The Airship to Orbit Project
jpaerospace.com
jpaerospace.com
But if they've been at it for 25 years, it raises an the question, how have they been funding their research for so long?
Though it's good to focus some % of our attention on alternatives, and I'd feel more comfortable going to space on a balloon instead of a rocket.
Yes, though this strikes me as competing with space stations more than launch vehicles. (It would be a convenient way to e.g. quickly get a space station around Mars.)
The problem with rockets is that most of your fuel is used to lift... the fuel, that's also lifting your payload. We might get better at manufacturing fuel, but we're not going to get around the fuel weight problem without some major breakthrough.
On top of that I'm not really convinced they can put enough solar generation on there to drive the thrusters sufficiently, putting aside the additional costs of things like radiating off all the heat generated by the thrusters.
They wouldn't. That's why they're aiming to use plasma thrusters.
Here's my picture.
Let's say you want to use helium as a lifting gas. Hydrogen can be used too, the numbers don't really change. Helium has a molecular mass about 14% the molecular mass of air at the same conditions (pressure and temperature).
Imagine now you build an airship the size of the Hindenburg. About 200000 m3. Each m3 provides a lift of very nearly 1kg, so you can lift with such an airship 200 tons of stuff, but that includes the balloon itself, the cables, everything.
Now imagine the balloon has folds, like an accordion. As it goes up, you expand the balloon until it becomes some sort of very long and very fat sausage. It could even be mile-long.
Where will the balloon stop ascending. Let's say you design the internal pressure to exceed the external pressure by about 1% at sea level. The balloon stops roughly where this 0.01 atm pressure is about 7 times higher than the external pressure (because helium compressed 7 times more than air has the same mass). That happens where the atmospheric pressure is about 0.0015 its sea level value, and this happens at about 50 km height [1]. You could say you are half way to space.
Once you get to this point, you need another source of lift. This is airplane type of lift, except that you don't need wings, because the entire balloon can be tilted slightly upwards and function like a gigantic wing. In order to not suffer from the tyranny of the rocket equation, you need reaction mass. For this you have an outer shell around the balloon that works as a funnel. You scoop whatever air is at that altitude and direct it to inside of a combustion chamber, and you push it at high velocity on the other side. You accelerate slowly over many days. Maybe during the day you use solar panels to heat up the air, and during nights you use hydrogen that you have onboard, and which has a huge energy density. On second thought you might even use hydrogen as a lifting gas, so you have plenty of it at hand.
As you accelerate at some point you reach supersonic and then hypersonic speeds. We are used to thinking these speeds are very destructive to the airframe, but at extremely high altitudes, where the air density is, let's say 1/10000 the density at sea level, maybe they are not so destructive. As you pick up speed, some of the lift comes from the orbital motion. Little by little you keep going up and keep speeding up. I don't see why you can't reach 7 km/s.
[1] https://www.engineeringtoolbox.com/standard-atmosphere-d_604...
Critical bits of Columbia's aluminium airframe melted at about 100km. There's about 250x less air at 100km than at 50km. All in all I'd say this is fanciful.
The burning up temps wouldn’t be until getting close to orbital speed.
Also is it worth considering that this thing would have a super high volume to surface area (by being huge).
Note, there is absolutely nothing scientific about this claim of mine. Just a made up heuristic that seems plausible to me.
Would love to be proven wrong.
Seems promising. Why not use an elongated blimp shape? Why the v?
And why can’t the space craft lift off from the ground.
It aims to be a hypersonic vehicle. Blimps aren't brilliant for that use case. (There may also be a structural advantage since it's basically two air beams.)
> why can’t the space craft lift off from the ground
They're using a balloon to get to the edge of the atmosphere and then a lightweight craft to slowly accelerate to orbit from there. The lightweight craft would be too delicate to survive in the atmosphere. The low-altitude craft too heavy to cruise to orbit.
For the upper stage: it would only be an airship at the start, then transition into an inflatable hypersonic lifting body before eventually reaching orbital velocity. Very similar to how a seaplane starts swimming by displacement, then transition to gliding on the water before eventually taking off.
