Re: STS-75 TSS Tether Break

bjorn@tt-tech.se
Mon, 26 Feb 1996 10:58:21 +0100

Jim Varney (jvarney@mail2.quiknet.com) wrote :

>> I can't say I share your certainty.  That tether is quite thin and I  =20
doubt
>> it will be visible to ground-based observers.

>> A most unusual satellite to look at, to be sure; my guess it
>> will be quite ordinary-looking, though.

Though I live at 59 N, and have not had a chance for a
first-hand experience, I favour Philip Chien's views.

I took part in a discussion (at RPV) about a previous
tether satellite (Delta launch), which in fact was observed
as a beautiful needle (or even exclamation mark !)

I don't remember the diameter, but even a 1-mm string would be
only 0.016 cu.m. when reeled in, which is quite reasonable.
Reeled out, it would be 20 sq.m, almost like a Zenith-2 rocket!

However, since it would be seen as an elongated object, only
part of that light would reach each receptor in your eye.
If your eye's resolution is 3 arcminutes, you would get 400 m
of tether (at 400 km distance) for each receptor. That would
be 0.4 sq.m., or a surface brightness of about +6 ?

A pair of 7*50 binoculars would receive 49 times more light,
at 7 times the length, so it would improve surface brightness.


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