[HN Gopher] SR-72 'Son Of Blackbird'
       ___________________________________________________________________
        
       SR-72 'Son Of Blackbird'
        
       Author : graderjs
       Score  : 50 points
       Date   : 2021-09-23 09:37 UTC (13 hours ago)
        
 (HTM) web link (www.19fortyfive.com)
 (TXT) w3m dump (www.19fortyfive.com)
        
       | aj7 wrote:
       | If it can carry armaments, who will tolerate it as an
       | intelligence gathering plane? And how can one know what its
       | mission is in real time?
        
         | Arainach wrote:
         | To not tolerate it, you need something fast enough to shoot it
         | down.
        
           | throwaway210222 wrote:
           | Incorrect, you shoot down something else afterwards.
        
             | Arainach wrote:
             | That's generally not how these things work. Shooting down a
             | plane that you feel invaded your territory is one thing;
             | shooting down something else makes you the aggressor.
             | 
             | This was well established with U-2 and SR-71 flights in the
             | cold war.
        
               | Youden wrote:
               | Sending the U-2 or SR-71 is like sending spies. Something
               | most countries do and so expect and tolerate of others.
               | 
               | The SR-72 has strike capability. It's more like sending
               | an assassin or rolling a tank into a foreign country.
               | That's an act of war.
        
               | Arainach wrote:
               | Unless it _actually_ strikes, no country is going to
               | escalate an overflight to a different hot strike. Air
               | powers regularly fly along the borders and intrude and
               | have for the last 70 years. Overflights were deemed acts
               | of war during the cold war as well - that 's why the USSR
               | tried to shoot down all of the U-2 planes they could
               | (ultimately succeeding on Gary Powers' flight) and any
               | other things they considered spy flights (such as the
               | KAL-007 crisis). At no point did they escalate in other
               | areas. War is hell, and countries go to great lengths to
               | avoid it - even when they're angry.
        
           | sudosysgen wrote:
           | Which many countries have. S-400 is designed to hit targets
           | going at Mach 14.
        
       | tyingq wrote:
       | Unmanned, 98 feet long, and mach 6 sounds like a lot could go
       | wrong. Lot of kinetic energy there. I know we already have (close
       | to) this with missiles, but they tend to have A->B missions.
        
       | cdolan wrote:
       | I thought the true top speed of the SR-71 is either highly
       | classified or truly "unknown".
       | 
       | How does the article justify saying the 72 will be roughly 2x the
       | speed of the 71?
        
         | numpad0 wrote:
         | There was a declassified manuals for one of Blackbird models
         | from few years ago, and it wasn't inconsistent with Mach 3.75
         | top speeds. Maybe they do 3.6669999 or 3.78925 but can't be
         | like it could go all the way to 22 flat out in a straight line.
        
         | Arnt wrote:
         | It was seen by Soviet pilots and radar (it was poorly visible
         | but not invisible). As to top speed, from what I've heard
         | that's a matter of how much wear and tear you're willing to
         | incur.
        
         | noisy_boy wrote:
         | You don't have to know the actual speed to say, "whatever the
         | (classified) speed was, we will double it".
        
         | HPsquared wrote:
         | It depends on your definition of "top speed": on the Blackbird
         | and other supersonic aircraft, higher speeds mean higher
         | temperatures. It's possible to sprint for a short time and
         | absorb some of the excess heat, but have a lower limit for
         | continuous operation. The shorter the duration, the higher the
         | speed.
        
         | baybal2 wrote:
         | There is very big, fundamental problem of flying at mach 4+
         | anywhere in the atmosphere: heat from aerodynamic friction >
         | heat dissipated.
         | 
         | All, and everything that flew so fast before relied on
         | evaporative cooling, and under the evaporate, I mean the solid
         | parts of the spacecraft/airplane/missile.
         | 
         | For a reusable craft, it will mean big disposable heat shields.
        
