Author Topic: Upper Stratosphere "near-space" station for "space" tourism?  (Read 7610 times)

Offline AlexCam

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I know that JP Aerospace doesn't seem to make much headway with their "airship to orbit" concept.

Still, I wondered whether their concept of a stratospheric station (based approximately 140,000 feet above sea level or about 40km up) would be an interesting addition to the sub-orbital "space"travel crowd. Yes, it is technically not in space and no, there is no weightlessness involved, but the view would be quite stunning and could be enjoyed for some time, not just a few minutes.

Day trips or one-night stay-over trips up there including "dinner with a view"  could be an interesting (cheap?) alternative to the 250k 6 minute joyrides with Virgin Galactic.

Here are some stunning views from weather balloons from the upper stratosphere, you can clearly see the Earth's horizon as round:
http://2.bp.blogspot.com/_Dx_J1JC8mag/S6uNMR23W1I/AAAAAAAABk0/R0RXBqcNogs/s1600/Helium-balloon_2__701051a.jpg
http://spacekate.com/http://spacekate.com/wp-content/uploads/2010/09/High-Altitude-Balloon-206.jpg
http://diegoguevara.com/blog/wp-content/uploads/2010/04/TheeBlog-IcarusProject4.jpg

Offline hop

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I know that JP Aerospace doesn't seem to make much headway with their "airship to orbit" concept.
A huge surprise ;)
Quote
Still, I wondered whether their concept of a stratospheric station (based approximately 140,000 feet above sea level or about 40km up) would be an interesting addition to the sub-orbital "space"travel crowd. Yes, it is technically not in space and no, there is no weightlessness involved, but the view would be quite stunning and could be enjoyed for some time, not just a few minutes.
If you could make such  a station, it would also be quite attractive for astronomy and cosmic ray research. Depending on location, it could also serve as a communication relay. Depending on how your transport worked, you could also get quit a bit of free-fall on the way down. For the adventurous, you could offer the option of jumping :D

But building something with such a large payload and indefinite life at that altitude appears quite challenging. Especially if you want to maintain it at a relatively fixed location.
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Day trips or one-night stay-over trips up there including "dinner with a view"  could be an interesting (cheap?) alternative to the 250k 6 minute joyrides with Virgin Galactic.
6 minutes is the zero G time, the whole flight is a bit longer, and both the powered portion and reentry should be quite thrilling in their own right.

Edit:
There has been some successful work done with long duration high altitude balloons with fairly significant payload, e.g. http://www.csbf.nasa.gov/balloons.html

However, these are at the mercy of the wind, and the payloads are still small in comparison to what is being discussed here.
« Last Edit: 08/07/2011 07:59 PM by hop »

Offline gbaikie

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I know that JP Aerospace doesn't seem to make much headway with their "airship to orbit" concept.
A huge surprise ;)
Quote
Still, I wondered whether their concept of a stratospheric station (based approximately 140,000 feet above sea level or about 40km up) would be an interesting addition to the sub-orbital "space"travel crowd. Yes, it is technically not in space and no, there is no weightlessness involved, but the view would be quite stunning and could be enjoyed for some time, not just a few minutes.
If you could make such  a station, it would also be quite attractive for astronomy and cosmic ray research. Depending on location, it could also serve as a communication relay. Depending on how your transport worked, you could also get quit a bit of free-fall on the way down. For the adventurous, you could offer the option of jumping :D

But building something with such a large payload and indefinite life at that altitude appears quite challenging. Especially if you want to maintain it at a relatively fixed location.
Quote
Day trips or one-night stay-over trips up there including "dinner with a view"  could be an interesting (cheap?) alternative to the 250k 6 minute joyrides with Virgin Galactic.
6 minutes is the zero G time, the whole flight is a bit longer, and both the powered portion and reentry should be quite thrilling in their own right.

Edit:
There has been some successful work done with long duration high altitude balloons with fairly significant payload, e.g. http://www.csbf.nasa.gov/balloons.html

However, these are at the mercy of the wind, and the payloads are still small in comparison to what is being discussed here.

