TO THERE AND BACK AGAIN

Chapter 2: Using and Understanding Science Fiction Nomenclature space travel dilemmas in Science Fiction by: G.F.WILLMETTS

 'Space....The final frontier...'

Ask anyone on the street what they most associate with Science Fiction and space travel is usually the first thing mentioned. The image of a rocket heading towards the stars is so ingrained in Joe and Joan Public's heads that they rarely see anything else.

It is such a firm image that Moon and Space Shuttle flights appear less extraordinary than they actually are. Science Fiction space flights have given great expectations that whatever America or Russia space agencies offer pales in comparison.

We expect so much and have got so little. Decades of Star Trek have got so many used to space travel that they probably think we're likely to go there and come back again.

Despite the many people who have been influenced by Star Trek to join NASA or other space agencies, the show itself has probably fulfilled the desires of the many for space adventure. All this has to be in mind when embarking on writing a Science Fiction novel where space travel is involved or is part of the key theme.

With futuristic or Earth-colony based storylines, there is a lot of serious information that needs digesting if you want to maintain some sort of credibility in your writing.

What really separates the dream and reality are the fundamental laws of science. We have observed that nothing of any significant size can exceed the speed of light, preventing any Earthborn spaceship reaching and returning from the nearest star within a life-time.

Albert Einstein's law states that as an object approaches the speed of light, its mass will encompass and spread to all points of the universe. You aren't going to come across many such incidents like that, although you could be forgiven for believing we're a bi-product of previous activity.

All Science Fiction does in that respect, is to keep the dream alive for when such barriers are no longer insurmountable. There is always the hope that some advanced alien species will one day believe likewise, visit and show us ways to either travel faster than light or side-step the limit.

There is an outside chance that Man himself might make such a breakthrough but it would have to take advantage of some new discovery in astrophysics to make it possible. There are always new things being discovered in astronomy about the universe but whether it could be applied to space travel is a matter for debate.

Understanding our reality's current space travel limits is the first step for any Science Fiction writer to consider before evolving his own theories.

The SF writer discoveries will shape his reality, even if it's only a means to propel characters to where the real action is. If the art of getting there is equally appealing, then the variety of options available that other writers have also used should also be considered.

Constructing a Science Fiction reality that extends from our own planet will, by necessity, follow a similar pattern to what will be now be described. Improvement discoveries in space travel are far likely to come from first hand experience than telescope observations. The details or visiting the planets in a similar order may differ but it is unlikely to be ignored.

Any off-world frontier will be a matter of progression to the planets first rather than taking massive steps out to the stars. Space, like the ocean's depths, is a place for deliberation and planning. Mistakes are fatal and rescue missions practically impossible.

Getting the inside story about our own space efforts can be found in any Spaceflight book or encyclopaedia entries without elaboration on its history here. Our starting point is what happens next as the desire to explore our Solar System is met by the appropriate budget.

The key point to remember is all our current rocketry has depended on liquid chemical fuel combustion to enable spaceships to leave the Earth's atmosphere. Propulsion is built around jettisoning ignited fuel to push the spacecraft forward. Once in space, the spacecraft has to use fuel to prevent being drawn back by the Earth's gravitational attraction.

This can be done with anything that can be propelled with sufficient velocity through a nozzle. Maintaining a sufficiently high orbit for any period of time requires occasional thrust manoeuvres for the same reason. Forward and manoeuvring propulsion improves the further from the Earth the spacecraft travels. Other than the Earth's gravitational pull, the spacecraft will normally continue forward until something stops it.

Space stations will stay in place if areas of space are selected where effects of gravity are neutralised by the opposing forces between a planet, its moons and the sun. Joseph Louis Lagrange, a 17th century French mathematician and astronomer, first deduced this information.

This maths indicated two safe areas around Jupiter and proven by the fact that some asteroids are safe there. Earth has 5 of these Lagrange points and of interest to specialists if they want to have a permanent orbital space station.

If none of your characters have never heard of Earth, then don't even think of calling them Lagrange points! Find another name that describes the same phenomenon.

To reach the Moon, additional thrust is also needed if the spacecraft is to arrive within a short time or risk running out of the vital supplies that keeps the life support operating. This additional thrust is compensated by the return trip as Earth's gravity does much of the real work, pulling the spacecraft towards it. These are important details to remember as no manned spacecraft has yet to leave Earth's influence. Short Moon flights will be easy compared to visiting the planets.

