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Rocket-Boosted Orbital SR-71 Derivative

KJ_Lesnick

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Allegedly, I've heard mention some time ago of a concept (not sure how serious it was, although allegedly it was physically possible) that featured a modified SR-71 which would would be fitted with a booster/thruster-pack system to enable it to get into orbit. Allegedly, the temperatures the blackbirds reached during high-speed flight were similar to the shuttle-reentry temperatures!

I actually heard this mentioned in at least one book about the Blackbird (and it wasn't an unreliable book, although I don't remember the title off hand), and heard it mentioned a few other times. WTF???

Anybody ever heard of anything like this or have any more information? If it was mentioned in a book it can't be classified, I'm pretty sure!
->If this is true, the Blackbird would have to be able to fly at unbelievable mach-numbers, well above what is normally listed as being capable of (even higher than the estimates I assumed), and it also raises some questions as to the engine's capabilities -- would they keep working until almost to orbit, or would they be shut down with the rocket doing all the work at high-speed and altitude?


BTW: I did NOT make this up
 

Skybolt

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Mmmm, just my opinion: problem wouldn't be skin temperature, but configuration and structure. For one, during reentry at hypersonic speed the CG would be very different from a normal supersonic (even trisonic) flight.
 

Just call me Ray

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...I'm almost tempted to say that someone's been playing Ace Combat 3 a little too much....
 

Orionblamblam

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KJ_Lesnick said:
Allegedly, I've heard mention some time ago of a concept (not sure how serious it was, although allegedly it was physically possible) that featured a modified SR-71 which would would be fitted with a booster/thruster-pack system to enable it to get into orbit.

In a word: bullcrap.
 

Michel Van

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Allegedly, the temperatures the blackbirds reached during high-speed flight were similar to the shuttle-reentry temperatures!

total bullcrap.

SR-71 Titan hull get max +570°C
Shuttle heatshield get max +1650°C
(titan melt at +1668 °C)

is a star, is it a meteor ?
No is a SR-71 braking up and burning up during reentry...

and SR-71 has not reaction control system like X-15 or Shuttle on board.
so a space flight with out control...
 

overscan (PaulMM)

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Don't take it the wrong way, but extraordinary claims need verifiable sources.

"I read it in a book sometime" isn't a verifiable source. Given the unlikeliness of the claim, you'll find most people here will react in the same, sceptical, way.
 

Orionblamblam

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Michel Van said:
[
and SR-71 has not reaction control system like X-15 or Shuttle on board.
so a space flight with out control...

Additionally, the empty weight of an SR-71 is about 67,000 pounds. The *Space* *Shuttle* could not put it into orbit... and someone seriously thinks that a bolt-on rocket pod could do the trick? Pfffff. Not unless Skunk Works invented fricken impulse engines and warp drive.


The closest I'd dare come to justifying this particular story is the LASRE experiment:
http://en.wikipedia.org/wiki/LASRE
 

sferrin

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They took a D-21 and put a solid booster on it so it stands to reason that if you took a Blackbird and mounted it on an SRB. . . (isn't that how rocket science works? ;D)
 

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sferrin said:
They took a D-21 and put a solid booster on it so it stands to reason that if you took a Blackbird and mounted it on an SRB. . . (isn't that how rocket science works? ;D)

That's not how rocket science works (orion isn't the only certified rocket scientist around here, you know ;D ), but you might be on to something. It is possible that they conceived some sort of orbital insertion device (think Pegasus) that would be fired from a Blackbird. Let a few indications of that concept leak out over time and it is perfectly "reasonable" that the open-source press and the aviation afficionado community would transform it into an orbital version of the Blackbird.

To my knowledge, though, the only thing they ever seriously considered shooting off of a Blackbird (apart from weapons like the AIM-47) was the D-21, and we all know how well that worked out. It is possible that a non air-breathing object may have fared better than the drone did, but that's just speculation on my part. Like I said, as far as I know outer space and the Blackbird have never been credibly linked, apart from the fact that NASA used various versions and that space-based objects helped push it into retirement.
 

sferrin

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For the record I was bull$hitting. ;) BTW did you know at one time they'd hoped to launch a mini X-30 off the back of a Blackbird? Don't know how serious they were about it but ISTR one concern mentioned in AvWeek was that they didn't know if it could get the thing flying fast enough.
 

starviking

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I wonder if someone was confusing the SR-71 with the X-15? There was a proposal to get a orbital spaceshot with an X-15 mated to various boosters. http://www.astronautix.com/craft/x15b.htm

After all to the uninformed both the X-15 and SR-71 are fast black aeroplanes... ::)

Starviking
 

KJ_Lesnick

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From what I was told it wasn't a D-21, but a modified SR-71 attached to a booster. I assume maneuvering thrusters would be added for maneuverability in space?