Nice link.
One thing apparently not done and/or has little interest, is trying to make balloons go fast.
I would suppose that the fastest any balloon has gone is due to wind speed, but can you make a balloon have a faster velocity than say 300 mph and not due to wind speed. And I mean in the sense of drag race or stunt. You have a land speed record for a car; what would a balloon speed record be?

The way I would think you would do this [get a balloon speed record] is by using buoyancy [rather than engines/jets] and so it would be speed going straight up.

Because of my strange interests, I think of balloons as not just lighter than air, but also as lighter than water. Or if you like, anti-gravity machines [they are the only anti-gravity machines that have actually ever been made].

So in the classification of balloons or anti-gravity machines what could the fastest speed attained?

I tend to think that lighter than water "vehicles" could go the fastest- they seem to me to be the easiest to get to 300 mph or faster. Or for a few thousand dollars or less, a lighter than water vehicle could "achieve this record speed" with what I tend think as less trouble than a lighter than air vehicle could do it.
Or said differently if the "race" is to reach fastest velocity below the speed of sound- I bet water could do this the fastest and cheapest, but to reach supersonic speeds perhaps air balloon would faster and cheaper to develop. [Though I would exclude the speed possible from falling- such as tying a brick to a balloon and having balloon burst at 80,000':).]
« Last Edit: 08/07/2011 10:09 PM by gbaikie »

Offline Andrew_W

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I tend to think that lighter than water "vehicles" could go the fastest- they seem to me to be the easiest to get to 300 mph or faster. Or for a few thousand dollars or less, a lighter than water vehicle could "achieve this record speed" with what I tend think as less trouble than a lighter than air vehicle could do it.

I can't find a link but there was a proposal for a positive buoyancy submarine or bottom launched torpedo that would "fly" up to attack surface ships with only its buoyancy and hydrodynamics to get pretty good lateral speed, from memory 30knots(??), a few years ago that I read about it, its big advantage was its stealthiness.
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Offline gbaikie

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I tend to think that lighter than water "vehicles" could go the fastest- they seem to me to be the easiest to get to 300 mph or faster. Or for a few thousand dollars or less, a lighter than water vehicle could "achieve this record speed" with what I tend think as less trouble than a lighter than air vehicle could do it.

I can't find a link but there was a proposal for a positive buoyancy submarine or bottom launched torpedo that would "fly" up to attack surface ships with only its buoyancy and hydrodynamics to get pretty good lateral speed, from memory 30knots(??), a few years ago that I read about it, its big advantage was its stealthiness.

Hmm. I don't think lateral speed is a strong point in regards to using a torpedo in terms of buoyancy. Nor stealth.
I would use conventional propulsion for lateral direction.
So maybe have torpedoes "range the depths" with conventional propulsion [and 30 knots seems like about right cruise speed] and because of sheer depth be more stealthy. And once within range of a target, use buoyancy to punch upwards, and reach target at such velocity that avoiding being hit is impossible [and at such high speed the torpedo would be quite "visible" on sonar, but it is a second or so away from impact].

The problem with this type of torpedo, is it doesn't seem to fit the needs of US navy, and perhaps would be better for enemies of US navy. Mainly because US navy doesn't have any problem killing any target, whereas the enemy does have to struggle to hit US assets.

Offline gbaikie

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"I tend to think that lighter than water "vehicles" could go the fastest- they seem to me to be the easiest to get to 300 mph or faster. Or for a few thousand dollars or less, a lighter than water vehicle could "achieve this record speed" with what I tend think as less trouble than a lighter than air vehicle could do it."

I wanted to put some numbers to this assumption and get a closer approximation.
So start with a tube 16 meter long and 1 meter in diameter with 1 cm thick walls. And put a conical cap on one end.
If placed vertically in water [ocean] and pushed it 33' below the water, the air inside would compress to 1 atm and the volume of air would half.
If pushed to it 132' under water, the air would compress to 4 atm and the volume of air would half again. Or:
Each 33' or 10 meters under the water is 1 atm
33' 14.7 + 14.7 = 29.4 gauge
Doubling 29.4 is 58.8 psi- 4 atm
Doubling 58.8 psi is 117.6 psi- 8 atm
So,
33' halves volume
132' quarters
264' 1/8th the volume
If you go below 264' the volume of air will be less than 1/8 the length of tube or less than 2 meters of the 16 meters. And you need about 2 meters of tube to be fill with air to float. Or at some point below 264' the tube will sink and increase it's velocity of sinking the deeper it goes.