           | mdorazio wrote:
           | You seem to be ignoring the space shuttle entirely, which
           | handled the heat of re-entry at 17,000 mph and was still
           | reusable. You have to make trade-offs on weight and materials
           | (like heat tiles), but it's not impossible.
        
             | baybal2 wrote:
             | Space Shuttle used expendable ablation, thermal barrier
             | materials, and thermal mass of its structure.
             | 
             | All of that was only to last for a few minutes of re-entry,
             | not constant flight in such conditions.
        
             | nradov wrote:
             | The Space Shuttle wasn't reusable in any meaningful sense.
             | It required a complete overhaul after every mission,
             | including replacement of many damaged ceramic heat shield
             | tiles. And it only flew at hypersonic speeds for a few
             | minutes during re-entry.
        
           | HPsquared wrote:
           | The Blackbird used fuel as a heat sink. This sounds like
           | something affected by scaling laws, such that a larger craft
           | would have more mass available for heat absorption.
        
             | baybal2 wrote:
             | Yes, fuel as coolant worked at around mach 3, but at mach
             | 4+ the kerosene itself may not not be energetic enough to
             | both sink heat, and produce more energy than the energy of
             | incoming airflow.
             | 
             | Supercooling the fuel may work to some extend.
             | 
             | Having the entire aircraft being a flying liquid hydrogen
             | tank is another least improbable option.
        
               | masklinn wrote:
               | > Yes, fuel as coolant worked at around mach 3, but at
               | mach 4+ the kerosene itself may not not be energetic
               | enough to both sink heat, and produce more energy than
               | the energy of incoming airflow.
               | 
               | The blackbird did not use kerosene, it used JP7,
               | specially designed for high range of operation as well as
               | being usable for cooling and hydraulics.
               | 
               | > JP-7 is unusual in that it is not a conventional
               | distillate fuel, but is created from special blending
               | stocks in order to have very low (<3%) concentration of
               | highly volatile components like benzene or toluene, and
               | almost no sulfur, oxygen, and nitrogen impurities.
               | 
               | JP-7 is famously hard to ignite, the blackbird needed TEB
               | shots to start ignition, and was initially started by
               | driving the engines with a starter cart composed of
               | paired V8s (later replaced with a smaller and simpler
               | compressed-air starter).
               | 
               | The Waverider used the same fuel, and fuel-cooling, and
               | reached Mach 5.1.
        
               | baybal2 wrote:
               | > The Waverider used the same fuel, and fuel-cooling, and
               | reached Mach 5.1.
               | 
               | Not so much as coolant, but as a thermal mass reservoir,
               | and only for a few minutes.
        
               | HPsquared wrote:
               | I suppose heat _flux_ is still a limiting factor that 's
               | independent of scale. Though things like liquid
               | evaporative cooling (by "sweating") also become more
               | practical with larger scale (more mass available). Not
               | sure how big it would have to be though...
        
             | fmajid wrote:
             | It also had body panels that had gaps at ordinary
             | temperature (and leaked fuel), and the gap closed as the
             | metal expanded with heat. Also, the US did not have enough
             | titanium production capacity so bought it from the USSR
             | using shell companies...
        
               | masklinn wrote:
               | Not the body panels, the _fuel piping_.
        