BTW: What temperatures are typical during a re-entry on the space-shuttle?
 

fredgell

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Just a side note or two - I can recall at least one 60s SF magazine - Galaxy, IF or similar - with a Laumer story and an illustration of a space interceptor - the SR71. A lazy artist no doubt.

I seem to recall reading that Saro had some similarly wild ideas about getting a variant of the 177 into low orbit.

Regards

Fred
 

Michel Van

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What temperatures are typical during a re-entry on the space-shuttle?

Shuttle heatshield get max +1650°C or 3002°F

and wat for a booster they wana use ?
a SR-71 weight 27214 kg or 60000 pounds empty

Space Shuttle ? makes no sence...
with USAF Titan III D ? to heavy...

can it be that source mix up SR-71 with a X-15 Orbital Proposal ?
 

archipeppe

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I fully agree both with Scott and Michel Van.

It is simply impossible to take the SR-71 (even deeply modified) and put it into orbit because it wasn't designed to do that.

Regarding the X 15 in 1958-59 there where several proposals to boost it into orbit. The most seriously was, of course, a suborbital launch (with apogee higher than 150 kms) achieved with a XSM 64 Navaho booster.

Clustering some Navaho (and I have some doubt that this thing could work) it would perhaps possible to achieve a single at least double orbit, but nothing more than that (considering that X 15B would be rather different by the original version).
 

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flateric

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Combining two first items will hardly lead to the third one...
 

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Orionblamblam

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sferrin said:
BTW did you know at one time they'd hoped to launch a mini X-30 off the back of a Blackbird?

Hypersonic Air Launch Option, Popular Mechaics art here:

http://www.secretprojects.co.uk/forum/index.php/topic,250.msg1540.html#msg1540

At the time I was in university, and got a chance to speak with one of the X-30 program managers.... they did *not* like the HALO concept. IIRC, it was a Dryden concept that would ahvesucked money right out of the NASP program office, and at the time the NASP folk wanted to go straight to SSTO.

Well, it worked out great for everybody... :p
 

KJ_Lesnick

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Remember, how I said it was mentioned a few other times?

One of the people who mentioned it was an aerospace-engineer. Allegedly said that according to his computations that temperatures the Lockheed SR-71A reached in flight during cruise (heat-soaked and all) were about the same as the temperatures the Space-Shuttle achieved on re-entry.


While the SR-71 may be retired and all that I'm reluctant to even post this -- I just hope I don't get a "heart attack" or "disappear" without a trace!


Kendra
 

Orionblamblam

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KJ_Lesnick said:
Allegedly said that according to his computations that temperatures the Lockheed SR-71A reached in flight during cruise (heat-soaked and all) were about the same as the temperatures the Space-Shuttle achieved on re-entry.

Depending on just what is meant, this is certainly true. The SR-71 was made from titanium in part due to the fact that it would spend so much time heat-soaking that the whole structure would get blisteringly hot. Conversely, the Shuttle is made largely from *aluminum.* The Shuttle spends very little time heat soaking, and the parts that get nuked are the silicon tiles on the underside. The aluminum structure sees relatively little of that heat.

In the end it's an interesting-sounding tidbit, but ultimately not enlightening to say that the SR-71 gets as hot as the Shuttle.
 

KJ_Lesnick

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How much heat does the shuttle/shuttles-tiles soak-up?

And what's the typical re-entry temperatures (if they're not the same as the maximum)
 

Michel Van

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fist Picture show Skin temperature of a SR-71 in Fahrenheit
second Picture show skin temperature of Space Shuttle during reentry
in Kelvin and Buran Shuttle in Celsius. here Temperature in Fahrenheit:
yellow 2700°F (Titan metal get soft)
Orange 2240 to 1016°F
Green 1016 to 764 °F (SR-71 hottest spot the engine get 1050°F)
Red 755°F (SR-71 nose and wing edged get only 484 to 570°F)
blue 206 to 170 °F

Mythbusters_by_Mythbusters_Club.jpg

we have official busted the myth
 

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starviking

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Doing some conversions:

The hottest spot on the SR-71 (engine) gets to 566°C. The hottest parts of the plane's body reaches about 300°C. On the Buran the highest temperature is 1482°C, and the Shuttle reaches 1650°C.

