Space? No: Stratosphere!

Reading articles about space tourism, there are a couple of terms that are thrown around – more as marketing slogans than for anything else. "Near space", "upper atmosphere" and "high altitude", just to name a few. But what do they usually mean? I would like to attempt to put them into perspective, so that we can see them for what they really are.

First of all, space (meaning "outer space"):

Where space begins is a matter of definition. The usual definition is everything not within the earth’s atmosphere. Of course we could get particular and exclude the surface and atmospheres of other planets, but from our perspective from "down here", we usually just throw the other planets and celestial objects into the grab bag of "space". This will probably start changing once it’s normal for people to be flying around up there and once leaving space for them means to stop off on any old planet/settlement, not only earth.

At any rate, leaving the earth’s surface might be the start to a journey into space, but the journey is only completed once the earth’s atmosphere is left. This means that we first of all need to define the term "atmosphere". Generally speaking, this is "where there’s air". The only problem is that this is quite a gradual condition, so that we have to then define how much air we’re talking about.

For practical purposes, a consensus in the scientific community has been built at around the 100-kilometer mark. Or, English, 60 miles. But since scientists don’t use miles, we’ll keep to the metric system. The only problem is that this "break" is in a part of the atmosphere called the ionosphere. There is an ionic atmosphere (atoms and electrons stripped of their connection) both above and below this point, it just decreases as one moves farther and farther away from earth’s surface. A satellite orbiting at 110km will fall from that position within days, simply because there is too much friction, too much air floating around. Even at 300km, for instance, a satellite will gradually experience too much drag to stay up there forever.

Meaning, most space junk will take care of itself within years, perhaps decades – simply because there’s "stray" atmosphere up there!

Of course, you have to draw the line somewhere, so I really have no problem with the 100-kilometer mark.

Now – back to the marketing. If you look up high-altitude flight, you’ll sooner or later realize that they’re talking about anything which flies above international airliners, meaning above 12,000 meters. High-altitude flight, however, doesn’t even reach up to 20,000m, or only a fifth of the way up in the official atmosphere and only a bit more than twice as high up as Mt. Everest. I mean, I agree that this is not exactly "low altitude", but do you really want to call it high? It’s true that we don’t have jet engines that can fly in the thin air up there. NASA is, of course, working on Ram- and Scram-Jets to compress the air a bunch before it’s used for ignition.

Then, of course, there’s near space. This usually means reaching levels even higher than "high-altitude" – anything between 20km to 100km, or 4/5ths of the height of the official atmosphere!

Now I’m not going to say that there isn’t a reason for this. For someone hovering around in "near space", it’s hardly any different from outer space. The view is similar and one certainly needs a space suit to stay alive. Gravity, on the other hand, is like being on the earth’s surface – for only when one is in orbit is there weightlessness. Just to demonstrate the similarity of the stratosphere and of space, here is a picture:

 

So, which is it? Space, or the stratosphere? The only give away is that (at least in this non-panorama view) there is no curvature on the horizon. This picture was, as far as I know, below 30,000 meters altitude, or around three times as high as Mt. Everest. I would not mind looking out of my capsule window at this view and at the stars (which you can’t see in this picture), that you can see even in the middle of the day.

Now, how about the real thing:

 

 

There you go. Recognize the curvature? The same clouds, but less atmosphere on the horizon? I'll admit that the resolution is much higher for the second picture.. But if you didn’t put the two pictures side by side, you could think of both of these as space, right? In this picture you can’t see the stars either, even though this is the view that one would have from the orbit of the Hubble Telescope – meaning that here there is absolutely nothing between you and the stars.

And there’s another difference. When looking down from the vantage in the first picture, the ground doesn’t change – meaning you’re not moving. Of course there’s day and night, cloudy and clear weather, but the landmarks remain the same. In the second picture, you can see the same spot on the ground every hour and a half. In the first picture there is absolutely no motion while in the second one, the surface of the earth speeds by at 36,000km/h!

Now, if you really want to go to near-space, you would at least have to go above the ozone layer, at about 33 kilometers, where ultra-violet light is filtered out. You would be, however, still "only" in the middle of the stratosphere. A purist, on the other hand, would have to go up twice that high, into the middle of the mesosphere – or, "middle sphere" - meaning, the sphere between earth and space. Well, actually, between atmosphere and exosphere, that awful thing that puts drag on our orbitting satellites.

At the top of the mesosphere (or even in the middle of it), for all intents and purposes, you really are at the "edge of space", but only if you don’t listen to the marketing. For them, the edge is in the lower stratosphere, at least 50km lower.

Now, I know this might be a bit tedious, but it does help sometimes to differentiate!

The Next Layer of Air

Walking up to the top of Mt. Everest, one would find that the air is not only thin, but that it's technically too thin for most humans to breathe in. Good that it's not another 500 meters higher, otherwise it would really not be possible without oxygen.

At the same time, air pressure there is three times as high as on the Martian surface, meaning that it's still relatively thick for a rocky planet.

Twice as high as Mt. Everest, however, is where the real fun begins. For that's about where what we know as the troposphere ends. Above it, there is no life, no weather (wind, snow or rain), no moisture, no clouds - only very cold, very thin air. Welcome to the stratosphere.

If you book a "near space" flight, this is where it will take you.

But if you think that this no longer constitutes an atmosphere, then you are highly mistaken. Compared to space, this is even a "thick" atmosphere - of course all such matters being relative. While the Stratosphere reaches from about 18km (at the equator) to 50km, this is not even the layer of air in which space dust/particles burn up as what we know as "falling stars". That's the next layer, the Mesosphere (meaning "middle orb"), where everything from outer space either burns up because of the friction the air here causes or is slowed down enough that it can usually make it to the earth's surface as a meteor. This is where the space shuttle blew apart on re-entry.

