Since the MLG door gap should be small, I think the scale magnitudes are at least ballpark. The sample sinks in water so it's quite heavy compared to TUFI. I was wondering if it could be a variant of the earlier developed RCS (as shown at the top of this thread, bonesmccoy #1 post).. less damage-resistant, and heavier than the new improved HRSI-TUFI. We *are* talking about functional shuttle prototype #1, it might not have all the latest ceramics installed, especially in odd closeout areas.
Also, if Columbia did not have *all* it's early RCS replaced (especially around the MLG door or other closeouts) and the foam projectile tests were done with the latest TUFI, then the tests done are not relevant to the Columbia.