Saturday, November 20, 2010

Terraforming – a future for our system Part 1



A starting description



Terraforming, it is a mix of Latin meaning ‘Earth-formed’, well, how do you form another Earth, we are on the one and only after all. Earth may be our mother, but, it cannot handle its growing children for much longer – that means we must spread out into space. Our solar system contains 3 other planets, none of which are habitable due to their position in the solar system, their atmospheres and their own core structures. There are also many other moons and asteroids that we can exploit for our expansion and survival. But, how do we get to our destination, where do we settle and how do we go about the business or Terraforming, well, I’ll have some fun explaining that. This should give both you and me tons of ideas, or possibly, a voyage through the solar system.

A short history of Terraforming



In 1961, the genius we all know, Carl Sagan, published an article in the Science journal about “The Planet Venus”. It described the process of seeding Venus’s atmosphere with algae and converting the CO2, water and nitrogen into organic compounds. As the Carbon was reduced the greenhouse effect would be lessened, leading to a comfortable climate. The carbon would then be incinerated by the high surface temperatures of Venus. If only Carl Sagan was right, for the clouds of Venus are rich in Sulphuric Acid. Even if the Algae could survive in such a hostile atmosphere, the atmosphere is extremely thick, resulting in pure oxygen molecules – causing the surface to be covered in a fine graphite powder. This combination could not last forever, alas; the organic carbon would eventually combust and be released once more as CO2. But his dream was not yet over…



Sagan also visualized making Mars (We’ll get to that later) habitable for Human and sentient life in “Planetary Engineering on Mars” for the journal Icarus. Three years later, NASA delved into this field, addressing the issue of planetary engineering officially in a study, but somehow, they used the term ‘Planetary Ecosynthesis’ instead, meaning the conversion from a low oxygen and high CO2 atmosphere to one rich in Oxygen. The study concluded that Mars is habitable, or at least more habitable than the other choices. Due to the water trapped inside, it’s 24 hour day rotation and ‘an’ atmosphere it is possible to make Mars a habitable planet… I haven’t told you about any of the problems that must be challenged – but we are Human, it is our nature to use our imagination, to always strive to find a solution to our problems.

*Sigh vv* if only we had Carl Sagan around today.

Transportation from the Earth to the Solar System


Obviously we have nothing at the moment that can transport us across the vast distance of space faster than light, apart from a few theories of Alcubierre drives, curled up dimensions and quantum wave forms. We do however; have technology under way that could transport us to locations in our Solar System, but obviously not the Orion Spur.

Propulsion

In a century we have flied in the skies, then 20 years later thanks to British ingenuity, the jet prototype was created, allowing us to travel faster than that of sound. 1969, July the 20th proved that humans had the ability to create spacecraft that could venture out into space with the landing of Apollo 11 on the moon.
All current spacecraft today use rocket propelled systems, but there are a few in progress that do not rely on this burden of bipropellant or solid fuel. 


I shall explain some of the more traditional monorockets, to the most thrillingly complicated Ion trusters.

Many rocket engines require the combustion of fossil fuels at an enormous rate x by the length of the journey. When the solid, chemical or bio fuel is combusted it bursts out of the thrusters as hot gas. This gas is allowed to squeeze its way through a high expansion ratio nozzle, of which is why today’s thrusters are bell shaped. We all know that gases will seeks any way out of a compressed space to the wide upon space due to the Earth’s rotation, and when it combusts this effect is multiplied. Equal and opposite reactions occur, forcing the rocket forward… but, what if the gas has to fight to get its way out of the nozzle – the acceleration of the mass is increased, converting the furnace thermal heat into kinetic energy that will hurtle the mass over the void of space. Exhaust speed can reach 10 times the speed of sound at sea level. As I mentioned earlier, rocket engines require massive volumes of fuel – this is the downside of the rocket, as this requires the highest amount of power.., and finances from the government and whatever company or research dev that is launching it.

But wait… here comes the holy grail of every propulsion scientist, of every Homeworld fan – Electromagnetic Propulsion or also known as ‘Ion Thrusters’, one of which I shall passionately explain in its full wonder and detail.


Ion thrusters rely upon a type of electric propulsion used for spacecraft propulsion, the thrust is created through the acceleration of ions. The electrostatic field propels the ions, this is known as the Coulomb Law, and this accelerates the ions in the direction of the magnetic field. Similarly, the Lorentz force is used on the ‘electromagnetic’ Ion Thruster – note that the term ‘Ion Thruster’ denotes the electrostatic or grided Ion Thrusters only.


Compared the hungry needs of the solid/bio/chemical fuelled rockets, the Ion Thruster only needs to absorb up to 200 KW and it can travel 5000 mN – specifically, the VASIMR, using Argon propellant.

The energy needs are however relatively high, relying on Xenon, Argon, Liquid Caesium, Hydrogen, Nuclear Fission… and possibly in the future the arch of cold fusion – the power of the sun. The first mission to use the simpler evolution was SETR, used by NASA Lewis. SETR-1 was successfully launched in July 20th 1964, it proved its worth as the technology operated as predicted in space. The electrostatic propulsion used mercury and caesium as a reaction mass. SERT-II was launched 1970 February 3rd, using 2 mercury ion engines for thousands of running hours.


Also to be appraised, the Indian Space Research Organization launched the GSAT-4 satellite in April 10 2010, utilizing the GSLV mk II rocket – despite some flaws, it is expected to bring the life expectancy of satellites from 10 year to 15.