         | VLM wrote:
         | A couple comments on supersonic aircraft:
         | 
         | There are no jet engines ever made that I'm aware of that can
         | run at supersonic speeds. The fastest mass air flow rate I've
         | ever personally heard of was some Soviet thing that didn't
         | immediately self destruct around mach 0.98. The way supersonic
         | aircraft generate thrust while supersonic is the inlet geometry
         | does WEIRD things to turn supersonic cold low pressure air into
         | low subsonic hot higher pressure air. Most jet engines are
         | happiest with inlet air flowing around 200 to 400 mph. If you
         | run a jet engine above some critical subsonic speed
         | occasionally shock waves will impact the compressor and every
         | time the compressor rotates the blades will hit those
         | shockwaves, and they rotate pretty fast... So the MTBF for a
         | SR71 compressor blade might be 100000 hours at a nice subsonic
         | mach 3.25 but whack it with supersonic shock waves every
         | rotation and at mach 3.5 the MTBF for a compressor blade might
         | be one hour. The nozzles in front of the engine fully retract
         | at mach 3.25 and I'd interpret that as the inlet system is not
         | designed to run "much above mach 3.25". There's a story about a
         | flight over Libya where the pilot pushed a SR71 to mach 3.5 and
         | that engine was likely pulled and sent to scrap yard after that
         | stunt.
         | 
         | The other side of the problem with inlet geometry is the inlet
         | temp gets very hot so you have to go ramjet to get most of the
         | thrust because trying to generate significant thrust will melt
         | the turbine blades off. So hypothetically if you got 10K pounds
         | of thrust by increasing the temp of the air by 1500 degrees and
         | the inlet was dumping 800 degree air at mach 3.25 into the
         | engine, the combined exhaust temp would be 800+1500=2300
         | degrees which is getting hot for turbine blades (all numbers
         | made up). So the second engineering limit on why the SR71 never
         | flew at mach 9 or whatever is based on public engine designs
         | and the temperature of mach 9 air when slowed to subsonic,
         | there are no metals you can make a turbine out of. In fact at
         | mach 6 or whatever its kinda mysterious how they keep the
         | ramjet from melting itself. Must look like a rocket engine with
         | cooling passages for fuel everywhere. So based on the published
         | engine design (and is the published data trustworthy?) there's
         | no way to bypass enough air to not melt the blades off the
         | turbine above mach 3.something because nobody has high enough
         | melting point metals. As with the compressor situation I'm sure
         | a 3.25 rated turbine blade that has a MTBF of 100000 hours
         | might survive an hour or two at 3.5, but the engine is scrap
         | after that flight.
         | 
         | The third supersonic comment is mach number is not constant
         | with altitude so a pessimist person could say a mach 6 that
         | flys high enough could very well indeed have a slower
         | groundspeed than a sr-71 or even a 747. If the speed of sound
         | at 120Kft is like 190 knots, then mach 6 at 120Kft would be a
         | ground speed of merely 1140 knots. Famously the SR-71 could
         | achieve ground speeds of 1800+ knots (supposedly...). So its
         | simultaneously true that a SR72 might run twice the mach number
         | but if it runs at a high enough altitude like my 120Kft
         | example, its possibly only 2/3 the ground speed of a SR-71. The
         | flight envelope of the SR-71 from the declassified manual is
         | available; note it could not run supersonic below 20Kfeet or
         | so. This also comes up in discussion of interceptor missiles;
         | there's a huge difference in speed between a plane that can't
         | go supersonic below 20Kft and a SA missile that can go mach 5
         | or whatever at ground level right off the rail. So its not as
         | simple as "a mach 4 surface to air missile can never hit a mach
         | 6 airplane" because mach 6 at 120Kft is much slower than mach 4
         | at ground level.
        
           | sudosysgen wrote:
           | Scramjet engines can combust the air at supersonic speeds.
           | Rumors are that the Chinese and Russians flew scramjet
           | aircraft multiple times.
        
         | geocrasher wrote:
         | It's accepted that the top speed of the SR-71 was likely around
         | Mach 3.5. The Mach 3 records were just for show, and pilots
         | have said that even at Mach 3 when they pushed the throttle
         | forward, it just went.
         | 
         | This article also says that the SR-72 will use "a dual-mode
         | engine that combines turbine and ramjet technologies." The
         | SR-71 already did that.
        
