Hypersonic Inflatable Heat Shield Test a Success
NASA Successfully Tests Hypersonic Inflatable Heat Shield
“A large inflatable heat shield developed by NASA’s Space Technology Program has successfully survived a trip through Earth’s atmosphere while travelling at hypersonic speeds up to 7,600 mph. The Inflatable Reentry Vehicle Experiment (IRVE-3) was launched by sounding rocket at 7:01 a.m. Monday from NASA’s Wallops Flight Facility on Wallops Island, Va. The purpose of the IRVE-3 test was to show that a space capsule can use an inflatable outer shell to slow and protect itself as it enters an atmosphere at hypersonic speed during planetary entry and descent, or as it returns to Earth with cargo from the International Space Station.”
Brilliant! But who is the intended user/s?
I think it’s mostly ‘blue sky’ R&D at the moment. NASA are answering the question “can it be done?” first. If the answer to that is “yes” then the various other teams will start thinking about utilisation and practical applications.
Thanks Ben. In that case it’s doubly brilliant!
Practical applications have been identified by NASA. They include larger Mars robotic missions and ISS return using much larger inflatables.
See the NASA’s Space Technology Roadmap TA09 “Entry, Descent and Landing” at this link:
http://www.nasa.gov/offices…
Table 1 has the various “pull” technologies where mission applications have already been defined for various technologies, including inflatable decelerators (HIAD) for ISS down-mass.
Karl
It’s great to see the HIAD / IRVE technology being pursued and developed by NASA STP. Tax dollars spent that will result in a real and useful capability. Keep up the good work.
IMHO at least, this technology could easily lead to the DSH element of the new exploration archetecture being fully reusable – it would allow for aerobraking back into Earth orbit rather thant having to throw the vehicle away into interplanetary space at the end of every mission.
Yes, Yes, Yes! This is exactly the sort of R&D that I insist NASA should be doing for industry, for the military, and for its own use. I’m doubly pleased because it’s a much more subtle technique than what is generally being proposed these days, and it (hopefully) signals a renewed faith in science and technology, as opposed to brute force methods.
At the risk of sounding like a Legophiliac, I believe that combining together more subtle, refined technologies — like inflatable heat shields and shells, integrated draco thrusters (SpaceX), and scramjet braking — will give us much better answers than BFRs, sky cranes, and bigger parachutes. And, in theory, it also increases the odds of developing more universal methods and hardware, which differ only in parameter values, instead of having to develop systems/equipment unique to each destination and mission type. (Has anybody actually looked seriously at scramjet atmospheric braking of spacecraft, or am I living in a dream world?)
The real challenge, I think, no matter what your launch and landing philosophies, is in detecting, designing and engaging failure modes, but I think that’s going to be true whatever your game plan is.
This hypersonic testing of the IRVE concept is just one step along the path. I sure hope NASA will carry it forward, and in a timely manner, instead of canceling it in the middle like they have so many previous programs.
Steve
Scramjet atmospheric breaking of spacecraft?? 🙂
Time to get in that dream ship and pull that into really lol
Has it been attempted before?
How would a scramjet break?
Would you have to funnel the air in another direction some how or some how burn up energy which would slow you do some how???
Clueless
I’ll leave that typo lol. I know how they break lol I mean brake lol
DTARS,
A minor Point: Braking, not breaking. We definitely do not want the latter.
I’m perfectly serious about the idea of scramjet atmospheric braking of spacecraft. You know I’m a strong advocate of reusability, and a system with no moving parts (or a least a minimum of moving parts) is an ideal candidate for reusable systems. It is also a viable idea mass-wise. And if it is necessary or advantageous to eject components (or fuel) during reentry, doing it when you hit lower scramjet speeds means you’re much more likely to recover ejected stuff intact and relatively nearby than ejecting it higher/faster.
We’ve been doing staged launches since the Chinese first developed rocketry, so why not staged reentries. The more conservatively we use each reentry “stage,” the greater its survival factor, and the more reusable and long-lived the whole spacecraft becomes, more like an airliner.
If we want a specific analogy for scramjet atmospheric braking, think of the reverse thrust mode on aircraft engines once they are wheels down. Scramjet braking would be used while still at altitude, not on the ground, obviously, but the basic concept of baffling your thrust to point “forward” is the same (forward would be down if you’re coming in with nose-up attitude). I can imagine four baffles opening on the sides (nose-up) to vector the scram thrust toward the ground. Sort of like attitude control vernier launch rockets used in reverse.
