Everyone over here on HN seems to be quite negative about the SABRE engine. While there's very little evidence for this engine being useful for orbital applicat

Everyone over here on HN seems to be quite negative about the SABRE engine. While there's very little evidence for this engine being useful for orbital applications, it is instead a very compelling idea for a Concorde and/or SR-71 replacement. Scramjet engines don't seem to be happening anytime soon (I just listened to a Queensland University researcher saying that their research may yield an actual engine in 4-5 decades). This idea of pre-cooling the incoming air seems closer to reality.