There is a certain amount of questionable credibility whenever there are space-battles between opposing spaceships. It isn't cannonfire that is most dangerous but the ability of one spaceship to crowd another into a planet's gravity field that is likely to cause the opponent's demise.

To propel a spaceship in exotic manoeuvres involves not only a large fuel supply but its own battle to maintain a steady flight against gravitational forces. It makes very interesting space opera films but is unlikely to be reflected in reality.

Any sudden movement in flight will always have to be compensated for in the opposite direction to maintain a flight path. The space pilots of films and TV are far more remarkable than the actions they are seen portraying. Space should not be viewed as either an ocean or similar to an atmosphere, despite it being depicted that way.

Newton's Laws of Motion state that an object will continue on its path unless defected by something else. In space, that 'something else' happens to be gravity, although this can be used to an advantage. The unmanned Voyager space probes currently leaving our Solar System employed the rotational effects of Jupiter and Saturn to increase velocity than boost by chemical rockets. In space-travel, we are still at the height of Stone Age technology with very limited resources.

Chemical fuel will allow us to explore our neighbouring planets providing the correct navigation windows are chosen. Navigation is based on where the planet is going to be not where it currently lies in its orbit around the sun. With most planetary orbits being elliptical in relation to the Earth there are times when Mars is closer than others. No manned flights are being considered to Venus because its atmosphere is so hostile and Mercury has both extremes of temperature. Obviously, fuel conservation dictates that a Mars voyage should only be undertaken when it is closest to Earth. You cannot afford to waste fuel chasing your target.

The larger the spacecraft's payload, the more fuel it has to carry and the larger it becomes. All current spacecraft are launched from the equator to obtain the benefit of using the Earth's rotation to providing additional free velocity. Launch from anywhere else and your fuel load is substantially higher.

Spacecraft returning to Earth would obviously benefit from landing in the Arctic or Antarctic circles where rotation is negligible. It is a combination of politics - no one country is allowed claim to either wasteland - and bad weather conditions that prohibits such options. It should be noted that during the 60s-70s when America and Russia were regularly launching spaceships that the UK received dry hot summers and snowladden winters. The effects of such massive launch vehicles should always be considered with the effects on any planet's atmosphere.

The days of the lone inventor building a spaceship in his garden and taking off is simply an impractical myth. The sheer size, fuel requirements and technical knowledge let alone a suitable budget makes such dreams impossible. Even if the inventor discovered a new space flight technique, other expertise would still be required to complete such missions. E.E. 'Doc' Smith's Dick Seaton and the Skylark (the 4 book Skylark series) lacks credibility with what we know today.

Interplanetary flights will start from orbit than from the ground. There is an immediate conservation of manoeuvrability fuel and the ability to carry a much larger payload. Such flights would be long, arduous and extremely boring for a crew likely to be on-board for a couple of years.

Slowing down at the destination can be achieved by using the planet's own rotation to absorb the velocity with the spaceship never landing, employing a shuttle to the planet surface. Even then, at its closest, Mars is 18 months flying time away.

Russian investigations of the long-term effects of weightlessness are a matter of concern for all astronauts. Deprived of gravity, bones loose calcium and become fragile. Too long in space and no astronaut will be fit enough to land after a long voyage. Exercise is not enough and any spaceship will have to have sections that rotate to provide sufficient gravity to overcome these problems.

There must also be sufficient oxygen, food, fuel, supplies and activities to keep the crew occupied. You cannot send an AA repair van in case there are difficulties as Apollo 13 illustrated. A rescue spacecraft would never catch up. A trip of such distance would result in being on the planet for at least a couple months before returning to make it worthwhile. The time is likely to be longer if a suitable return trip window is missed. A self-sufficient environment capability will be a common consideration for all interplanetary spacecraft.

You might well ask why bother to go at all? Motivation for going is of much interest in SF as the trip itself. Both America and Russia have sent robot probes to land on Mars and Venus. Why risk astronauts' lives in what could be regarded as a dangerous expensive pursuit with little to show for the trip? What would the people of Earth benefit from such trips?

The Earth does not have an infinite supply of fossil fuel. There are little enough resources the Earth has that can be regarded as infinite. It's estimated that many natural resources will run out in approximately 300 years given our current population growth. Spectral analysis of nearby asteroids, planets and moons indicates a wealth of mineral resources.

Our technology takes time and practice to develop. Where else can you look if the Earth's sources are depleted but to the nearby planets and their satellites? Relying on something to turn up at the right time risks our own extinction. We need to gather fresh material or colonising other planets now rather than later.