And around 264' it's neutral buoyant. And as it rises, the volume of air will increase and it will accelerate upwards.
So roughly the maximum depth of water should be around 250' to 300'.

I imagine, that before the top of tube reaches the surface, it will probably be going faster than anything as ever travel underwater. But I am hoping that a significant amount speed will added AFTER the top of tube is at the surface and doesn't have as much drag from the water AND at this point it has the most buoyancy- about 7-8 gees of thrust [but at that high level of buoyancy it will only be for a brief moment [maybe a second].

If one isn't interested in adding velocity after the top of tube reaches the surface, one could use a much smaller tube [shorter and less diameter]. And perhaps start from a deeper depth.

The first thing I will "test" is my assumption that before top of this tube reaches the surface, it will be going fairly fast- by which I mean over say 100 mph.
Rough rule thumb, less than 30 mph no significant drag. 30 to 60 mph requires say 1 gee, 60 to 80 2 gees, and 80 to 100 mph somewhere around 3 gees.
And this "test" requires a more precise description. So:
Have 10 meters of tube made from aluminum walls and bottom part made of steel walls:
10 meter length mass: .848 tonnes of Aluminum
6 meter length mass: 1.47 tonnes of steel
Giving total mass of 2318 kgs, and make it 2.4 tonnes.
It's weight in the water will less than 2318 kgs. but we can ignore this.
The air in the tube and the less massive aluminum will cause to tube to point upwards. And the different masses of material is more significant in this regard, once it reaches surface.
The total/maximum  buoyancy is 12.56 cubic meter and slightly more than 12.56 tonnes in saltwater. And 1/8th is 1.57 tonnes of lift vs about 2.4 tonnes vehicle mass [it sinks]. And 1/4 is 3.14 tonnes of lift vs 2.4 which results in .7 tonnes of upward force. And 1/2 is 6.28 tonnes which results in 3.88 tonnes of force.
So some of it's velocity will occur between 132' and 33' below the surface and we can assume the .7 tonnes or less could result in speed of 30 mph [13 meters per second]. So how fast does it go between 132' and 33'?
Which is 99' or 33.1 meters. Without any acceleration at 13 meters per second it will travel further than 33.1 meters in 3 seconds. And so the acceleration time has to be less than 3 seconds and the range of acceleration is .7 to 3.88 gees [6.86 m/s/s to 38 m/s/s].

[An important aspect of this will depend upon water drag at higher speed, but I will first ignore this and later try to include it. And btw, it might possible that this drag "allows" higher speed, because it might allow fractions of seconds "longer" in higher acceleration "environment".]

Now, there two "points of interest", the top of the tube as it nears the surfaces and the level of the air inside the tube [relative to surface- and fraction of the tube filled with air].
The point of .7 gee and 132' under the water is 132' from bottom of air inside the tube [or top water inside tube]. And 1/4 of tube fill with air is the length of tube divide by 4- and so, 4 meters from top of tube. And as the tube goes up the air in the tube goes down {relative to tube].
To characterizes the less than 3 second during which acceleration goes from .7 to 3.88 gees, the last second of the less than 3 seconds will have greatest difference, meaning it will have something like 1 to 3 gee in a period of one second. And because of accelerate time involved will around 2 seconds instead of less than 3 second.
So from 13 meter per sec add about 10 meters/sec of acceleration in first second and last second when going 23 m/s add 6 and 12 m/s
having total of 41 m/s [91 mph].