I would think that scramjet braking could be used to reduce the strain and required precision on both parachute and fly-back systems.
Steve
Steve more thoughts lol
Your post teased my mind
Imagine my spheres very like lots of surface area but heat shield like floating in on the air not burning up because they are light compared to their area
Scramjet atmospheric braking of spacecraft?? 🙂
Time to get in that dream ship and pull that into really lol
Has it been attempted before?
How would a scramjet break?
Would you have to funnel the air in another direction or some how burn up energy which would slow you down???
Clueless
Can the Bernoulli effect be used to change the direction of thrusts????
What about just having a rocket engine pointed in reverse. The last time I brought that up Mr. C said that lighting a rocket engine in reverse would be near impossible. Couldn’t there be some kind of sheild that made this possible??
How could heat sheild energy be turned into thrust???
Could you have a system where your heat shield is a fuel similar to a solid rocket fuel and the heating of your shield start a thrusting to slow you down???
Isn’t this whole idea about increasing surface area relative to weight to increase the speed at which you slow down to decrease heating on the vehicle surface??
Curious George
Has any work been done on scram jet braking and baffling thrust at such high speeds. I would think if you can do the at high enough altitude where the air forces are less sever that it would not be so bad. Get slow Before you yet to low.
DTARS,
George, my response is rather lengthly, so I’ve started it as a new chain within this post, so that I can get the Max page width, instead of making it 17 feet long.
Steve
Didn’t the Russians do this back in 2010? They called it Air-Breaking or something…
LOL, good one! Putting on my movie geek hat, the maneuver done by the Aleksei Leonov in the movie 2010 was called aerobraking, but if I’m not mistaken it was actually aerocapture since it put them in orbit around Jupiter without an initial orbital insertion burn. Of course I could be talking out my arse.
From what I remember in the 2010 movie they called the aerocapture device in front of the Leonov a “bah-loot”.
I remember the Russians trying it quite a few years ago, but to my knowledge, nothing was ever recovered.
This may be good news for more massive Mars payloads.
I am not sure that the inflatable heat shield would be good for missions like Orion’s return to earth orbit where it comes screaming in at over 20,000 mph. But it ought to be good for LEO missions, etc. for other capsules and perhaps spaceplanes of various shapes and sizes? Who knows, maybe they can do an inflatable for high speed re-entry such as Orion’s.
There is nothing in the concept that limits it to LEO. There is in fact some reason to suggest it may even be more durable than current shields given transient/chaotic atmospheric effects.
This technology is intended to SCALE reentry weight/volume limitations. It is immediately interesting to landing large, direct descent (e.g. interplanetary velocities) Mars landers, should anyone want to do a M1-A1 tank class “rover”.
You might also be able to deorbit Hubble and/or the ISS safely (for putting in the Smithsonian perhaps) with such.
So why is it currently so … small potato’s? It’s in development, and there’s a small budget. You of course start small. Because you’ve got to learn how to stabilize and guide such a craft.
By the way, if you were going to deorbit a small asteroid (say chock full of a rare mineral), you’d use such technology with a direct descent from SOLAR orbit. Your biggest issues – guidance and control.
Of course you’d terrify half the planet when doing so, but …
noofcq:
Good points about this tech being highly scalable and durable. For cis/lunar craft, these aeroshells can be deployed once and used many times to aerocapture or aerobrake into Earth orbit. For direct EDL landings on Mars, all you’d have to do is deploy the capsules ‘chutes to jettison the shell after it’s job is done, right?
We should all remember how NASA’s Transhab got kiboshed because some Congressional committee member that didn’t want our astronauts “…living in no balloon!” (probably more worried that the low price tag meant that it was ‘cheap housing’ compared to the Russians). As it turns out, expandable habitats are safer than the ‘pop cans’ used by everybody so far.
So, let’s not get all hung up on statements like “I ain’t gonna risk out astronauts asses during reentry on a ballooon! “.
This tech will open up the solar system as much as advanced propulsion systems will, especially for the trip home.
My idea of the best homeward route would be to aerobrake using Earth’s atmosphere so that you end up at one of the Earth/Moon Lagrangian points. Less energy to dissipate on the way in and a gravity well to use as a slingshot on the way out.
tinker
tinker:
For direct EDL landings on Mars, all you’d have to do is deploy the capsules ‘chutes to jettison the shell after it’s job is done, right?
