Tag Archives: space travel

Star Wars ISD – a good design, or not so hot?

https://en.wikipedia.org/wiki/Star_Destroyer

Oh, man. The majestic Imperial Star Destroyer.  I’ve said before it was one of the reasons I fell in love with Star Wars. Here it is in all its glory. Bristling with weapons, a space-going aircraft carrier cum assault ship. According to Star Wars: The New Essential Guide to Vehicles and Vessels, the 1.6km long ship carried 9,700 soldiers, 72 TIE fighters, 20 AT-ATs, 30 AT-STs and an assortment of barges, gunboats, transports, shuttles and Skipray blastboats. Look at it, all angles and details, with its huge bridge (complete with picture window) and shield generation domes. Be still my beating heart. I built the plastic model, of course, and added lots of spiky details. It was/is a thing of beauty, and a joy forever.

And yet, that’s not what the battle cruisers in my novels look like. Why is this so?

Not, as you might imagine, the copyright issue. Nor is it anything to do with streamlining. In space, streamlining is not an issue. (In fact, the space battles in the Star Wars movies were giggled at by most of us who know a little about space. Those fighters maneuvered as they would in atmosphere, diving and curving like World War I Sopwith Camels.) Getting back to the capital ships, provided they stayed out of a planet’s atmosphere, they could be any shape the mind can conceive. Let’s face, it that pointy bow is unnecessary, even if it looks cool. Same with the angled deck surfaces.

My reservations about the design are more about that bridge structure. Would you really put all your commanders in such an obvious place? I know it’s based on a sea-going ships’ superstructure but I think even in the world’s navies, the actual command centre is well-protected, within the ship. That great T-bone up there is an obvious target. Remember when, in The Empire Strikes Back, an asteroid collides with the bridge of one ISD and takes out the ship? Oops. And then the bridge of the great SSD Executor is hit by a rebel fighter in Return of the Jedi. Double Oops. What’s more, those shield generators must have a pretty mighty job to effectively blanket the whole ship from that position. Clearly, from the previous, with a certain lack of success.

So my ships aren’t pretty. They’re a bunch of rectangles stuck on top of each. The largest and lowest contains the hangars, the hydroponics, the artificial gravity generators, and down the far end, the engine rooms. The level above contains the troop accommodation and training areas, kitchens, workshops and the like, and the highest contains the bridge (although well down the decks) and Fleet accommodation. It’s a big ship, more like 5km long, plenty big enough to support a task force. And of course, it would usually have escorts to protect it. Although it carries quite a bit of its own protection in the hangars and the weapons (missiles and energy weapons) deployed around the decks. The shield generators are on the lowest level and carry charge to a network of emission sites over the hull.The ships have two drive systems, one for shift space when they travel enormous distances through different dimensions, and another for travel in normal space. Like Star Wars ships, they can make a jump within a system, arriving fairly close to a planet. The drives themselves use controlled nuclear fusion. Don’t ask me how. Just look at a star. We know it works.

So… would any of you care to share your observations or feelings about Lucasfilm’s creations? Or wax lyrical about your own?

What would you weigh on an exoplanet?

picture of an exoplanetI was reading an article from somebody, all enthusiastic about the exo-planets the Kepler probe keeps finding. They’re all many times larger than planet Earth even if they’re in the ‘Goldilocks’ zone. You know the one – not too close, not too far, just right. That is, a planet neither too close to its primary nor too far away, where liquid water could exist. My immediate reaction was ‘sure, but we’d weigh too much’.

Then I began to wonder how much more. I’m not a mathematician – never have been. In truth, I can’t add up to save my life. So I’m counting on you (ha ha) to correct me if I get this wrong.

I discovered this site http://www.exploratorium.edu/ronh/weight/ and learned that gravitational pull weakens by the radius squared. So let’s say you weighed 60kg on planet Earth. Planet Gliese 581g is estimated at 2.6 Earth masses and 1.4 Earth radii. So yes, you’re going to weigh more on Gliese 581g, but not 2.6 times as much. If I’ve got this right, the increased diameter of the planet means you’ll weigh about 1.3 times as much – so about 78kg. That’s certainly not a huge imposition. And all of a sudden, I’m bouncing in my chair, going oooh oooh.

Here’s some estimated figures about Gliese 581g, taken from this fascinating website http://phl.upr.edu/projects/habitable-exoplanets-catalog

Mass = 2.6 Earth Radius = 1.4 Earth  Temp = average surface temperature, so this place, at 10, is rather cooler than our 15 degrees (NASA’s figure from 2008), but the estimate of average temperature assumes an Earth-like atmosphere, which is a pretty big assumption. On the face of it the planet zips around its sun in a fraction of the time it takes ours, taking only 32 days as compared to 365. But that might not be the case, since the Gliesean day may be much longer than Earth’s. The figures don’t mention period of rotation, which I find a tad surprising. As a comparison, Venus’s ‘day” (the time it takes to rotate on its axis) is actually longer than its year (the time it takes to orbit the Sun.) (http://www.universetoday.com/14282/how-long-is-a-day-on-venus/)

So there you have it. I found out today that a candidate for Torreno (capital of the Coalition of Worlds in Morgan’s Choice) may be only 20.2 light years away. And with the shift drive of the future, that’ll be a place to add to your holiday plans.

