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Some Questions on 2300 AD Era Ships

When I started looking at interstellar speed differences, it became rather clear that we need some more serious thrusters. Without them it becomes very hard to slow down enough to discharge in some systems - going to Barnard's star from the sun is going to impose 140 km/s velocity on the visiting ship! None of the presented designs seem to have engines that could give that kind of delta-v.

Most of the time, 2300/2320Ad ignores such things because Stutterwarp is so fantastically efficient and effective. However, I agree that there needs to be some answer to the question you pose.

I don't think that's as big a problem as you may think... remember that while Stutterwarp is reactionless, it doesn't negate gravity. The entire trip from Sol to Barnard's Star will be spent leaving one gravity well (Sol's) and entering another (Barnard's), and both will have a cumulative effect upon the realspace velocity of the ship. Granted it won't be much, but it is something Astrogators will have to take into account when plotting FTL transits.

One can also use gravity wells to slingshot, as well as 'gravitybrake.' I would think that stutterwarp ships, upon entering a system with a large residual velocity difference can either take a long spiraling route in-system to shed/gain residual V, or repeatedly dip into a 0.1G well to 'gravitybrake'.

Of course, one could also handwave it, saying that the quantum-teleporting effect of the Stutterwarp drive automatically readjusts residual volocity differences. Perhaps that's part of the 'gravistatic' charge that builds up on a Stutterwarp drive.

(Come to think of it, maybe -in some other version of 2300AD- its' the delta-V between systems that is the 'limit' of an FTL drive, and not the distance between the systems. hmm...)

Anyway, my two cents...
 
That's an excellent article to deal with a problem I've always had with stutterwarp: matching relative velocity. I'd bet that all methods are used in combination along with suitable quantum handwavium in the drive itself. One thing's certain: astrogator would not be an easy job on a 2300ad ship
Andy P.
 
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I think astrogation is like flying a jet: most of the time it is about selecting the right option on the autopilot. It is the rare exceptions and overall strategy that require skill.

If the pilot of a ship wants to go from Gateway to a particular habitat over Tirane I would guess the following steps are involved:

The pilot decides on the overall flight, especially what gravity assists and discharges may be needed. The trick is finding a flight that is as fast, cheap, safe and elegant as possible. Since planets are moving, the exact flight time and position might be changed and there might be various delays, the real flight plan is more like a huge bundle of possible flights, with the preferred one at the core. There is good software for this and lots of navigational databases with the orbits of everything major. The software can search out possible flightpaths automatically; most pilots never use anything else. Real pilots of course know how to handle uncertain data, badly charted systems, drive quirks and totally unexpected situations: this is (they say) real astrogation.

Requesting departure from Gateway traffic control, logging a preliminary course out from Earth. Traffic control will give a certain flight corridor to the ship that avoids all the other traffic and objects. The pilot (and likely his organisation) will negotiate timeslots; some spacelines will have preferential treatment, there might be bidding systems for the most desirable slots and corridors.

The ship disconnects from Gateway, and uses its own thrusters and perhaps tugs to move sufficiently away from the safety zone around the beanstalk before engaging the drive. This is basically piloting, knowing how to handle the nontrivial inertia of the ship (especially if it has rotating parts) with a set of thrusters. Good ships of course have software that makes this easy, good pilots know the limits of the software.

The ship begins to move away using the drive. At this point the flight corridor might simply be put into the autopilot until further notice. The pilot will stay on watch for changes (which are likely in a busy place like Earth orbit) and update based on this. Most of this part is merely button-pushing, except for big contingencies like being inspected by the OQC (back to fine grained thruster fiddling again, as well as the prospect of having to redo the flight plan due to the delay).

Once outside Earth traffic control (I would guess about a 100,000 km or more away) things slow down even more. The (best fit) flight plan is run on the autopilot and the crew only needs to check comms and scanners occasionally. The transition to superluminal speed may be impressive for passengers, but it does not make much difference to the crew except that comms become trickier.

If the plan is to do a quick slingshot past Jupiter to get the right velocity vector things speed up again after a few hours. The ship enters Jupiter traffic control space (this is such a busy place that it is needed, although it is not as strict as near Earth), gets clearance for a certain trajectory as well as navigational updates (look out for the sulphur dust trail from that recent eruption of Pillan Patera on Io!). Again the pilot needs to be on watch, but it is likely pretty uneventful.

