Island in the sky - helium launch platform

[Fullhawking]

Overall, an interesting concept, but it will be quite a long, looong time before anything like this is seen. More practical would be a space elevator taking whatnot out off our planet. However, that is still not going to happen for many maaany years, but still more likely then the isle in the sky.

 

[johnfullerroot]

What about using a combination of the space lift and the platform? Have the platform at say 20km and then a lift in orbit? How feasible is this? I am sure there is something I haven’t considered?

The lift would have less distance to extend. We would be saving more than 20km of cable. Also, if the platform was filled with helium then in theory it should be able to float at 30km +.

Also what is gravity like at that height? Surely at 30km the earth’s gravitational pull is largely reduced. The extremely thin atmosphere at that altitude would also help reduce friction for rockets. Also re-entry is not always necessary. When it is necessary then a shuttle should be used that returns to Earth and not to the platform. Also a platform like that would probably prove useful for a large variety of experiments within many different scientific fields. Also many people would pay money to experience a few days on the platform.

From my perspective a platform would be a step closer to space. I think this topic should be fully evaluated and refined.

 

[russ_watters]

What about using a combination of the space lift and the platform? Have the platform at say 20km and then a lift in orbit? How feasible is this? I am sure there is something I haven’t considered?

Keeping it stationary would be a problem.

The lift would have less distance to extend. We would be saving more than 20km of cable. Also, if the platform was filled with helium then in theory it should be able to float at 30km +.

Since the space elevator would need to be something like 30,000 km long, 30km isn't significant.

Also what is gravity like at that height? Surely at 30km the earth’s gravitational pull is largely reduced.

Since the Earth's radius is 6300 km, 30km isn't much of a difference.

The extremely thin atmosphere at that altitude would also help reduce friction for rockets.

The space shuttle climbs through most of the atmosphere in a minute and is going a small fraction of the speed it needs to reach orbit. Launching from altitude may cut a couple of percent form that.

 

[jonnytooze]

Hi all,

This is my first post on this forum.

I've been thinking about this idea for a while so decided to do some searching online and found this thread. I think the concept I came up with is very similar, although my ideas are maybe not so grand as space adventure.

My thinking was of having a landing strip on the platform so high altitude aircraft could hop from platform to platform around 8-10km from ground level, therefore being able to raise maybe a thousand feet extra and jump up into the jet streams without expanding much energy at all, and utilising them better.

Obviously, the cost to create these platforms would be huge but with oil running out (and I know its probably not as been as people think...), aircraft fuel will only get more expensive, and will eventually run out all together. I think when oil supply really is an issue, then people will demand it for localised public transport rather than options to get a sun tan.

Either way, anything to do with aviation is expensive, the new terminal at Heathrow cost £4.3 billion which is a fair old whack. At a guess, 10 times that amount a platform could be created, to at least support a single small runway / control tower although maybe not in a converntional sense? I mean the runway itself has less width than a Zeplin, and also the aircraft used to operate a 'hopping' service could be smaller as they would only need to hop from platform to platform therefore carry much less fuel.

The runways at Heathrow are fairly long (like 4km) but, if they were hanging in the sky, why would they need to be so long? Surely the planes could just get up speed by dropping off the platform, or steam launch, or a slight downwards slope to the platform? And stopping quickly could be easily achieved by cables, or an slight upwards slope to the platform? So could the length be 1km? The planes could be smaller too... Maybe just takes the beds out the front! And they would be in constant operation apart from maintenance that could be carried out on the ground, or minor work on the platforms themselves.

That's a runway just 4 times as long as the Hindenburg and three times as wide (you'll need room on there for planes to wait, and emergency/management/passenger facilties.

So;

- We know that large airships work
- We know that they have generally solved the wind issue
- We know that they generally get more efficient the larger they are (this is an assumption so shout me down)
- It would be fairly easy to land on as the platform could just rotate head to wind.


But;

- How much helium would be required to support maybe two planes, 1000 people, steel cables connecting it to the ground, various buildings and vehicles, and it's super structure, at a guess of 5000 - 10000 tonnes (depending on the type of aircraft and construction). At a guess, it would need to be around 300,000,000 cubic feet? But not all within the superstructure, the cables could be self supporting with mini-airships attached at points up the cables providing additional lift.

- How would it stay in one place when planes are landing? Battery powered thrusters, (solar/wind charged)?

- How would people get to the platform? Helium lift sounds like the best idea, maybe 200 people at a time (a plane load)?

My thinking around the future would be that the platforms would evolve over time, growing larger, more efficient, and possibly supporting high platforms connected to a lower platform. Maybe that would help lead into options of a space platform?

Apologies for the absolutely garbled brain storm with no spelling or sanity checks and probably highly inaccurate assumptions. Still, I look forward to hearing any comments.

Many thanks,
Jonny