I almost skipped the videos embedded in this article, but they are well curated gems. A few tidbits I found amazing:<p>- 800°F (and above) was the temperature of their <i>cooling</i> air<p>- the engine ran too hot for electronics, so they designed a <i>hydraulic</i> mechanical computer responsible for regulating various inputs<p>- the roar from the two external 400 cubic inch Buick V8 engines originally used to start the aircraft was so irresistible to the hotrod enthusiasts running them that they sometimes neglected to disconnect in time before the starter engines overran RPM limits and "puked their guts out under the airplane" - they had to buy up so much replacement stock as to deplete every single junkyard across the USA of that particular model (so the story goes - probably hyperbole but a fun tale!)
For those that want to know more about the Buick engines and their replacement, here's [0] a writeup about it.<p>[0] <a href="https://www.thesr71blackbird.com/Aircraft/Engines/starting-the-sr-71-blackbirds-j58-engines-ag330-start-cart" rel="nofollow">https://www.thesr71blackbird.com/Aircraft/Engines/starting-t...</a>
I remember quite well the day the auctioned off a unique "jet fuel analyzer" that was used to do some of the specialized testing for these exact aircraft.<p>It was not a benchtop unit, it was a forklift model :\
A handful of the surviving planes are in museums. If you're at all interested in aviation and have the chance to see one, do. There's something special about them that doesn't come across in pictures.
This is probably one of the coolest planes and it's SOP is to leak fuel until it gets going enough that the heat seals it's seams due to expansion
Recent and related:<p><i>NASA asked several former SR-71A staffers to help secret restart</i> - <a href="https://news.ycombinator.com/item?id=49890733">https://news.ycombinator.com/item?id=49890733</a> - Sept 2026 (401 comments)
In the 90s, NASA refurbished and extensively modified a mothballed supersonic Soviet-era Tu-144. The modifications included fitting different (Tupolev) engines. The total cost was $350M. It was used as a flying laboratory.
When I see this, I can only think of modern high-altitude balloons. My gut tells me the SR-71 would be an ideal interceptor for that new threat (despite not being an interceptor itself).<p>The balloon issue cannot be addressed by any modern US aircraft, and spending expensive missiles on low cost balloons seems like wasting money and resources.<p>We'll know soon.
The SR-71 was never designed as an interceptor, and would require extensive modifications to carry and employ weapons. Not going to happen. There was an earlier YF-12 interceptor program but it never proceeded beyond the prototype stage.<p>High-altitude balloons are hardly a new threat. They have been used for decades, although some recent Chinese models are more capable than before. Regular tactical aircraft already in the US inventory are perfectly capable of shooting them down.<p><a href="https://www.af.mil/News/Article-Display/Article/3288579/f-22-safely-shoots-down-chinese-spy-balloon-off-south-carolina-coast/" rel="nofollow">https://www.af.mil/News/Article-Display/Article/3288579/f-22...</a>
Current aircraft <i>is not</i> capable of reaching those balloons, read my other commentary. Your link points to a Chinese balloon that dropped way below its operational range.<p>SR-71 or not, there are already contracts for filling this niche:<p><a href="https://www.war.gov/News/Contracts/Contract/Article/4613098/contracts-for-sept-28-2026/" rel="nofollow">https://www.war.gov/News/Contracts/Contract/Article/4613098/...</a> (search for "swamp gas").<p>If money is flowing to counter/develop high-altitude balloons and declared as <i>urgent</i>, it's likely it's flowing in more than one vein.<p>The frame modifications you mentioned are already specified and tested, part of the YF-12 programme. It can easily carry air-to-air missiles instead of reconnaissance equipment, and the frame has flown with that configuration.<p><a href="https://en.wikipedia.org/wiki/Lockheed_YF-12" rel="nofollow">https://en.wikipedia.org/wiki/Lockheed_YF-12</a>
The service ceiling of the SR-71 is still well beneath the altitude of a modern balloon. The speed isn't necessary, and it's altitude record has been beaten by other modern jets.<p>If we're spitballing solutions, balloons are slow, fragile and move in relatively predictable paths. An F-15 could reach the same altitude, and launch it's own balloon with a small solid-fuel booster that also corrects the trajectory. If the interceptor balloon could get within 1-2km of the target balloon, then a cheap kinetic weapon firing HEI projectiles might be enough to destroy it.
The F-15 can climb 30,000 feet.<p><a href="https://en.wikipedia.org/wiki/McDonnell_Douglas_F-15_Eagle" rel="nofollow">https://en.wikipedia.org/wiki/McDonnell_Douglas_F-15_Eagle</a><p>That is the <i>lower bound</i> of what modern high-altitude balloons can reach. Back in 2023 multiple balloons were observed much higher than that up to 50,000 feet.<p><a href="https://en.wikipedia.org/wiki/List_of_high-altitude_object_events_in_2023" rel="nofollow">https://en.wikipedia.org/wiki/List_of_high-altitude_object_e...</a><p>This is still in the lower spectrum for such balloons. BS 13-08 reached 176,000 feet back in 2013 (there is reason to believe spy balloons would not go that high though).<p><a href="https://en.wikipedia.org/wiki/High-altitude_balloon" rel="nofollow">https://en.wikipedia.org/wiki/High-altitude_balloon</a><p>So, you're wrong. There is no US aircraft that can reach them (unless they drop low as they did in 2023). The US likely wants to hit them before they go low.<p>The SR-71 is uniquely suited for this task, having reached up to 90,000 feet during testing. It was <i>specially made</i> for some kind of hybrid space war possibility (not balloons, but something high up there).
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