Monday, October 17, 2011

Space Combat in The Black Desert: Actual Rules

         Happy Monday, RocketFans! For those of you still with us, thank you so much for sticking it out during the long silence after our move.  Long story short, our DSL provider marked us down as "disconnect" instead of "transfer" after our move, and our slot in the rural router (which is as rare as an empty parking space in Rome) was given to the next person on the list.  It took tedious negotiations and finally a switch to satellite Internet in order to get us back online.

          But enough about that.  How about an update on the game?  The following is far from a final draft, but it shows my general idea about keeping space combat in the Character scale and all that jazz.  Questions, comments and criticisms are always welcome.

          Enjoy, RocketFans!

In order to fully explain the different phases of a space conflict, we will use a sample scenario and a made-up group of PCs to provide examples of each phase of the process:
The Heinlein rocket Annabelle Li commanded by an AI of the same name, leaves Terran Orbit for Luna. Her crew are made up of a Lunarian Freebrawler (Tildé), A Nurilla Pilot (Tuskeege), A UACSian Medic (Wade), and a Briturkish Engineer (Niles) Annabelle herself is an NPC. The scenario involves a shady spacecraft on an intercept course, a case of mistaken identity, and an opportunity for all of the PCs to show their stuff.

Phase 1: Detection
“We are now in the groove. Secure from acceleration.”
Tusk's native Nipporusk, made thick by his fangs, was easily cleaned up by Annabelle Li's translator. The Nurilla and AI had worked together for years.
Wade sighed wistfully. “Bye-bye gravity. We hardly knew ye...” he said. He unstrapped and floated free from the Life-Support station. For the next thirty-six hours, they would be in free-fall, until captured by Luna's feeble field. “I'm gonna check on Pablo. I'm sure he either needs to potty or needs to be changed by now.”
“Have fun with that, hon.” His wife, Tildé, teased him while entering a program into the flight computer. “Beginning traffic search of Trans-Lunar vectors.”
“Is that quite necessary?” Their Engineer, Dr. Niles Du'Kah, inquired, “It's not as if we're expecting trouble, are we?”
Tildé's full mouth quirked a half-smile. “Well...maybe you aren't-”
The exchange was interrupted by Annabelle's crisp British accent. “There are eight spacecraft on the current Trans-Lunar Injection. Three will intercept our vector within the next twenty-four hours, plus or minus eighteen minutes. Flight data being displayed now.”

The first phase of a conflict in space is finding out where the potential threats are. Space is vast, and even on the most crowded vectors between planets, only a handful of spacecraft will be anywhere near each other, and of those a very, very few would be able to get close enough to engage one another.
Even then, the combatants will likely never be close enough to see one another with the naked eye.
Fortunately (or not, depending) detecting other spacecraft in the void is almost ridiculously easy – in fact, the rule of thumb is “everyone sees everything in space”. Because of this, there is no point trying to hide a spacecraft's movements in any way, as even a rocket coasting with an internal temperature low enough to kill the crew will show up like a floodlight anywhere within half a million kilometers. In game terms, a Very Easy Avionics Skill Check will detect any spacecraft not in the shadow of a celestial body with no problem.
By simply determining the brightness and speed of a rocket's exhaust, an Avionics check can extrapolate it's mass, acceleration, and flight vector. This information will give away the rocket's class and type, and maybe even which member of that type the specific rocket is.
Coasting rockets are no less difficult to learn about, as their vector can be determined and then backtracked to their point and time of origin with a little computer work. By downloading or analyzing records, the rocket's identity can be established.

Example: Once the Annabelle Li has reached cruising speed, the crew go about their duties, starting with a Very Easy Avionics Skill Check to survey the space around them. The Li's Avionics Dice are +2D, which means that as long as Tildé's PC doesn't roll a 1 on the Wild Die, the roll will succeed. She doesn't, so the GM lists off a complete picture of their orbit through his AI NPC.