           | masklinn wrote:
           | > It's accepted that the top speed of the SR-71 was likely
           | around Mach 3.5. The Mach 3 records were just for show, and
           | pilots have said that even at Mach 3 when they pushed the
           | throttle forward, it just went.
           | 
           | FWIW the official record is Mach 3.3, Air & Space/Smithsonian
           | reported that it'd been clocked at 3.4 by USAF, and Brian
           | Schul claimed to have exceeded 3.5 during evasive manoeuvres.
           | Mach 3 was never claimed to be anywhere its limits. Hell, the
           | design / cruise speed was 3.2.
        
             | geocrasher wrote:
             | I was generalizing, but your point backs mine up all the
             | same. Thanks :)
        
       | MichaelMoser123 wrote:
       | How do the intelligence gathering capabilities of the SR-72
       | compare against that or the various reconnaissance satellites?
       | Why do they need this plane, if they can get comparable
       | information from space?
        
         | _3u10 wrote:
         | One of the main advantages of the plane is ease of refueling.
         | You either have to wait for a satellite pass or maneuver the
         | satellite which eats into its very limited fuel.
         | 
         | The information may be comparable but the latency is not.
         | 
         | Think of it like playing CoD on satellite internet vs fibre.
        
           | [deleted]
        
         | joshAg wrote:
         | The sr72 has 2 advantages over satellites.
         | 
         | 1) satellites are very predictable, so it's possible to hide
         | things from them.
         | 
         | 2) satellites are very very far away, so the sr72 can get
         | better pictures by dint of being closer.
         | 
         | This article touches on both examples where satellites were
         | predicted and planned around and some discussion of satellite
         | imagery limitations:
         | https://www.npr.org/2019/09/05/758038714/can-president-trump...
         | This one has a bit more focus on resolution and capbilities:
         | https://www.universetoday.com/143298/thanks-to-trump-weve-go...
        
       | AlbertCory wrote:
       | Maybe someone here happens to have a link to the video by the US
       | pilot who was shot down in Vietnam and severely injured, told he
       | would never fly again, and yet became a Blackbird pilot. Fun
       | stories about flying it.
       | 
       | It's long, but well worth it, I promise. I'm not sure if this [1]
       | is the one I'm thinking of, but it's the same guy anyway.
       | 
       | [1] https://www.youtube.com/watch?v=Ndamj_Ewod8
        
       | goshx wrote:
       | Off-topic: what a terrible mobile experience. You have to dig for
       | the content between all the BS ads.
        
         | bloopernova wrote:
         | On Android, I highly recommend Firefox with the ublock origin
         | extension.
         | 
         | On apple mobile devices, I bought "Adguard pro" which seems to
         | work pretty well.
        
       | uniqueuid wrote:
       | The question is, of course, for which mission profile you even
       | need a manned and/or large plane like this.
       | 
       | Will this be autonomous? Will it be superseded by loitering
       | munitions, drones and super fast rockets?
       | 
       | Another nitpick: > similar size and range as the SR-71 and will
       | likely engage in the same missions.
       | 
       | The SR-71 was an espionage plane, not an armed one as far as I
       | know.
        
         | AlbertCory wrote:
         | You missed the opening:
         | 
         |  _The Lockheed Martin SR-72, also known as the "Son of
         | Blackbird," is a hypersonic unmanned aerial vehicle_
         | 
         | btw, the Blackbirds are in lots of museums. I've visited one in
         | Tucson and another in Seattle.
        
         | Arrath wrote:
         | > The SR-71 was an espionage plane, not an armed one as far as
         | I know.
         | 
         | That would be the YF-12, a prototype interceptor built off of
         | the A-12, the A-12 being the base from which SR-71 was also
         | derived.
        
         | whalesalad wrote:
         | Having family and friends deep in the industry, and a dad,
         | grandfather, uncle and grandmother who worked at Lockheed and
         | specifically the Skunk Works - this is not real. This stuff
         | gets made up all the time.
         | 
         | The real stuff being done at the Skunk Works is not stuff you
         | will ever _ever_ hear about.
        