Big difference.

One thing, and maybe Orionblamblam could comment on this (as you are the Forum's Uber Aerospace Engineer) - would it be possible for an aerospacecraft derived from the SR-71 to be boosted into orbit and return safely?

I ask this because I remember reading a long time ago that during the early stages of the Space Shuttle competition some proposals did not need heat-shielding as they were much lighter on re-entry - because of the large amount of internal tankage in the designs. I'm wondering how light a dry SR-71X would be on re-entry...

KJ: can you dig up any references?

Starviking
 
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interesting .. the soviet uragan BS and SR-71 BS threads are sticking together.
 

Just call me Ray

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Michel Van said:
fist Picture show Skin temperature of a SR-71 in Fahrenheit

No, first picture shows Adam Savage and Jaime Heiniman :)

Ok I'll quit being stupid now.
 

Orionblamblam

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starviking said:
One thing, and maybe Orionblamblam could comment on this (as you are the Forum's Uber Aerospace Engineer) - would it be possible for an aerospacecraft derived from the SR-71 to be boosted into orbit and return safely

Not with modern propulsion technology. An SR-71, no matter how heavily modified, would just not be able to get to orbit unless you posit antiproton-based propulsion systems. It's just too heavy and has too little available internal volume.

Now assuming you put SR-71's into a shroud on top of an Ares V booster and launched them into orbit... you could get one to survive re-entry if you covered the underside with insualtion such as the Shuttle has, but that would thoroughly muck up the plane's aerodynamics.


I ask this because I remember reading a long time ago that during the early stages of the Space Shuttle competition some proposals did not need heat-shielding as they were much lighter on re-entry -

All Shuttle designs needed heat shielding. Not all needed *ceramic* heat shielding. Some designs used metalic shielding, such as the X-20 and the X-33/V* were supposed to use. But this was also complex and heavy, and prone to damage. In essense it was molybdenum *foil*. Imagine plowing into a flock of seagulls at 400 MPH in a plane made of foil.

Some designs for recoverable first stage boosters use no advanced materials. If the maximum speed your vehicle will reach is about Mach 5 of so, you can in principle simply make the underside of your vehicle out of thick (centimeter-plus) low-grade aluminum. The aluminum has a low melting point, but it also has very high thermal conductivity. That will wick the heat away fast enough , and provide sufficient themal mass, that no point on the surface gets to a damagingly high temperature. But this only works to Mach 5, maybe Mach 6.
 
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just a query, could the aerodynamics of a heavily modified SR-71 ( thermal protection et al) allow it to reach even Mach 3 , on its own power?
 

Orionblamblam

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avatar said:
just a query, could the aerodynamics of a heavily modified SR-71 ( thermal protection et al) allow it to reach even Mach 3 , on its own power?

Highly unlikely. The requirements for surviving re-entry (blunt leading edges, around 4 inches radius) and the requirements for Mach 3 flight (sharp leading edges, radius ~.1 inches) are mutually exclusive. There are some spiffy new ceramics that should allow for sharp leading edges on re-entry vehicles, but they'd weigh a ton compared to the current metal and fiberglass structures. The inlets would be particularly entertaining... not only dealing with the sharp edges of the inlets and the spikes, but somehow shutting the inlets off so that you don't get hypersonic air flows through the nacelles wreaking havoc. Plus, ain't no such thing as a turbojet engine that likes to be stuck in orbit: greases and oils outgas, seals freeze up, all kinds of horribleness.
 
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thanks for that reply ... about the last part of your reply .. could the J-58 be modified for any kind of trans-atmospheric flight? ( relatively low altitude)
 

starviking

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Thanks for all the Orbital SR-71 and heatshield info Orionblamblam - very useful.

Starviking
 

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Don't chines also have good heat-absorbing properties? I remember seeing a V-2 derivative the Germans were building in WWII that had it's fins extended all the way to the nose forming a chine. Either way, it was designed for way longer ranges than the V-2 (could fly 3500 nm allegedly) and higher speeds too.

While an unrelated question... a plane flying at temperatures on par with Orbiter atmospheric entry would glow right? Not only the metal but even the air around it right?


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Orionblamblam

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KJ_Lesnick said:
Don't chines also have good heat-absorbing properties?

You don't want to absorb heat on re-entry.

I remember seeing a V-2 derivative the Germans were building in WWII that had it's fins extended all the way to the nose forming a chine.

