Is the Space Hose a Viable Solution for the N-Prize Challenge?

[gutemine]

Hi !

I was pointed to this forum to get some help and technical advice and verification of a new kind of low cost Space Tower: the Space Hose.

In a nutshell it is about using a lightweight hose made from PE foil which is blown trough from the bottom and is using the frictional forces of the flowing air to produce continuous lift for supporting the weight of the hose.

It was designed as an alternative approach to solving the N-prize problem which is about putting a 9,99 gram satellite into space for 9 orbits and winning
£ 9999,99 when staying within the £ 999,99 budget. Because of the "geostationary" orbit a space tower offers it would mean keeping the tower upright for a total of 9 days.

You can find a brief presentation including most of my poor math in the attached PDF file.

I'm aware that this approach is not a very realistic one due to the huge stability problems when going for a single hose, but the math showed that it could be feasible to support a 100km hose and the needed raw material and energy consumption would be within the N-prize budget, hence I think it is worth sharing with you.

By using plain air at a reasonable blowing speed as the medium for continuously transfering the frictional force to the hose it overcomes most of the limitations of the existing inflatable space tower and the space fountain concept.A head diffusor is making the air blowing out sidewards on top with only a small downward momentum to support the payload and prevent tearing the hose.

Have fun reading the slides and input is welcome because I'm pretty sure that I must have done something fundamentally wrong in my math!

gutemine

PS: Sorry, for the bad graphics and the funny comments in the slides - I had to compress heavily to get below the 256k limit of N-prize the forum for attachments and the N prize spirit which originates from the halfbakery is also about the entertaining value of potential solutions

 

[russ_watters]

Because of the geostationary orbit a space tower offers it would mean keeping the tower upright for a total of 9 days.

...

...a 100km hose and the needed raw material and energy consumption would be within the N-prize budget, hence I think it is worth sharing with you.

Geostationary orbit is about 23,000 miles, not 100km. I don't think having a payload sit on top of a tower for 9 days would qualify as being "in orbit".

 

[gutemine]

The top of any tower is always 'geostationary' in the pure sense of the wording :-)

But you are right, this is not what is understood as geostationary orbit in the general sense.
I added "" around the "geostationary" to prevent further misunderstandings, thanks for pointing this out !

I checked with the N-prize owner and he confirmed that if the SAT it would stay in 100km height being outside of the "launch device" for 9 days and hence would have circled the Earth (center) 9x this would count as orbiting and hence be within the rules.

Remember the N-prize is also about original ideas to achive the over all goal within the budget and weight limit. So my question to him was the other way around - if a 'geostationary' orbit in 100km height would be also accepted, and the answer was yes.

gutemine

PS: English is not my mother language, so I hereby excuse for typos and not 100% perfect wordings. But I'm more concerned about the math and physics in the proposal.

 

[DaveC426913]

I checked with the N-prize owner and he confirmed that if the SAT it would stay in 100km height being outside of the "launch device" for 9 days and hence would have circled the Earth (center) 9x this would count as orbiting and hence be within the rules.

Sorry, I am confused now.

How do you get the satellite to stay at 100km for 9 days once it has detached from the launch device? It will not circle the Earth at all. It will fall straight back down.

To circle the Earth at 100km, it will need to be given a sideways velocity component of somehwer in the neighbourhood of 17,000mph (orbital velocity).

 

[gutemine]

Sorry for the confusion, but ask a bouncing ball in a fountain - he knows the answer.

And 'outside' doesn't always mean 'detached'.

And the slides also contain some math about blowing out at orbital speed with a de Laval nozzle - so maybe even this would be possible.

Expansion of 1m³ air from the ground to 100Pa in 100km already gives an amazing expansion power as the used ideal gas formula would suggest.

But this is a follow up problem - I'm more concerned about all the things I have done wrong in my friction power/pressure calculations.

 

[DaveC426913]

ask a bouncing ball in a fountain - they know the answer.

And outside doesn't mean detached.

OK, so it's still in the grips of the launch device, just suspended on air instead of anything solid. Might want to check with the N-prize rules on that one.

And the slides also contain some math about blowing out at orbital speed with a de Laval nozzle - so maybe even this would be possible.

Blowing out - at 17,000mph? I think that will "blow out" all his hard work on calculations for material strengths.

And it better be more than "possible". This idea is dead in the water without this (major) component. Getting to 100km is a trivial feat compared to achieving 17,000mph velocity.

So far, you've pushed the car out of the garage. Now your theorist is saying "it might be possible to put an engine in it to get it moving". You're a loooong way from winning any races.

 

[gutemine]

The slides are already including that blowing out that fast is unrealistic for such a weak structure.

But this is not planned either - the slides suggest that you would need to change hose diameter to better prevent things like hypersonic flows ;-)

But this is one of the things I failed to fully understand. Because of the decreasing pressure with increasing height the air would expand and flow faster until at some place (without diameter change) the flow would be breaking the sound barrier - so this hose would work as a kind of "fixed diameter de Laval nozzle" ?

 

[DaveC426913]

The slides are already including that blowing out that fast is unrealistic for such a weak structure.

OK so you're back to a novel method for making stationary tower, with your satellite simply resting on top.

Might want to check with the rules on that.

 

[gutemine]

I can check the rules once more :-)

BUT the primary question is would the tower work ?

At least for the first few km the friction force calculation should be pretty accurate to balance the hose's weight - so there would be 'only' the stability problem remaining ?

The classic space tether works with the centrifugal force of the counterweight at the top - would a downwards blowing diffusor at only 100km (if it is stabilized against sideward movements) work as a sustitute to generate the stabilizing pull force ?

The Inflatable space tower people already have put the fixes for the stability problem(s) in their patent - see the straw pack comment in the slides, and the suggested Dyneema strings strengthening.

 

[DaveC426913]

I can check the rules once more :-)

No need.

The prizes will be awarded to the first persons or groups to put into orbit around the Earth a satellite

The space hose has no legs unless they get that "blow out" working.

 

[gutemine]

The space hose has no legs unless they get that "blow out" working.

Why ? You are still orbiting the planet at 100km height if you are on top of such a structure - which would be quite an achievment.

And I'm not so sure about instability at very fast flow rates either - as long as the diffusor provides a surpressure the hose should be pretty stable even if the flow inside would be pretty fast (but with low denseness)

Wouldn't an elastic hose suggest that the pressure inside (besides friction and the diffusor) is always the same then outside ?

But this compexity of the problem is why I asked for help and advice ... so thanks for your patience with me !

 

[russ_watters]

OK so you're back to a novel method for making stationary tower, with your satellite simply resting on top.