Phase Two: Determination
Tusk shifted in his harness. “Bogey One confirmed; a Duchess transport out from Yggrasill Station. It's the Georgiana Spencer. Unarmed; no threat.”
“Send them our regards; pledge of assistance and all that jazz.” Wade suggested. “Never hurts to be neighborly.”
“You are a true gentlemen, sir.” Niles commented sardonically as Tuskegee chuckled. It was a peculiarly ominous sound.
“Bogey Two is a Heinlein transport.” Tildé reported,” Unknown origin; her vector traces back to Low Earth Orbit...possibly the surface.” She turned to Niles.
Is that even possible?”
“It can be done,” Niles mused, “but not for any good reason I can think of.”
Tusk nodded his agreement. “Marking Bogey Two as 'Suspicious'. Time to intercept, seventeen hours, twelve minutes...mark.” He turned to the rest of the crew, behind him. “We still do not know about Bogey Three.”
“Data uploading now.” Niles answered.
“I hate it when y'all get all serious.” Wade grumbled as he began typing on his console. “Guess I better make some calls...”

Sometimes knowing the who, what and where of a rocket is not enough; you have to know the why as well. The Determination Phase of space conflict is when the crew gets the opportunity to discover more about the spacecraft in their general vicinity.
The simplest way to do this is to let the computer take the information from the Avionics Check and search its database of known spacecraft. Most rockets have filed a flight plan with local traffic control and their departure times were recorded. It only takes a Moderate Computer Operation Skill Check to determine who most civilian craft are in the Black Desert.
Some craft, however, are not so easily discovered. Military craft, while common in some locations, will have their flight data and manifests classified, offering little more information for the curious than the initial Avionics check can uncover. Others are smugglers, freebooters and other shady rockets that lifted from unofficial spaceports and lack flight plans altogether, or else have payed someone to conceal their movements. In these cases, more creative methods must be found.
A Moderate to Very Difficult Computer Operation/Hacking Skill Check can reveal the relevant information on an unknown military spacecraft. This Check is modified by the Avionics value from the Detection Phase. For every Difficulty Level passed above Very Easy on the initial check, all checks in the Determination Phase are lowered by one Difficulty Level.
In addition to Hacking, the PCs may also attempt to use Allies and Contacts to find the information for them. Allies will usually help the PCs, if they can, in exchange for a favor in return, to be determined later by the GM. Contacts are more expensive, requiring a bribe. The value of the needed bribe is usually L$U 500 times the Difficulty Level. For ease of use, a table has been provided below:

Difficulty Level
Very Easy
L$U 0
L$U 500
L$U 1000
L$U 1500
Very Difficult
L$U 2000
L$U 2500
In addition to the bribe, the PC must make a Moderate to Very Difficult Bargain Skill Check. If the PC has money to burn, They can increase the bribe, thus decreasing the Bargain roll's Difficulty. Likewise, if they are short on cash, they can attempt to bargain at an increased difficulty.
An Automatic Failure on the Bargain Check not only means the bribe is wasted, but that the Contact in question betrays or cheats the PC is some way. An automatic success means that the bribe is L$U 500 less than it otherwise would be, even if that means no bribe is needed. Bribing can be attempted with strangers; The level of Difficulty starts at Very Difficult and the Bribe values are doubled. All other rules involving Contacts apply.
While the Avionics bonus can help the NPCs searching on the Player's behalf, it does not modify the Bargain Skill Check.

Example: Tusk, Tildé and Niles roll Computer Operation to determine the identities of the Bogeys, each taking one. Wade, not skilled in computers, declines to roll until he sees a chance to assist in some way. The initial Avionics roll made by Tildé was a 14 (she got a Wild Bonus), which is enough to drop the Difficulty for each of the Bogeys by two Levels. Tusk easily digs up the info on the Georgiana Spencer (a Moderate Check reduced to Very Easy). Tildé, however, has less luck. The GM decided Bogey Two is the bad guy, and made the Difficulty Impossible. Even reduced to Difficult, Tildé only rolls 22- three less than she needed. Niles makes his roll and succeeds in uncovering the other red herring.
Since Tildé failed her roll, Wade takes a different approach. Using his large Dice Pools in less-than-noble Skills, Wade calls one of his many contacts. The GM determines the Difficulty for the Bargain Check is Difficult, But as the PCs are very limited in funds (only L$U 950 in total) Wade's actual Difficulty is Impossible. The Skill Check only has a slim chance of success.
Phase Three: Decision
“-and thanks again, Charlie. Yes, just use the locker combo and that liter of Martian Burgundy is yours. You sure earned it.” Wade cut the connection. “and that's that, folks. Our mystery rocket blasted out of Europe three days ago. No official flight plan was filed, but Charlotte dug up a transaction for a full load of fuel prior to departure. Single-H and Lox, not water.”
Niles whistled. “One does not surface-fuel with cryogenic gases without ill intent.”
“Fourteen hours until intercept.” Tusk said.
Tildé smiled without mirth. “At least Bogey Three turned out to be harmless.”
Annabelle cleared her non-existent throat. “All hands, prepare for action.”
Wait, are we fighting or running?”
“Are you serious?” Annabell responded, “We run. I've just been detailed!”