Planetary landings by robot probes have yielded some information but are limited as to what they can do. Any instructions sent in the event of hazard take a couple minutes to arrive and by that time the robot is lost. An astronaut on the spot would be in a position to make and initiate decisions.

A first hand observation can yield far more than any robot or camera eye. Important decisions are acted on immediately. Large mineral samples can be analysed on the spot or returned to Earth. Such developments, will enable limited colonisations as we leap-frog to the outer planets.

Other than war, space exploration has enabled the most rapid technological developments on Earth. This has been more apparent from the American than Russian programme where the manufacturing companies sold commercially. The need for miniaturisation developed the silicon chip that replaced the valve-based computers. The silver-foil sheets to keep things warm. Heat resistant materials.

Most of it finding a use in the home as well as in space. The list is endless. Industries and jobs are supported. One only has to compare what's available today in the home to the early 60s, to see the technological jump that space travel has generated. A large jump such as this is unlikely to happen again with interplanetary exploration but the benefits are bound to be felt. A better environmental control system. Improved crop techniques for agriculture.

Compact water distilling equipment. Air purifying equipment improvements. There will always the possibility of some sort of new revolutionary scientific or technological breakthrough from this research.

One thing Man won't find on Mars is Martians. Although there is a carbon dioxide atmosphere, other than the possibility of some lichen variation, there will be no life as we know it or even non-carbon based life. Mars has too little water, not enough sunlight and far too much carbon dioxide to make it practical to sustain life (more details on alien life in a future chapter).

For a similar life-supporting environment to our own, we would be expecting cyclic movement of carbon, oxygen, nitrogen and water. There would be variations of such cycles for species living in methane or other exotic gas based planets. The recent discovery of possible organic material from Mars' distant past is no indication that life truly flourished there.

Organic compounds have been found in a variety of meteorites suggesting that the elementary building blocks for carbon-based life is probably wider spread than once thought. This increases the likelihood of life but gives no indication that it will flourish.

After the exploration of Mars, Man will probably want to move further out. The Asteroid Belt offers opportunities for ore mining providing it can be returned to Earth. Some proposals suggest attaching rockets to the most promising asteroids, using its own material for a power source, directly them back to Earth for orbital mining. Such mining is likely to be hazardous with prospectors away from Earth for years before returning. Larry Niven's Tales Of Known Space compared such prospectors to the gold-hunting frontiersmen from the Old West, willing to suffer poor conditions for great riches.

Apart from being reasonably physically healthy, intelligent and level-headed, astronauts must be able to cope with claustrophobic confinement of the spacecraft environment while not suffering agoraphobia when they realise there's nothing outside of their vessel. Irrational fear can be caused by anything.

People on-board American and Russian space-stations have discovered that the ground-crew developed a habit of treating them impersonally and with demands that often exceeded their physical abilities. The further Man travels from Earth, the greater this gulf will grow.

Certain comparisons to naval vessels in command structure discipline for spacecraft have greatly influenced Science Fiction in all its forms, despite the fact that in reality it is more akin to an air force crew. Any space flight crew today has more than one officer capable of piloting with the others briefed for emergency procedures.

Multi-tasking is the key to good organisation with crew requirements kept to a minimum. Menial jobs are divided by rota to the crew rather than employing any blue collar workers solely for such purposes. This is unlikely to change with any major advancement in technology.

To travel to Jupiter and beyond, we need look to two of the best SF examples available, both also depicted in films with their solutions graphically illustrated. From Arthur C. Clarke's novel and the Stanley Kubrick film: 2001: A Space Odyssey, the U.S. Discovery made the trip to Jupiter {in the book, it went onto Saturn, but in view of 2010, we'll settle for Jupiter).

To provide a source of gravity, a centrifugal wheel was incorporated into the Discovery's hull and the astronauts exercised daily. Non-essential crew were kept in hibernation for the trip to conserve air and food resources. In 2010, the Leonov had the entire crew unit revolving and aerobraking in Jupiter's atmosphere was used to reduce their velocity on arrival.

Both illustrate the practical problems of interplanetary flight based on our current technology. Given the investment, both spacecraft could be made today.

No matter how it is depicted in media SF, space travel itself is boring and slow. Course corrections can be controlled better and more accurately by computer. Major catastrophes requiring human solutions rare. If some interplanetary object is going to hit the spacecraft, there will always be plenty of warning for minor course corrections to avoid it. Everything moves in predictable paths. There is far too much idle leisure time and not enough to do. The practical easiest solution of any long-distance space flight is to sleep the journey frozen in hibernation.

