From: Ted Molczan via Seesat-l <>
Date: Fri, 13 Feb 2015 23:32:55 -0500
Kevin L. Walton quoted from an article about space debris hazards:

> ... NASA and the Defense Department use radars and electro-optical sensors to
> track space objects as small as five centimeters in size, so there'd be ample
> warning [of a collision]

NASA does not conduct space surveillance. USSTRATCOM does, but sometimes losses track of objects, so there can be no
guarantee of warning of a collision.

A recent example is the Falcon 2nd stage 14052B / 40142, that re-entered over South America on 2014 Dec 28 UTC and
rained debris on Brazil. Three large COPV tanks fell in the municipality of Santa Rita do Pardo. A building in Andradina
sustained what appeared to be minor damage from a debris strike. 

The rocket stage was 7 m long and 3.66 m in diameter. Its mass was about 4700 kg. 

USSTRATCOM did not issue any TIP messages warning of the re-entry, and had last issued a TLE update 9 days before
re-entry. Had the object been on a collision course with another orbiting object during that time, there would not have
been any warning.

14052B / 40142 had been decaying from a GTO with a very low perigee height, resulting in high drag which made it very
difficult to track. Even during the periods when it was not lost, its orbit was not known with great precision, so
collision warnings would have been of doubtful reliability.

Ted Molczan

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Received on Fri Feb 13 2015 - 22:33:24 UTC

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