Sunday, June 17, 2012

Physics of psychology

Every once in a while I let water out from the well to soak the grounds. This is a traditional process known in physics as 'Evaporative Cooling'. The heat in the soil is taken up by the water to evaporate, and leaves the soil itself cooler than before. It is necessary to avoid an excess of water here - hence usually requires half-an-eye as frequently as possible.

So I had half an eye my attention was drawn to motes being carried along by the current. Every time the water flowed through a dip the mote 'fell' into the depression and swirled in the eddy for a while before eventually finding their way.

I'm tempted to compare what I observed here with the way most of us humans appear to 'think'. Our thoughts usually tread a defined path - one constructed by our social environment, education, and the circumstances we find ourselves in. Now and then we encounter a scenario alien to us - one where we are out of our depth (pardon the pun), one that demands we draw upon all our previous experience for comprehension ... just like the mote encountering an eddy in it's path that it must travel before moving on.

The rules of physics govern not only our physical perception of the world, but also how we comprehend the world around us.

Monday, June 11, 2012

Are there such things as high-altitude air-currents the way there are sea/ocean currents? Does the meteorology department maintain such a map? What is the average velocity of such an air-current? What is the depth of such a high altitude air-current?

Let's assume for a moment the answers to the questions raised above are favourable. Laugh a moment if you will at my naivete, it may be possible to use balloons (See? I told you to laugh at my naivete already) to lift such an airship working with the currents. The questions to answer here are

  • How would one control altitude and attitude here?

  • How much payload could such balloons take?

  • How close to GEO can this idea take us?

Venting the gas to atmosphere would be wasteful. Perhaps the volume of gas to be vented could be collected in a container. Any discardables (such as soiled clothes/uniform/consumables) would then be used as ballast to to return the excess volume to the surface. A low-power beacon could be used to home in on the returned balloon to reuse the gas for the next trip.
An alternative would be carry on board apparatus to filter/extract lift gas (hydrogen/helium) ; but would the volumes be feasible here? The alternative would be to carry apparatus to condense (such as water) fluid into empty containers.

Both mechanisms above restrict us to the limits of atmosphere. The perishability of the container used also comes into play because temperatures may vary from 1500C to -100C.

Using a balloon, How does one rise higher once outside Earth's atmosphere? One mechanism is to vent the contents within the balloon to provide thrust in the desired direction ... hmm. I'm not satisfied with this - will have to think more.

Saturday, June 09, 2012

One giant step ... done using baby-steps.

Since the Mars One programme appeared in the news a couple of days ago, I find myself letting my thoughts freewheel. The idea of dispatching a team to live permanently on the Red Planet and earn their living from the people who choose to watch them live on the media here on the Third Planet seems extremely unusual to me. For instance, what happens when more people want to watch the team in delayed video rather than live? How long before the audience are sated?

Somehow the concept of providing serviceables from Earth on a regular schedule (every two years) too makes one pause for thought. Not that it's unachievable - the Apollo teams were on the moon for 2-3 Earth Days at a time. Two years is just a few orders of magnitude larger. But I digress - I wanted to make this post about launching off-earth, instead of off Earth's surface. Because it is easy to talk and throw ideas around instead of learn from experience, throw ideas around is what I'm going to do.

When we talk of space flight we begin with escape velocity. Escape Velocity is the velocity necessary to escape the gravitation pull of a body to it's surface. Here this is atleast the velocity necessary to escape from Earth's gravitational pull. This value is calculated using the formula

Here, v = escape velocity
g = gravitational acceleration
r = radius of Earth

Solved using the MKS system, this value is 11200 metres per second.

That is, 11.2km/second. It doesn't seem much, until one thinks about it. Just to give an idea of the scale involved the longest public runway on Earth at present is 5.5kilometres. Therefore to be able to escape from Earth's gravitational pull, one would have run up-and-down the runway in less than 1 second! Even the famed SR-71, the fastest aircraft on record with a velocity of approximately 3.6 Mach (4410km/hr), can't do that! Hence the need for rocket technology.

The tricky thing here is that escape velocity is not necessary! Once up at the geostationary earth orbit (GEO), it is quite possible to change the shape of the orbit. The Apollo moon programme called this technique 'Trans Lunar Injection' (TLI). The trouble is getting up to GEO altitude 35786 km ! Well now, most programmes try to reach that altitude in hurry - but I say, 'Wait'.

Why not up to 35786 km in stages?

Let the first stage be high altitude aircraft - carrying food, provisions, and capable of independent movement ... say capable of moving upto 100km above Earth. But this still leaves us with 35686 km to travel. Traditional aircraft encounter loss of lift at such high altitudes. But materials - carbon nanotubes, and such that are extremely strong, and lightweight. Perhaps a lift surface constructed of such material may be used to marry several engines to lift upwards? I'll post more later when the idea is a little more mature in me mind. What say you?

Thursday, June 07, 2012

The Warlord of Barsoom beckons

All our eggs lie in a single basket. No matter how distant they may be placed - they're still on Earth, still subject to the caprices of Nature. We, Humans, have only inhabited Earth for a few million years at most. Compared to the Earth's age of nearly 4 billion years, the miniscule duration for which we have been around makes us fragile humans vulnerable as a species.

We need to spread out a bit - except that particular option is limited by prohibitive costs, and imagination, and a touch of laziness. Going by popular science fiction of the heady years when the 'move to space' ruled people's imagination - by 2001 there should have been a permanent colony on the moon. 2001 - 11 years ago! Of course, Science fiction being fiction the timeline may be a little behind the times. George Orwell's classic '1984' technology of high end communications networks only began to become available globally in the early 2000s. By this yardstick we are still on track - except that the global financial crisis, and the restive behaviour of various peoples makes it very unlikely to establish a base on the moon in the next decade.

In all this though, we have forgotten a bit of history. The last age of exploration - although initiated by the Imperials, was consummated only by private enterprise. Perhaps the Moon, and Mars too shall follow the same model. The age of sea exploration was undertaken first by various Princely States even before the Industrial Revolution. As soon as new lands, and markets were discovered they were followed by private enterprise.

Perhaps private enterprise, and individuals should consider investing in resources off Terra. Escaping gravity is prohibitively expensive, ergo - it is necessary for private enterprise to justify the expenditure on their balance sheets here on Earth. The Mars One project may, or may not succeed. Regardless, it will kindle imaginations for a while. It's already giving me ideas... ideas to marry with various science fiction 'concepts'.