Might want to check with the rules on that.

Based on the logic the OP is currently using, my car, sitting in my garage, qualifies for the prize.

 

[russ_watters]

Why ? You are still orbiting the planet at 100km height if you are on top of such a structure - which would be quite an achievment.

You need to google the definition of "orbit".

 

[gutemine]

Based on the logic the OP is currently using, my car, sitting in my garage, qualifies for the prize.

If your garage would be 100km above sea level - yes !

But you are getting now the spirit of the N-prize - it is about achieving something very likely to be impossible with a very unusual approach. And it only is not allowing ovieously cheating (asking your space shuttle astronaut friend to take the N-SAT on his next trip and float it in the shuttle for 9 orbits - then you share the prize money)

The other participants so far just try the ordinary things (balloons, rockets, combination of both...) so I went for the impossible and tried to solve the space tower problem :-)

So back to the original question - can a hose hold it's own weight just from the friction force of blowing air trough it and what happens if it goes to space (which starts at 100km) ?

BTW - the 100km in my slides are only because of the N-prize origin of the idea. In my understanding the friction force of flowing air holding the structure should work also up to 36.000 km - BUT because of the very weak pressure there the hose would probably become instable or collapse (or would a diffusor work in this case also to recover at least a small pressure surpluss of 100Pa?).

You need to google the definition of "orbit".

Wikipedia says about orbit: Orbit is the gravitationally curved path of one object around a point or another body. I'm missing the word speed in this definition ...

 

[russ_watters]

If your garage would be 100km above sea level - yes !

A particular altitude is not part of the definition of an "orbit".

So back to the original question - can a hose hold it's own weight just from the friction force of blowing air trough it and what happens if it goes to space (which starts at 100km) ?

Well certainly a hose can hold itslef up based on air pressure and friction inside. That's what this is:

https://www.youtube.com/watch?v=iQWq9XjT8mY

...but can it be scaled-up to 100 km? I think that's just a pracitcal problem: I doubt any material can stand up to the required pressure at the bottom.

Wikipedia says about orbit: Orbit is the gravitationally curved path of one object around a point or another body. I'm missing the word speed in this definition ...

No, you're missing the word "tower". If gravity dictates the curvature of the path, then a tower can't be dictating the path.

Then the speed is what you need to shape the "gravitatinoally curved path" so it doesn't intersect with the ground. Note, this path need not be circular and the winner of this contest will not likely use a circular orbit but an elliptical one.

 

[russ_watters]

...but can it be scaled-up to 100 km? I think that's just a pracitcal problem: I doubt any material can stand up to the required pressure at the bottom.

By the way, if you can find the weight and strength of the material you want to use, it isn't difficult to calculate the pressure and airflow requirements. For instructional purposes, I can certainly help you with that.

 

[DaveC426913]

Why ? You are still orbiting the planet at 100km height if you are on top of such a structure

gutemine, this is not an orbit. Every mathematically-able person on this board will agree. And I'll bet my paycheque that the N-prize judges will agree as well.

No need to take my word for it. Ask them.

 

[gutemine]

Thanks for all your input!

Regarding the petrol station advertising wiggle device. This is intentionally desinged to wiggle - the diameter of the hose is reduced upwards to increase the speed of the airflow which reduces the airpressure until the outside air can balance this and hence the hose is folding. This stopped flow then causes the pressure to increase until it blows up again. So this is designed as a kind of strange upward pendulum.

My design is not this way. If you add a diffusor on top you can create a pressure surplus which holds the whole thing stable and by blowing downwards you get a stabilizing pull.

In the halfbakery where the same problem was pointed out (but without the entertaining video) I suggested a simple experiment to understand the difference:

Take a condom and put it over an adhesive strip tape roll and then blow trough the hole of the roll upwards. This gives a nice upright position :-)

But you now have the problem of the inflatable space tower - pressure will increase dramatically with height, and you end up with expensive kevlar balloons to hold the pressure (but is is not that worse - so a big thumbs up for their idea!)

Then you do the same after cutting away with a scissor the small repository piece at the top. Blow again - you have to blow faster, but it still works to hold the upright position. The remainder on the top works as a pretty bad diffusor. This is what the space hose would be (even when in our experiment the pressure increase of the diffisor does the job, not the friction - but you cann't buy that long condoms to verify) - so the experiment is cheating a little bit.

If you then cut away the entire head so that the opening at the top has the same diameter then the rest of the hose/condom you will fail - no matter how hard you blow. The Bernoulli effect is aginst us.

As soon as somewhere in the hose/condom the diameter shows a small imperfection making it smaller, then the flow speed will have to be slightly higher, which means at that place the pressure will drop within the hose and as soon as this happens the athmosperhic pressure will win and the hose will collapse at that place. The air then still flows but it would be totally instable even when friction gives still the upward lift (then you really have a space flag not willing to stay upright). Hence a small pressure surpluss is a must, but this is the way an upright hose should work. The space tether people are sugegsting a counterweight for generating the stabilyzing pull - in my case the diffsor produces the pressure surpluss and by blowing downwards also the needed pull.

PS: I have to enter a meeting now, but I will try to answer the other questions no later then evening

gutemine

 

[mugaliens]

gutemine, I read through you posts and slides. Your proposal meets the N-prize rules. In summary, the object rides the moving column of air to the 100 km point, where it exits, and is thus outside, but remains attached. Technically, it's in geostationary orbit. Nine days later it's completed 9 orbits.

I do wish people would stop focusing on the rules and respond to your question of whether or not it's feasible. I'm an aero guy, and your numbers look ok to me, but it's been decades since I crunched fluid flows.

My concern is the stability of column in turbulent flow. http://www.youtube.com/watch?v=L4ujpHqbxiI"shows what usually happens, although your dynamics are somewhat different (higher pressure, a diffuser/thruster at the top...) Obviously the column of air will loose pressure as it rises, just as does the atmosphere.

Also, I don't recall your final numbers on internal pressure, but if we assume it's at twice ambient pressure all the way to the top, however, your 10" column of air will itself weigh 2,309 lbs, though half will be supported by ambient, which leaves us with 1,154 lbs of additional mass to support. That'll be supported by the increased internal pressure, of course, but the bag will have to support 2 ATM along its entire length.

I'd say give it a trial run with perhaps a 500' column and see how it behaves.

 

[russ_watters]

gutemine, I read through you posts and slides. Your proposal meets the N-prize rules. In summary, the object rides the moving column of air to the 100 km point, where it exits, and is thus outside, but remains attached. Technically, it's in geostationary orbit. Nine days later it's completed 9 orbits.

