From your own article: > In effect, by the time it took a SAM system could lock onto an SR-71 traveling at Mach 3 and launch a missile, the Blackbird was alrea

From your own article: > In effect, by the time it took a SAM system could lock onto an SR-71 traveling at Mach 3 and launch a missile, the Blackbird was already moving beyond the effective range of the missile. It wasn't purely faster than the missiles, it was fast enough to get out of range of radar and tracking for ground based missiles and beyond the effective range of the missile before it could reach the jet. Fired from an already moving jet at altitude missiles would have a longer effective range as it would spend less fuel getting to speed and gaining altitude.