JP Aerospace and the Airship to Orbit program

[Jonfliesgoats]

Airships don't make cargo mass irrelevant.  Far from it, actually.  The higher we go in the atmosphere the larger our envelope has to be to support a given mass.   So to lift, say, twenty tons of vessel and cargo at sea level, you need a given volume.  At higher altitudes that volume gets much bigger, which is why weather balloons look like floppy jellyfish at launch.  They have extra material at sea level allowing them to expand and displace more air at altitude.  Also, remember going a little higher in the atmosphere causes a big loss in pressure and density.

The problem is that current and foreseeable materials all have a measurable mass per square inch or square meter or whatever unit electrifies your toilet seat.  So at some point the weight of extra envelope per square meter is greater than the buoyancy you gain for the extra volume.  This is compounded by the fact that balloons don't expand like neat little spheres, but are somewhat less efficient with their mass.

Balloons and airships are cool, but they are subject to limitations like anything else we build in this universe.  Until we have a revolution in materials, today's balloons will perform only marginally better than the high altitude balloons of the late fifties and sixties.

 

Lifting a rocket to a given altitude by balloon may have some advantages, and has been done before.  I don't want to burst everyone's bubbles (Get it?  I entertain myself so much!) about balloon launch systems.  Balloon launch may be viable for lightweight payloads, using smaller rockets to launch micro satellites, etc.

[Jonfliesgoats]

Airlaunch from planes faces a similar problem.  To get an orbital flight out of a rocket, even one launched from a plane, the rocket has got to be big.  Big rockets need bigger, special planes.  Bigger, special planes combined with big rockets come with big engineering and maintenance challenges.

Does this mean air-launch to space is dumb?  No.  It means some scales of launch favor vertical rockets, while smaller launches may favor stratolaunch types of programs.

[Rakaydos]

2 hours ago, Jonfliesgoats said:

Airships don't make cargo mass irrelevant.  Far from it, actually.  The higher we go in the atmosphere the larger our envelope has to be to support a given mass.   So to lift, say, twenty tons of vessel and cargo at sea level, you need a given volume.  At higher altitudes that volume gets much bigger, which is why weather balloons look like floppy jellyfish at launch.  They have extra material at sea level allowing them to expand and displace more air at altitude.  Also, remember going a little higher in the atmosphere causes a big loss in pressure and density.

I'm pretty sure you didnt actually do more than skim the airship proposal, because you dont even attempt to address their solution to that problem.

Short answer? An Imperial Star Destroyer sized blimp that never goes lower than the highest altitude "normal" balloons, and is built for the lower pressure, lower turbulence operating environment. Regular balloons carry cargo as far as they go, cargo is transferred to the monster designned for NO LESS THAN extreme altitude, which  handles the transitions from displacement lift, to aerodynamic lift, to hypersonic suborbit, to orbit.

Edited November 23, 2016 by Rakaydos

[Nibb31]

The problem is that any atmosphere that is thick enough to provide bouyancy is also thick enough to produce drag (and extreme heat) at hypersonic speed. You can't have both high-bouyancy and low-drag, and a Star Destroyer sized blimp is going to have massive drag.

[Rakaydos]

22 minutes ago, Nibb31 said:

The problem is that any atmosphere that is thick enough to provide bouyancy is also thick enough to produce drag (and extreme heat) at hypersonic speed. You can't have both high-bouyancy and low-drag, and a Star Destroyer sized blimp is going to have massive drag.

There's a square cube law thing going on there (drag goes up with cross section, buoyancy goes up with volume) that makes bigger airships better at that, but it is a known issue.

The JPA people are looking at experiments done in the 60s that used active plasma manipulation to reduce drag by 80 or 90 percent, at least in the lab. They need to get at least 40% drag reduction in the real world to get this concept to work.

[Jonfliesgoats]

It seems you are upset.  I get it.  It's exciting to think that some compromise of buoyancy, speed and high technology will lead to great advances.  This is why it's natural and understandable to have an emotional reaction to skepticism regarding any given proposal.  Plus, any idea that is submitted for consideration is open for criticism.  It's easy to see this as an attack on you rather than a discussion of your suggestion.  I get that too.  I've been there more than I care to admit.  I have been the guy walking out of meetings thinking "Who was that jerk who told me I was chasing my tail, and how do I ruin his lunch?".  I get it.

Beyond the obvious problems with drag, we have to look at the resources involved with active plasma manipulation, maintaining a large craft that can ascend to this environment to support the desired payloads.  By the time you look at the engineering challenges. It seeme like it's easier just to launch a big, old rocket.