No, "technically", it is sitting on top of a tower. It is not in orbit.

 

[russ_watters]

gutemine, I read through you posts and slides. Your proposal meets the N-prize rules. In summary, the object rides the moving column of air to the 100 km point, where it exits, and is thus outside, but remains attached. Technically, it's in geostationary orbit. Nine days later it's completed 9 orbits.

No, "technically", it is sitting on top of a tower. It is not in orbit.

When something is in orbit, there is no external force holding it up - there is only gravity pulling it down.

 

[gutemine]

Maybe let's use a neutral example to end the discussion about orbit:

For thousands of years mankind accepted the rule that water is not able to flow uphill. Then Achimedes invented his screw. You could argument that now the water is pumped, but it definitely is a continuous upwards flow. So maybe Achimedes would not have gotten any prize money either, but that wouldn't have made his invention one inch smaller.

Regarding the air pressure weight - that's the good thing about pneumatics - the weigth of the air is not a problem (if there is not pressure surplus) because the hydrostatic pressure is the same inside and outside the hose if there is no air flow. Which means there is nothing the hose needs to balance with its strength. Which is especially true if the hose is open on the other end (=top). On sea level air has a hydrostatic pressure of approx 100000N/m² which would make even Atlas crack if he would have to hold it on his shoulders. But there is no problem with this, because our body is under the same pressure and feels pretty comfortable with that. A hose has the same pressure relief, so you may only need to hold the surpressure of the resistance pressure 'loss' - but I'm not even sure about this, because it is a flexible hose and not a fixed pipe.

The slides contain also the worst case pressure needed if the hose is closed and all the weigth at the top (about 0,6 bar) which is nothing modern materials would not be able to hold (not the thin PE foil, I agree, but the suggested Dyneema string srengthening like the Polyamid in your garden hose should be sufficient). The formula to calculate the needed strength of the walls of a tank is pretty simple and easy to use. And the diameter is not the optimization point - you get linear force increase, but also linear weight increase when the pressure and wall thickness is the same.

The 10" were only to make it within the N-prize budget, a real space hose for doing something usefull would be either bigger or a straw pack of such hoses (BTW I would prefere the later)

Maybe I should ask the question on my math more generic:

If I blow trough a very long hose from 1 bar into vacuum (and are ignoring friction), what pressure will the hose (not a fixed wall pipe) have ?

I already know that speed on the vacuum side will not be infinite (I think it is about 740m/sec because of ideal gas law in case of normal room temperature in the vacuum, real case calculation at -90 degree Celsius is in the slides)

Then you make the hose go upwards, and the hydrostatic pressure adds, but gets balanced from outside as already described.

Then your add friction and what pressure do you get then ?

gutemine

PS: If I have a rocket with enough fuel to continuously blow also downwards I can fly around Earth as slow as I want at any height - and you want to tell me that this is suddenly not an orbit ? If yes, then this is OK with me - no problem from my side !

PPS: An electron is also orbiting the atom core, and the orbital 'speed' is determined by the electromagnetic forces (and some quantum mechanics so it is not really speed) and not the gravitational one. This is why lots of orbit definitions even lack the word gravitation

A particular altitude is not part of the definition of an "orbit".

The N-prize rules are asking for the 100km height to reach 'space' - in general you are right, otherwise cyling Earth with a bicycle 9x would also get you the prize money, or simply waiting for 9 days. - BTW I liked the space garage approach. And thanks for the offered help on the strength calculation - as soon as we agree on the pressure gradient in the hose I will have to re-do that.

 

[DaveC426913]

gutemine, I read through you posts and slides. Your proposal meets the N-prize rules. In summary, the object rides the moving column of air to the 100 km point, where it exits, and is thus outside, but remains attached. Technically, it's in geostationary orbit. Nine days later it's completed 9 orbits.

Yeah, mug where are you getting this from? It is not in orbit at all.

By your logic, I could sit in my basement, suspending a pingpong ball using my vacuum cleaner, and claim, not only that it is in orbit, but that it will orbit the Earth every 24 hours.
By your logic, a http://eastmanind.com/eastmancommercial/HOVERMOWER/tabid/187/Default.aspx" , which rides on a cushion of air, is in orbit.


That's ridiculous.

 

[DaveC426913]

PS: If I have a rocket with enough fuel to continuously blow also downwards I can fly around Earth as slow as I want at any height - and you want to tell me that this is suddenly not an orbit ? If yes, then this is OK with me - no problem from my side !

Correct. That is not an orbit.

See above examples of other comparable setpups that are also not orbits.

And the N-prize judges will agree. I guarantee it.

PPS: An electron is also orbiting the atom core

No it isn't.

The N-prize rules are asking for the 100km height to reach 'space' - in general you are right, otherwise cyling Earth with a bicycle 9x would also get you the prize money, or simply waiting for 9 days. - BTW I liked the space garage approach. And thanks for the offered help on the strength calculation - as soon as we agree on the pressure gradient in the hose I will have to re-do that.

Your idea does not meet the criteria for orbit. Ask the judges at N-prize.

Do this before putting any more time into your proposal.

 

[gutemine]

Well, I already checkd with Paul (who IS the 'jury' - because he invented the prize and took care of the funding). He agreed that my proposal meets the spirit of the competition and I would be allowed to partizipate with this approach. And yes, I have sent him the slides and he said the space hose would qualify as a launch device to space!

He sent me the forms already to officially join - I just would need to fill them out, sign them and send back to officially participate. That doesn't mean that I could make and win the prize money - but the other competitors have pretty the same problem. If their broadcasting device fails and they could not proove the 9 orbits they would not get their prize money either - even if their N-SAT would perfectly orbit infinitely.

With the planned approach and materials I probably could do a 1-2km 'test flight' within a few weeks - 90% of the other partitcipants have not even an idea when they could do their first test flight. And if it would make only a few hundred meters - where is the problem - most of the home-brewn rockets have the same first launch (if they are lucky and make a lift-off at all)

I'm not planning to cheat and ask your for permission - I'm simply creative in solving the puzzle, and try to have fun while doing so.
I'm also trying to be honest and open minded by sharing my (bad) math and (weird) assumptions and ask clever people for feedback if and what I have done (awfully) wrong - to prevent missing something and waste all our time,

If I'm doing this already - then I'm simply sorry.

gutemine

PS: In your basement you could at least claim that you are orbiting the sun.

