Re: Distinguishing Fireballs

Don Heller (dheller@danea.jpl.nasa.gov)
Tue, 09 Jul 1996 15:44:13 -0700

Thomas Ashcraft wrote:
> 
> Question 2:     I am looking for visual ways to distinguish natural
> meteoric fireballs from re-entering man-made debris fireballs. Does anyone
> know references for this information?
> 
> Thank you.
> 
> Tom Ashcraft
> 72632.1427@compuserve.com
> New Mexico

This problem seems similar to the problem of distinguishing ICBM warheads from
decoys in Ballistic Missile Defense Systems.  The techniques involve using a
phased-array radar and supercomputer to track and determine the mass and drag,
as well as the length and radar cross-section of the unknown object.  One can
also send diagnostic pulses along the wake to determine ablation and material of
the body.  This is an ultra-simplified, non-classified (I hope!) description of
the immense complexity of the task.  So I think not.  According to Whipple, 90%
of meteors are stony, but 90% of those found are metallic.  He says it's because
stony fragments look like any other rock, so they are often not noticed.  Stony
meteors are the ones that break up spectacularly, and I would guess that parts
of spacecraft, at least metallic parts, would not.  I have seen many sub-orbital
break-ups from my years at the Cape:  hundreds of plates of .064 stainless from
Atlas tanks, Titan III solids, 2nd & 3rd stages, etc.  None looked like meteor
trails to me, but on the other hand, modern spacecraft can use composites or
ceramics that break up or ablate like stony meteors.

Of course, I'm just skulling, no hard data.

Donald W. Heller, Voyager Flight Team

Simplest job description on the project:
Make everything work with everything else.