           | uniqueuid wrote:
           | Congratulations on an interesting family then!
           | 
           | I guess the public will eventually learn some things.
           | Personally, I'm not so much concerned about technology that I
           | don't see as much as about technology that is cheap and
           | effective enough to be out there: remote controlled sniper
           | rifles, bomb-dropping drones, chemical weapons.
        
             | whalesalad wrote:
             | I don't know the good stuff either. I know stuff that's
             | been unclassified but everything else is a mystery to me as
             | well. My family has great stories but they are also
             | committed to the integrity of the mission.
        
             | atonse wrote:
             | Have you read the article about how Israel remotely
             | assassinated an Iranian nuclear scientist? [1]
             | 
             | Not a sniper rifle but remotely controlled and AI assisted.
             | It was right out of a movie.
             | 
             | [1]
             | https://www.nytimes.com/2021/09/18/world/middleeast/iran-
             | nuc...
        
               | rich_sasha wrote:
               | That's what I would say too if in fact all I had was an
               | Iranian cooperative, or Israelis on the ground.
        
               | [deleted]
        
               | uniqueuid wrote:
               | Yes that's what I was referring to.
               | 
               | It seems we are catching up to some scifi fast. Let's
               | hope it's not the Daniel Suarez version.
        
           | poisonarena wrote:
           | my uncle works at nintendo and he confirms its real
        
           | robotresearcher wrote:
           | We've heard of at least:
           | 
           | P-38, P-80, U-2, SR-71 (etc), F-117, F-22, and F-35
           | 
           | have they stopped making things we will hear about?
        
           | enkid wrote:
           | We know the US is working on hypersonic weapons. It makes a
           | lot of sense to put that same technology in a reusable UAS.
           | This doesn't seem like such a stretch as to be instantly
           | dismissed. I would take reports about it with a grain of
           | salt, and the SR-72 designation is there to grab headlines,
           | either from the news source or Lockheed Martin, but it's very
           | feasible for them to be building the thing described in the
           | article.
        
             | whalesalad wrote:
             | You are correct. Hypersonic, autonomous aircraft and
             | weapons? Yes. Will it be the SR-72? No.
        
               | enkid wrote:
               | So is your problem the designation, or the actual concept
               | that is being developed? Because, frankly, who cares what
               | it's called. The important thing is what it can do.
        
               | whalesalad wrote:
               | My problem is with neither - it's with the way the
               | aviation community will jump on theories and build them
               | up into big snowballs that are usually not even remotely
               | close to reality or might even be talking about an
               | aircraft that simply doesn't exist.
               | 
               | So I don't get stoked about news headlines like this
               | because generally it's just fun masturbatory stuff that
               | doesn't hold a lot of truth in the real world.
        
               | [deleted]
        
               | colechristensen wrote:
               | A release like this has to be a chess move or entirely
               | made up. You don't just share weapons platform plans for
               | no reason. You underpromise, overpromise, lie, brag, or
               | misdirect in order to achieve some outcome.
               | 
               | You see it and ask yourself "why?" and "how much is BS?"
        
             | devoutsalsa wrote:
             | By hypersonic weapons, do you mean missiles? Are they even
             | useful? To follow the curvature of the earth, they have fly
             | higher than a subsonic cruise missile, making them fairly
             | easy to spot. Not sure how hard they are to shoot down.
        
               | colechristensen wrote:
               | Flying very high and very fast poses timing challenges,
               | in order to shoot it down you have to see it, make the
               | decision to shoot it down, and then have an interceptor
               | which is fast enough to make up for the detection lag,
               | get to altitude, and get to location.
               | 
               | For something that could cross the continental US in a
               | half hour or less, you can imagine there is not a lot of
               | room for delay.
        
               | sudosysgen wrote:
               | Modern SAM systems are made to launch in less than 15
               | seconds after detection. Their missiles go 2km/s+, and
               | they are made to detect targets from 400km+ away. The
               | SR-72 would not be the most difficult target they are
               | built to engage.
        
