The brightness of 96076B

Allen Thomson (
Mon, 30 Dec 1996 19:31:49 -0800

Ted Molczan wrote:

>Regarding the issue of the object's unusual brightness, Rainer Kracht
>reports that he has found that not all Titan 2nd stages have the same
>brightness. For example, 96029B's std mag is 3.74, while 91017B's is
>4.89. This narrows the gap somewhat, but 96072B's std mag seems to be
>between 2 and 3. On the 30th, I found that 2.1 fit the obs well.

   I wonder if pictures of the booster before or during launch would
shed any, ah, light on the matter. IIRC, such pictures have been
released for most T-IV launches.

>Regarding my speculation about heating at perigee causing out-gassing,
>Alan Pickup advises that the atmospheric density at 160 km probably is 
>too low to cause heating.

   I think that's right.  According to Jeff Richelson in "America's
Secret Eyes in Space (ISBN 0-88730-285-8), KH-8s not infrequently
did death-defying swoops to 125 km or so, presumably to increase
resolution.  I doubt that they'd have wanted to be taking pictures during
significant heating.  Also, people who deal with reentry vehicles have a 
rule of thumb that "gas light" starts at around 300,000 ft (~>90 km)..