Ain’t science grand?

Humans are such fragile entities

The more I read about the strangeness of our universe, the more I wonder if we, humanity, will ever colonise other planets. There’s not much chance we’ll settle on a diamond planet and I have to wonder how we’d go on many of the ‘earthlike’ planets already pinpointed. We are such fragile entities, we humans.

I’m in the throes of writing a sequel to my space opera Morgan’s Choice, which accepts the existence of political groupings of star systems into coalitions, federations and the like. Hey, I’m not special in that respect. Lots of SF writers have done the same thing, with great success – Elizabeth Moon, Jack McDevitt, Isaac Asimov etc etc and of course, Star Trek, Star Wars and the like. But how likely is it really?

Like all other animals we are closely attuned to our environment, more so than many of us actually realise anymore. In these days of electricity we can heat or cool our homes, spend half the night watching TV, or reading books, source food from all over the world so nothing is ever out of season, cross distances that took years in days. Yet we cannot escape the factors which shaped us.

I think there are five vital factors we will not easily overcome.

The first is our perception of time.

I use the word ‘perception’ advisedly, because time is something we measure for ourselves to put ourselves into context, if you will. But whether we think the sun is rising where we are, or setting, our bodies are built to expect a ‘day’ of twenty-four hours or so, because that’s how long it takes for the planet to revolve on its axis. What’s more, if we are suddenly wrenched from one time of day to another, as happens with long distance air travel, it takes time for our bodies to adjust. (It’s called jet lag)

Next is gravity, what we call weight.

We have evolved to suit the amount of force the planet exerts upon is. The advent of space travel and weightlessness has proved how important gravity is to our ability to function. Without gravity our bones lose density and muscles atrophy.

Then we move on to air.

Most of our atmosphere, what we breathe, is nitrogen, with twenty-three percent oxygen and a bunch of other gases in smaller quantities, including carbon dioxide. It also has a level of density. There’s more of it at lower altitude (see gravity). See what happens to mountain climbers if they climb before becoming acclimatised. Their bodies can’t cope. And if that mixture of gases changes past a certain level of tolerance, then what?

Then there’s temperature.

Humans exist in an apparently wide range of climates, providing they can find protection from the elements. But the range is actually not that wide in the scheme of things. This article in New Scientist speculates that global warming of only about 11° would render many places on our own planet ‘unliveable’.

The last factor is light.

Earth orbits a G class star which emits light towards the red end of the spectrum. We’re used to seeing colours in that light. If we lived on a world orbiting a cooler star with redder light, or a brighter star with more bluish light, we’d see colours differently.

Humans are adaptable. That’s why the species has been so successful. But even so, we’ve only ever had to adapt to the extremes of one planet. If humans are to venture to other planets I believe we will have two choices; terraform the planet into another Earth or modify the settlers to cope with the conditions. That would mean physically very different races of humanity occupying different planets. And here again, SF can offer plenty of examples. One that springs to mind is Moon and McCaffrey’s joint effort, Sassinak, where members of the Star Fleet have different body characteristics, depending on which planet they come from.

I admit I don’t take that route in my own writing. I simply assume all planets are earthlike, with only small variations in light, heat, time and gravity. I reckon I’m in pretty good company. Come on SF fans and writers, what do you do, what do you prefer?

Planet-hopping might not be so silly

Stars in Orion's beltMy science fiction book The Iron Admiral: Conspiracy includes a certain amount of planet-hopping. In fact, all my SF does. Now, I know that there will be some sneering and lip-curling over this. But don’t be in too much of a hurry to point a derisive finger.

Come with me on a cosmic journey. We’ll start here, on dear old Mother Earth, the only planet we know a huge amount about. Journey back in time, four hundred years… The world was beginning to open up. Intrepid explorers travelled to the other side of the Earth in search of trade and riches. Dutch merchant ships sailed from Amsterdam to what is now Jakarta in Indonesia to trade in spices. At the turn of the 17th century, they sailed down the west coast of Africa, re-provisioned at Table Bay and then set off past Madagascar and across the Indian Ocean up to Java. Makes sense, really, if you look at the journey on a map; down to the tip of Africa, then up at an angle to Indonesia. The journey took a year, sometimes as much as eighteen months if the winds were poor or the storms struck hard.

Then in 1610 Henrik Brouwer did something completely counter-intuitive and sailed south from Table Bay. Makes no sense, does it? Well, yes it does. The Earth is not a 2D Mercator’s projection on a tabletop, it’s a spheroid. The distance around the equator is greater than the distance around the lines we call ‘latitude’ to the north and south. Brouwer took advantage of that fact to shorten the distance he had to travel east and had the bonus of the reliable winds of the ‘roaring forties’ to push his ships along. All he had to do was remember to turn left when he reached the longitude for the Sunda Strait, sail up the coast of Western Australia and he was home. Taking this route shortened the journey by two thousand miles and more than halved the duration. The route was not without its dangers – as you’ll find in my book ‘To Die a Dry Death’ – but that’s another story.