               | ceejayoz wrote:
               | > Not sure how hard they are to shoot down.
               | 
               | Judging from anti-ballistic missile efforts, quite hard.
        
               | bumby wrote:
               | > _Are they even useful?_
               | 
               | Potentially, yes. For example, for the same reasons you
               | list, they are capable of being used in space-defense,
               | like anti-satellite or ballistic defense.
        
               | enkid wrote:
               | Something going mach 5+ is going to be extremely
               | difficult to shoot down. Typically, they boost up to high
               | altitudes then come back down to lower altitudes to
               | actually strike the target (boost glide). Looks like the
               | air force is also developing a cruise missile which would
               | fly at lower altitudes.
        
               | sudosysgen wrote:
               | It's not that hard to hit something going Mach 5 or so at
               | high altitude. That translates to speeds of just over
               | 5000km/h.
               | 
               | The really hard thing is to hit targets that go close to
               | orbital velocity (for example when trying to hit a
               | hypersonic missile going 11 000km/h+ or a ballistic
               | missile going 20 000km/h.
        
         | lumost wrote:
         | The yf-12 was a fighter version of the SR-71 cancelled during
         | the Vietnam war.
         | 
         | Missile launch platforms greatly benefit from high speed and
         | high altitude. A hypothetical Mach 6 aircraft at 100k feet will
         | likely have at least double the A2A missile range of an F-16 at
         | 30k ft launching the same missile . Given that most long range
         | A2A missiles peak at Mach 5 it would be extremely difficult to
         | engage such a platform.
        
           | aerostable_slug wrote:
           | Not just A2A. There were studies done on arming SR-71s with
           | SRAMs in the chines -- both downrange and crossrange
           | performance was massively improved.
           | 
           | https://lh3.googleusercontent.com/proxy/EmV9xz0SUL1NW08RDs3Z.
           | ..
        
         | chinathrow wrote:
         | > The SR-71 was an espionage plane, not an armed one as far as
         | I know.
         | 
         | And a very fast one.
         | 
         | https://theaviationgeekclub.com/sr-71-blackbird-pilot-tells-...
        
         | numpad0 wrote:
         | Probably be used to deal with nuclear TELs and people on
         | backseats in sedans? YF-12 and M-21 variants of A-12 had bays
         | and launchers but none of Blackbirds had necessary cameras for
         | air to ground weapons.
        
         | [deleted]
        
         | jhgb wrote:
         | Technically the YF-12 was armed.
        
         | sambe wrote:
         | The article states that it's unmanned and emphasises
         | intelligence capabilities.
         | 
         | I thought SR-71 had some strike capabilities, but I could be
         | mistaken.
        
           | uniqueuid wrote:
           | Thanks, you're right.
           | 
           | That raises the interesting question of how large, hypersonic
           | UAVs are expected to be used.
           | 
           | What kind of intelligence mission benefits from a fast flyby
           | but cannot be performed by a satellite?
           | 
           | What kind of attack is fast but cannot be from a guided
           | weapon?
        
             | goodcanadian wrote:
             | _What kind of intelligence mission benefits from a fast
             | flyby but cannot be performed by a satellite?_
             | 
             | The orbits of satellites are known. The target can arrange
             | activities to occur when there is not a satellite overhead.
             | A fast flyby can occur at any time with little or no
             | warning.
        
             | pge wrote:
             | Satellites were great during the cold war when the targets
             | were consistent, and the satellites could be put in orbits
             | with good coverage of those areas (eg Russian military
             | bases). Spy planes like the SR71 and U2 that fly high and
             | fast to evade detection or destruction are essential for
             | getting immediate photos of an area that may not have
             | regular satellite coverage.
        
             | 7952 wrote:
             | Maybe geolocating cell phones or WiFi?
        
             | germinalphrase wrote:
             | " What kind of intelligence mission benefits from a fast
             | flyby but cannot be performed by a satellite?"
             | 
             | Perhaps they expect the spy satellites to be immediately
             | blown up in this conflict.
        
