Back when I was flying High Power Rockets at Blackrock these guys used to come out and use our FAA waiver to do their testing, they've been doing incremental testing for more than 25 years - that they did just go off and build their big idea first (so many space companies do and most fail) but instead have worked on this bit by bit, they're definitely in this for the long term
Good ideas can take a lot of time, and if this very concept doesn't turn out to be useful, maybe they will learn things along the way that will have good applicability. I think it's absolutely amazing that they are persistently progressing on their idea.
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?
Initially I think it was out of their own pockets, and they had a bunch of keen volunteers, who were also launching 'pong sats' high altitude balloons for highschool science experiments. While I was around the went from launching rockets out of boxes at ground level to doing it 20 miles up. More recently I think they've had some DoD funding
Here's his YouTube channel. I don't know about the viability, but I loved the concept so much I started writing a sequel to my Station Breaker novels around the concept.
Won't traditional rockets become more cost effective over time? The main KPI for most agencies is cost per ton to orbit, and given that is is targeting lightweight operations, it's increasingly more niche.
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.
> Won't traditional rockets become more cost effective over time?
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.)
No. Not really. Not unless we invent some magical fuel with tons of energy that weighs close to nothing.
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.
I don't buy that the available payload mass will be sensible when including the amount of power generation needed, especially considering that most satellites would probably still need a heavy chemical stage to boost them to their operating orbit.
Eh, solar panels are useful in orbit as well. They're particularly useful for avoiding the need for a heavy chemical stage because you can use them to power light weight ion thrusters instead.
If using solar, they can only accelerate half the time, thus amplifying the effect of drag, since now they have to speed up enough on the day side to also cancel out the drag losses on the night side.
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.
An orbital mirror could be a relatively simple option to allow acceleration during the night and multiply the solar energy during the day. Plenty large target, less atmospheric distortion/losses so shouldn't be all that hard to hit.
Hopefully you don't own a house in the path under the ship. It would be really annoying to have bright flashes of day light sweep through randomly at night. Also probably not great for global warming and insect life.
I don't think ion thrusters would work, for the balloon to maintain orbit you'd still be somewhere with enough atmospheric drag to be a problem. Ion thrusters only produce millinewtons worth of thrust, so they're very much relying on a no drag environment and the ability to run for continuous use for weeks to years.
ion thrusters won't get you to orbit or into an orbital insertion. They are only really helpful to slowly increase or decrease the speed in the direction you are already heading via some other propulsion method.
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.
Good question. I googled and found out that the highest clouds are the noctilucent clouds. They don’t contain dust, but tiny ice crystals, which are less than 0.1 microns in size. They can be found as high as 80km. Maybe you calibrate the airship speed so that hitting such a cloud in the “danger zone” does not damage the balloon. When you are above 80 km, you step on the gas.
I don't know the answer to that. But there's a pretty good chance the dust would get deflected in the boundary layer. The more problematic part is when you got to the orbit and there is no more air to form this boundary layer, and specks of dust will hit the balloon directly. I suspect that the microscopic holes that they form will let some of the gas out, but not enough to make a difference.
I've got the following numbers: 120km and 53km. The former is the altitude at which re-entrying orbital vehicles start burning up. The latter is the current world record for lighter-than air altitude.
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.
Is the orbital airship ever intended to return to the upper atmosphere or do you just build a new 1-2 mile long ship for each trip? How would it slow down?
That's part of my evaluation process when I need non-technical services like plumbing. If the website contains the relevant information but is an eyesore, I feel that they prioritize doing good work over fancy marketing materials.
For many things, yes. Local plumbers will often get most of their work via word-of-mouth, for which doing good work is necessary. In which case, being terrible at marketing to me signals that your work is good enough to stay busy without trying.
Note, there is absolutely nothing scientific about this claim of mine. Just a made up heuristic that seems plausible to me.
This lets you avoid the rocket equation as you don’t have to carry your own fuel. Presumably you’ll be using solar powered ion drives to gradually speed up.
Seems promising. Why not use an elongated blimp shape? Why the v?
And why can’t the space craft lift off from the ground.
> Why not use an elongated blimp shape? Why the v?
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.
> Why not use an elongated blimp shape? Why the v?
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?")
> do if the ions you’re using are collected from the atmosphere around you rather than coming from a tank on your vehicle
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.
9 days to get to orbit? They overestimate people's patience. People would rather sit on a burning fuel tank for a few minutes than wait 9 days in a small airship.
I mean people go for two week cruises and end up exactly were they started. I think there would differently be demand for it if price was low enough. Hell I think just normal airship cruises would around the alps or Africa would be amazing.
Not really relevant though. The airship to orbit concept aims to get both high and fast, whereas the XKCD/What-if you linked hinges on the fact that just getting high is not sufficient.
(This still leaves open the question of whether the proposed airship could actually overcome drag to get as fast as they hope.)
Ok, so they use an airship to get to the edge of the atmosphere - but isn't the gravitational pull there still strong? According to Wolfram, the edge of the atmosphere is about 100km above the surface of the Earth, and the gravitational pull there is about 0.97G, compared to 1G at the surface. So how much less fuel is required to get into orbit from that point? Is it significantly less?
This does not look like a serious project at all. Go look at their blog and check out their mission control van[1]...
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...
Don't know whether the Air Force ever tosses money at long shots, but this would appear to be one.
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]
“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).”
> We need to get payloads into space, and cost per kilogram is what matters. Why do this?
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.)
Using the atmosphere to keep you off the ground feels like you have a problem where for every atmospheric molecule bouncing off your bottom pushing you upwards you're incurring a drag cost. My gut says that that means it's never going to work, but guts aren't always very good at engineering.
It *may* work if you had some impressive wireless energy transfer, but that means you probably would not actually save any cost in the grand scheme of things.
Blimps sound like they should be good for space, but as a concept they're oversized and full of hot air unfortunately.
I might not understand your concern but to me this seemed clear enough:
> 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.
> The first stage is an airship that travels from the ground to 140,000 feet
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.
How much heating would accelerating to orbital velocity at the “edge” of the atmosphere create? I’d expect that if there’s enough atmosphere to create lift there’s probably enough to cause the craft to burn up.
> if there’s enough atmosphere to create lift there’s probably enough to cause the craft to burn up
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.
SSTO doesn't rely on aerodynamic lift, it can fly higher than a lift-based vehicle can to avoid air resistance/heating. I suspect you can fly high enough that burning up isn't a problem, but I don't see how you reach that as a conclusion by analogy to single stage to orbit rockets.
> SSTO doesn't rely on aerodynamic lift, it can fly higher than a lift-based vehicle can to avoid air resistance/heating
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.
Single Stage To Orbit doesn't have to be an atmosphere breathing multi-engine lifting body craft, it can be a conventional rocket that just doesn't care about being efficient.
Burning up as you accelerate is also an engineering problem that is not 100% solved for hypersonics. Almost solved, but not risk free.
As an example, Starship can theoretically SSTO on Earth, just with no payload and no means of returning. Totally inefficient and actually useless, but technically SSTO.
Only when that 2-stage stack is properly validated.
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.
L/D ratio at hypersonic speeds is bad. So, the thrust has to still be a significant fraction of the weight of the vehicle. There's no "slowly" accelerating to orbit.