For the lower stage: I suspect the shape is more like a branding thing, and knowledge transfer ("perhaps some of what we would have to learn about v-shaped blimps can be learned in the lower atmosphere?")
This [1] looks like a plasma propulsion engine [2]. They'd need to carry propellant. That said, they're pre-staging, so the traditional rocket equation doesn't apply.
[1] https://www.youtube.com/shorts/uTfrXf_WHEY
[2] https://web.archive.org/web/20161018201525/http://alfven.pri...
(This still leaves open the question of whether the proposed airship could actually overcome drag to get as fast as they hope.)
And then there's the submarine.
With the memory of the Titan implosion wandering in my head, I would never go near what appears to be a "home brew" submarine. Event at shallow depths.
And the mention of AI on the page about that sub is... odd...
Yeah, just no.
JMHO.
It kicked off under an Air Force contract [1].
To be clear, I'm not anywhere near the aerospace industry, and have no actual knowledge other than what the media gives me -- but the pictures on their web site look like someone's garage rather than a professional aerospace lab.
BTW, it looks like that contract was (a) very short lived, and (b) not aimed at the orbital stuff. [1]
What the heck is active drag reduction?
“Passive devices by definition require no energy. Passive techniques include turbulators or roughness elements geometric shaping, the use of vortex generators, and the placement of longitudinal grooves or riblets on airfoil surfaces.
Active control requires actuators that require energy and may operate in a time-dependent manner. Active flow control includes steady or unsteady suction or blowing, the use of synthetic jets, valves and plasma actuators. Actuation may be pre-determined (open-loop control) or be dependent on monitoring sensors (closed-loop control).”
An example: continuously changing wing surface (https://www.gauss-centre.eu/results/computational-and-scient...)
I don’t know either something like this has been built or flown.
They're fuzzy on how they get from ground to 140,000 feet. But the hard part of orbit is speed, not altitude.
Electric propulsion can be orders of magnitude more efficient than chemical rockets [1]. The problem is their thrust is too low for anything beyond cruising. Cruising into orbit doesn't typically work because you'll fall into the ground before you get up to speed. But if you're using the atmosphere to keep off the ground, maybe it could work? (I'm sceptical.)
I wish them the best luck, but this is an odd project. And it's not clear it's saving any fuel or rocket structure.
Blimps sound like they should be good for space, but as a concept they're oversized and full of hot air unfortunately.
> The first stage is an airship that travels from the ground to 140,000 feet. There it will dock with a waystation floating at the top of the atmosphere. Cargo and crew then transfer to a large 'Orbital Airship' for the nine day journey to orbit.
Right, this is the entirety of their description of that airship. An airship which is supposed to go higher than any plane has ever flown [1], within the realm of high-altitude balloons [2].
EDIT: It looks like it just balloons up to 140k feet.
There is generally a window between these speeds. Lifting bodies are good at staying in that window. (As your speed increases, lift increases, which pushes your aircraft up and into thinner air.)
This element of the problem--transitioning from aerodynamic lift to orbital speeds--is shared with SSTO. There are a lot of tough things about SSTO. But not burning up as you accelerate isn't one of them.
The only reason to do SSTO is so you can use an air-breathing engine. That's why practically every recent SSTO draft looks like an airplane.
This team appears to be using a reaction engine for thrust, so I'm not sure how they're planning on dividing the work between buoyancy, lift and reaction. But the whole point of using an airship and making it massive is so it can generate lift in air too thin to keep a metal tube flying.
> don't see how you reach that as a conclusion by analogy to single stage to orbit rockets
Because SSTO has been extensively studied, this is a problem SSTO would have to deal with, and in no case was it a dealbreaker.
Burning up as you accelerate is also an engineering problem that is not 100% solved for hypersonics. Almost solved, but not risk free.
Totally agree it's a difficult engineering concern. But it's being thrown around like a physics limit when it simply is not.
TBH, Superheavy+Starship, right now, is probably cheaper than the fully expendable SLS.
Also, if all the materials will be cannibalized in orbit (or never land on Earth again, like the Lunar Starship), it makes no sense to send the mass in a reusable vehicle.