He speculates that the craft were dummy targets put into space by our military, and that the streaks were the product of electromagnetic rail guns that have been developed as part of a top secret United States weapons program. The videotape would then be showing a test of these weapons. This interpretation would at least take away the hostile aspect from these events. But the implications of  this scenario are also quite extraordinary. The Star Wars program instituted by President Reagan in 1983 has not been developed to the point of being operational, and probably would not be so for at least ten years, if it will be at all. So any top secret program that might have been seen on the Shuttle videotape would have to have been under development for some time, perhaps even decades. This implies a secret level of scientific achievement that is much beyond what is normally attributable to the military today, or to any scientific establishment. It also implies that the current Star Wars system has been a tremendous waste of money, since equivalent defense systems have already been secretly developed over the years to the point of being operational.

Source: MUFON 1994 International UFO Symposium Proceedings, pages 108-136, Jack Kasher.

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