Recently sold on eBay was a display model for a vehicle labeled “SIPS.” No other data was available. However, this appears to be an upper stage modification for the LIM-49 Spartan surface-to-air anti-missile missile. Which suggests that the first “S” in “SIPS” standard for “Spartan.” Perhaps something like “Spartan Integral Propulsion System” or some such. However, this seems to appear to be a complete vehicle…. the very large first and second stage motors, as well as the warhead section, *appear* to have been replaced with a new, small booster with fins. Perhaps this was meant to test the third stage of the Spartan… or perhaps it was meant to be a way to find some use for the Spartan third stage after program cancellation, as some sort of scientific test vehicle.
The other photos from the ebay auction have been uploaded to the 2022-06 APR Extras folder on Dropbox for Patrons and Subscribers.
The diagram below shows the complete Spartan missile.
