Yes, the A-10 is built to be raked by .50 cal, and even some 20mm and keep on flying.
That is a permissible airspace.
It is not designed to absorb surface-to-air missiles, air-to-air missiles, or radar guided anti-aircraft artillery at the altitudes and airspeeds that the Warthog flies.
I’m not saying ditch the A-10. Quite the opposite, it is a very valuable aircraft that we need to keep for future use. It’s just not as effective for close air support in an impermissible airspace as a faster F-15 or B-2 armed with JDAMs.
The problem is the zoomie Generals think that JDAMs are the only answer, when that 30mm cannon in the A-10 is a more economical solution in many environments like Afghanistan.
The plane was designed to survive multiple hits from up to 23mm armor piercing or HE rounds and designed to fly with one tail and half a wing missing and only one engine. The engines were also placed to reduce IR signature.
No, it would probably not survive a big radar guided SAM.
But I bet if it hugged the ground with evasive maneuvers at low speed it would be very hard for a fighter traveling twice as fast to get low enough to get a good lock or to spend enough time on target to accurately engage with guns: it would be like trying to kill an armored roach running around the kitchen floor while you ran through the kitchen.