Once free from Jupiter gravity it is time for the serious part of the trip. Again, most of the job has already been done and it is mostly about loading the right flightpath and cranking up the drive to max. The pilot will likely adjust the ship orientation with the thrusters to ensure that any collision with interstellar dust will make minimal damage (depends a bit on the ship shape and the angle between the realspace velocity and the stutterwarp pseudomovement). Not crucial, but insurance companies and safety inspectors like it.

Once arriving in the Alpha Centauri system things speed up slightly. If necessary more velocity adjustments are done, and since traffic is lighter here there may not be a traffic control near the outer planets. That means the pilot need to broadcast position himself, and make sure he doesn't get too close to any other. The probability of hitting each other is of course essentially 0%, but again safety regulations suggest erring on the safe side - plus, in many systems there might exist trigger-happy police or military ships looking for smugglers, pirates and Kafers.

Approaching Tirane the pilot negotiates a flight corridor with traffic control. This is likely the most annoying part of the trip, since the delays in communications are still long. Depending on traffic, how expected the ship is, relative orbits of the ship and destination etc a corridor is assigned. At any time in a busy system like this there may be several ships "hanging" close to the traffic control zone waiting for their turn.

Again, the autopilot runs the flight corridor until the ship comes close enough that it has turn of the drive, and then thruster autopilot and the real pilot make the final approach (possibly helped by tugs or downloaded commands from the habitat; some habs really like controlling nearby ships directly, something that pilots generally hate).

Finally the ship docks and various connection checks get done, as well as whatever decontamination, documentation and registration the local bureaucracy wants. The pilot also orders the chief engineer to begin stutterwarp discharge (another matter some bossy habitats might want to send a representative to check that it is done properly).

Have I missed anything?

While this kind of routine travel is pretty unglamorous I think there are some potential adventure seeds here. Just imagine the potential if the competitor to a shipping firm could sneak in subtle errors in the optimization of flight plans of their ships, slowing transports? Conversely, what if a brown dwarf was found that helped velocity adjustment rather than length of travel - those coordinates would be a great industrial secret. Political decisions might affect the PCs departure timeslot adversely - if they *really* need to get away, how to do it without breaking the rules? If habitat flight control has access right to send navigational commands, what if somebody hacks it? It might also be fun to pit the frontier pilot used to navigating "by hand" against the intricate rules and etiquette of Core traffic control.
 
Overall looks good. Couple of quick comments:
1. If/When a starship has to adjust its' heading, it will mostly use control moment gyroscopes; not thrusters. Thrusters use fuel (in the case of 2300ad they seem to love using H2/O2 for everything) which can be more efficiently converted into angular momentum by converting it to electrical power by the ship's fuel cell or MHD generator and then into angular momentum with the moment gyros. A commercial ship particularly interested in cost-cutting would not want to burn more than they absolutely had to. I'd imagine most starships would only burn fuel for velocity changes or when their control gyros became saturated and they needed to shed excess angular momentum.

2. Jupiter, as the largest planet, would be very popular as a momentum exchange point for stutterwarp equipped ships. I think that it might have a *larger* and more complex traffic problem than the Cis-Lunar traffic control system. Consider:
-Recent solar activity can effect Jupiter's radiation bands' extent...those bands are on the order of 1000 rads per some ridiculously small exposure like an hour. I don't recall off hand.
-You've already mentioned the IO plasma torus
-there are many Jovian moons. We know of 59 or so today. Count on there being more. Any one of which is likely attended by a dust pattern whose density variations could effect stutterwarp ships.
-As a popular spot for velocity adjustment, a gas giant could have numerous "heavies" i.e. ships whose relative velocity is very high. They are moving fast and are at greater risk from microparticle collisions and would have priority in the traffic pattern. That's gotta be annoying.
3. The pilot/navigator watch during interplanetary cruise would likely mostly be on the bridge waiting for the (automatic) navigation RADAR to alarm on proximity...and never having it happen in his whole 20 year career.