Over the years, sea travel became faster and more reliable. Steam and then diesel replaced sail. When my family migrated to Australia from Amsterdam the sea journey took about a month. Apart from the improved mode of transport, the ship also avoided the long journey around the Cape of Good Hope by going through a short cut – the Suez Canal.

Eventually, the obstacles forced upon us by oceans and continents were removed, too, with the advent of air travel. These days you can get on a jet at Schiphol in Amsterdam and get off twenty four hours later at Perth International Airport. With airliners like the beautiful and now-departed Concord, you could do the journey in half the time. So in four hundred years we have shortened a journey that took about a year – let’s say 350 days – to one that routinely takes 1 day or (with the right aircraft) an awful lot less. Wow.

Still with me? Trust me, it’s all relevant to space travel. Imagine what reaction a person would have received if, in 1600, she’d said that in four hundred years, we’d be able to travel from Amsterdam to that southern continent we didn’t know anything about, in less than a day.

Yes, but that’s just the Earth, I hear you say. We’re talking inter-stellar distances. For Pete’s sake, the nearest star system from ours is over 4 light years away. Very true. We have no way of spanning these vast distances in anybody’s lifetime. Regardless, the notion of ‘hyperspace’ in science fiction to allow for the possibility of space travel has been around for a long time. I don’t think I ever saw an explanation of hyperspace – just that the ship entered another dimension, if you will, travelling externally to our normal, 3D + time. But hey ho; never let the facts get in the way of a good story. The Grand Master, Isaac Asimov, did rather a lot of planet-hopping. Have a look at his ‘Foundation’ series. Many of the more modern writers like Mc Devitt and Moon have FTL (faster than light) travel but show it as still a very time-consuming business with journeys taking weeks or months..

I don’t believe that restriction is cast in concrete. Even Mc Devitt in his book ‘A Talent for War’ postulated a quantum drive, where a ship moves from one place to another instantaneously. We don’t hear so much about worm holes these days, but they would also allow for an instantaneous transfer.

I refer to my version of hyperspace as ‘shift space’. I’ve done that deliberately because in my universe the ships use the geometry of extra dimensions to get around. Ships ‘shift’ to another dimension for the duration of a journey. It’s pretty much accepted that our 3D notion of the universe is just a perception, that there are many other dimensions we are not equipped to see. Such an understanding certainly helps to explain the apparent complexities of quantum physics and the anomalous behaviour of sub-atomic particles. Way back in the 1980’s Carl Sagan in his wonderful TV series ‘Cosmos’ showed us a tesseract  (http://en.wikipedia.org/wiki/Tesseract), a four-dimensional object portrayed as best we could in a 3D world. To understand what you’re looking at, think about a standard, 2D drawing of a cube. According to mathematics, there are many, many more than four dimensions out there, not to mention parallel universes. The biggest limitation imposed upon us in reaching a real understanding of things like this is that we are constrained by our own world view and our ability to perceive. As far back as 1884 E.A. Abbott in his book ‘Flatland’ (http://en.wikipedia.org/wiki/Flatland) described the problems of seeing three dimensions in a 2D world. We are faced with the same thing, on a 3D scale, if we attempt to visualise four, five or six dimensions. Or many, many more.

However, I can give you some sort of idea of where I’m coming from. Take a piece of A4 paper. Let’s label two diagonally opposite corners as A and B. Starting from B, we can reach A by going straight up one side then along the top to A. Hang on, you say, wouldn’t you just go across the diagonal, thereby reducing the distance and time taken? Sure you would. Now curl the paper over into a cylinder. All you have to do to get from B to A is move along a straight line. The length of the line will depend on how you make the roll (short edges together or long edges together).

Now take point A in one hand and point B in the other and bring them together so they meet. Getting from B to A in this instance is like walking from one room into another.

That’s my notion of ‘shift drive’. I have included some duration in the journey in the book because I found it useful. Don’t ask me how the shift drive (the engine that makes it possible to take advantage of the geometry) works. I’m speculating a fusion drive to do something or other. When I work it out, I’ll let you know.

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Since I wrote this article, I’ve come across the Sabre engine, which can operate in both atmosphere and vacuum, and can travel at 5 times the speed of sound. Such an aircraft could make the trip from Sydney to London in 4 hours. That’s four (4) hours. http://www.reactionengines.co.uk/sabre.html So a trip from Amsterdam to Perth would probably be a little bit less. Say 3.5 hours? So we’ve come down from 350 days, to 1 month, to 1 day, to 3.5 hours. Rams the point home, doesn’t it?

27 Jan 2013 And now there’s this. http://www.space.com/19416-hypersonic-spaceliner-fly-passengers.html. A spaceliner which will do the trip in 90 minutes!!! Wow. Just wow.