There are lots of parallels in aerospace history.  Active boundary layer control, wing warping, parasite fighters from dirigibles, parasite fighters from fixed wing bombers, ornithopters, orotary rockets, VTOL, tilt-rotors (Slaughter the sacred cows!).

BUT:

Good science requires an open mind.  Submarine launched ballistic missiles are complicated, but successful, for example.  Helicopters are crazy complicated in comparison to STOL airplanes, but have undeniably made their mark. 

Maybe I am missing something?  I have researched this proposal more and it still seems unnecessarily complicated.  What are you seeing about this that I am not?  Also what advantage does this offer that other proposed launch systems don't offer?  

To me it still seems like a complicated, technowhale in the sky.

 

 

[todofwar]

On Thursday, November 24, 2016 at 2:04 PM, Jonfliesgoats said:

It seems you are upset.  I get it.  It's exciting to think that some compromise of buoyancy, speed and high technology will lead to great advances.  This is why it's natural and understandable to have an emotional reaction to skepticism regarding any given proposal.  Plus, any idea that is submitted for consideration is open for criticism.  It's easy to see this as an attack on you rather than a discussion of your suggestion.  I get that too.  I've been there more than I care to admit.  I have been the guy walking out of meetings thinking "Who was that jerk who told me I was chasing my tail, and how do I ruin his lunch?".  I get it.

Beyond the obvious problems with drag, we have to look at the resources involved with active plasma manipulation, maintaining a large craft that can ascend to this environment to support the desired payloads.  By the time you look at the engineering challenges. It seeme like it's easier just to launch a big, old rocket.

There are lots of parallels in aerospace history.  Active boundary layer control, wing warping, parasite fighters from dirigibles, parasite fighters from fixed wing bombers, ornithopters, orotary rockets, VTOL, tilt-rotors (Slaughter the sacred cows!).

BUT:

Good science requires an open mind.  Submarine launched ballistic missiles are complicated, but successful, for example.  Helicopters are crazy complicated in comparison to STOL airplanes, but have undeniably made their mark. 

Maybe I am missing something?  I have researched this proposal more and it still seems unnecessarily complicated.  What are you seeing about this that I am not?  Also what advantage does this offer that other proposed launch systems don't offer?  

To me it still seems like a complicated, technowhale in the sky.

 

 

It does offer the ability to get to orbit without the strain of rocket engines, so probably capable of really fast turn around. Also high isp, and you can even use the atmosphere to accelerate part of the way. 

How does lift work in the upper atmosphere? What if the airship deflated as it accelerated, relying more on lift less on buoyancy as it got to higher speeds? That way a constant output that overcame drag, with a reducing drag profile, could keep our accelerating to orbital speeds. 

[Jonfliesgoats]

Yeah.  It may be more feasible than I originally thought.  If the process can be sufficiently simplified to reduce points of failure, it could be good.

[todofwar]

Also, if you use a more cylindrical shape, you can get much larger volume for large cargo at the same drag since drag will go up with the cylinder radius not the cylinder length. And you can probably link a few together. Maybe float a track that they accelerate on. Wait, now we have a train to orbit and that would be so awesome!

Back to reality, I do wonder if the best design for this might not be a really long tube, almost like an eel flying at high speed. Of course, cargo would need to be carefully distributed. 

[Steel]

16 hours ago, todofwar said:

I do wonder if the best design for this might not be a really long tube,

you mean like a rocket?

 

[wumpus]

On 11/24/2016 at 2:04 PM, Jonfliesgoats said:

Maybe I am missing something?  I have researched this proposal more and it still seems unnecessarily complicated.  What are you seeing about this that I am not?  Also what advantage does this offer that other proposed launch systems don't offer?  

To me it still seems like a complicated, technowhale in the sky.

Basically, for the simplest case blimps and dirigibles should, at least in theory, scale better than airplanes (read stratolaunch and to a lesser degree the L-1011/Pegasus system orbital makes.

It should have the same advantages:

• Less "delta-v" to orbit since you aren't wasting power fighting the atmosphere as much
• No wasted fuel for inclination changes: just start from the right latitude and you won't need the inclination change
• the "right latitude" can be right on the equator for maximal free delta-v due to Earth's rotation.

And it will likely fail because it is easier to stretch the gas tank that little bit (1-2k delta-v?) to cover all of the above instead of building a complicated blimp-to-orbit system.  Especially one that involves blimps docking with blimps, and passing things as heavy as a rocket.  It might mean a rocket half the size of a sea-level launched rocket, but it is still cheaper to design and build rockets twice as big as such an air-based system.

