19 January 2020


"That's impossible, even for a computer!"

Turns out, it IS impossible for a computer, though a navigation computer is an essential part of hyperspace navigation in Traveller.

No matter the tech level, a navigator is required to roll against their navigation skill.

In GURPS: Traveller (3e) this is Astrogation.
In Traveller: Interstellar Wars (4e) this is Navigation/TL (Hyperspace).
In LBB Traveller it was Navigation.

All three versions mention the programs needed to be loaded into the computer to make a jump.

The question is: Why does there need to be meat in the loop?

GURPS has Computer Operation/TL for operating a computer, but doesn't call for this skill to run the navigation program.

The pilot is not called on to make a roll with any penalties, so it must be simple and easy to get the ship where it needs to be and pointed in the right direction.

In my Traveller universes, it's because the nav-comp is actually a psionic device.

A jump is a mechanical process.  You align the ship very precisely to be pointed at the destination system.  If there is no mass large enough to precipitate the ship out of jump-space along the line the ship is pointed at the distance the drive is set for... you spend a week in jump-space and go nowhere.

Space is big and a 100 diameter sphere around a star is small, very small.

Because jump travel is routine and reliable... and the precision needed to aim mechanically is very high...  Something besides mechanical aiming must be going on.

That's the nav-comp.  The navigator uses the main computer to generate a flight plan and the navigation program uses this, positional data and sensor data to calculate the jump which is fed into the nav-comp.

The nav-comp is actually part of the jump drive.  It's reading what the navigator meant and that adds precision to the jump that's not evident in the precision of aiming the ship.

What this implies is there are disadvantages which preclude someone from using the nav-comp, or even learning the requisite skills.


  1. I thought that one could buy nav programs or nav robots that would perform as 1 level under the 'power' level of the program or the bot?

    AutoNav-3 gives you actual Nav-2.

    I think that's from early or mid LBB edition. Dunno about GURPS or D20 or 2D6 or Dobedobedo systems.

    It was both having to keep nav/astronav system (be it the ship's cobonculator or an astronav/pilot robot) in tip-top shape, and having that -1 penalty and the expense of the gram or bot, that makes relying on them (program or robot) not too cool in frontier worlds, where proper servicing could be spotty, and more common in core worlds, except in hide bound Vilani 'my ancestor's ancestor's 40 generations past ancestors never used programs solely or robots, so I won't tolerate that new-fangled Solomani clapped-together garbage on my ship/line/ducal fief.'

    Hivers? Yep.

    Solomani? As a spite to the Vilani, of course, and you save on crew salaries and life support, also.

    Aslan? Well, the females yes, males, maybe.

    K'kree? Who cares?

    Droyne? They'll never tell.

    Vargr? Something they can't browbeat and use charisma on? Nope!

    Zhods? Inscrutably so... especially with a psionic interface.

  2. Aha! LBB 8 - Robots, from GDW, allows for astro-robots, either mobile or fixed. Starting at TL12, and obviously getting better at higher TLs. So those pesky Darrians probably got some sweet astro-droids.

    Just in astro-classifications, programs are: Pilot, Nav, Steward, Survey, Grav Vehicle, ATV, Ship's Boat, Gunnery, Electronics, Mechanical, Engineering, Gravities, Communications, Tactics, Ship Tactics, Fleet Tactics, Admin, Legal, Trader, Cargo Handling, and Emotion Simulation (required for Admin, Legal and Trader (and should be for Steward, too) and, of course, Medic.

    Of course, a bot that can handle all of that or some of the more difficult ones are gonna be expensive.

    LBB2 - Starships, allows for Generate to be used to generate a flight plan, fed through the Navigate program, to run the Jump program.

    Again, dunno about non-Classic Traveller, or Your Traveller Universe.

    But the old school computer rules are more like those you'd expect from a PDP system or some IBM Fortran running system than some high-tech HAL 9000.

    1. I looked up the procedure in The Traveller Book rather than Book 2 and it was run generate then navigate then jump of the appropriate number AND have the navigator roll against their skill.

      I'll admit I am not very familiar with Book 8. We'd been playing for a while when it came out and we didn't really consider bots. To add them in would have knocked over some apple carts.

    2. The bots from Book 8 were... interesting. The system made it so that frontier shipowners most likely wouldn't be able to use them, as they needed high-tech support and came from a high-tech (TL12+) system.

      Affordable for Tukera Liners or Imperiallines or navies. Not for some retired Scout or a Merchant on the edge.

      My players liked having an 'astro-droid' until the overt skill and function rolls and the semi-covert and fully covert rolls all started adding up to it was just simpler for the players to do it all their own.

      Though... Doing the Kinunir adventure and adding functioning defense, engineering, maintenance bots and a HAL9000 type computer sure spiced up the adventure and sure stuck it to those players who would sneak a look or purchase from the game shop. Hehe.

      Same with Annic Nova. Add a semi-autonomous cobonculator to a plague ghost ship from some unknown race and...

      Really made players trying to justify keeping the Kinunir or other navy ghost ships not worth the hassle, and better for the salvage rights.


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