PPS: I just checked the orbit definition at the NASA Homepage (which in my understanding are pretty competent in this field):

An orbit is a regular, repeating path that one object in space (!) takes around another one.
And according to the NASA definition space starts at 100km above surface.

http://www.nasa.gov/audience/forstudents/5-8/features/orbit_feature_5-8.html

And yes, later their explanation gets lost with orbital speed, and gravitational forces (which is OK with me) - but that doesn't change the basic words of their own definition. If I would follow your argument even a space elevator 36000 km (or even 2x) long with a geostationary counterweight would not reach orbit either because it is still connected to the planet (and the first 100km would move identical to my proposal).

 

[DaveC426913]

Well, I already checkd with Paul (who IS the 'jury' - because he invented the prize and took care of the funding). He agreed that my proposal meets the spirit of the competition and I would be allowed to partizipate with this approach. And yes, I have sent him the slides!

Your proposal does meet the criteria - because it contains a passage addressing horizontal velocity. Whether it addresses it realistically, on the other hand, is your problem, not his.

I am simply saying you'll have to get that part working. So far, it is just a single speculative passage in your notes - but that part is going to be by far your biggest challenge.

Again, I feel you're concentrating on pushing your racecar out of the garage. As for getting it moving toward the racetrack, your proposal merely says "there is the possibility that we may be able to put some sort of engine in it at some point in the future."

I'm not planning to cheat and ask your for permission - I'm simply creative in solving the puzzle, and try to have fun while doing so.
I'm also trying to be honest and open minded by sharing my (bad) math and (weird) assumptions and ask clever people for feedback if and what I have done (awfully) wrong - to prevent missing something and waste all our time,

Yep. And we're giving you feedback about the missing piece.

I am trying to help, even if it risks discouraging you by having you see get some perspective on how far you need to go from here.

Don't discount that 'getting up to orbital velocity' requirement.

 

[DaveC426913]

...gets lost with orbital speed, and gravitational forces...

"...gets lost..."?

. If I would follow your argument even a space elevator 36000 km (or even 2x) long with a geostationary counterweight would not reach orbit either because it is still connected to the planet (and the first 100km would move identical to my proposal).

The space elevator has that orbital velocity component. That is how it will impart it to the satellite (remember, the definitions for 'satellite' and 'launch mechanism' are carefully defined as separate in the N-prize rules).

Yours does not have that velocity component to impart to the satellite because it is 35,786-100 = 35,686km too short.

 

[gutemine]

The mssing piece in my understanding is not the defintion of orbit - there are plenty.

Achimedes didn't concentrate on the meaning of the world flow either. He simply solved the problem to make it go upwards.

I already realized that I asked for too much at one time, so I tried to ask simple questions like 'what pressure will have a long frictionless hose blowing from 1 bar to vaccum' - and I didn't get any answer (yet).

If you want to eat an elephant you have to start somewhere, but it tastes the same no matter what his name was when he was alive (but don't tell me that we are trying to eat Dumbo - my childrean would be into tears)

And there are quite a lot of people enjoying getting their cars (and other weird devices) out of their garage on a daily basis.

If the space hose would work only for 1000m - this manmande built structure would be already higher then the tower at the gulf (with I am sure had a bigger construction budget) - and if it would be fun to try it, I don't have a problem to proceed.

To prevent misunderstandings - I'm not discounting or ignoring the orbital velocity component, the slides even suggest that with a de La Val nozzle in such a low pressure you maybe could even blow out a small object at orbital speed. But beeing 100km above surface (= space) already has a big schientific value (besides that you would NOT be weightless there which would make the stay probably even more comfortable if we would be able to put humans there this way), and could be used for things like low cost broadcasting, telemetry, air traffic control,...

In the halbakery I started already a thread that the real energy for 1kg beeing (!) in orbit is amazingly low (if you just add the needed height and kinetic energy). It is only a poor 32MJ more then on the surface (and yes, at orbital speed) - which is about the equivalent of burning 730g of Jet fuel. The energy is wasted in getting there, not for beeing there, so why not solving one problem after the other ?

And I already explained that if the friction = lift approach would work at 100km it maybe would work also up to 36000km

gutemine

 

[russ_watters]

Regarding the air pressure weight - that's the good thing about pneumatics - the weigth of the air is not a problem (if there is not pressure surplus) because the hydrostatic pressure is the same inside and outside the hose if there is no air flow. Which means there is nothing the hose needs to balance with its strength. Which is especially true if the hose is open on the other end (=top). On sea level air has a hydrostatic pressure of approx 100000N/m² which would make even Atlas crack if he would have to hold it on his shoulders. But there is no problem with this, because our body is under the same pressure and feels pretty comfortable with that. A hose has the same pressure relief, so you may only need to hold the surpressure of the resistance pressure 'loss' - but I'm not even sure about this, because it is a flexible hose and not a fixed pipe.

Before you can say strength is not an issue, you need to actually calculate the pressure required inside the hose at the bottom. Of one thing I can guarantee you without doing the calculation: the pressure will not be trivial. It will matter.

If I blow trough a very long hose from 1 bar into vacuum (and are ignoring friction), what pressure will the hose (not a fixed wall pipe) have ?

The question is so badly conceived as to be unanswerable. If you supply 1 bar of pressure at the bottom of the hose, no air will flow because that's the static pressure of the column of air. You need to provide greater than 1 bar of pressure to make the air flow.

And thanks for the offered help on the strength calculation - as soon as we agree on the pressure gradient in the hose I will have to re-do that.

Without the weight of the hose, you can't calculate the pressure gradient. So you need to select a possible material first, find its weight, then calculate the required friction force to hold it up.

Well, I already checkd with Paul (who IS the 'jury' - because he invented the prize and took care of the funding). He agreed that my proposal meets the spirit of the competition and I would be allowed to partizipate with this approach. And yes, I have sent him the slides and he said the space hose would qualify as a launch device to space!

Based on what you said in your second post, it sounds like you deceived him. Did you tell him that it was at 100 km altitude and supported by the hose? Because in your second post, you said "being outside of the launch device" which makes it sound like it isn't still supported by the hose.

In the rules, it says the satellite cannot be attached to the launch vehicle. So it is clear to me that just sitting on top of a tower - at any altitude - does not qualify.

The mssing piece in my understanding is not the defintion of orbit - there are plenty.

Achimedes didn't concentrate on the meaning of the world flow either. He simply solved the problem to make it go upwards.

You're missing the point: just achieving 100km of altitude and sitting on a tower doesn't solve the problem they are trying to solve. Getting into orbit is a big problem and solving it is the goal of the N-Prize. Just sitting on a 100km tower - as daunting a challenge as that is - is much easier than getting into orbit. Once you are clear with the N-Prize organizers about the concept, they will realize that your device does not meet their criteria.

 

[DaveC426913]

The mssing piece in my understanding is not the defintion of orbit - there are plenty.