It’s just reentry … although the Russian version of this back in 2002 tried to … add a wrinkle .. heh … of another annular ring post reentry that turned it into a parachute … perhaps going a bit too far on the stability front.
The concept is all about low mass high volumetric drag … which can be implemented numerous ways, including the way IRVE currently does it – may not need to be inflated balloons – could be a high expansion foam, for example (has control challenges).
As to orbital inflatables, yeah, there was all of that (reminded me of an earlier issue with deplorable spacecraft structures … sometimes they’re a hard sell because the simpler/better approaches sometimes look harebrained at first glance).
Spent time explaining inelastic/elastic collision dynamics to get the point across, but what helps is talking about Kevlar and how bullet proof vests/armour work. BTW, all materials in space suffer degradation through different mechanisms – that’s the second rub to inflatables (silicone is your friend here …).
With reentry, you have to consider the heat loading and dissipation (ablation/radiative transfer), as well as the structural load distribution. For aerobraking/aerocapture, you need to alter the shape to control the trajectory / stability of the vehicle – “hypersonic surfing” if you will.
My idea of the best homeward route would be to aerobrake using Earth’s atmosphere so that you end up at one of the Earth/Moon Lagrangian points.
Yes – if you’re doing something like NAUTILUS-X, Exploration Gateway Program, propellant depot, and maybe robotically bootstrapped lunar ISRU too.
But you’d be breaking all the political rules to do so.
In other words, something close to Huntress’ architecture. It’s maddening that the answers were known long ago, but wilfully sabotaged by people inside and outside of NASA.
Not really sabotage. More like self-interest. Possibly with a conveniently aligned theory of national security. And cynicism of capabilities.
All are elements of human nature.
The trouble is that we don’t struggle enough collectively against this, because we are attracted to certain “unfair advantages” that later screw us, because we were too stupid to not see through the hype enough to realize they were actually … a disadvantage to us.
Perhaps we’ll need to get by this, before we can do the right thing.
The bright spot is that we are at a point where it is possible to have other options besides nationalism driving space exploration.
Now, if we can only get somewhere with that, before it gets killed by the nationalists, sour because they lost the football while squabbling …
Could an inflatable heat shield be used to permit say DreamChaser to safely re-enter from lunar orbit?
George,
I’m not really sure what you have in mind with the spheres, but my off-the-cuff answer is: not really relevant.
I don’t know what parts you’re already comfortable with, so I’ll make this fairly complete and hope we don’t miss anything key.
There are two different forces to consider, and counteract, on a reentry. The most obvious and familiar force is what we normally think of as “down,” and is caused by gravity — the spacecraft and the Earth are mutually attracted, just like any two (or more) masses in the universe. This is Isaac Newton and his apple, and is actually much the simpler of the two forces to deal with. Your floating spheres and the Bernoulli effect are relevant to this force.
The second force, the one which causes all the fun, is the momentum that the spacecraft possesses because it is traveling on an orbital path around the Earth. While in orbit, the nose of the spacecraft points along the orbital path, which is constantly changing; its heading will change by 360 degrees, relative to the universe, during each orbit.
So, you launch and keep firing your rockets until you reach orbital altitude. At that point, you stop firing your rockets (you’ve used most of your fuel by then) and you continue on, staying in orbit at a fixed altitude (we’re ignoring atmospheric drag and other external effects). You stay in a fixed orbit, even though your rockets are no longer firing because you’re in a vacuum; there’s nothing to stop you. This is called a “free fall orbit.” Gravity is trying to pull you down to Earth, but your orbital forward momentum is trying to throw you away from the Earth (at a tangent to your obit) and the two are exactly in balance, so the net result is no change; you stay in that free fall orbit. If you had burned your rockets longer before shutting them off, the situation would be exactly the same — but you would be in a free fall orbit at a higher altitude.
And now the key concept in orbital mechanics which is often a stumbling block, because it’s not intuitive — in any free fall orbit, your orbital altitude and orbital speed are directly related to one another. If you go to a higher orbit, you’ll travel at a greater speed along that orbit. Likewise, if you slow down your orbital speed (with a retro-burn), you’ll end up in a lower orbit. Keep that idea straight, because everything else in orbital mechanics follows from this rule.
Also, notice that I keep saying speed, not velocity; there’s a difference. Orbital speed is how fast you are traveling along the orbital path (and could be measured in mph, same as a car on flat ground), but orbital velocity is how fast you are completing orbits (orbital velocity at LEO altitude is about 1 rotation every 90 minutes, or 2/3 of a rotation per hour). In physics, speed is a scalar quantity; it has a magnitude only. While, in physics, velocity is a vector quantity; it has a magnitude and a direction.