So traveling around 41 m/s when air in tube is 33' from surface, and acceleration in next second is 3.88 gees [minus water/air drag] to 5.23 gees at max and lowers to zero within that second. And since tube is 16 meter long and half is filled with air at this point, the top is 2 meters from surface, or in less than 1/20th of second it will go above the surface. And once bottom of tube goes above surface of the water all acceleration ceases- this occurs in less than 9/20th of a second or 8/20th of second after top of tube reaches surface.
Hmm. So in that second 38 m/s/s peaking to 51 m/s/s and rapidly decreasing to 0 m/s/s. So adds about 15-20 m/s.
And giving top speed of around 55 to 60 m/s [122 to 133 mph].

Not as fast as I thought but fairly fast for a balloon.
« Last Edit: 08/09/2011 03:13 AM by gbaikie »

Offline RanulfC

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"How fast can a balloon go?"
REAL tricky question, you need to define both "balloon" and the "fluid" it's going through.

We've tested "inflatable" structures at high-mach speeds but they weren't "just" pressure supported like a "normal" balloon is. Since it was a "reentry" design in the first place it was more geared towards high-drag (and slowing down) than it was to being speedy. The JP Aerospace design is also a balloon in the normal sense so I'm not sure how they are going to go about getting something like that "up-to-speed" as it were.

The nice thing about a "hotel" balloon is it doesn't have to go "fast" but just be able to stay "in-place" which will probably have to be some sort of electro-thruster type as I don't think "propellers" work at very high atitude. Shouldn't be a major issue since you can use a good portion of the "surface" area to base solar cell arrays on.

gbaikie; something to "add" to your calculations. Specifically a "balloon" in water has a way to cut the drag WAY down on the way up: By expelling air under high pressure out the nose cone you can effectivly break-up the water and surround the balloon in a "low-drag" gas zone allowing REALLY high speed.
(Supercavitation is what it's called See:
http://www.popsci.com/scitech/article/2004-06/supercavitating-torpedo
http://www.tech-faq.com/supercavitation.html
Unfortunatly it doesn't work in air that I'm aware of)

Oh, and what Andrew_W was talking about was that the "bottom-based" torpedo would be able to not only stealthy in a vertical direction but be able to move a great distance horizontally by using manuevering surfaces to trade part of it's upwards speed for horizontal speed. There are concepts to use alternating positive-negative buoyancy control for both propulsion and steering. Both under water and for Lighter-Than-Air (LTA) airships:
http://www-pord.ucsd.edu/~rdavis/publications/4Gliders.pdf
http://www.fuellessflight.com/
http://gradworks.umi.com/32/73/3273254.html

The idea being that as a vehicle rises or sinks within a medium, like a glider it can "trade" part of its vertical velocity into horizontal movement. By alternating between a "positive" and "negative" buoyunt state a vehicle can move great distances horizontally with little or no active propulsion use.

Well, in theory anyway, in practice especially with airships you tend to need more propulsion energy than you could get with just using buoyancy control and the energy requirements for changing your buoyancy isn't trivial either. Still for "shuttles" going to and from the "hotel" there are possibilities....

One idea I havent' seen yet is the idea of "tethering" the Aerostat Hotel to the ground and running "shuttles" up and down the tethers. Additive to that you could have the main 'tether' members being hollow and use a partial "fountain" concept to offset some of the hotel mass.
(The "Fountain" has a ground level electromagnetic accellerator portion which fires high speed "projectiles" inside of the hollow members. By reducing the air pressure {vacuum is better but probably cost prohibitive near the surface} inside the members the projectiles retain more energy from the accelerator for a longer period of time. The idea is that the projectiles reach the top of the "loop" and are deflected by magnets on the "Hotel" and turned to drop back down another hollow leg of the system where they fall to the bottom completing the "support" system. Part of the energy they gain in falling is extracted to {again} turn the projectile around and accelerate it up again which reduces the overall energy needs of the system somewhat.)
http://www.orbitalvector.com/Orbital%20Travel/Space%20Fountains/Space%20Fountains.htm
(Yes I know it's for an RPG, but they folks who play Traveller have some of the BEST explanitory articles for REAL science I've ever found :) )
http://www.strangehorizons.com/2003/20030714/orbital_railroads.shtml
http://www.wisegeek.com/what-is-a-space-fountain.htm