The original design for the A-9, second stage of the A-9/A-10 ICBM. The design was found to have unsurvivable center of pressure travel as Mach number changed... it would have tumbled. That's why the A-4b had conventional swept wings.

a plane flying at temperatures on par with Orbiter atmospheric entry would glow right?


Yes.
 
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An opinion: Some of the members have a point, I think.

If the SR-71 is advertised to go Mach 3 and orbital velocity is about Mach 25, it would take three (3) successive stages, each imparting at least Mach 7.5 (total of Mach 22.5 for all three) + the SR-71 having air-breathing engines that only work in the atmosphere, to get to Mach 25.5.

Each lower rocket stage would probably need to be 6 or 7 times the thrust of the one above it to accelerate about 7 Mach numbers in each stage. They'd have to be pretty big, for sure. A big launch vehicle could do the trick, especially the Saturn V. Or go through the trouble of designing a new one? Expensive!

Also, the SR-71 probably wasn't stressed---or even designed---to reenter the atmosphere from space, which is what I always considered likely for that supersonic interceptor. The TPS has to be beefed up a whole lot first. That would add to the gross weight and require an even bigger launch vehicle.



overscan, quoted:
"Don't take it the wrong way, but extraordinary claims need verifiable sources.
"I read it in a book sometime" isn't a verifiable source. Given the unlikeliness of the claim, you'll find most people here will react in the same, sceptical, way."


Thank you. I'll try to remember that, since I'm fairly new around here. My practical experience, with my personal research and with my Dad's college textbooks, covers 40+ years of regular effort. Unfortunately, I never had the money to pursue a university degree. (College was always very expensive.)

However, some of the information I'm aware of is obscure and no longer available to me. The same can hold true for anyone on this chat board. Internet links and other sources can disappear at any time, for instance. All I can do is try and be as descriptive and thorough as possible.
 

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KJ_Lesnick said:
Allegedly, I've heard mention some time ago of a concept (not sure how serious it was, although allegedly it was physically possible) that featured a modified SR-71 which would would be fitted with a booster/thruster-pack system to enable it to get into orbit. ...
Anybody ever heard of anything like this or have any more information? ...
BTW: I did NOT make this up

What many responders are forgetting, is that there was a program to do performance testing of a lifting body
shape with an aerospike rocket engine, that mounted said lifting body shape with its aerospike
rocket engine on the back of an SR-71. The program was called LASRE (Linear Aerospike SR-71 Experiment).

This experiment flew a number of times in the late 1990s time frame.

This program was not to boost the SR-71 to orbital speed but to use the SR-71 as a flying supersonic wind tunnel
to test the performance of the lifting body half shape and its aerospike rocket engine.

It is quite possible that the many photos published of the SR-71 with this lifting body half shape and it's aerospike
rocket engine on the back of an SR-71 caused some misinterpretation. After all, to the uninitiated, the lifting body
half shape looked like a fairing for the rocket motor on the back of the SR-71.

But there were indeed a number of flights of an SR-71 with this configuration, which did happen. And they also cold
flowed propellant through the aerospike in flight for the performance testing. I believe there were plans to hot fire the
aerospike in flight, but I think they ended the program before that as the cold flow experiments were determined to
be adequate.

So the goal was not to make the SR-71 orbital, although the testing was to eventually help make the lifting body with
its linear aerospike engine orbital, in the form of the X-33 program.

So part of this is NOT a myth.

And yes, an SR with a rocket motor mounted on its back did fly !
 
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Now I understand what you meant the first time, KJ...

You're entirely correct that the SR-71 could have launched a smaller vehicle from the aft centerline of the fuselage and have the smaller craft proceed to orbit under it own rocket engines.

Assuming, of course that the fuel/oxidizer combo and the mass ratio was great enough to do the job. There could have also been a 2-stage craft with a smaller payload.

A had a book that I lost concerning the SR-71 which featured a Mach 4 reconnaissance drone that was launched from the SR-71 at a standoff distance and then programmed to survey territory without risking the safety of the pilot.

So, you do have a point in your assertion.
 

starviking

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KJ_Lesnick

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In regards to chines... I kind of meant aren't chines good at dealing with high-speed flight?
 
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Lee

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KJ_Lesnick, quoted:
"...aren't chines good at dealing with high-speed flight?"

Your question reminds me that the forward wing chines on the Space Shuttle were added to the design after it was found by experiment that they allowed the whole Shuttle to be built 20% lighter. Later versions were built with even more advanced construction techniques that save even more weight.

The answer is yes, chines do help supersonically.


[/quote]
 

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