It's only with 2010 that we see the problems that arise when hibernauts waken and having a physically active crew available to restore them to physical health after an extended sleep. Although not depicted, I can't believe that none of the 8-crew Leonov weren't in short-term hibernation techniques during the flight themselves to conserve their own resources. By hibernating for short periods only, they are less likely to suffer the same effects as the revived American crew.

The main problem of any hibernation process is the loss of muscle tone and tightening of tendons. This is of far greater importance than possible brain damage from keeping the body in prolonged freezing temperatures. Coma patients have their muscles exercised regularly to ensure such problems doesn't happen or to at least minimise the problem.

Frozen sleep prevents machines being used to massage the body. For an astronaut revived from hibernation, the effects are likely to be far worse. It would take weeks rather than days to make a full recovery even in a low-gravity environment. It is possible that such hibernation could be controlled better if the astronaut is periodically raised to near room temperature so machines could massage limbs and muscles without waking.

In Science Fiction, hibernation isn't a new idea and extends to interstellar rather than interplanetary flight. Many authors, amongst them Cordwainer Smith, Frederick Pohl, Frank Herbert, Poul Anderson and Anne McCaffrey have exploited its use. Larry Niven's Known Space stories have an alien designed device called 'Stasis' where anything within its field was immobilised for set intervals.

This was not so much a hibernation, more a total cessation of activity within the field. Life continued as before once it stopped. When considering the alien technology option be prepared to account for the same problems that terrestrial technology has rather than purely as a deux ex machina cop-out.

Now we are looking at space flight beyond our own Solar System, there are other practical problems to consider. These are very similar to interplanetary flight only a million times worse. Whereas air and food can be forever recycled, reliance on chemical fuel alone will not be enough.

Gravitational attraction, as already mentioned, from another planetary body will conserve fuel that can be used to leave orbit. Using a planet's rotational momentum to gravity assist an acceleration or slingshot a spaceship's velocity is probably the most economic cheapest technique.

Air-braking against a planet's rotation is also the most economic way to slow down. Having the planets in line, as was done with the Voyager probe, to do this doesn't happen very often. Neither effect will give the minimum of a tenth of the speed of light to enable a suitable shortened interstellar flight velocity.

Self-contained gravitational fields, like those of James Blish's Spindizzy devices used in his Cities In Flight books allow unlimited mobility for unconventional looking space vehicles. Propulsion is achieved by attraction or repulsion between gravity attracting objects. Internal gravity is only maintained by ensuring that the heaviest object is at the bottom. It does, however, lead to interesting possibilities where the ground is where you want it, allowing the full use of walls and ceilings for walkways and multiplying the surface area.

Incidentally, revolving spaceships like the C57D from the film Forbidden Planet may well maintain an internal gravity but this does not demonstrate how any forward thrust is achieved. Unless some other means is being concealed, a revolving craft isn't likely to stray from one spot. UFOs, despite their often circular shape, have rarely been described by witnesses as revolving. Such fiction is therefore probably limited to the movie and TV screens. Anyway, who's to say that the aliens don't use the circular walls of their ships instead of its smaller floor base and have the interior walls revolving?

The problem with anti-gravity devices lies in the same area as faster-than-light (FTL) space travel. If you are justifying this in any great detail then you are defying most of what Einstein has defined. Many SF writers have viewed this situation in much the same manner as when Einstein's theories superseded Newton's, figuring that some new physicist will re-define the limits yet again. Although this is not impossible, such considerations will also have to cover not only relativity, inertia and gravity but how matter acts together.

Einstein himself never solved the Unified Field - what links matter and energy together - problem and this would have to be regarded as the starting point for resolution. Saying that, there is no guarantee that even with the answers that it could improve space flight times.

It was proposed some time back ago that igniting atomic bombs as a means of propulsion would provide an economic acceleration. This has largely been dismissed in view of the dangers of hard radiation left in its wake. Like all such accelerations, a suitable reverse system has to be employed to bring the spacecraft to rest again afterwards. The greater the velocity, the greater the chance of collision since the spacecraft is moving too fast for minor course corrections or to observe the approaching danger. Depending on the size of the object, the spacecraft is just as likely to destroy it or themselves in the collision.