No, the Stratosphere is so thick that it even stops light from reaching earth's surface. Well, not much light, but enough to make it safe for us to run around outside. Right in the middle of the Stratosphere is the ozone layer, which stops a good bit of the high-powered ultraviolet light from the sun, turning it into low-powered infrared light - what we usually just call heat. Or at least warmth.

And surprise! At the top of the Stratosphere, it's warmer than on top of Mt. Everest!

And warmer than many a cold winter's day here in the temperate zones on the surface. But don't worry, water would not freeze or even turn to liquid up there because the air is quite thin (again, relatively speaking in relationship to the earth's surface), and because there's no water in the air anyway.

So what we find is really a world between worlds - absolutely nothing going on. The first satellites (and space junk) are flying by at about 100 Kilometers higher, at 10km/s by the way. Ten Kilometers per Second! 36,000 Kilometers per Hour! But if those satellites have to stay at that low orbit for very long, they will slow down quickly, because of atmospheric drag, and soon fall back out of orbit, burning up / breaking apart in the Mesosphere before traversing through the Strato- and Troposphere on their way to the surface.

If we put a floating object in the atmosphere, it would not move. Relative to the earth's surface it would stay in one spot, except for gradual drift resulting from the fact that the earth rotates. Other than that, the object would not even need to be tethered to the earth's surface. That means that an object put above Timbuktu would stay above Timbuktu, needing only occasional adjustments because the earth spins.

Nothing moving, nothing around, no space junk, acceptable temperatures, thin air. The latter point can be solved only with a space suit or a pressurized capsule. Is it any wonder that I think the stratosphere should be our first goal, long before we try populating space?

Stratosphere First!

I haven't posted for a while, probably because I've been concentrating on too many things at once. Connecting now to a number of posts I did almost a year ago, I think I've gotten "stuck" on a subject that I will be on for a good a while. The pieces have now come together and I've caught a grand vision..

Stratosphere First

On our way into space we forgot one incredibly important stop: Our own atmosphere.

Our atmosphere is viewed as something to get through on the way to somewhere else. We fly through it when we go continent hopping, for instance. And although it protects us from much of space's junk in the form of meteors, we only want to get through it on our way to low-earth orbit (above ca. 150km). We see the atmosphere more as the drag that it is for these satellites than as a resource for human settlement - except, of course, in the form of cartoons like the Jetsons.

Now, there are many places on and around the earth that could be colonized - the oceans, under the ocean, high mountains, underground, deep underground, Antarctica, low-earth orbit etc.. There is one "area", however, which should be the focus of all earth and space lovers: The Stratosphere.

For a Space Lover, the Stratosphere is like a different planet - one that you would love to land on but have no suitable surface to do so. What to do? Either stay in orbit and make no direct contact with the planet or drop down into the atmosphere and set up shop. There is usable air, although it is even less than on the Martian surface, but it can be compressed, filtered and be used. Admittedly, there's almost no water that can be used. But otherwise, in the case of the earth's stratosphere, the air doesn't even need to be filtered! Except for extracting the ozone in the ozone layer.

Of course you need a space suit from the lack of air pressure, if you want to go for a "walk". Only, since you're not in orbit, you better be tied on well - or have a good parachute - just in case you slip over the side. Gravity is about the same up there as it is on the surface of the earth.

Besides, isn't it a thousand times cheaper being only 20-50km away from your supplies than thousands to billions of kilometers? Getting to and fro might be a challenge (being above where normal airplanes fly), but it's nothing like trying to supply the ISS. And underneath the ozone layer (ca. 31-34km), at least, one is protected from much of the ultraviolet radiation that the sun is throwing at us permanently.

The view is great: The sky is black so that you can go stargazing even during the day. 99% of the atmosphere is below you, so there's hardly any air to reflect all the sun's light racing by to the earth's surface. When looking down, one sees the earth as a foreign object. It covers half your view - but what curves!

For the Earth Lover: Yes, this is part of the Blue Planet. Everything that's blue (and white, if it's a cloudy day) is below you. Sunlight is a bit stronger here and there are no clouds to get in the way of your solar panels. And, since there is absolutely no wind, while the air (what little there is) is dry as a bone, thin solar can become a hard reality. There is absolutely no weather to disturb solar collection. Here you can build your house of cards as if you were inside and not have to worry about the slightest wisp of wind to knock it over. This means that after a surface has been built to lay them on, the panels, which can be built as thin as aluminum foil on a stiff sheet of plastic, only need to be laid out. They could look like stiff, blackish cold-cut packaging lying around and don't even need to be tied down!
And why not just use all that excess energy to make a bit of ozone to help out the earth rebuild what aerosols took away? This could certainly be a goal especially for the (southern) Australian inhabitants.

Here you likewise have the unique opportunity to combat global warming. Just by your very presence you would be blocking some of the sunlight which is about ready to hit the greenhouse below. Stretching out a thin, dark film (collecting energy?) would catch the sunlight pounding on the earth below. My prediction is that the global warming war will be won or lost in the stratosphere.

Besides, there's an enormous amount of research which needs to be done there: Hubble-like telescopes (meaning they are hardly disturbed by the atmosphere), weather observation, other earth observation, experiments with high altitude flight, etc..

Do you think we'll be able to keep the military away from this?

So whether you are a dreamer or a practical person, the stratosphere has something to offer everyone. It will change the way we think about "getting off the ground", building an important intermediate step before trying to colonize the solar system.

As one can see, I'm convinced. Now, who is going to join up to boldly go where no man has lived before?