Of course like most "neat" concepts the up-front costs are going to be a bear to deal with, but the fountain has the advantage that it can actually be built from the "ground-up" which helps a bit :)

Randy

Offline sanman

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Guy with balloon wants to do "near-space" tourism:

http://www.wired.com/autopia/2011/08/inbloon/

Offline RanulfC

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Guy with balloon wants to do "near-space" tourism:

http://www.wired.com/autopia/2011/08/inbloon/
I seem to recall JP had/has a similar concept but using a powered version.
Hmmm, maybe someone can get the Strato-Bowl re-opened as a launch site?
http://stratocat.com.ar/bases/56e.htm

The problem with a "simple" balloon is the needed ground-launch, in-flight tracking and recovery assets come pretty close to being the same as with a rocket and with less "turn-around" time reduction capability. I've yet to see someone manage to get the business case to close. (The again I see the same "issue" with the idea of a "near-space" station itself :)

Having said that though the NSS with a ground connect tether has the possibility of some sort of "high-speed" ground-to-station transportation that eliminates the majority of the issues with balloon operations. Of course the "getting-down" is always easier than getting up :)

The "Near-Space Corporation" http://www.nsc.aero/is using a modification of the FMX-4/5 design as a "Near-Space data/sample return" vehicle:
http://www.eaa.org/experimenter/articles/2010-01_facetmobile.asp
A "full-size" version might have "possible" applications, but it still comes down to the economics of the whole venture and what kind of "target-market" you are serving, how, and how much cost-vs-income the actual con-ops will be. Not something that is easy to figure out or even research due to a lack of hard data.

There are a LOT of assumptions and more than a bit of probably "wishful-thinking" in the idea of a the NSS as a tourism attraction or a viable money-making concept. I'm not sure how, or who, would pay for the professional and needed research and data collection but it's something that really badly needs to be done to either put the idea to rest or move it forward.

Randy

Online grakenverb

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This company has been promising a high altitude airship for around 10 years, but not much has come of it.........


http://www.wsgi.com/stratellite.php


Online FutureSpaceTourist

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Just found this thread.

I know that JP Aerospace doesn't seem to make much headway with their "airship to orbit" concept.

Yes it's hard to see progress as they do a lot of testing on such a small scale (and it is a 30 year programme that they're only a bit over halfway through!).

Things are due to get a bit larger scale in the relatively near future. They're hoping to fly their scale 90 foot Ascender by the end of this year: http://jpaerospace.com/blog/?p=5147
« Last Edit: 04/27/2013 06:53 PM by FutureSpaceTourist »

Online Asteroza

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Don't forget the LiftPort guys, they seem to be using their kickstarter momentum to get back into the high altitude tethered balloon game.

Offline JasonAW3

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What about a thin shell hard structure?

     Perhaps made from layers of Graphene paper, bonded together with a sort of aerogel polymer?  100 layers should give a fairly substantial structure, (Ribs and girders could be molded directly into the overall structure, to minimize mass and increase potentile lift) and should be able to handle fairly high speeds that soft skin ballones couldn't.

     You might even be able to create a negative boyancy strurcture out of this craft, (Or fill it with a hydrogen / silicon based aerogel, with a negative boyancy factor).

Just a thought...

JasonAW3
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Offline Vultur

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The Dark Sky Station concept strikes me as something that could well work (no physics problems like the orbital airship) but it would likely take WAY more funding than JP Aerospace could reasonably get to build a full-size one.

The envelope(s) would have to be simply massive, and the cost of helium would likely be prohibitive. It might even be a significant drain on helium reserves.

I guess you could use hydrogen (how flammable is it with oxygen at that partial pressure at 140,000 ft?) but if this is going to be a tourism thing,  safety regulations might kill it. (Though I guess you could base it in some country that doesn't have those regulations).

Offline QuantumG

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The last plans I saw were to use hydrogen for the Dark Sky Station. It's very safe at that altitude.
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