Experimentations into using the annihilation of matter by anti-matter as an energy source now has terrestrial science hoping to compete with TV's Star Trek shows. Currently the problems lie with creating sufficient anti-matter and its containment. The radiation expenditure if used would probably make nuclear bombs pale in comparison. It would be extremely hazardous to be behind any Starfleet vessel firing its engines whether you have shields or not! Such may also be the case with ion drives and any other propulsion method likely to generate hard radiation bi-products.

Within the Solar System, planetary orbits and trajectories are measured in Astronomical Units (AU). One AU equals 149,600,000 kilometres (92,956,000 miles). Leaving our Solar System for the stars produces a whole different scale of measurement using the speed of light.

A beam of light travels approximately 299,792,458 kilometres/second (186,282,396 miles/second). A light year is approximately 9,460,980,645,161.3 kilometres (5,865,700,000,000 or 5.8657 x 10^12 miles) that a light ray travels in a year. Calling it a light year does not really hide the enormous distance being described. Figures of this magnitude are hard to imagine and become meaningless, until you want to travel them.

Rather than rely on large distances to be referred to as light years away, a secondary unit, the parsec, is used. The parsec is an abbreviation for part-sector NOT part-second. One parsec equals 3.26 light years and is the distance our sun and the Earth moves in one degree arc in the galaxy. That's 30.38 trillion kilometres or 19 trillion miles.

This figure is arbitrary to our star system and, like the AU, is unlikely to be applied by aliens with no connection to Earth and least of all as a means to measure velocity (blows the Star Wars film faux pas in illustrating Han Solo's ignorance of the term and of the time setting).

Call the distance any name you like and let the reader or viewer decide what you mean by implication is safer. For your own benefit, decide upon an equivalent scale to ensure distances make some sort of sense based on the speed of light.

All these measurements have to be taken into account not only for the voyage but in sending messages back. Through conventional space, communication is limited to the speed of light. Should a spacecraft reach this velocity, it'll travel faster than any messages sent. This is something akin to America's Pony Express where messages went as quick as the fastest horse. As a spacecraft approaches the speed of light, time dilation means ship time will be slower than on Earth and might not even be possible to make sense of any messages that span over decades to be received. Should a quicker means of communication be developed then it will be in proportion to the same means for space vessels themselves to go faster.

The problems and solutions to communication have been addressed by such notables as James Blish's Dirac Communicator in his short story Bleep and Ursula LeGuin's Anisble in The Dispossessed using mechanical instantaneous communication ignoring regular physical laws. In Robert Heinlein'a Beyond This Horizon, telepathy between twins is suggested as the means to deliver messages. Presumably any communications will be a reflection of the means for interplanetary travel.

The time dilution effect at light speeds means that a month on board will possibly be centuries at home. Life on board won't seem any different but will be slower compared to life outside. This still has nothing to do with the distance the spacecraft will actually be travelling. A 40 light year flight will still be that distance. All of it is the effects of relativity and those seriously interested in these problems should consult current physics texts on the subject.

Scientists have calculated that it would take at least 40 years (4.29 light years) to reach our nearest star, Proxima Centauri, travelling at one tenth of the speed of light. This velocity is the fastest that we could ever hope to reach at this time. Such a voyage would be fruitless unless there was the possibility of an inhabitable planet at the destination or could make a return trip home. Vega was the first star discovered to have planets 26 light years away.

The nearest star system believed to have planets is Barnard's Star at 5.9 light years distant. Such an expenditure of life and resources would only be worthwhile if there was something worth visiting as no one would return within our lifetimes. A habitual planet means the possibility of colonisation. Seeking life currently in our local star neighbourhood is therefore currently restricted to radio-telescope observations.

For the present, any interstellar flight will be strictly by our own devices. Attaining that one tenth of the speed of light should have most of you pondering on how Man could tolerate the acceleration. In Earth's atmosphere, the most gee-force man can tolerate is Mach 4 (4,258 kilometres or 2,640 mph).

In space, Man has travelled much faster at 39,897 km/h (24,791 miles per hour) with Apollo 10. Providing acceleration is gradually built-up, the human body is quite capable of tolerating even greater velocities, especially if his body is not being suddenly pulled in a different direction. This doesn't affect having centrifugal revolution on board, as you'd still be moving relative to the spacecraft.

Again, we are addressing the problem of why do we need to go in the first place? Asteroid mining must surely be fulfilling all of Earth's resource requirements. If, as many people believe, aliens from other star systems have visited the Earth in earlier times, they might have left some sign for us to follow? Arthur C. Clarke's short story The Sentinel that became 2001: A Space Odyssey had the author thinking that such alien artefacts would be left off-planet.