The judges of the the N-prize will be crystal clear about what they consider an orbit.

Ask them. Eliminate the confounding details in your propsoal - just tell them you plan to suspend the satellite on a tower 100km up, over a fixed point on Earth.

See what they say.

I will wager one jillion dollars on the answer.

 

[mugaliens]

Yeah, mug where are you getting this from?

http://www.n-prize.com/assets/rules_in_full.pdf" . To wit: "10. Acceptable Methods of Attaining Orbit
Any method of attaining orbit is acceptable, provided it does not breach the rules or spirit of the N-Prize Challenge. Examples might include (but are by no means limited to) conventional rockets; balloon-launched rockets (rockoons); gun-launched projectiles; or combinations of these or other methods. All entrants are strongly advised to contact the organisers at the outset to ensure that their proposal falls within the rules and spirit of the N-Prize Challenge."

Ask them. Eliminate the confounding details in your propsoal - just tell them you plan to suspend the satellite on a tower 100km up, over a fixed point on Earth.

Gutemine reported he's already done that, and that they confirmed his concept meets their rules with respect to their definition of the term "orbit."

ETA: If you find something in the rules which specifically disqualifies his idea, I'm all ears. The rules appear, however, to encourage out of the box thinking.

 

[JaredJames]

So by the logic I'm seeing here, everything is orbiting the planet earth, plants, animals, pebbles, the ocean... (you get the idea).

Anyway, if my understanding of what Gutemine is saying, if you were to build a skyscraper 100km high, he (and apparently the N-Prize judges) would consider anyone on the top floor to be in orbit. And if they were to fly a kite that would be considered a successful satellite launch and orbit (despite still being attached). Am I correct?
Which means they must also consider a person in a 1km skyscraper (or any of the above examples) to be in orbit. The only reason they can't win is because of the "must be above 100km" rule. I think that's a fair assessment of the situation here. This 'space hose' is simply an extension of the Earth in the same way as Mount Everest, in fact, why not just deploy from atop such a mountain so you don't need such a long pipe.

On a more serious note, where would you get 100km of such a hose within the budget? What would you use to pressurise it? I've never heard of any systems that could apply a suitable pressure over 100km, especially not vertically into space.

 

[DaveC426913]

ETA: If you find something in the rules which specifically disqualifies his idea, I'm all ears.

Yes. Their use of the term orbit.


Let me be clear:

1] Orbit means its path is bound by gravity, not by a supporting force such as a tower. Don't take my word for it. There are many ways to word the definiton of an orbit, but none of them involve being supported on top of a tower (and yes, that includes the space tower).

2] N-prize judges are OK with the OP's proposal because the submission itself actually does address the orbit requirement. It poses an idea for "blowing out" the satellite tangentially (though it is only one line, it is enough).

3] However, the OP, in his discussion with us, is changing his goalposts. He now thinks that he doesn't need that tangential velocity to meet the requirements.

4] If he updated his proposal such that it claimed to do nothing more than sit at the top of the tower, I guarantee the N-prize judges will tell him it does not meet the criteria.

 

[JaredJames]

ETA: If you find something in the rules which specifically disqualifies his idea, I'm all ears. The rules appear, however, to encourage out of the box thinking.

11. The Satellite
The satellite must have a mass of between 9.99 and 19.99 grams, including the weight of any propellant or fuel. The organisers reserve the right to weigh the satellite before launch (or to have it weighed by a third party) to ensure compliance. The satellite must be a single object; for example, a cloud of un-connected co-orbiting particles does not count. The satellite may include (for example) shielding or fuel that takes its weight over the 19.99 gram limit, but orbits will not count toward the 9 orbit target until such over-weight items have been jettisoned or consumed. As noted, other items (spent rockets; shielding etc) may enter orbit with the satellite, but must not remain attached to it. Nor may the satellite be dependent upon the co-orbiting items in any way (for example, for relaying communications) during the nine qualifying orbits.

According to the above rule, the satellite must either:
a) not remain attached to the launch hose, which means that on detachment from the space hose the satellite must be traveling fast enough to overcome Earth's gravity and remain in orbit (as pointed out previously), which it would not be.
b) remain connected to the tower (assuming they allow the whole system to be classified as the satellite), which purely based on the rule above, the 'satellite' (if you can call it that) would (massively) weigh over the maximum 19.99 grams (satellite + hose + whatever supplies air pressure to the hose), therefore excluding it from the prize.

That, is how the rules say you can't do this, without the need to debate the definition of orbit.

 

[gutemine]

Sorry for not answering earlier, but I will try to reply on your feedback and valuable inputs (but I have to do this step by step, so again sorry for editing this reply multiply)

First of all I'm aware that all of you are trying to help, and you are definitely not discouraging me. As I already explained from the energy perspective the difference between beeing in orbit and gettign their is so irritating (and to the disadvantage of teh step of getting there - which includes reasonable speed and height) that I thought solving one after the other would be a good engineering approach.

The problem with convential approaches (like simply building a smaller rocket for a smaller payload) don't work too good either - some pieces (like the weight of the tanks for holding pressurized fuel, size of an efficient rocket motor or fuel pump, or even a simple communication device to say 'I'm here, are not easy scalable - so the Idea of the N-prize is also about new and crazy ideas (which maybe would scale back to the real problem).

Let me maybe make another simple example: Instead of trying to build a smallweight powerfull radio transmitter maybe even with a GPS Receiver to log the location why not just using 1m² of aluminium foil. Just becasue Sputnik started the 'I broadcast, so I'm here' business doesn't mean that this is the only way to proof.

1m² of aluminium foil properly expanded could produce enough radar reflection so that it is tracable from Earth - without emmiting anything actively.

NASA can trace far smaller pieces in space and does this on a daily basis. And 1m² of aliminium are easy to get within the budget and weight limit.

But this is just to illustrate that a different solutin doesn't mean to be a bad one, or one against 'the rules'.

The Wright brothers also preffered to solve one problem after the other - first the steering (patented) then the wings (self tested and optimized) then the propellor (self tested) the engine (self built), then the flyer, then the suitable testing/launching place - and then they had a lift off and the entire problem was solved. If they would have been told 'without an engine/propellor your wings will not fly' the problem maybe would have been solved by somebody else.

But back to the problem ...

 

[JaredJames]

Gutemine, I see little point in you replying to anything else regarding your entry into the N-Prize unless you can explain how you will get around rule 11 as I have pointed out above.

Anything?

In the rules it say's you have to prove it completes 9 orbits and that they have to be satisfied with the evidence. The "I broadcast, so I am here" business let's you know exactly what it is you are tracking, a simple radar reflection does not.

