Thursday, November 25, 2010

Space Combat in The Black Desert IV: Weapons!

I was going to put out a post yesterday, but my wife had a better idea.  Best laid plans of mice, right?

     Anyway, since last post was about IPVs and why they are so hard to destroy, this post is about the weapons used to destroy them - and rockets and pretty much anything else in space.  We'll start with the basics:


     Spacecraft weapons come in three flavors in The Black Desert: Beam, Fusion, and Kinetic. Beam weapons means lasers.  This is pretty much it; plasma is a crappy weapon in realistic space combat because it expands into a cloud and dissipates too quickly to be of use except in some Character-scale melee combat (that is so another post), and particle beams, while both looking and behaving like phasers and turbolasers and whatnot are a little out of our technical league. But lasers are just fine; we have lasers that can vaporize a tank in three seconds now.  Granted, with silica aerogel insulation rockets will be harder nuts to crack,  nevertheless lasers can fulfill the requirements of a Hard SF RPG combat system.
     Lasers have, like everything else, advantages and disadvantages.  The advantages of lasers are their theoretically infinite range and instantaneous strike capability.  In other words, you can't dodge and you can't outrun something that hits you going at light speed.  Lasers can miss; and targeting was the bane that killed the YAL-1 airborn laser system in the first place.  The major disadvantages are that lasers generate a lot waste heat, and the laser itself is the best target of an attacker's laser.
      What this means, in practical terms, is that lasers engage in "staring contests" in an attempt to burn each other out.  Since lasers power virtually all spacecraft propulsion systems, this is roughly the same as shooting the tires in a car chase and shooting the bad guy's gun out of his hand at the same time.
     The obvious solution, of course, is to shoot first.  The next best thing is to have more guns, or lasers that don't hook into your engines.  You can kill two birds with one stone (pun intentional) by stocking cheap, autonomous Laser Missiles/Satellites that fly in formation around your rockets and try to fry the other side's lasers while yours are safe.  Assume that the other side ain't stupid either, and you have wings of Heinleins carrying L-sats in their primary payload bays on both sides.

     Such is the nature of arms races.

     The next category of space weapon we will discuss is Fusion weapons.  These do not include nukes of any kind for reasons that will become obvious in the following section.  The major Fusion weapons in The Black Desert are the Fusion Torches on the rockets themselves.  I realize that this is the second time that a space weapon is also a propulsion system and I can't help that.  When physics hands you a Massively-Powerful-Weapon-O-Massive-Destruction, real life economics dictates that you don't waste billions on R&D trying to outdo it.  The economics of an indie game designer dictate that you don't either, so there you have it; Fusion Engine=Kill-O-Zap.
     I mentioned in a previous post, when you has such a powerful weapon in your Character's arsenal, you must limit it or face breaking the game.  Fortunately, Fusion Torches are pretty limited; in addition to having short ranges, the Torch uses up so much propellant that it's only good for a few shots before you run out of gas.  Therefore, you will want to save its ten-million-degree plume of radioactive death for the most expensive and heavily defended targets.  Targets like the nigh-invulnerable IPVs, that can stand up to almost anything but not to a Fusion Torch.  At least, not for very long.

     Thus, balanced in maintained in the Universe.

     The final type of space-borne weapon in The Black Desert is the Kinetic weapon.  This is basically Mass+Speed=Ka-Boom.  As Rick Robinson pointed out, anything moving at 3 kps will hit you with a force equal to its own mass in TNT.  Doesn't matter if its lead, lunch or laundry- at orbital speeds it's all deadly.
    This is why nukes are impractical. The added expense of an atomic warhead is wasted because the radiation is not especially higher than the rocket can tolerate and the heat storm you get in atmosphere has no medium to travel through in vacuum.  It is much cheaper to make a missile with no payload that is designed to explode in to a cloud of tiny particles in an enemy's vector.  Think about it; a ten- ton solid projectile and a huge cloud filled with ten tons of coin-sized debris is still ten tons. The physics does not care about form or composition, only mass.  And you have to admit that a ten-ton cloud of debris is a lot harder to dodge than a projectile.
     In the Heinlein PDF, I mention that the eponymous rocket's military version is equipped with twelve Piranha Kinetic Missiles.  They follow the example above; once launched, they approach the oncoming Space Wing's vector and explode into choking clouds of debris that rapidly spread out.  The clouds spread out and are almost impossible to avoid, especially at high speed.  Even with diffusion as the clouds spread, having a dozen of these missile-clouds in front of you will pretty much ruin your day.  And your ship.

     Piranha indeed.

     Now, there are tried and true tactics for avoiding the ghastly fates promised by my arsenal of space weapons.  They will be discussed in the next installment of Space Combat in The Black Desert.

    By the way, if you celebrate Thanksgiving, I hope you have a safe and happy one.  If you don't, have a safe and happy one anyway.  If you protest the celebration of Thanksgiving as glorifying the beginning of the end of Native American culture...In The Black Desert universe, the American Middle West is part of the Union of the Americas, and is under the leadership and cultural mores of the remainder of North America's native population.  This is one of the first things I decided to do with the campaign setting, a decision I made over two years ago now.  Granted, giving fictitious land back to the natives two hundred years from now is not much, but it's the best I can personally do right now.

    So everybody have a happy and safe whatever. 



Tuesday, November 23, 2010

Space Combat in The Black Desert III: IPVs

    I have been at the Doctor's Office all day today, so this may not be the longest of posts.  That being said, I'll bet most people in the States will be doing the Thanksgiving thing for the rest of the week, so I'm gonna try to give you all some pithy content to remember me by.