By reaching them, we would be showing a developed civilisation capable of space travel and may have the aliens make a return visit. An interesting theory even if it reveals nothing about the aliens' intentions for when we become space-farers. Would they treat it as a warning, threat or a sign of developing maturity? Such a proof would shatter many pre-conceptions Man has believed about himself and his place in the universe and will be the subject of a future chapter.

The biggest need for leaving Earth is the consequences of staying in one spot. In militaristic terms, should a natural catastrophe or aggressive alien invasion take place, we're all stuck in one place. Spreading Mankind to the stars will at least improve our species survival for the long term.

One interesting speculation occurred to me recently was that if alien starships disposed of some of their wastes like our terrestrial airliners do, then it puts a whole new reflection on the nature and content of a comet. It has been discovered by spectral-analysis that a comet is a mixture of diluted acids in any iced watery base. Aliens might have passed by, but all they've left are their sops. The chances of a comet sustaining much damage should it collide with a planet is minuscule compared to that of a solid meteorite.

An important thing to remember about colonisation is the effect Mankind has whenever it invades and introduces new species to what has once been an isolated environment. On an alien planet with a similar atmosphere to that of the Earth, there is no guarantee that foodstuffs will be edible. A slight difference in alien vegetation's amino acids and it would be poisonous. The introduction of terrestrial vegetation will initially start a battle over minerals.

A victory for terrestrial plant-life may well kill off the planet's own vegetation. If the reverse happens, colonisers will either have to depend on hydroponics - plants grown in soil-less cultures - as they did in the spaceship or starve. Hopefully, by the time such colonisation plans are under-taken, gene therapy might well adapt for any amino acid variations and local foodstuffs.

The considerations so far have concentrated on a possible return trip within a life-time. Possibilities are better if such expeditions are willing to stay at the destination. Chief choice amongst these has to be the 'Generation Ship'. You may not arrive, but your great great great grandchildren might. Generation Ships would probably have to be built from or as part of an asteroid to provide necessary living space and self-supporting environment for at least 50 families to be accommodated.

A large population would be required to ensure that there was always a healthy mix for the genetic pool. Alternatively, additional stock could be carried as fertilised eggs in vitro that could be brought to fruition in flight or at arrival to conserve space. Apart from chemical rockets, ramscoops would be employed to collect free hydrogen atoms in space for fuel. Although these atoms aren't as freely available as supposed, the energy requirements will only be required for manoeuvring rather than thrust.

Many SF authors have questioned the viability of such a Generation Ship. People brought up in such a spacecraft will have no memory of Earth and might not want to leave the ship when they arrive. The training of these people by their forebears may turn their work into rituals that are observed but not understood. All the training in the world will not help interstellar astronauts who find claustrophobia the normal way of life. Although feasible, the results of such a project may never be sent back to Earth and investors may be harder to find. Whether this would stop families volunteering for such an expedition is debatable as it might well be seen as the great adventure.

There is always the possibility that some new faster way of travelling will be discovered and practically every SF writer has used such means to travel outside of current physics laws to reach distant star systems. Science Fiction crime stories become meaningless if it takes the detective several centuries to arrive at the scene of the crime! The same applies with any other sort of galactic problem.

Existing within a single time frame has become a persistent problem for many SF writers. In reality, it looks highly improbable that a galactic empire could be held together merely by the military force of one individual or family. Would this be true if they held a monopoly over a product that most worlds wanted? Such monopolies give power bases as Cordwainer Smith with the life-prolonging stroon in Norstralia and Frank Herbert's prescient melange in his Dune series illustrated.

E.E. 'Doc' Smith's later Skylark (book: Skylark Of Valeron) employed an inertia-less drive where the spacecraft stopped relative to the motions of the galaxy to achieve velocity. As the galaxies are spreading apart at the rate of 5-100 km/sec per million parsecs, any spaceship attempting this will be left behind with no chance of returning home. There is also a high probability that it would be destroyed by colliding with any thing from a star to an asteroid.

If there is nothing currently available or man-made that can bridge the distances, are there any natural space phenomenon that can be successfully exploited?

The most obvious is that of gravity wells or Black Holes. These are essentially imploded stars that absorb any matter or energy that approaches them.. It was once theorised that travelling through the centre of a Black Hole would give access to another part of the galaxy coming out of a White Hole. Oddly enough no one has ever seen a White Hole or confirm that they would be linked.