Once enough information has been gathered to determine friend or foe, the PCs must decide what their next course of action is. There are only two choices; Flight, or Fight.
This choice involves a bit of a gamble. Running has the advantage of living to run another day, with the potential risk of using too much propellant and being unable to slow down at one's destination. Fighting it out is usually easier on the gas tanks, involving only minor vector changes to reach an advantageous position, but is dangerous in its own right for reasons that should be obvious.
PCs can make, Engineering, Nuclear Engineering, Spacecraft Operation,and Strategy and Tactics Skill Checks in order to determine the best course of action.

Example: By spending two Progress Points (one before the Skill Check and one after, for a total on +1D+1), Wade manages to succeed at his Bargain Check. The GM makes something up about an emergency “cash drop” of contraband hooch and gives the PCs just enough info to let Niles make an Engineering Check and confirm Bogey Two is a threat.
Tusk and Tildé make Spacecraft Operation and Strategy and Tactics Checks respectively. Based on what the PCs know (that the mystery ship is probably a nasty customer and the Annabelle isn't armed for battle) the GM advises discretion. The PCs decide to make a run for it – change their vector just enough to make it impossible for the pursuing spacecraft to get in range without overextending their available -V and being unable to safely land on Luna.

Phase Four: Preparation
“That's the last of it,” Niles reported. It had been a hectic twelve hours. “We've topped off our main and auxiliary maneuvering tanks, and the sensor diagnostics show no problems.”
All laser turrets ready and active.” Tildé reported. “L-Sats one and two programmed and ready for launch. The Caltrop is fueled and awaits final program. She turned to the others, her face half-lit by her SmartScreen, “Here's hoping we don't need it.”
“Amen to that,” Wade agreed. “Life-Support on all decks off-line. All compartments evacuated except Control Rooms one through three, and the Keel. Infirmary's on standby. Here's hoping we won't need that, either.”
Wade crossed the main Control Room to speak to his wife. “Pablo's in a Rescue Ball and strapped down in the Keel. I've sedated him. Just in case.” Louder, he announced, “ Time to suit up, Lady and Gents.”
“And use the facilities,” Niles added, “I remember one time during the war I neglected to and-”
“T-minus thirteen minutes to Engagement window,” Tusk interrupted, much to the relief of the rest of the crew. “Preliminary evasion programs selected. I cannot promise miracles; we've little in our Safety Threshold to work with.”
“We'll do fine, I'm sure” Annabelle soothed, “In fact, I'm willing to bet my skin on it.
While the others laughed, Tildé wrapped a rosary around her left hand and exchanged a quick kiss with her husband. “See you on the other side, mi amoré.”
“I now have control,” Annabelle announced. “Please, attend to business, friends.”