More as I get 'em
Feld
 
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Given the previous discussions in this thread, there would likely be plenty of interesting gyroscope systems onboard, especially if there are rotating habitats. The interactions between them, thrusters, bigger engines on some ships, and the drive would be interesting to say the least. So many degrees of freedom to mess up or get damaged... (for space battles I would expect gyroscope damage to be a potential killer, as the ship may seriously lose orientation control)

Communications delays for traffic controls might be an issue. Near Earth they are on the order of a second or less, like a very bad Skype conversation. That is probably manageable. Around Jupiter the delays would be longer, making dealing with control more like a slow chat.The distances are longer too, so it is likely not too stressful. However, in such an active environment communications disruptions might be very problematic and not too uncommon.

Communicating with a warping ship seems messy. The message gets split into nanosecond chunks. The drive introduces noise that can be removed with a notch filter, but if the ship is approaching the signal source it may "jump over" parts of the signal - the wavelength of a bit of information better be longer than the jump length. That suggests relatively low data rates, perhaps even excluding video. The message will also be speeded up or slowed down. When moving away superluminally from the source signals can clearly never reach it, and it will get earlier signals replayed backwards - this is bad for traffic control when it needs to warn a ship. I would guess that a ship that is actively communicating often turns off the drive briefly to get a clear window (but during battle, when all of this really matters, this can of course not be done - signals engineering for submunitions is probably mindbending). All of this suggests that messages get sent as chunks like current plane-tower dialogue, rather than chatting in front of the viewscreen a la Star Trek.
 
Re: Timelag
I think that the timelag involved with Earth-Mars communications is about 1 hour, so any messages will generally be in text form, rather than audio or video....
 
>Earth-Mars communications is about 1 hour

1 hour would be about the worst case times for earth-jupiter .... jupiter is a bit more than 45 minutes from the sun

earth is roughly 8 1/2 minutes from the sun and mars about 13 minutes so assuming they are on opposite sides of the solar system thats about 22 minutes each way
 
Peter:

generally, comm lags are counted both directions, since to person A, it takes an hour to get a response from mars, and between an hour and just under 3 to receive response from jupiter.

Anything past about 5 seconds round trip lag is annoying enough that most people won't want to be live.
 
>it takes an hour to get a response from mars

45 minutes worst case more like 12 minutes best case .... plus actual times of messages

>Anything past about 5 seconds round trip lag is annoying enough that most people won't want to be live

SPACE is BIG !
looked at another way its almost like being in australia and participating in discussions involving mainly americans .... almost guaranteed 7 hours lag <laughing>

seriously there's few situations I can imagine in space except local planet/orbit areas where lightspeed comms isnt going to exceed your 5 second round trip lag even many moons are going to exceed this eg io > europa much of the time
 
Precisely.

Two-way conversations are strictly a local phenomena.

Oh, and RTC with mars at worst case requires a third point relay... something about losing the signal in that big plasma ball...
 
These comm lags adds a lot to the isolation for outposts within a colonized system. Since they are small it is uneconomical to send message missiles very often, so they will suffer the lags, reducing the number of messages sent. This is good for GM use, since PCs can be nicely cut off from civilization when the inevitable emergency happens. It also means that the outpost people are likely to culturally diverge, building their own micro-culture like people overwintering in Antarctica. Everybody knows everybody, everybody has seen the same programs and played the same games, everybody uses the same in-group references - and the PCs are total outsiders.

On the other hand, something I think colonized space is littered with is communications and navigation satellites. Given cheap access to space and the need for ship-planet and ship-ship communications, most major bodies are by now orbited by at least one or two active satellites. In my own setting there is a lot of competition between communications companies to get traffic through the satellites at popular bodies, while less popular and remote bodies have old government-issue satellites or rickety remnants from now bancrupt local commcorps. An interesting adventure seed would be for the PCs to be sent outsystem to find out why a number of satellites have started to disappear - is somebody stealing them, or are they trying to weaken communications? Why do the belters warn them that the 'Oort gremlin' will take them too if they inquire too much?
 
Good thread. Interesting looks at 2300 tasks.

I've always thought that synchronizing your vector with the new star system was a problem glossed over in the game.

Anders I like the way you describe it.

Thanks!
 
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