Besides, how would you deploy 1m^2 of foil with less than 19.99 grams to work with? A simple transmitter and battery would take far less than any device for constructing a foil sheet.

First you remove orbit by sitting it on a tower and then you plan to use foil to track it, I think you are making far too many assumptions about what is "within the spirit of the n-prize" and what they will accept as orbiting and proof of 9 days worth of orbital existence.

 

[gutemine]

Before you can say strength is not an issue, you need to actually calculate the pressure required inside the hose at the bottom. Of one thing I can guarantee you without doing the calculation: the pressure will not be trivial. It will matter.

I actually calculated the pressure as good as I could (and included this in the slides). I'm fully aware that the calculation is good only for maybe the first few km at the bottowm (and I'm not even sure about this), but because the airpressure goes down dramatically beyond a few km (50% after 5km) these are the critical ones, so using this formula up to the top should OVER estimate the problem, shouldn't it ?

The question is so badly conceived as to be unanswerable. If you supply 1 bar of pressure at the bottom of the hose, no air will flow because that's the static pressure of the column of air. You need to provide greater than 1 bar of pressure to make the air flow.

Sorry for the bad wording, but this is a language problem for me (Englis is not my mother language) If the hose would be vertically - one end 1 bar (standard athmosphere) and the other end of the hose open to a huge vacuum chamber, allowing for a reasonable time of stationary flowing would be probably have been a more precise description.

But if I understand you right the pressure gradient should be similar to a hose at 1 bar all the time and 1 bar surpluss at on end (=2bar) , and open to the 1 bar atmosphere at the other end ?

Without the weight of the hose, you can't calculate the pressure gradient.

This is what the slides do - asuming a minimal size of the hose which would be reaslistically within the N-proze budget (I just googles PE foild prozes and checked what diameter and thickness I could afford)

After getting this weight (300-1000kg for 100km = amazingly low) I checked how fast the flow would need to be to create this weight as friction loss = power on the wall of the hose in the direction of flow.

So you need to select a possible material first, find its weight, then calculate the required friction force to hold it up. Based on what you said in your second post, it sounds like you deceived him. Did you tell him that it was at 100 km altitude and supported by the hose? Because in your second post, you said "being outside of the launch device" which makes it sound like it isn't still supported by the hose.

This is exactly what I did (but I decided on a payable and available material first - as the slides say - I hate to wait for nano-tubes) Paul is fully aware of this - but other teams which plan to combine balloon with rocket launch also decided first to build and test their balloon for reaching the 30km (and not any real orbital speed there either - even on a very windy day) - and he didn't bann them either - why should he, because they also meet the spirit of the N-priize and have the same unrealistic chance to succeed.

And it should be possible to feed air ONLY with the needed kinetic energy to be eaten up by the friction and not a dramatic pressure surpluss too, but the slides also contain the calculation for the 0,6 bar needed if all pressure loss would have to be feeded. And I checked with the tank strength formula that the pulling strenght of dyneema could hold this not really exciting pressure (unless you are a thin PE foild) even at the bottom. But I'm not even sure if this pressure surpluss strength would be needed. That is the great thing about Bernoully that he shows how easily you can convert pressure and flowspeed (only a diamter change away) - and the friction is going up with the v² in case of turbulent flow. You now get ecactly the weakness point in the inflatable space tower approach, and the strength of using the friction force. But the slides also contain a calculation on the wors case (hose closed at the top), then the pressure is only slightly higher even in the worst case of a cyclinder with all the 300km weight on top - simple piston formula what supressure you get - but I' m not sure if this is correct to be overlayed on top of the hydrostatic pressure ?

In the rules, it says the satellite cannot be attached to the launch vehicle. So it is clear to me that just sitting on top of a tower - at any altitude - does not qualify. You're missing the point: just achieving 100km of altitude and sitting on a tower doesn't solve the problem they are trying to solve. Getting into orbit is a big problem and solving it is the goal of the N-Prize. Just sitting on a 100km tower - as daunting a challenge as that is - is much easier than getting into orbit. Once you are clear with the N-Prize organizers about the concept, they will realize that your device does not meet their criteria.

Yes, but if somebody would be able to build a canaon on ground which creates orbital speed on its outlet (but no height at all - the inverse problem of the space hose) he would also qualify if he at least has an idea how to solve the height problem (maybe by pointing it upwards, double the speed and overcome the air resistance by using a big buble gum ball shield conitinuously bringing as isolation for protecting the N-SAT inside -- why not let him participate and have fun trying ? And yes, I'm aware that his N-SAT would be smashed when leaving a normal cannon (unless maybe it would be just rolled alluminium foil and not expensive electronics - sorry for the joke)

 

[gutemine]

Gutemine, I see little point in you replying to anything else regarding your entry into the N-Prize unless you can explain how you will get around rule 11 as I have pointed out above.

Anything?

In the rules it say's you have to prove it completes 9 orbits and that they have to be satisfied with the evidence. The "I broadcast, so I am here" business let's you know exactly what it is you are tracking, a simple radar reflection does not.

Besides, how would you deploy 1m^2 of foil with less than 19.99 grams to work with? A simple transmitter and battery would take far less than any device for constructing a foil sheet.

Sorry, I'm still not finishing answering the old questions and you have already a new one :-)

The aluminium foil N-SAT was just an illustrative example to overcome another problem.

If I would decide not to put the N-SAT on top (see the slides for details - for example because I need to blow it out) I could for example make it go up inside the hose with a balloon or a parachute (remember I have air flowing up to 100km with a pressure of at least 200PA and pretty fast too - meaning a balloon is not only relying on buoyancy) - and the later would maybe already have all the Aluminium foild I need.

Just another example of creative thinking: Cut a circular 1m² piece of Aluminium foil, then cut stripes to the center of let's say 5cm (yes, you will loose a lot of triangualr foil pieces due to the diameter loss). If you then roll the aliminium foil arms by your fingers to the center and would take this device to space - the arms would unroll without any problem or extra energy on relief and if you would release it from your hand with only a minimum spinn it would form a nice christmas star in space.

But you are asking already for the propellor - could we discuss/finish the wings first ?

PS: But don't be discouraged, input and ideas are welcome - I just share mine with you and asked for help - remember the beginnign of the thread?

 

[JaredJames]

Just anotehr example of creative thinking: Cut a circular 1m² piece of Aluminium foil, then cut stripes to the center of let's say 5cm (yes, you will loose a lot of triangualr foil pieces due to the diameter loss). If you then roll the aliminium foil arms by your fingers tpo the center and would take this device to space - the arms would unroll without any problem on relief and if you would release it from your hand with only a minimum spinn it would form a nice christmas star in space.