If you keep on burning after passing LEO and then GEO, you finally reach a point where the balance of the two forces falls apart, because gravity has been decreasing with altitude while momentum has been increasing with altitude (which makes sense because you’ve been pumping more and more thrust into it). When you reach the magical point where momentum “wins,” your spacecraft will break free of orbit and go sailing away from the Earth. That magic velocity (as opposed to speed) is called escape velocity, and every planet and moon has its own value for escape velocity, based mostly on its mass, but also affected by its density (and other factors too small to worry about here).
OK, the bottom line in all of this is, by the time your orbital altitude is high enough that you’re free of atmospheric and other effects and can go into free fall orbits, your orbital speed is really high, and it’s this orbital speed that we have to get rid of on reentry. Looking at a simple, John Glenn mission (up to LEO; three orbits of the Earth; reenter and splash down), he reached a maximum speed of 17,526 mph (28,205 km/h) and had to reduce it back down to basically ZERO (relative to the Earth’s surface) before hitting the ocean, or he’s very dead. If we look at a mission returning from another planet, we’re coming home at traveling far in excess of this because we had to exceed Earth’s (and the destination’s) escape velocity in order to go interplanetary, so add another 10,000, or so, mph to the speed we have to shed.
So, floating down against gravity is insignificant; Bernoulli effect can have an effect, based on the orbital speed, but it’s a drop in the bucket. What you’re looking for, what we’re all looking for, is a way to “slow down slowly,” in order to avoid the heat and other atmospheric friction effects. No one has an answer, yet. What we need is something that we will think of as anti-gravity (in all likelihood, if something is found, it won’t be anti-gravity, but that’s how we’ll all think of it). What we really need is a momentum canceling (or at least reducing) technology (momentum incorporates more than speed; it’s the combined speed and mass effects that need to be tamed). In a logical universe, this technology, if found, would also become the basis for our much needed collision/particle shields.
”Has it been attempted before?“
Not successfully that I can find, and only attempted on a small-scale bench experiment.
”How would a scramjet brake?“
A scramjet is much like a ramjet; it uses incoming “ram air” that’s being shoved down its throat (from the environment) by virtue of its passing through the atmosphere at high speed to compress gases for ignition instead of using complex turbine systems (thus the no-moving-parts attribute), and its exhaust products are generally environmentally friendly, not the horrible filth that airplane engines pump out. The down side is that you need either high speed movement or an external (highly) compressed air source to start the thing operating — in other words, no supersonic ram air source, no jet operation. This is one reason why I present it as an intermediate stage (going up or down); you have to get into its operating envelope before it does anything (but, once you’re there…).
Assuming that you have the materials and control technologies to handle the heat and pressure, any jet, of any type, can be used to push (provide thrust) in any direction, not just straight out the back end. When you land in a commercial jet engine airplane, you hear a definite change in the engines sounds and experience a few seconds of airframe vibration (especially if you’re sitting over the wings); This because the pilot engaged the reverse thrust throttles, which inserts a heavy duty plate (at a specific angle) in front of the outputs of the jet engines; the engine thrust is bounced off these baffles and the thrust then is applying force pointing forward, instead of the normal to-the-rear thrust. This “reverse thrust” slows the plane’s forward progress along the runway, working against and canceling the remainder of the plane’s forward momentum. With “scram brakes” you’d do the same thing; you baffle the thrust into the direction exactly opposite of the spacecraft’s residual motion, slowing it down. By the time you’re close enough to the land/water to see your landing site, your spacecraft attitude is going to be nose up, your residual motion is going to be tail down, so the scram brakes need to be thrusting straight down (the complete opposite of your residual movement). You, or your computer, throttle back on the scram brake thrust as you come down so that your touch down (or splash down) velocity is a very tiny bit above ZERO. As I said before, I envision (4) ports opening up on the lower sides of the spacecraft (N,S,E,W) when needed, and the scram thrust being baffled down and out from these ports. More conservative engineers would elect to try putting them on the bottom first, but I see this as endangering the hardware. Based on Shuttle experience, I see putting them on the bottom as making them single-use and/or many months to refurbish. They are also safer “ported” if multi-landings of a spacecraft are planned for a mission (or in an emergency).