There is also a little question of the over-whealming gravity forces that will compress and destroy any spaceship attempting to even explore this possibility. Even an anti-gravity generator would fail against nature's most powerful natural force. Using one for a possible slingshot would not fare any better since the attraction appears to emit in all directions. It might be possible for a spaceship close to a Black Hole's 'event horizon' (an area that is regarded as the safest you can get near) to utilise energy absorbed that it vomits up through its funnel but that is purely speculation.

The intense interest by astronomers and physicists in Black Holes can largely be attributed again to Albert Einstein. He theorised that the surface of our universe to be like a flexible rubber mat with the stars and planets indenting it with their gravity fields. Obviously, a black hole is sinking a deep hole into this mat and therefore could be bending points in the mat and cutting the intergalactic distance if you can jump across but not entering the hole itself. With the universe constantly expanding, there is no guarantee over choice of destination or returning.

Without proof that this works, such trips are unlikely to be taken. Evidence of any size Black Hole near our own Solar System has yet to be established. Einstein's view expresses the universe in a very linear fashion while the universe is inconveniently three-dimensional and if true is likely to be more complex than we could imagine.

While on the subject of Black Holes, we shouldn't forget 'wormholes'. These are thought of as being capable of doing what Black Holes can't, namely providing access points to different parts of the galaxy where there is a fracture in Einstein's rubber mat. Should such holes may exist, they are likely to be minute and unable to allow spacecraft through.

Larger wormholes may well have similar gravity and worse radiation problems than Black Holes. If there were any within the vicinity of the Solar System, these wormholes would have been noted by now, simply because they are likely to generate a unique energy signature that radio telescopes would have detected.

If our own universe's physics laws makes travelling faster than light impossible, why not move to a reality with different laws? Interestingly, there is some evidence of this. At atomic level, Quantum Mechanics has shown that a different set of physical laws appears to be functioning. It is remotely possible that as we exceed the laws governing our part of reality, we could discover another set of physics working that we can interact with. Quite what these changes will entail is open to anyone's imagination and something Science Fiction writers have frequently exploited.

The most obvious of these is Hyperspace. Issac Asimov is probably recognised as being the most successful exploiter of this dimension, even if he wasn't the first. The main change in Hyperspace is that distance is inverse to our reality. A short distance travelled there would be many light years here. Once it was possible to calculate co-ordinates, the entire galaxy opens up for travel. There would, of course, be problems like returning to our universe too near a star, planet or even a Black Hole and some means would be required to detect such problems before emerging.

Oddly enough, the use of Hyperspace is seen by many people as the ultimate solution to interstellar travel and has been vividly portrayed in the Star Wars films and TV's Babylon 5. Variations of this have been named 'Stargates' by such luminaries like Arthur C. Clarke in 2001: A Space Odyssey and in the recent film Stargate. Here, gates are created to known, at least to the aliens, destinations. Star Trek's warp drives are probably exploiting a multi-dimensional arena, especially as their spaceship's velocities accelerate extrapolatory to the higher warp they travel. Babylon 5's Hyperspace jump gates appear to be set up 10 light year intervals for most conventional spacecraft and at safe points to prevent spacecraft crashing into each other. Larger spacecraft appears to survive longer in Hyperspace, together with the means to generate their exit holes but still require external co-ordinates for easy transit.

If there is a Hyperspace, we still have no means of detecting or exploiting it at this time. The potential of such a means brings other planetary bodies into the same time frame as our own and Science Fiction will have the opportunity to turn factual. If there are alien spacecraft exploiting Hyperspace, then detection, as applied to wormholes, should be possible. With nothing detected, this may be just another Science Fiction dream.

Should you be considering extra-dimensional planes and think why make it more complicated and go for fewer dimensions, Cordwainer Smith exploited this possibility in his Instrumentality Of Mankind stories and called the technique Planoforming. Here everything is compressed into two-dimensions before being transported. Such travelling techniques are not without their pit-falls as his short story, The Colonel Who Came Back From Nothing At All (anthology, The Instrumentality Of Mankind) demonstrated.

Such instant travelling techniques are very akin to teleportation. A.E. Van Vogt's Greater Galactic Empire in his Null-A novels exploited a distorter device that could shunt spaceships or people across the galaxy to known destinations. They were still capable of conventional space flight but made interplanetary flight in a matter of days, allowing for temporal drag.