Arguably the most important phase of a space conflict, the preparation the PCs make prior to an engagement can mean the difference between life and death, to say nothing of success and failure.
As mentioned before, rockets are complex machines and there are no non-essential crew aboard. Each member of a rocket's company has a lot they can do to secure every advantage possible once their craft comes into contact with a hostile.
In a nutshell, the mechanics involved are fairly simple. Characters make relevant Skill Checks at the Difficulty Level of the encounter (Moderate to Impossible). Their successes, in turn grant bonuses later, during the Engagement and Resolution Phases. Possible Skill Checks and their results are described below:
Strategy and Tactics
+1 to Attack Rolls
+1D to Attack Rolls
-1D to Attack Rolls
+1 to all PC Rolls
+2 to all PC Rolls
-2 to all PC Rolls
Opposing DL decreased by 1
Opposing DL decreased by 2
Opposing DL increased by 2
Spacecraft Operations
Opposing DL-1
Opposing DL -2
Opposing DL +2
Gunnery Maintenance
+1 to Damage Rolls
+1D to Damage Rolls
-1D to Damage Rolls
Telepresence Maintenance
+1 to Telepresence Rolls
+1D to Telepresence Rolls
-1D to Telepresence Rolls
Avionics Maintenance
Opposing Attack DL -1
Opposing Attack DL -2
Opposing Attack DL +2
Nuclear Engineering
+1 to Safety
+2 to Safety
-2 to Safety
Spacecraft Maintenance
+1 to Hull
+1D to Hull Strength
-1D to Hull Strength
Damage Control
+1 to Damage Range
+2 to Damage Range
-2 to Damage Range
Future Checks -1 DL
Future Checks -2 DL
Future Checks
+2 DL

While these Skill Checks are enough to grant modifiers in and of themselves, GMs should reward good role-playing in this phase as well. Progress Points can be rewarded for announcing a PC's Check result in character, with a PP Bonus for inspired ideas or role-playing. Encourage the Players to get into the tenseness of the encounter, which can only enhance the gaming experience.

Example: The Players make several dice rolls, trying to gain advantage. The GM designed this scenario as a Difficult Level encounter, so that is the DL of the PC's Skill Checks.
Tusk gets a success on his Astrogation/Avionics Check and his Spacecraft Operation Check. The GM make notes on the opposing craft's log.
Tildé makes an Automatic Success on her Gunnery Maintenance Check, which increases the damage from the Annabelle's lasers and missiles by an entire Die. She fails her Telepresence Maintenance Check, however, earning no benefit or penalty.
Niles succeeds at his Nuclear Engineering and Spacecraft Maintenance Checks, which improve the Li's Safety Threshold and Hull Strength respectively. However, he gets an Automatic Failure on his Avionics Maintenance Check, Increasing the DL to beat on Fire Control to Impossible. Rather than announce this fact, Niles' Player says nothing and passes a note to the GM. This earns Niles an extra Progress Point.
Wade also gets an extra Progress Point; the bit about his fictitious son Pablo was role-playing gold. He makes his Damage Control and Medicine Skill Checks with no problem.
Phase Five: Engagement
Part 1 – Maneuvering
“-Bogey Two is still tracking. That monster must have replaced half her cargo capacity with auxiliary tanks.” Tusk raised his visor and took a quick drink with one hand while keeping to his controls with the other three. “ The Spencer has also kept pace, keeping us between them and Bogey Two.”
“If that's just a merchant, I'll eat my hat,” Wade said from his station. “Three to Two she's a smuggler. Pro'bly what our mystery friend's actually after.”
Tildé shrugged. “Independence City would starve without smugglers,” She reminded them. “Besides, we're committed now.”
“How's our gas, Doc?” Wade asked.
“We've enough for Lunar de-orbit and descent, plus a five percent margin. More than enough for Tuskegee, but not nearly enough to Torch in combat.”
Tusk smiled at the compliment, “We gave it a nice try, anyway.”
Annabelle abruptly reported, “Bogey is launching missiles. Two contacts, Thrust/Mass indicates KKVs, Mk II Piranhas, most likely.”
“Rotating maneuver engaged, flywheels only” Tusk responded.
“Launching L-sats,” Tildé responded, “Time for a staring contest.”
“What about the Caltrop?” Wade asked tensely.
Tildé shook her head. “Stare first, target practice later.”