”Can the Bernoulli effect be used to change the direction of thrusts????“
I would say, No. But there are many people much better qualified than I to answer that question.
”What about just having a rocket engine pointed in reverse. The last time I brought that up Mr. C said that lighting a rocket engine in reverse would be near impossible. Couldn’t there be some kind of shield that made this possible??“
I agree completely with Mr. C. There are a number of problems with this, any one of which is a game breaker. Quite aside from things like added mass and additional control systems, it’s justifiably considered bad practice for a number of engineering reasons. It’s also against the grain from a Physics point of view. If you’re not already familiar with it, look up “stall speed” as one example. As a general rule in both Science and Engineering, there’s no such thing as “nothing,” and you never “stop” a system in action in order to make changes (or do anything else).
”How could heat shield energy be turned into thrust???“
Any form of energy can be turned into thrust, if you’re stubborn enough. The question should be, is there an effective, efficient, and sufficiently safe way to turn the heat shield energy into thrust. Once again, there are experts who know far more than I, but my answer is, No. You can bake a cake with a 60 watt light bulb, but it’s not at all a desirable methodology and will never replace my oven.
”Could you have a system where your heat shield is a fuel similar to a solid rocket fuel and the heating of your shield start a thrusting to slow you down???”
No. The key word too often omitted from these discussions is “contained.” How many people would run into trouble if they insisted on using their cigarette lighters when the lighters weren’t inside their cases? Would you use a gun “loaded” with gun powder but no bullets or shell casings? Would you heat soup on the stove without a pot? What you suggest I think would almost certainly be christened “the Bomb.”
The biggest drawback with any solid fuel, in my opinion, which is what you would have to use in this question, is that once a segment/piece, of any size, starts to burn, there’s no way to “turn it off” again. There are lots of people who will argue that, saying, you can do this, or that, but it has been my experience that all of their proposed “fixes” actually create less tolerable, more dangerous situations. But, once again, there are people who know much more about this than I do, but I, for one, will never be convinced. Solids and HSF should not be mixed.
“Isn’t this whole idea about increasing surface area relative to weight to increase the speed at which you slow down to decrease heating on the vehicle surface??“
Context, George. If we were talking sailboats, party balloons, light sails, falling leaves and parachute jumping, I would think more about your question. But these concepts of basic Physics do not apply to spacecraft landing on Earth, our Moon, Mars, or any of the other places that have been discussed for HSF missions. Even robotic missions would (and should) come under the gun for applying this idea to reentry and landing.
Well, that’s my shot at answering your questions.
Steve
Steve
Thanks for your detailed answer based on my silly questions. I hope someone else benefits from your lesson other than me.
Lol what if someone read this and said you know we really should do some more work on scram jet braking and did 🙂
I wrote this earlier so I’ll past it in.
Steve thanks for the scram jet idea. The last time you talked about scram and ram jets you did it in a post where you were telling me that rockets and jets fly in two different environments and suggesting that never the two shall meet. And I remember thinking some how there is a way!
Lol I keep wondering about jets having a pressure sweet spot, not even Mr. C seems kooky enough to give me a straight answer. Lol
Has you can tell by my questions, I agree this is the type of work NASA/NACA should be doing more of.
Hopefully SLS will die soon and NASA can get back to providing the secrets, the magic, as no one else can, so others will be able to build affordable sky liners to outer space.
Hope
Plus this lol
Old fashion rockets
I was reading about how Spacex’s grasshopper is about to start testing in the next few months and it brought to mind how people would post that Spacex is no big deal, they only use old old fashion technologies which were proven by NASA decades ago!!!
I guess that just proves the point that our great space program could have flown recoverable, reusable, affordable rockets years ago with these old fashion technologies, but DIDN’T!!!!
Also I heard someone talk about Skylon and their reaction engine trying to make the point that Spacex’s attempt to make reusable missiles and capsules was already a thing of the past.
I say bring it on! If the jet rocket reaction engine does work and is a game changer, I don’t think a single stage to orbit is the best application of it. I think a two stage system using the reaction engine would get more payload to space using less fuel therefore some of the R and D done with Spacex recoverable boosters could be used to design a better cheaper lifter than the SSTO Skylon. I’m no rocket scientist but a two stage rocket jet plane looks like the best future LEO solution to me.
Plus the faster someone starts making space cheaper the faster the market starts changing to create that space future. And be ready for that game changer when it comes.
Some times I feel I should just stay quiet here.
You do a great job here Steve!
Thanks for your thoughtful time.
George