     As the title suggests, I will begin by discussing IPVs, or more specifically, Strategic Spacecraft.  Thanks to Wings 3D, one of the many, many optional programs that Ubuntu has let me download, I have been able to build a CG model of said Stategic Craft.  Let's take a look, shall we?
Strategic Spacecraft. 

  The ends of the spacecraft contain the fusion reactors and magnetic sail "poles".  The cylinders behind those contain the IPV's hydrogen propellants.  Next, there are two docking rings, capable of transporting eight Heinlein rockets apiece.  Cargo pods are mounted beneath the rings.  The little spheres contain life support gases and lithium for the active radiators that are not shown in this model.  The exact center of the spacecraft is the primary habitat ring, which houses all the crew, medical facilities, offices, command and control elements, and food and exercise equipment.  I have also not pictured the avionics booms, connecting spars and...well 90% of the detail.  It's just a basic mesh; in February, when I will have my first IPV up for sale, it will be hand-drawn in all the detail of the other deckplans we put out.  I will use the model here to make a perspective drawing, if you're lucky...  

I know it looks like a space station, and that's for a good reason.  It is, a mobile command and control station capable of rapid response any where between the orbits of Terra and Mars.  How fast?  With constant boost, and an acceleration of 0.001g, It is twice as fast as the fastest spacecraft in existence today.  It only takes an IPV a mere 2.4 months to reach Mars orbital space from LEO, compared to 5 months via asteroid cycler.

     Space is really freaking big.

    To make sure everyone has the same mental picture of how one of these things flies, I made this handy diagram of the magnetic sail in relation to the IPV:

 
     For those who are unfamiliar with how a magnetosphere looks, The stubby end is the one facing the sun; the ship is traveling to the right.  It is safe to fly in any orientation except parallel to it's long axis; the poles are vulnerable to damage from debris.  The fun part is that there will be auroras around the fusion plants, just like there are in Alaska and Australia.

     These things are tough nuts to crack; just as Jon's Law shows that a Fusion Torch is the ultimate weapon, the Magnetic Sail is the ultimate shield.  Because it's designed to repel debris and stellar radiation, it can shrug off lasers, shrapnel, kinetic kill weapons and even nukes with relative ease.  The only theorized effect as of 2010 is that the sail will inflate and accelerate the IPV away from the attack.

     I assume that eventually, the sail will overload and shut down.  It will in The Black Desert at any rate; otherwise it would be a pretty pointless game.

     Tomorrow, we will arm our imaginary Space Wing and see what kind of trouble they can get into.  Have a good night!

       

Monday, November 22, 2010

The Consequences of Writing Hard Science Fiction

     The thing about writing Hard SF is that you have to take into account all of the consequences of your actions.  With The Black Desert, I thought I'd be okay; there's no FTL, no transporters...in fact, most of the tech seems to be mid-21st century, not twenty-third.  I did that for a good reason, by the way: For one thing, its easier to predict mid-century tech, but the main reason is the consequence of having people live so much longer.  In The Black Desert, lifespans reach up to two centuries.  Because of this, the scientific and engineering "old guard" are around for decades longer, and keep the "young turks" with the radical ideas from taking over.
     Those aren't the consequences I am bemoaning in today's post.  My problem is not taking into account all the consequences of my propulsion systems for spacecraft.  I thought I had it taken care of, because I took into account Jon's Law by making Fusion Torches a weapon and all that good stuff.  But while I had the military consequences worked out, I forgot about the economic ones.  I forgot about the L-Drive.
      Like I said in a previous post, the L-Drive is a species of Lightcraft.  I chose this particular propulsion system because its realistic, and it's cheap.  I needed these factors in order to justify groups of PCs flying around in rockets.  After all, if a single launch costs hundreds of millions, Players aren't going to nip off to the Moon to check out a rumor.  The beauty of the L-Drive is that while a spacecraft is in the atmosphere, it does not use propellant.  It can get away with using the atmosphere under its bell.  This is the best feature of the L-Drive, because the Delta-V needed to go from Terra's surface to Low Earth Orbit (LEO) is roughly equal to the Delta-V needed to go from LEO to Luna.  Sounds fantastic, right?  Fortunately, I found a video on Youtube showing the prototype in action:
   



     How cool is that?
     Unfortunately, I hadn't thought out all of the consequences of having such an awesome drive in my game.  The biggest advantage of the L-Drive is also the biggest headache for game design: it doesn't use propellant in atmosphere.  Think about what that means, RocketFans.  The fuel cost of launching practically anything into orbit from our ridiculously deep gravity well is now essentially zero.  Sure, it still takes gigawatts of power, but I solved that with D-He3 Fusion. What's the problem?   There is no reason not to keep shipping stuff up from Terra.  Heck, there is no reason to live in space!  I did the math; with this drive, its actually cheaper to go from Luna to Terra's surface and then go to Lthan it would be to go from Luna to L5 directly.  Commuting to Luna would be comparable to flying to Europe on business today.   
     Needless to say, this puts a cramp in my ideas about permanent settlements in space.  
     But that's okay; once I got over the initial shock, I realized that all this easy access to orbit makes the Black Desert even cooler than I thought!  The orbital space around Terra will be loaded with habs, hotels, research stations, fuel depots, transfer points, and any other thing you can think of.  It may not have a more than a few hundred permanent residents, but there will be thousands of transients traveling to and fro, and that means even more NPCs for characters to interact with.  Even better, running adventures on Terra and in space is simpler, and anything that add potential locations to a game is a good thing.
    I still need to do more research on all of the consequences of my propulsion systems (I haven't even worked out all of the Plasma Sail stuff, yet)  but I am confidant that whatever those consequences are, they will make the game even cooler.   
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