With this faster and more efficient Ion Thruster technology, colonization of the moon and even the wonders of Mars may become possible in the next 30 or so years. All that needs to change is the political situation (expect a long haul) and a fore cheapening of space projects and technology.


Cold Fusion power



Despite the large amounts of power acquired by Nuclear Fission, it does have many set backs. One of them is the massive amounts water that are used, and the mega tons of Nuclear radiation. Then of coarse you can look at the Cold War – and as a result the disaster at Chernobyl.

Fusion, or another branch known as Cold Fusion, is the fusion of nuclear atoms at room temperature, meaning that you won’t get fried while you’re in the room – in contrast to normal fusion that creates massive miles of heat, just like that of our sun. Interest in this field of Fusion rapidly increased as the scientist, Martin Feischmann, set up a tabletop experiment involving electrolysis and heavy water on a palladium electrode, then with Stanley Pons in 1989, a leading electro-chemist at the time. Miraculously, both of them reported anomalous excess heat, of what they said would defy explanation except in nuclear terms. They further reported finding traces of a nuclear by-product, including tritium (H3), Helium-4 and neutrons.

But, all good things come to a close end at least, as enthusiasm turned to scepticisms, as the replications of the test failed. This heightened several views that Cold Fusion is not likely to occur – but from my view point, not likely doesn’t mean not at all, there is still a chance of perfecting such technology. But, scientists in 1989 did fought that it was very much dead, a pathological science of far flung hopes and dreams. But the dreams continue on as scientists explore new ways to activate this fusion power.

Why, if this were to continue, it could not just be used on Ion Thrust technology but also that of the Hyperdrive, of which would take us lightyears to other stars in our galaxy.

Cryogenic Sleep



It takes months or even years to reach destinations in our solar system – as was observed with the Voyager probes, Viking 1 and 2, and even the slow trip from the Earth to the Moon with the Apollo-11. Then of coarse, how many people is your space craft going to carry, tens, hundreds, thousands. And just how much supplies they need to live – how many will they go through in a short period of time? Well now, depending on the size and speed of your spacecraft, you can only carry that many people due to supplies and time for a determined period of time.

However, Cryogenics is or Cryostasis, is the term of which living cells are preserved by frozen Clathrate – of which forms gaseous substances under hydrostatic pressure. Living tissue is damaged when it is dehydrated of water and ice forms between the cells. The vapour pressure of the ice is lower than the vapour pressure of solute water, as heat is removed at freezing point; water is drawn from the living cells and crushed in-between the expanding ice crystals.

Additionally, as cells shrink, the solutes inside are concentrated in the remaining water, increasing the intracellular ionic strength and interfere with the intercellular protein organization and other intercellular structures. Eventually the solute concentration of the cells freezes, preserving the tissue and turning it to ice – or something balanced in between.

Clathrate is utilized at 77 K to penetrate and saturate biological cells causing clathrate hydrates to form cages in the cells and extracellular matrix. This process prevents the de-hydration and crushing of the cells.

Semen was preserved by Cryopreservation in the 20th century, while blood, special cells for transfusion, stem cells, Umbilical cord blood, Tissue samples, Eggs, Embryos, Ovarian tissue, why even plants have been preserved. So, could we, very soon, preserve people and organic supplies and rocket them off from the Earth or the Moon and out into the ocean of space in-between the shores of our planet and to the wondrous mysteries of our solar planets.

Artificial Gravity



For the past 40 years, human crews in space have been tied down by zero-gravity. As time passes by, their bone structures adapt to this gravity – but are affected by gravity sickness once they are reintroduced the Earth’s gravity. Gravity is very possible to create however, with a spinning object; this is known as artificial gravity. It can be put into effect with a centrifugal force – of which would see through to a comfortable time for colonists bound for the solar neighbourhood.

Has anybody reading this watched Babylon 5, which is an excellent example of what I shall talk about. A rotating ship will make the feel of gravity in the inside of its hull, just like with the body of rotating planets. The rotation drives any objects towards the hull due to the centripetal gravity; therefore the appearance of an outward pull is obvious. The pull of gravity due to the centripetal force is created the hulls inertia to travel in a strait line; if it cannot then it will be forced to rotate. So, the gravity felt by the objects is the reaction of the hull reacting to the centripetal force due to the force on the object, Newton’s Third Law.



However, you’re rotating a very large object made of steel and other matter, obviously there are issues.
.Kinetic Energy: Spinning up part of or all of a ship requires tons of energy, in the form of a propellant or a large motor, and maybe a counterweight instead to spin in it in the opposite direction.

.Extra structural strength is needed for rotating objects to avoid structural failure, this is 10 tonnes per square meter, and this is relatively modest for most construction projects.

.Friction energy would cause the rate of spin to decrease due to contact with non-spinning sections of the ship. This would possibly also see the main ship slightly spinning; it would be very embarrassing for a crew. So extra motors would have to compensate for this flaw.


3 comments:

  1. a technical error: your usage of centrifugal force is incorrect.

    and for the mathematically inclined readers, a spaceship of radius 'r' must complete a full revolution in 2*pi*(r/g)^.5 seconds, where g is the gravitational acceleration at earth, 9.8 m/s^2

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  2. Thanks Matt, that's is very helpful of you. Obviously a ships must revolve faster than the Earth to maintain a near-earth gravity seeing that is way more smaller.

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