NASA Provides Results Of Scramjet Test

Guinnessy writes "Last March, NASA carried out the world's first test flight of a scramjet-powered aircraft. The Industrial Physicist has the latest results from this test. According to the article scramjet-powered missiles and aircraft could be in mass production as early as 2010. This piece is also a good introduction for those unfamilar with scramjet technology."

Comments

Great news!

[AKAImBatman]

One thing that has often concerned me is the matter of lift from the wings/lifting body. Obviously this design should be able to go into orbit with a relatively minor assist from rocket engines. However, how much lift does it actually get? Is it possible to build a craft that can use wing lift all the way up to LEO? If so, could it then be possible to obtain a flight envelope on the way back down?

The primary reason why I've concerned myself with this, is that the Space Shuttle literally "falls" out of orbit in a very steep dive. The idea is to re-enter somewhere over the Pacific and shed enough speed to land just before the Atlantic. Obviously, it was important the normal flight operations didn't overfly the USSR. The problem with this sort of profile is that the Shuttle takes on a tremendous heat load from the aero-braking. Yet there's nothing really inherent in the atmosphere that says the the Shuttle MUST take on that load.

To get to the point, would it be possible to return in a glide or powered flight without the requirement of a heat shield? i.e. Could a vehicle obtain a thin-atmosphere flight envelope and reduce its speed at a more gradual rate? Perhaps even to the point where no shielding is required?

Any aerospace engineers in the know want to comment?

Re:Great news!

[Hakubi_Washu]

Hm,
I'm no expert either, but I would tend to think that the re-entry problem is not height, but the speed required to stay in orbit. In order to return to earth you hve to reduce speed pretty heavily (The reason SpaceShipOne didn't "reach orbit" was that it can't ever reach the necessary speed in the first place). If you don't do this "fast" enough you'll not reach earth surface, but continue to orbit, albeit way more eccentric. It is possible to land in this way, a lot of mars flight plans include this multiple aerobraking/atmosphere dipping, but it takes a) a lot more time, as your orbit takes you pretty far outwards between the "dips" and b) it is way more risky as your calculations have to be very precise (Otherwise... You know what flat stones can do on water? :-)
As I said, I'm merely a /.-reading geek, but I think this is pretty much what the problem looks like...

Re:Great news!

[jafac]

Orbit is more a function of speed than a function of lift or drag.

Exactly right.

One coule achieve orbit at "sea level" so long as one was going fast enough, could somehow maintaint that speed given the aerodynamic drag at that altitude, and encountered no terrain obstacles.

The hope of the Scramjet is;
Obtain enough velocity while still within the atmosphere to attain orbital velocity, while overcoming drag via engine thrust. Of course, the vehicle will eventually run out of fuel, so the next aim is;
At this altitude, obtain SURPLUS velocity, which can be used to gain altitude (no longer via aerodynamic lift, but through sheer newtonian momentum). As altitude is increased, there will be a point where there's not enough air to run the engine, yet there's still enough air to create drag. That drag, plus speed lost to attain altitude, will slow the vehicle down. If the engine produced enough surplus velocity, then, in theory, it could reach what we normally consider to be LEO (about 200 miles?). It's even theoretically possible to reach higher orbits, or even escape Earth's gravity altogether - if we can find a material that can stand the thermal loading during the attainment of this surplus velocity, and if we can carry enough fuel with us to burn. But outside of the realm of theory lie the cold hard facts that we don't have materials like that, so we'll probably just use rockets to attain higher altitudes.

In which case, it seems to make more sense to use the scramjet on a BOOST vehicle, and stick to a rocket upper-stage to propel your orbiter or payload. The scramjet booster should be recoverable, of course. So it's looking more and more like the future model of space flight is something like what Scaled Composites came up with:

A smaller Orbiter or Payload-type vehicle, rocket propelled, piggybacked on a larger booster vehicle. Probably also piggybacked on an even larger carrier.
(say - a modified C-5, carrying a large booster to an altitude of say, like 60,000 feet or so (what's the C-5's service ceiling?) - Drop the vehicle, that uses an initial rocket boost, or perhaps turbofans, to get up to Mach 2-3, a Scramjet for mach 3-15 or so, then at a given altitude, release an upper-stage for orbital insertion and maneuvering. The Booster stage returns for recovery, as well as the carrier. The upper-stage vehicle doesn't really need to be reusable. Unless it's manned. The most expensive hardware would probably be the Booster vehicle. If the upper stage is manned, well, there's a lot of very expensive avionics and life-support stuff you'd want to recover and re-use. But we're no longer talking about something the size of the Shuttle. Not even the combined Booster/Upper-stage. I guess a C-5 could probably carry something that large, but since the Carrier is doing the bulk of the heavy-lifting that would otherwise have been done by the Shuttle's main engines and external tank, the Carrier shaves a bunch of mass off the Booster/upper-stage, which leaves a lot more capacity for payload.