Should you, the aspiring SF writer, decide upon Hyperspace to take your interstellar spaceships to the stars then look on this dimension with care. Other writers have only thought of it in terms of space/time inversion. There may be other physics laws likely to be inversed as well and just as likely to affect the spacecraft unless it's protected from such rigours. It might even be a dimension that doesn't even require a spaceship to travel through, but then it's also called teleportation.

All of the above has explored mechanical means for space flight. With our rapid understanding of the genetic code, it might one day be possible to breed pilots better adapted for space travel like Cordwainer Smith did in his short story, Scanners Live In Vain. This might not only be in the physical sense, but also adapted either for a longer life span or capable of changing the sense of time so years pass as seconds.

Ultimately, such changes could result in the individual becoming his or her own spacecraft. A.E. Van Vogt explored this possibility with his metamorphs in The Silkie capable of transforming themselves into bodies suitable for any environment. Velocity might be no different to a conventional spaceship but the capabilities for survival will be greatly enhanced. Spider and Joanne Robinson's Starseed merged their humans with a space-faring symbiote species, thus preserving the original stock in some form.

If it should prove impossible to physically travel to the stars, then it is conceivable that DNA designs could be sent as radio signals so some enquiring alien could manufacture representatives of our kind. The biggest drawback to such plans is the enormity of the data that has to be sent, not to mention the likelihood that information could be lost, damaged or changed in transit. Fred Hoyle's A For Andromeda and the film Species had alien species do it to us with rather disastrous results. What they deem as normal is likely to be deadly to us. Donald Moffitt's The Genesis Quest and The Genesis Effect did the reverse where human DNA was reconstructed on an alien planet.

An uneducated copy of any sentient life-form will act in its own interests for survival or be educated by the alien discoverers into their own educational system that will either benefit or drastically change it for the worse. Without a necessary template for behaviour, it is far more likely to act like a primitive animal than a diplomatic representative without some means of providing the original educational source.

As previously mentioned, if all else fails, find an alien species willing to provide the FTL drive or some other way to reach across the cosmos. It should be remembered that such ideas are generally cop-outs or deux ex machina. It is very unlikely that the laws of the physical universe are any different elsewhere and will still require some sort of justification to the reader as to what is going on.

If attempting to understand all of the above has left you mind-boggled, then keep details of your space travel technique as sparse as possible. Becoming technical will only leave you open to ridicule and disbelief. Establish only enough information to allow some credibility and leave it to scientifically-orientated minds to debate its possibilities.

If all else fails, there is no reason why variations of the above space travelling techniques can't be applied in your own stories. Hyperspace is used by so many authors that it's practically taken for granted by readers with little explanation. Developing anything new is just likely to a variation on things that have been done in the past. The most important thing to remember about any propulsion system is the effect on the society that develops it. How will its finance be justified? Are there likely to be any bi-products used by society that can't be ignored in the story background? Do they take it for granted and become blasÈ to its use and let accidents happen? Will there be an increase in trade? How do you justify the reasons why people want to space travel in the first place?

The early days of Science Fiction often viewed space travel with romantic notions of spectacular flights and daring-do. Mankind is a little more pragmatic about such things today. Bluffing when there is so much information about interplanetary travel is known is not advisable. Interstellar flight is more speculative but has had more Science Fiction writers treading the ground to come up with some means of travelling that is truly original.

Space travel may be a small part of your overall story but its effects are far-reaching and may help to better grasp how it shapes your society and reality. Man will obviously one day expand out into the galaxy. The desire for survival and new territory will drive as strongly as the need for resource replenishment. Whether such needs can be met with advanced technology development is still in hands of the Science Fiction writer.

G.F.WILLMETTS

Choosing any books to read or reference is likely to depend on the author's own reading or knowledge. Apart from stories referred to in the chapters, I will be listing other books that should be considered reading for either information or technique. This list isn't exhaustive and you're just as likely to have fun investigating book-lists given in the SF Encyclopaedias or by other people. I have endeavoured to list books that are at least easily obtainable rather than rely on obscure books.

additional reading:-

• Chanur series by C.J. Cherryh - hyperspace travelling problems.
• Destination: Void by Frank Herbert - hibernation in flight
• Gateway by Frederick Pohl (first book of HeeChee) - asteroids
• The Gift From Earth by Larry Niven - hibernation in flight
• Sunjammer short story by Arthur C. Clarke (The Wind From The Sun) - solar power flight.
• Think Blue, Count Two (The Instrumentality Of Mankind) by Cordwainer Smith - hibernation in flight.
• A Brief History In Time by Stephen Hawking - current space theory and Black Holes.
  
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Books in the Time Travel genre