The Engagement Phase is when actual interactions between opposing spacecraft take place. Depending on what the PCs decide Phase Three, this is the time that Rockets either run, or fight. Our example story covers both options; starting with Maneuvering.
When maneuvering to avoid engaging another spacecraft, it is important to remember that physics cannot be cheated or discarded. The goal of maneuvering at this point is to open up the range between the two spacecraft enough that the opposing rocket cannot reasonably attack and cannot close the range without running out of reaction mass. Even with this simple goal in mind, the task is easier said than done.
A normal spacecraft's cruising speed is something past 3 km/s. Even at a spacecrafts normal acceleration of 1 or 2 g, blasting hard to port for a single round will only change a rocket's vector by 420 meters for every three kilometers traveled. Obviously, It will take much more force to get the rocket really moving in another direction. This can be done by expending more than one point of -V per round. Remember, any acceleration over 5 gs requires a Stamina+Acceleration Maneuvering Skill Check to remain conscious.
Another thing to consider is that the rocket must still tack back to it's original Vector (or at least, pointed at its original target) before running out of propellant. Treat this type of maneuver as similar to any other type of rocketry: For every point of -V spent in maneuvering, the same number of points must be spent to correct the maneuver and get back on the original course.
Evasive Programs
Spacecraft move too fast for biological reflexes to keep up. The Guidance Procedures Officer's main job when trying to shake an opposing rocket is to set up an evasive program for the flight computer to follow. When maneuvering in a space conflict, the GPO makes a single Spacecraft Maneuvering Skill Check at the encounter's Difficulty Level to execute the program. At that point, the computer takes over, having a Dice Pool equal to the spacecraft's Avionics Dice +3D.
Example: Tusk makes his Spacecraft Maneuvering Skill Check, and succeeds at the Difficult Level. The mystery craft has a Very Difficult Level for opposing the Annabelle Li, but Tusk's preparations lower that to Difficult. This means that the pursuing craft cannot attack in the coming round. This can continue, with Tusk's Player making all of the rolls against Bogey Two's Difficulty Level, but the players and GM agree that this would be tedious. Instead, it is agreed by the Group that once Tusk's roll executes the Li's preprogrammed evasions, all of them will take turns rolling the computer's Dice (5D), while Niles monitors the available Safety Margin.
Through a mixture of luck, Progress Points, and the bonus from the Preparation Phase, the Annabelle Li avoids the pursuing spacecraft until their Safety Margin is expended. Unfortunately for our adventurers, the GM gave Bogey Two a huge amount of -V, meaning that the craft can easily keep up with the PCs and, once the Li's Safety Margin is expended, close to combat range.

Part 2: Combat
Whether through a failure to avoid their opposition or by original design, there comes a point when the lasers blink through space and the missiles fly. Combat in the empty wastes of space is not for the faint of heart, as even a minor hit on the spacecraft can spell death for the people inside.
On the surface, Space Combat is similar to Character Combat.


  1. Good to have you back and posting again...I know what its like to have to go cold turkey on an internet connection for a while...not fun.

    Did you intend to finish the article just as you got into the first few lines about combat? :)

    Also, what do you define a Delta V change as? Just an acceleration, or an acceleration and a counter acceleration to neutralise the first?
    If its just an acceleration in that one direction, then would you need 3 Delta V changes to get back on course?...1 to counter the first, 2nd to reverse that acceleration, and the last once you are back on course. I may be missing something tho :)

  2. Thanks for the support. I only ended the article there because that's all I had done. I haven't worked on this chapter for awhile...

    As for the meaning of delta-V in the game, It's clarified in the PDF on the Spacecraft Datalog available for free. To sum up here, the spacecraft's Delta-V value is the the number of points worth of propellant in the spacecraft's tanks available for maneuvers. A point is an arbitrary (made up) value equal to the amount of propellant it takes to move the spacecraft at it's Acceleration value for one round (6 seconds). You can spend two Delta-V points to move at twice your acceleration, and so on.

    I'm not clear on how this will actually be used in the game just yet, which is why the article is incomplete. Mainly, a standard burn to Luna from Terra at 1g Acceleration will take 120 points (two minutes worth of thrust). Each maneuver such as dodges in combat) will take off x-number of points from Delta-V, based on difficulty. Or maybe for every extra point you spend, the difficulty of a dodge drops. THat's probably better.

    You probably figured out that I'm totally thinking out loud. :)

  3. Gotcha on the article...looking forward to the combat section :)

    I didn't know if you were abstracting the movement or either way, and probably a good idea not to get bogged down in too much detail, so that works for it wouldn't be too hard to add more realism if you needed too :)


Questions, comments, criticisms? All non-Trolls welcome!