Re:Great news!

[AeroNate]

Yeah, thermodynamically irreversible processes like friction and shockwaves turn kinetic energy into thermal energy, and in this case the atmosphere is heated to a plasma by the vehicle's motion relative to the atmosphere. (Mainly at the leading edges where the shock waves are, I think) So, you can attribute it to friction if you like. But the interaction between the vehicle and the gas/plasma is the heating mechanism. Once the atmosphere is heated at the leading edge, it flows back past the rest of the vehicle. I believe there is a thin layer of relatively cool gas in between the tiles and the hottest plasma. (It has been cooled by giving up some of its heat to the cooler surface of the vehicle. When there is a disruption of the flow (like when tiles are damaged on a shuttle) the resulting increase in turbulence can increase the transport of heat through this cooler layer and cause problems. If you could slow down higher up, then, yes, that would be good, but it is hard to do without causing heating because you have to push on the atmosphere somehow in order to do it. You could use an engine burn, of course, but that is very expensive and that means that you had to take extra fuel into orbit with you, which means that you could have had a bigger useful payload instead. I read somebody's explanation of why a winged reentry is inferior to a capsule and heat shield, and I bought his arguement, but I cannot remember it I'm afraid.

engine design

[Lehk228]

After reading the article and looking at the diagram i wonder how the vulnerability of scramjet engine compares with a turbojet or turbofan when it comes to impacting birds and or bats, though at this time i am sure these engines are only being used at very high altitudes and in controlled conditions but if they make it into production fighter aircraft they will be used at lower altitudes. the lack of anything blocking off the path of the air in the diagrams makes it look almost as if an object would pass completely through the engine without damaging it, though i'm sure the object would be burnt to a crisp.

Re:engine design

[Beryllium Sphere(tm)]

It sounds like the engine depends on careful management of shock wave locations and heat profiles. Running a foreign object through could not be good.

On the other hand these are for speeds above Mach 3, at which you'd better be in very thin air or you'll start melting your vehicle. There aren't many birds at SR-71 cruising altitudes.

It is just what we need.

[Behrooz]

It is just what we need. Or rather, it's a good stepping stone on the way to orbit.

Mach 15 at 100,000 feet is 10,200 MPH, which is also roughly equivalent to the following critical hurdles to cheap space travel:

10% of the ~185-mile altitude required for a stable orbit.
59% of the ~7.7 km/sec required to achieve low-earth orbital velocity.

NASA's budget is a drop in the bucket, approximately $15B out of total discretionary spending exceeding $850B, with a total federal budget exceeding $2.2 trillion... hah.

Hypersonic aerospace research is a good idea simply on its own merits, regardless of present applications. I certainly look forward to 90-minute sub-orbital shuttles from London to Tokyo, and being able to put things in orbit for less than $10,000/pound.

Affordable?

[bStrom]

The article says that the scramjet will be "affordable", but what does that really mean? Affordable compared to current commercial technology? Affordable compared to current scramjet technology?

The affordability, more than anything else, will determine whether this technology is adopted. This engine might get you to your destination faster, but if it costs 10x as much the majority of fliers (and airlines) won't pay.

Zero to 5000 in 10 seconds?

[serutan]

Did I read this right? ...scramjet engine fired for a planned 10-s test, achieving an incredible Mach 7, or 5,000 mph.

It reached 5000 mph in TEN SECONDS? Holy crap, dude!
If this is right I am truly impressed. Could a human passenger survive that acceleration?

Re:I call your bluff, sir

[gilroy]

OK. By the way, this is from less than two minutes of a Google search... it's particularly low-hanging fruit available to anyone who's open enough to actually, you know, look.

