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Location: UFOUpDatesList.Com > 2007 > Nov > Nov 16

Re: Skylab 3

From: Bruce Maccabee <brumac.nul>
Date: Thu, 15 Nov 2007 11:26:26 -0500
Archived: Fri, 16 Nov 2007 17:04:28 -0500
Subject: Re: Skylab 3

>From: Michael Tarbell <mtarbell.nul>
>To: ufoupdates.nul
>Date: Mon, 12 Nov 2007 10:31:30 -0700
>Subject: Re: Skylab 3

>>From: Bruce Maccabee <brumac.nul>
>>To: <ufoupdates.nul>
>>Date: Sun, 11 Nov 2007 15:53:10 -0500
>>Subject: Skylab 3


>>If you want to find an astronaut sighting of an unidentified
>>space object - USO; this one was not submerged - then here you

>>Comments welcome


>This is a very interesting case and analysis. A few aspects
>remain unclear to me:

>- Your calculation for the object size is based on an estimate
>for object distance, which in turn is based on the time delay
>between Skylab and the object entering earth's shadow. This
>makes the implicit (and probably unwarranted) assumption that
t>he object is in the same orbit as Skylab, and pierces the same
>point on the shadow zone surface. It would seem possible to
>obtain a variety of object distances --and hence sizes-- by
>relaxing this constraint, even for purely ballistic (i.e., non-
>maneuvering) trajectories. I note that you consider perturbed
>orbits later in the analysis, but as far as I can tell the
>implications for the object size calculation are not mentioned.

Of course, the farther away the object is assumed to have been
at the time of the fourth photo the larger it must have been to
have an angular size of .0029 radians (this assumes the 300 mm
focal length lens was used). As pointed out in the analysis
(especially the revised version now on my site), if the object
was another man-made satellite or something ejected from the
skylab (e.g trash), then it must have been no larger than 10 m
(maximum separation of reflective points of the assumed
satellite corresponding to the separation between the upper and
lower red 'dots') and hence no further away than about 10
m/.0029 rad = 3,400 = 3.4 km at the time of the fourth photo.
There is a problem with the assumption that it was this close
(or smaller and closer) when the Skylab went into the
shadow:regardless of where you place the object relative to the
Skylab, it would pass into the shadow no more than about 1
second after the Skylab.

The minimum estimated time difference between when the Skylab
entered the shadow and when the assumed other satellite entered
the shadow was 5 seconds. This corresponds to a distance of
about (5 sec) (7.6 km/sec) = 38 km.

This travel distance can be achieved by a supposed satellite
traveling 'above' the Skylab in an orbit that places it at a
slightly higher altitude. Both the Skylab and the assumed
satellite would have been in orbits with very close or identical
inclinations that intersect the shadow boundary at an acute
angle. About 21 degrees; this angle lies in the plane of the
orbit where the 'vertical' orbital plane crosses the
'horizontal' - perpendicular to the earth's radius-shadow

Assume the satellite or object happened to be above the Skylab
(i.e., at a greater orbital radius) at a distance of 38 sin(21)
= 13.6 km at the time that the Skylab went into the shadow and
assume the fourth photo was taken at this time. Then this would,
I think! have been the closest an assumed satellite could have
been to the Skylab and still have a 5 second time difference. At
this distance the size of the object would have been abot .0029
x 13.6 km = 39 m, about four times larger than a man made

The above calculations assume that the object was close when
they crossed the shadow boundary, but far apart initially (so
that the camera could not resolve the structure of the assumed
satellite in order to explain the single dot images).

One can 'reverse' the scenario and assume that the object was
close when they first saw it and that the four photos were taken
when it was close. Assume it then moved away (lagged behind in
its orbit) so that when the Skylab entered the shadow the
assumed satellite was at least 38 km away from entering the

In this scenario it would have been in an orbit very close to
that of the Skylab in terms of both inclination and altitude and
speed. One can assume even a small object, initially nearby,
which drifted 'backward' about 38 km.

If one assumes it was something small - perhaps from the Skylab
- then the questions would be, would it still be visible at 38
km, why didn't the astronauts see that it was moving away from
the Skylab, getting smaller and dimmer, during the 10 minute
observation and why does the fourth photo show more detail
(which suggests the object was closer during the fourth photo)?
Their report makes it seem that the object maintained a rougly
constant distance from the Skylab.

The comment that it never moved more than 10-20 degrees as seen
through the window makes it seem as if the object was 'keeping
station' with (remaining at the same approximate position
relative to) the Skylab.

One can try numerous scenarios of orbital intersection but I
think it will be difficult to satisfy the requirements of

1) 5 second time lag

2) manmade size of object (10 m or less) in an orbit

3) while also requiring that it be close enough to the SKylab to be
visible for 10 minutes, during which time the Skylab traveled
nearly 50 km. As Garriott pointed out during the debriefing,
the 'satellite' must have been in an orbit very close to that of
the Skylab.

4) no identification by NASA/NORAD

Even if one can figure out some way to explain the dynamics of
the situation, it still doesn't explain the red color (a
characteristic of the sighting that is 'orthogonal' to the

>- Garriott makes the claim that Skylab and the object were not
>in a region of the orbit in which sunlight was passing through
>earth's atmosphere (and thus reddening it). But it is
>unavoidable that sunlight illuminating Skylab and the object was
>passing through earth's atmosphere when both objects were in the
>vicinity of the edge of the shadow zone.

That is true, but the passage through the region where the
sunlight is reddened would have taken place in some number of
seconds at the end of the 10 minute period of observation, most
of which occurred when the Skylab and object were far from (but
approaching) the reddened area.

>- Given the potential ambiguities in the object distance/size
>estimate, must we not consider the possibility, as per a recent
>Space Shuttle mission, that the object was a piece of debris
>somehow jettisoned from Skylab itself?

As pointed out above, the smaller the size one assumes for the
object (e.g., a meter size piece of trash or less), the closer
it has to be at the time of the fourth photo, and the closer it
is to the orbit of Skylab and the more likely to be detected by
NASA radar.

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