Note that such a system almost certainly will compete with the "new guys".  Rocket lab and Firefly Space System each picked up a few million from NASA for small satellites, I suspect that any air launch would compete with this and not with Soyuz, Spacex, and Orbital.  The real key is that even if you can get the money will be trying to build *both* the airship and rocket with a few million dollars (note that the scaling issues are *nasty* for such rockets, and why Pegasus succeeded at all).

[Nibb31]

On 26/11/2016 at 5:03 AM, todofwar said:

It does offer the ability to get to orbit without the strain of rocket engines, so probably capable of really fast turn around. Also high isp, and you can even use the atmosphere to accelerate part of the way. 

No it doesn't. You still need propulsion to accelerate from 0 to 25000km/h while fighting atmospheric drag. There still isn't anything better than rocket engines to that.

[Rakaydos]

On 11/26/2016 at 11:56 PM, Nibb31 said:

No it doesn't. You still need propulsion to accelerate from 0 to 25000km/h while fighting atmospheric drag. There still isn't anything better than rocket engines to that.

Their proposed drive is  hybrid chemical/electric- ISP around 1000, but a Twr >1

[Jonfliesgoats]

Perhaps I don't understand your point about TWR?  Let me describe my continued skepticism and you can point out solutions to my concerns both technical and otherwise.  Again, this is not an attack.  It seems we are studying an elaborate play for venture capital to me. 

Once you put a payload on anything, you increase its mass.  So unless this hybrid chemical electric drive can generate more than, say, fifteen tons of thrust (a typical payload for a heavy rocket) its TWR is less than one.

On TWR:

We get confused in KSP when we look at engine TWR.  That refers to the thrust of the motor relative to the motor itself.  For example a General Electric CF6 B1F engine generates 56500lbs of thrust (roughly 248000 newtons of thrust).  The engine weights 4.5 tons.  It's TWR, as seen in KSP, would be somewhere around 5.

Four of these engines are used on the Boeing 747-400.  Rather than having a TWR of 5 or 20, the Boeing 747 (-8, 400, 200, SP) is incapable of increasing speed while aimed straight up.  This is because there is no thrust, airspeed, altitude combination, that sees a 747's TWR exceed 1.  This is before we even consider various forms of drag acting on the plane, which erode performance even more.

So TWR is almost irrelevant until we account for the job we want our vessel to do and the entire vessel and payload, including the motors.  In our case, we want something to make stuff move really fast in the atmosphere.  Low TWRs are out.

If you have a flying abject in the atmosphere at any altitude, it has to interact with enough atmosphere, by buoyancy or movement to create dynamic pressure, to support itself.  That means drag when the thing moves or mass and volume when the thing stops.  Absent this stuff, we descend.  Accelerating a bag of gas to 8km/second requires a lot of energy regardless of active drag mitigation, plasma control, boudary layer manipulation, etc.  It will take force and/or energy.  

 

Energy:

We haven't even talked about the energy required exceeding whatever you can get from solar panels.  Are we going to suspend nuclear reactors or fuel cells from this thing?  This thing either needs giant engines or giant reactors/fuel cells/batteries

Also, advertised performance and true performance are radically different between proposals and prototypes.  Avro went from advertising a VTOL, supersonic flying saucer in the fifties to a round, crappy hovercraft.

And, once all this is addressed how is this an advantage from a BF rocket or BF rocket dropped from a jet?

 

Technical Con-Jobs

i describe my doubts in laborious detail for one reason: Venture Capital Con Aristry!

People with money are no more informed about aerospace than anyone else.  Lots of proposals for the next great thing, which clearly have some humongous flaws, are simple plays by a few guys to lure some funds out of excited but uninformed venture capitalists.  We have seen this many times over.  These projects fail in the less pubicized, dirty endings to once brilliant proposals for flying cars, autogyros for soccer moms, etc.  All one needs is an exciting powerpoint presentation and a farce of a development program.  With those meager investments, you can get naive billionaires to shell out vast funds. 

So poking holes in these ideas isn't about making someone feel silly.  Truly great advances have come from people who are are dedicated to once silly ideas.  What we do need to look out for is that we don't let good people become devoted to shams and waste their energy and efforts.  My trouble isn't with the billionaires or con artists.  My trouble is with the dedicated, young engineers and pilots who naively hang their hats on these shams.

Poking holes in ideas is a way to refine good proposals the heaps of flim-flam con jobs that hit the publications and websites we all read.  

 

In short, I think this is a ploy to get money.

[Nibb31]

52 minutes ago, Rakaydos said:

Their proposed drive is  hybrid chemical/electric- ISP around 1000, but a Twr >1

Does it run on unobtanium or dilithium cristals ?

Edited November 29, 2016 by Nibb31

[Rakaydos]

3 minutes ago, Nibb31 said:

Does it run on unobtanium or dilithium cristals ?