Can anyone verify this unrolling of the aluminium foil in space? Based on the foil I have, when I roll it up with my fingers it shows no sign unrolling when released, it just holds its shape. Even if I give it a 'nudge'. I don't see why this would be different in space.

I know I sound really discouraging right now, but I prefer to see solid proof any of what you propose is possible.

 

[gutemine]

So by the logic I'm seeing here, everything is orbiting the planet earth, plants, animals, pebbles, the ocean... (you get the idea).

Anyway, if my understanding of what Gutemine is saying, if you were to build a skyscraper 100km high, he (and apparently the N-Prize judges) would consider anyone on the top floor to be in orbit. And if they were to fly a kite that would be considered a successful satellite launch and orbit (despite still being attached). Am I correct?
Which means they must also consider a person in a 1km skyscraper (or any of the above examples) to be in orbit. The only reason they can't win is because of the "must be above 100km" rule. I think that's a fair assessment of the situation here. This 'space hose' is simply an extension of the Earth in the same way as Mount Everest, in fact, why not just deploy from atop such a mountain so you don't need such a long pipe.

On a more serious note, where would you get 100km of such a hose within the budget? What would you use to pressurise it? I've never heard of any systems that could apply a suitable pressure over 100km, especially not vertically into space.

The hose material and its cost are in the slides and also a very basic energy calculation for the blowing power needed - and because the blower would be only supporting the launche device it doesn't could for the budget - only the fuel cost.

But off course such thin PE foil would probably not really work beyond a few km even on a windless day, even if you add a pendular stabilized diffusor o top pulling it upwards by finally blowing the air downwards.

But as a POC within the budget this is not more or less then what others spending thousands of dollars on prototypes or reasearch (also not counting for the budget) before their first test flight would do.

And achieving 1km with such a weird approach (a model air plane motor and propeller could support in this case the 8kg of weight if you use PE foild that you can buy from the next grocery literally speaking) is a similar archivement then a 30km weatcher balloon launch to test the nice N-SAT that you might have built.

And as I already said at the half bakery - if somebody is willing to try it I will bring the beer !

 

[gutemine]

Can anyone verify this unrolling of the aluminium foil in space? Based on the foil I have, when I roll it up with my fingers it shows no sign unrolling when released, it just holds its shape. Even if I give it a 'nudge'. I don't see why this would be different in space.

I know I sound really discouraging right now, but I prefer to see solid proof any of what you propose is possible.

Thanks for trying - you are now subcontracted to find a way to MAKE it unrolling (which should be a solvable task - but not sure about the easiness) :-)

But you now get the idea - Congratulation !

You think/make up a possible solution, check/calc/try it - and maybe have to come up with the next/better one.

Even the space hose is just a creative combination of existing ideas when I tried to figure out their problems and tried to overcome them (and created new ones which I'm pleased to hear from you, and maybe even solve with you together)

PS: That's why I included the parachute or the aluminium balloon in the slides (and not the Chistmas star) - they would work much better (actually the balloon on ground would be very similar to the parachute anyway - because you can hardly fill it to allow for the expansion on top (if it is not an hyper-ellastic weather ballon), but with 3.5m/sec you can already blow a lot upwards if it is only 9,9 gram). And some aluminium foil on the outside of the hose every few 100m would work definitely and form a nice dotted line to space on radar and also reflect the sun compared to the black foil hose - no need for expensive monitoring devices there either.

So sorry for misleading you - it was only for educational purpose (and hopefully you will not charge me for the foil).

 

[JaredJames]

Please can you answer regarding rule 11, with point A I still don't see how you achieve orbital velocity? Point B speaks for itself.

 

[gutemine]

Please can you answer regarding rule 11, with point A I still don't see how you achieve orbital velocity? Point B speaks for itself.

Now you are getting to an interesting point - remember I asked for advice and did some calculation already :-)

What really amazed me was when I did the ideal gas formula between top and bottom - due to the huge pressure difference (approximatel 1:1000) the expansion would be also HUGE (but less then the 1:1000 due to the temperature drop)

If the hose diameter would be fixed the speed of the air in the hose without any diffusion or diameter change would be already pretty close to orbital speed (aprox 5400m/s in my assumed example, and orbital speed is about 7400m/s if I remember right - it is late already, and the excact number is in the slides).

I know that this is by far hypersonic even at the low 100Pa pressure in 100km height. So you have 2 ways - try to find out if such a hose can withstand that (I think in the slides I asked 2x if this hose would work like a kind of upright standing de La Valle nozzle with fixed diameter by using not the diameter change to accelerate but the decreasing hydrostaic pressure of the medium)

And don't say instantly no - we still can do the Dnymeema strengthening as on the bottom, and still outside pressure and inside pressure should not differer that much on a hose (0 without friction I think - but not sure about this). So maybe you already have air at orbital speed in the hose without knowing ?

Actually this would be pretty logic in my understanding - because of the expansion into vacuum after leaving the hose this air is more likely to mix with the sorrounding air at very low but similar pressure, instead of dropping like a stone because of the not orbital velocity argument (Paul was pretty clever by stating some loose particles in orbit don't qualify).

But even if you keep the speed down in the hose by increasing/decreasing hose diameter (depending if flow is above or below sound speed) or by a diffusor recovering some of the flow energy and pressure loss you still have 620m³/hour going to 100km height and you could convert this to amazing speed as the ideal gas law would suggest (that's how the de Laval nozzle blowout made it into the slides - because it can work also as a diffusor to recover some pressure).

This means we should first check the math for the gasflow (then for the friction) and if we know which calculation is right (pressure drop due to friction is pressure surpluss, or only speed surpluss because of hose not pipe) hypersonic or not.
Just do some simple math with fixed temperature - if you start with 3,5m/sec flowspeed if you had isothermic flow after dropping the pressure approximately 1:100 you would be beyond the 340m/sec of the speed of sound - actually this 1000Pa is present approximately at the height of 45-50km - If I remeber right my physics lesson this is one of the reason why there the temperature recovers to almost 0 degree of celsius (so it is actually almost isothermic - but not on the way in between) after having dropped to -60 degree of celsius between 10.20km. And don't be too afraid of the sound barrier - remember we are expaindig here very slow over multiple km - this is as smooth as a turbulent flow probably can get.

So half of the hose could be flowing below and half above the speed of sound (up to orbital speed) ? Not very likely - but input/critics is welcome ?