"Commercially available infant formulas now contain a nutritional enrichment ingredient that traces its existence to NASA-sponsored research that explored the potential of algae as a recycling agent for long duration space travel." (ref)

Ski wear: "The NASA association began back in the 1970s, when Comfort Products adapted astronaut protective clothing technology to ski boot design. Specifically, the company borrowed heating element circuitry that kept Apollo astronauts warm or cool in the temperature extremes of the Moon, and used it to create built-in rechargeable footwarming devices that were supplied to leading ski boot manufacturers." (ref, emphasis added)

"In 1965, Johnson Space Center contracted with the University of Minnesota to explore the then-known but little-developed concept of impedance cardiography (ICG) as a means of astronaut monitoring. A five-year program led to the development of the Minnesota Impedance Cardiograph (MIC), an electronic system for measuring impedance changes across the thorax that would be reflective of cardiac function and blood flow from the heart's left ventricle into the aorta... the cost of the thermodilution technique [the old, invasive way] runs five to 17 times that of IQ monitoring [the new, NASA-developed way]"(ref)

"GROUND PROCESSING SCHEDULING SYSTEM - Computer-based scheduling system that uses artificial intelligence to manage thousands of overlapping activities involved in launch preparations of NASA's Space Shuttles. The NASA technology was licensed to a new company which developed commercial applications that provide real-time planning and optimization of manufacturing operations, integrated supply chains, and customer orders" (ref)

"STRUCTURAL ANALYSIS - This NASA program, originally created for spacecraft design, has been employed in a broad array of non-aerospace applications, such as the automobile industry, manufacture of machine tools, and hardware designs."(ref)

"SCRATCH-RESISTANT LENSES - A modified version of a dual ion beam bonding process developed by NASA involves coating the lenses with a film of diamond-like carbon that not only provides scratch resistance, but also decreases surface friction, reducing water spots." (ref)

"MICROSPHERES - The first commercial products manufactured in orbit are tiny microspheres whose precise dimensions permit their use as reference standards for extremely accurate calibration of instruments in research and industrial laboratories. They are sold for applications in environmental control, medical research, and manufacturing."(ref)

"SOLAR ENERGY - NASA-pioneered photovoltaic power system for spacecraft applications was applied to programs to expand terrestrial applications as a viable alternative energy source in areas where no conventional power source exists."(ref)

"DIGITAL IMAGING BREAST BIOPSY SYSTEM - The LORAD Stereo Guide Breast Biopsy system incorporates advanced Charge Coupled Devices (CCDs) as part of a digital camera system. The resulting device images breast tissue more clearly and efficiently. Known as stereotactic large-core needle biopsy, this nonsurgical system developed with Space Telescope Technology is less traumatic and greatly reduces the pain, scarring, radiation exposure, time, and money associated with surgical biopsies."(

Re:I call your bluff, sir

[mj_1903]

How about any of NASA's R&D to do exactly those things? If I recall correctly, the shape of the wings on many aircraft today are a direct descendant from research that NASA did on aircraft wings. Interestingly you may also not know that NASA found that a wing that was upside down with a small lip on the end was actually the best wing in terms of performance.

Composite structures in aircraft, such as the tail of the 777 or much of the Airbus super jumbo, owe a great deal to NASA's research.

Many new things have been learnt about the human body thanks to NASA research into human behaviour, in areas such as extended stays in isolation, the endurance of the human body and team work.

Many key elements of computers owe a lot to NASA funding miniaturisation for space craft and this has had a run off effect in many areas of human life.

Other posters have mentioned other areas, so I will leave it at that.

"a quieter ride"

[da5idnetlimit.com]

well, a scramjet will take you from an initial Mach 2-3 to the expected mach 7-10+ this technolgy is meant to achieve...

So you will still enjoy all the noise of the starting point up to mach 1, then have a nice, quiet acceleration to mach 2-3, and then suddenly leave all sound you produce about 500-600 feet behind you, instead of just the 70 feet sound buble displacement you enjoy at mach 3.

the whole point is that to you it will be quite silencious...but it really have to be made in high altitude...

If you were to engage the scramjet at low altitude (say launched as a missile from a mach 2.4 fighting plane) just the sound wave decelerating from the missile at low altitude would be sufficient to damage any building within a 2 mile radius...not to mention deafening a few tousand people.

Then, on impact, I think you can dispense with unstable/dangerous explosive...
you just need some hyperdense material at the tip, say 5 kg depleted uranium.

Now, if you caculate the inertia of 5 kg at mach 7-25, you will find it's a very damaging little kinetic monster you just created.

after all, the FIRST implementation of that thing is to be a missile in 2010-2015...so lets see what the probable effects will be...

E=mv^2

5000grams*(330m/s*(mach 7 to 25))^2

5000*(5336100 to 68062500)
26 680 500 000 to 340 312 500 000 Joules at impact...seems quite an energy dissipation problem...for the target, I mean 8p

my physics class is quite old now, feel free to privide the right formula or to correct me on any point... 8)