               | VLM wrote:
               | All you have to do is lase them.
               | 
               | Like handling security cameras... you can fire an
               | artillery shell at a security camera, but most of the
               | time security cameras are mission ineffective if you just
               | shine a bright enough flashlight (or laser) at them.
               | 
               | There's no need to cause an international incident by
               | blowing something up when all you need is a bright light
               | for a couple easily predictable minutes.
               | 
               | On the other hand a stealthy hypersonic flyby is probably
               | invisible.
               | 
               | Another military aspect civilians never want to talk
               | about is photo analysis depends on illumination and rando
               | satellite passes can't see into valleys and get messed up
               | if the shadows are weird enough. Just because technically
               | a satellite passed within range of Afghanistan as a whole
               | country, doesn't mean you can see what's happening on the
               | wrong side of a mountain with bad illumination and bad
               | view angle. There's a lot of satellites but not THAT
               | many. Afghanistan used to have boots on ground to launch
               | UAVs but not so much anymore.
        
             | knute wrote:
             | There are a limited number of spy satellites, and their
             | orbits are fairly fixed. If you need to look at a site you
             | have to wait until a satellite passes it (and the people at
             | the site will be able to know quite far in advance when a
             | satellite is coming). And there's no way to delay the pass
             | until the cloud cover clears.
        
               | sterlind wrote:
               | You could potentially hide a satellite from radar
               | observation the same way you can for planes. That's
               | apparently what the Misty program [1] did. Synthetic
               | aperture radar could take care of clouds, though you lose
               | color. Agreed about maneuverability I think.
               | 
               | 1. https://en.wikipedia.org/wiki/Misty_(satellite)
        
             | numpad0 wrote:
             | They probably won't send in U-2 or MQ-9 to stick ninja
             | swords through the roof of a luxury sedan past rings of
             | S-300 SAM batteries few hundred miles from shores.
        
               | fmajid wrote:
               | Are you referring to the Hellfire R9X "flying ginsu"?
               | 
               | https://www.popularmechanics.com/military/weapons/a301754
               | 25/...
        
           | runjake wrote:
           | You may be thinking of the YF-12, which was based off the
           | closely-related-but-not-the-same-at-all A-12 precursor to the
           | SR-71.
           | 
           | Brag: I've actually seen a YF-12, up close, at Edwards AFB.
           | NASA used them for testing for many years.
           | 
           | https://en.wikipedia.org/wiki/Lockheed_YF-12
        
       | ceejayoz wrote:
       | Related? https://twitter.com/rubenhofs/status/1440594839481946129
       | https://twitter.com/TheDEWLine/status/1440806852560707587
        
         | runjake wrote:
         | That airframe, while super super intriguing, isn't a hypersonic
         | airframe style.
         | 
         | It's most likely something for NGAD [1] purposes.
         | 
         | 1.
         | https://www.nationaldefensemagazine.org/articles/2021/9/21/a...
        
       | bloopernova wrote:
       | Somewhat on-topic, have there been any updates from Skylon or
       | SABRE engines lately? Single stage to orbit seems so sci-fi I
       | wonder if we'll ever get close.
        
       | tclancy wrote:
       | Given satellite technology and ICBMs, can someone explain why my
       | tax dollars are going to this science fair project for adults?
        
         | JanSolo wrote:
         | ICBMs are a large, blunt weapon. Their value is primarily in
         | their deterrence. The concequences of actually using them are
         | so unthinkable, that we don't really consider it unless it's a
         | very-last-resort kind of situation. Most of the time you want a
         | precision, guided munition that can destroy a house or a truck
         | or something small without causing too much collateral damage.
         | Until now, that has meant an airbase or a carrier nearby to
         | launch aircraft to carry these munitions.
         | 
         | However, with the XR-72, we can do away with those and just
         | launch our precision strikes from the US mainland. It's
         | cheaper, just as effective and hopefully will give emerging
         | superpowers (like China) pause when planning their defence
         | scenarios.
        