Presumably the electric part is powered by thin film solar cells across the mile long top surface, but the chemical part is apparently Al-enriched parafin and LOX.

[Nibb31]

Yeah, so magic then.

If they actually had a propulsion system that could deliver an Isp > 1000s with a TWR > 1, why bother with an airship ? The aerospace industry, and even the military, would be scrambling to buy the patent.

Edited November 29, 2016 by Nibb31

[Rakaydos]

7 hours ago, Nibb31 said:

Yeah, so magic then.

If they actually had a propulsion system that could deliver an Isp > 1000s with a TWR > 1, why bother with an airship ? The aerospace industry, and even the military, would be scrambling to buy the patent.

Er... I may have made the symbol go the wrong way. LESS THAN 1.

Not useful for a "real" rocket, not as efficent as a "Real" space engine, but with blanced values optimized for their application.

[wumpus]

5 hours ago, Rakaydos said:

Er... I may have made the symbol go the wrong way. LESS THAN 1.

Not useful for a "real" rocket, not as efficent as a "Real" space engine, but with blanced values optimized for their application.

Then the airship still doesn't matter.  Even if it only moved the airship ~1000 ISP is lousy for a jet [read high bypass turbofan].  And it won't operate without the airship (or until at least one stage with TWR>1 launches it into a relatively long-duration flight).

[todofwar]

18 minutes ago, wumpus said:

Then the airship still doesn't matter.  Even if it only moved the airship ~1000 ISP is lousy for a jet [read high bypass turbofan].  And it won't operate without the airship (or until at least one stage with TWR>1 launches it into a relatively long-duration flight).

But this isn't a jet engine, it's meant to operate where the atmosphere is so thin you can't use jet engines. General idea is it only needs to gently nudge itself to orbital speed over the course of several days. So low TWR is fine as long as it overcomes drag. Maybe if it starts going fast enough it can compress enough air to burn something, but I don't know for sure.

[Nibb31]

The propulsion still needs to overcome drag. I'm not aware of any SEP that produces that much thrust. And even with an Isp >1000, your balloon still needs to carry a massive amount of propellant, as well as be robust enough to maintain structural integrity and not burn up during hypersonic flight.

[Streetwind]

I think the trick is that it uses buoyancy as a replacement for lift. When stationary, it will float up to altitude XYZ and stay there, unable to ascend further. But when accelerated sideways, gravity no longer will pull it down quite as strongly, and it will begin to ascend again as it gains speed. This reduces drag, allowing further acceleration. If the vehicle can just go fast enough sideways, so the theory goes, the combination of speed and buoyancy will lift it to an altitude where orbital velocity is achievable under constant thrust - or something close to it, anyway. Even if the vehicle never reaches orbit, it'll make an excellent airlaunch platform. I mean, we mock airlaunches because they don't impart any meaningful speed or altitude - mach 0.8 at 15 km is pretty meaningless. But what if you could airlaunch at mach 15 from 100 km altitude, with a fully reusable vehicle? That would make a significant difference.

@Nibb31 - the planned engines are not pure electric propulsion. They're chemical engines with an electric acceleration stage for the exhaust plasma. Achieving enough thrust is merely an issue of adjusting the propellant input to whatever value you need, so that point presents no problem whatsoever. For me, the questionable part is how they're going to keep the electric acceleration stage running 24/7, if the ascent takes several days. After all, that implies that it will have to be flying through the night a lot.

[Nibb31]

No. If there is lift, there is atmosphere and therefore drag. If there is bouyancy, there is atmosphere and therefore drag.  

Either way, they need propulsion that can provide 9000m/s of dV while countering both the hypersonic drag that applies to a balloon the size of Manhattan and the gravity that applies to a several thousand-ton tank of propellant and the massive structure and heatshield that prevents that balloon from collapsing under its own weight or burning up in the 2000°C hypersonic airflow.

Edited November 30, 2016 by Nibb31

[magnemoe]

9 minutes ago, Nibb31 said:

No. If there is lift, there is atmosphere and therefore drag. If there is bouyancy, there is atmosphere and therefore drag.  

Either way, they need propulsion that can provide 9000m/s of dV while countering both the hypersonic drag that applies to a balloon the size of Manhattan and the gravity that applies to a several thousand-ton tank of propellant and the massive structure and heatshield that prevents that balloon from collapsing under its own weight or burning up in the 2000°C hypersonic airflow.

My take on it too, has an issue with the multi day lift to orbit, drag below 100 km is enough to deorbit an satellite in one orbit, they have to both fight this drag and accelerate. 
And at 100 km your flight speed need to be orbital speed to get enough lift as I understand.

They might escape heating by flying far higher than normal planes however they can not escape drag.