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From: bro@titan.rice.edu (Douglas Monk)
Newsgroups: sci.space.shuttle
Subject: Re: Discovery's launch: Am I imagining things?
Message-ID: <1937@kalliope.rice.edu>
Date: 30 Sep 88 21:20:18 GMT
References: <1104@cfa237.cfa250.harvard.edu> <3811@phoenix.Princeton.EDU> <1935@kalliope.rice.edu>
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Reply-To: bro@titan.rice.edu (Douglas Monk)
Organization: Rice University, Houston
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In article <1935@kalliope.rice.edu> phil@Rice.edu (William LeFebvre) writes:
>In article <3811@phoenix.Princeton.EDU> elturner@phoenix.Princeton.EDU (Edwin L Turner) writes:
>>>BUT....  At about 80 to 90 seconds into the flight, I and several
>>>friends independently thought we saw flame coming out of the right hand
>>>(no, right on the TV screen, so I guess that must mean its really the
>>>"left hand") SRB at the case-to-nozzle joint (where the cylindrical
>>>booster starts to flare toward the bottom). Did anyone else see this?
>
>It seems that many people saw it.
>>...
>I have it from a very reliable source that the plume was not unusual or
>indicative of near disaster.  It is apparently a normal occurence in
>the very high reaches of the atmosphere (near-vacuum).  ...

I too saw the mentioned apparition around the SRB, and was worried
about it. What I saw seemed more between the SRB and beneath the external
tank than to the side, though I think I saw a flicker or two there, also.
It certainly looked orange to me BUT:

I have seen similar flares before in launches. In a commentary program
on the Challenger that I saw on television about two years ago they ran 
replays of other launches from several angles, and in several instances there 
are moments when the shock waves coming off the boosters make visible flares -
but WHITE ones that appear to be contrail effects very similar to the
contrail vortices we see coming off the shuttle wings as it approaches
landing - in other words, made of water vapor or ice.

In the same program they mentioned in passing that the SRB exhaust is so
hot that it can make the bottom of the external tank glow with heat during
flight, but that this is normal and expected, and that the vortex of 
turbulence that is immediately behind the external tank actually may
dissipate some of the heat.

It thus seems to me that what we saw may indeed have been 
"an optical illusion" in the sense that we saw a normal shock wave contrail,
perhaps combined with external tank turbulence, reflecting the orange glow
of the SRB exhaust.

(For those interested in a more exact attribution of this program, it was
during of immediately after the Rogers commission, it explained the O-rings
in great detail, and it examined the history of O-ring failures in detail. 
However, it was quite some time ago, and I cannot be more specific. Does 
anyone else remember this program and give a more exact attribution?)


Thanks,
Douglas Monk		(bro@rice.edu)
Dept. of Computer Science
Rice University