           | TheOtherHobbes wrote:
           | How is China supposed to know if one of these is carrying
           | cameras, conventional bombs, or a warhead?
        
             | lmm wrote:
             | They aren't. But the trajectory means they can see it isn't
             | aimed at Beijing.
        
         | mmcconnell1618 wrote:
         | ICBM go up and down in a predictable arc. Sometimes they have
         | the capability to shift their path actively but not by much.
         | Hypersonic controlled flight vehicles have the ability to be
         | unpredictable and therefore offer more protection from
         | countermeasures.
        
           | arethuza wrote:
           | FOBS does allow you to at least change that arc so you can
           | effectively come at a target from any direction:
           | 
           | https://en.wikipedia.org/wiki/Fractional_Orbital_Bombardment.
           | ..
        
         | me_me_me wrote:
         | Well we need to feed the beast because we love freedom and if
         | you don;t you are free to go to gulag... or something along
         | those lines.
        
         | nnq wrote:
         | Bc there's some treaty prohibiting space-based weapons smth
         | smth... hence your satelite will not be able to carry missiles
         | (or use them without admitting it carried them).
         | 
         | ...and bc ICBMs are not weapons you'd want to EVER see used :)
         | 
         | You'd probably use this to hit a bad guy's
         | house/hospital/school inside airspace protected by another
         | superpower (hence drones and other stuff won't work) based on
         | ground based humint whose information will likely be stale
         | after a couple hours. It could mean way less victims than
         | conventional warfare, so ugly as it is, it's better than
         | destroyed cities and waves of refugees.
         | 
         | All in all cool to see superpowers doing dick measuring
         | contests with these kinds of stuff, compared to other horrible
         | stuff they could be competing at militarily...
        
         | dsr_ wrote:
         | I'm going to attempt to answer your question.
         | 
         | First, it's unlikely that this is a real project. War companies
         | produce lots of random ideas for presentations hoping that one
         | of them will catch on and get an initial program funded. A few
         | years ago there were animations of a V22 mashed up with a C130
         | to get a tandem winged VTOL cargo plane. The warporn gets
         | buyers in the mood, but what they actually buy are things like
         | the F35 program and "palletized strike missions", which is a
         | mid-air launch system for cruise missiles. Every cargo plane
         | with an in-air openable ramp becomes a cruise-missile launching
         | bomber.
         | 
         | Second, some prototype projects provide cover for other, more
         | secret projects. If everyone knows that a lot of engineers are
         | being hired for the SR-72 project, the fact that 25% of them
         | are actually working on something else in the same facility is
         | easy to disguise. Test flights of one hypersonic vehicle look
         | pretty much the same as test flights of a different hypersonic
         | vehicle.
         | 
         | Third, war companies provide a lot of skilled through
         | professional level employment in the areas where they operate,
         | and politicians find it acceptable to run employment programs
         | that way.
        
         | hindsightbias wrote:
         | Hypersonics is like fusion, everyone needs to be doing it.
         | They've been trying for decades and so far it's been a bust.
         | 
         | Queue news stories about Chinese or Russian hypersonics with
         | zero real data and calls by the MIC to close the "hypersonic
         | gap"
         | 
         | In the pantheon of weapon systems it is simply the most
         | expensive way to do something.
        
         | baybal2 wrote:
         | > Given satellite technology and ICBMs
         | 
         | I see an SR-72 being a hedge against losing both of the above,
         | or having them rendered ineffective.
         | 
         | Putting a nuclear munition on this thing makes sense to kind of
         | get ICBM like capability in a ditch, and ensures you have
         | something against the enemy who can reliably intercept ICBMs.
         | 
         | Same for the case spy sats get taken down. The chance of the
         | enemy having something that can intercept high speed
         | aerodynamic targets, as well as satellites at the same time is
         | minimal.
        
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