Finally you would still have all the remaining classical options like rocket start from top too if you feel more comfortable with that - remember you 'only' need to add 30,5MJ of kinetic energy for 1kg, which means peanuts for the 9,9 gram - and yes, I know that it is not that easy, that's why I would prefere to use what we already have (see previous paragraph)

And I already pointed out, even standing on the top of such a structure and still not leaving it on the 99th testflight would be quite an achievment and would give an ant or a cockroach astronaute wings at the NASA :-)
gutemine

 

[JaredJames]

30.5 MJ - that's 30.5 Mega Joules

Are you sure, that's a huge amount of energy?

EDIT:

even standing on the top of such a structure and still not leaving it on the 99th testflight would be quite an achievment and would give an ant or a cockroach astronaute wings at the NASA
gutemine

Why would standing on top of a 100km structure cause you to leave it? You wouldn't be traveling at orbital velocity to overcome Earth's gravity. The only time you would 'take off' from a structure would be when you are past the 36,000km mark. Or am I misreading it?

 

[gutemine]

32MJ is amazingly small - it is the burning energy of 730g of jet fuel and is the quivalent of 1km in orbit (pure cinetic and height energy needed)

I didn't say that standing there would make you leave - but I actually would enjoy the view (and the lack of sickness due to freefall). I just came back to the point of climbing that height is also nothing you should not feel proud of.

Could somebody please comment on the cas dynamics and speed question, because the real answer on getting (or having already) the needed orbital speed lies there in my opinion.

PS: If you use flowing air as 'fuel' to get there containing all the needed energy it would be idiotic to use something else for the final step to orbit anyway.
Just think about your gardening hose - inside the hose the water flows pretty slow, but after it goes trough the nozzle you can entertain the neighbour with it :-)

but I have to get some rest know - n8

 

[mugaliens]

So by the logic I'm seeing here, everything is orbiting the planet earth, plants, animals, pebbles, the ocean... (you get the idea).

No, as there remains the 99.9 km height ruling.

Anyway, if my understanding of what Gutemine is saying, if you were to build a skyscraper 100km high, he (and apparently the N-Prize judges) would consider anyone on the top floor to be in orbit. And if they were to fly a kite that would be considered a successful satellite launch and orbit (despite still being attached). Am I correct?

That's what I read in the rules.

On a more serious note, where would you get 100km of such a hose within the budget?

It's pretty inexpensive stuff, about $6 for 100 m, which means 100 km of it would cost $6,000.

What would you use to pressurise it?

A fan.

I've never heard of any systems that could apply a suitable pressure over 100km, especially not vertically into space.

Ok, then - the bleed air from a turbofan engine.

My primary concern is how does one get the column to rise? I would imagine it could be laid out on a straight, 100 km stretch of road somewhere, but once it's pressurized, it will not magically rise into the air, nor would an articulated exhaust "lift" nozzle at the end be able to lift it's entire length. In fact, you'd need many such computer-controlled and articulating nozzles along its length, which would require a tapering design to manage the airflow properly.

There are some huge challanges with this approach, no doubt.

 

[DaveC426913]

That's what I read in the rules.

How could you continually misread it? The word 'orbit' is used numerous times.

 

[JaredJames]

Ok, I was going for sarcasm with the first two paragraphs about "the ocean being in orbit".

I understand the whole orbit situation, I was simply asking for clarification on what gutemines understanding of the rules where by using those examples.

Regarding the 99.9km rule, I did mention that later on to say why someone couldn't win it by standing on the ground.

I'm still waiting for an explanation of how he would pass rule 11. Again, scenario a) requires the satellite to be at orbital velocity, I don't see how he will achieve this. Scenario b) is clearly breaches the rules.

$6000 is not cheap when the budget is supposed to be under £999.99 (about $1500).

 

[mugaliens]

Yes. Their use of the term orbit.

No, that's your definition, Dave. That's not what's specified in the rules.

If he updated his proposal such that it claimed to do nothing more than sit at the top of the tower, I guarantee...

Unless you're one of the N-prize judges, you can make no such guarantee.

http://www.n-prize.com/assets/rules_in_full.pdf" . It's up to them, not you.

"These rules may be amended at any time without prior notice. Such amendments will normally (but not necessarily) be made in order to clarify points, to close loopholes in order to ensure that all entrants remain within the spirit of the N-Prize, or for unavoidable legal reasons. Therefore, all entrants are strongly advised to contact the organisers before and during the preparation of their entry."

Gutemine did so. They (the N-prize judges) confirmed his design meets the rules. You're trying to second-guess their decision, which has already been made, according to gutamine.

If you don't like their ruling for some reason, talk to them.

I'm still waiting for an explanation of how he would pass rule 11. Again, scenario a) requires the satellite to be at orbital velocity...

Actually, this is a misnomer. All the rules state is "but orbits will not count toward the 9 orbit target until such over-weight items have been jettisoned or consumed. As noted, other items (spent rockets; shielding etc) may enter orbit with the satellite, but must not remain attached to it."

Therefore, he could meet the rules with a 15 gram ball balancing on the column of expended air, like a ball balancing in the breeze of an upturned fan.

Let's get back to the spirit of the N-Prize itself, something many here keep forgetting: "it is possible that loopholes in these rules may make it possible to complete the challenge in a spirit not intended by the N-Prize organisers." However, what is that "spirit?" Is it to think inside the box like we always have? Or is it to put a small object 100 km or higher and keep it there for 9 days?

Let's go back to the rules: "The N-Prize is aimed at amateurs, enthusiasts, would-be boffins and foolhardy optimists." and "Any method of attaining orbit is acceptable, provided it does not breach the rules or spirit of the N-Prize Challenge. Examples might include (but are by no means limited to) conventional rockets; balloon-launched rockets (rockoons); gun-launched projectiles; or combinations of these or other methods."

The organizers have already stated that a 100 km geostationary orbit meets both the spirit and the rules of the N-Prize. It's a matter of altitude and duration, not orbital velocity.

$6000 is not cheap when the budget is supposed to be under £999.99 (about $1500).

You are absolutely correct! I think one might be able to find it for less. How much less I haven't a clue, but possibly a lot less, as the small amount I found is retail quantity, and I have no idea what the diameter was. I just did a couple of quick searches.

 

[DaveC426913]

No, as there remains the 99.9 km height ruling.

Let's just be clear; that is a separate criteria, independent of achieving orbit.

Achieving orbit can be done without achieving 100km altitude.
Achieving 100km altitude can be achieved without acheivng orbit.
The N-prize requires both.

That being said, this chair and the oceans are not in orbit by any criteria, let alone the rules of the N-prize.

Like the chair and coean, the satellite on top of the tower is also not in orbit.