Thread

Former SR-71 engineer talks NASA's Blackbird revival program

110 points · 76 comments · rkagerer

gaigalas · 1791086277 · focus · HN ↗
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).
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.
We'll know soon.
1. nradov · 1791092151 · focus · HN ↗
  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.
  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.
  <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...
  1. gaigalas · 1791093268 · focus · HN ↗
    Current aircraft is not capable of reaching those balloons, read my other commentary. Your link points to a Chinese balloon that dropped way below its operational range.
    SR-71 or not, there are already contracts for filling this niche:
    <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/... (search for "swamp gas").
    If money is flowing to counter/develop high-altitude balloons and declared as urgent, it's likely it's flowing in more than one vein.
    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.
    <a href="https://en.wikipedia.org/wiki/Lockheed_YF-12" rel="nofollow">https://en.wikipedia.org/wiki/Lockheed_YF-12
    walrus01 · 1791097446 · focus · HN ↗
    > Current aircraft is not capable of reaching those balloons
    Is a missile a form of aircraft? Because there's variants of the Standard Missile which can hit a low earth orbit satellite, with the right timing, fired from effectively zero velocity and at sea level from a frigate.
    gaigalas · 1791098089 · focus · HN ↗
    Well, it's not reusable. You're wasting a resource destined for hypersonic deterrence on some sheets of mylar that float around.
    I mean, you can do that, but it would be a tremendous embarrassment.
    walrus01 · 1791098588 · focus · HN ↗
    > Well, it's not reusable
    No it's not. And it's indeed very costly. But on the grand scale of things of what the US DoD spends per day as a fully loaded lifetime cost to operate a single SSN, SSBN or aircraft carrier, it's a drop in the bucket. They spend absurd amounts of funds on all sorts of things.
    gaigalas · 1791105640 · focus · HN ↗
    Perhaps the issue is not money, but production capacity? Those take some time to build, and you don't want to deplete your stockpile on spy balloons.
    numpad0 · 1791114013 · focus · HN ↗
    missiles shot from fighter jets aren't reusable either, and ships that fire those missiles are as reusable as jets
    gaigalas · 1791116443 · focus · HN ↗
    I don't know which weapon would be used. A laser or a machine gun can take out a balloon if you're close enough. Even if missiles are used, closer range air-to-air are cheaper.
    Also, approaching the balloon in stealth with a plane that has its own radar system is considerably less paraphernalia than ships chasing balloons.
    I could be wrong about how the SR-71 will be used, but I'm very sure using expensive missiles designed for much more advanced threats to take out balloons is insanity.
    nradov · 1791123062 · focus · HN ↗
    You seem to be confused about basic aerodynamics. At those altitudes, attempting to shoot a balloon with a machine gun would be insanity. The high wing loading limits maneuverability so severely that the shooting platform would risk running into target debris.
    As of today it's not possible to mount a laser on a tactical aircraft (or SR-71) capable of destroying a balloon. There isn't enough space or power available. Perhaps that will change soon but for now it remains science fiction.
    gaigalas · 1791125897 · focus · HN ↗
    The conversation goes as follows:
    - Reusable/non-reusable
    - Cost/range
    The machine gun and laser are illustrative examples. I offered a cheaper short range missile as an option too, if those two bother you.
    At some point, I believed you got carried away by specific details about aerodynamics and laser payload (you are probably right!), but are ultimately irrelevant for the progression of the conversation: if you are closer, you can use a cheaper weapon.
    It's normal to get carried away (I do it all the time), and I'm fine with having my comments broken down and dissected. However, there are aspects of what I said that weren't answered, so they still stand.
    nradov · 1791135170 · focus · HN ↗
    When regular F-22s were already used to shoot down Chinese spy balloons they employed AIM-9 missiles, which are cheaper than AIM-120. But there's no need to get particularly close: in fact for safety they want to remain well separated from the target and never get on a collision course.
    But in general all of your comments here have been deeply uninformed about how this stuff actually works.
    gaigalas · 1791136446 · focus · HN ↗
    I appreciate the heads up.
    This is a low stakes brainstorming conversation, I presented my ideas as hypotheticals and shared my sources.
    Honestly, I was hoping someone more knowledgeable would share any better insight on what the recently work on the SR-71 frame would be used for in practice. That hasn't happened so far, but that's fine.
    "Your guess is bad because using the SR-71 for _____ in missions such as ______ would make more sense" would be stellar brainstorming about this beloved fan favorite.
    numpad0 · 1791129935 · focus · HN ↗
    You can't gun kill a balloon floating at 60k feet. That's not going to work. It has to be with an active or semi-active radar homing missile.
    The loadout will be like an F-15 with just one or two AIM-7 type missiles of appropriate generation and maybe the center tank. You configure and fly the plane to the altitude as usual, then when instructed, push the throttle all the way forward, do a shallow dive, then pull up to the precise absurd angle as you were briefed and keep it there. The number on the right go crazy and the number on the left goes down slightly less faster. At some point, you will see an angled rectangle with a dot in the center, itself in the center of a large circle on the HUD, and it says SHOOT, so you pull the trigger. You here the thunk of missile leaving, then nothing happens for 30 seconds, and the radio says target radar contact lost as expected, you do a 180 roll into a shallow dive and go home.
    I mean, that's how I as an armchair flightsim pilot think it'll go, but I'm sure this wouldn't be way off. Attempting the same with a gun installed on a Blackbird? That's just waste of everything from time of everyone involved to your own life.
    gaigalas · 1791131965 · focus · HN ↗
    Makes sense. You seem to know a lot of stuff! What do you believe the SR-71 frame is going to be used for?
    speed_spread · 1791150325 · focus · HN ↗
    The only thing it was designed for: recon. It's a spy plane. It has cameras and electronics up the wazoo. You fly it high and fast over a target, collect the info you need, refuel it and change target. Unlike a satellite, you can do that many times per day.
    Against the USSR it had become risky because missiles could reach it? And satellites worked great during the cold war. But in a scenario where things got hotter and you wanted regular fresh intel from deep within enemy territory, the SR-71 could be irreplaceable.
    numpad0 · 1791169146 · focus · HN ↗
    Militarily, it's the lowest-flying and the most maneuverable spy satellite with a turning radius comparable to the size of an European mini/microstate. That's it.
    Just speaking from a couch, maybe it's a simple 50:50 between the NASA administrator just wanting it flying and Boom Supersonic not doing fantastically. Anduril's mini F-16 drone having its air intake painted out in photos also comes to mind. Lessons learned by NASA from an SR-71 engine project is going to be invaluable for new entrants to supersonic planes and engines.
    nradov · 1791135877 · focus · HN ↗
    Yes, certain variants of the SM-3 (RIM-161) have a limited anti-satellite capability. And in general any current Standard missile could potentially be employed against a spy balloon depending on the exact engagement parameters. The problem is that they have limited range and it can be tough to get a launch platform to the right place at the right time to generate an intercept. The Navy surface fleet is already over committed, and ground based launchers have limited mobility. Hence it's more practical to use tactical aircraft like the F-22 or F-15EX for this type of homeland defense mission.

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