>>3
うん、だからその

> The near-term sea-based terminal program will modify already existing SM-2 Block IV missiles to address incoming ballistic missiles in the terminal phase.

つまり短期的なSBTというのが、下記のとおりASBMに対する暫定措置として行われたSM-2ERblockⅣへの改造なわけね

https://missilethreat.csis.org/defsys/standard-missile-2-block-iv/
> The Navy ultimately funded the modification of 75 of the 100 SM-2 Blk IVs produced. Five of the modified missiles have been expended in testing, leaving about 70 modified Block IV missiles available to the fleet as an interim defensive layer against antiship ballistic missiles.