Would a differential analyzer work? They worked fast enough to be used for targeting during WWII.
[1] This facsimile operated in part by synAC.We put men on the Moon with little more computing power than engineer's slide rules and a mainframe system that is beaten by a pocket calculator today.
I can see intergalactic travel being done without the need for computers beyond 1972 provided there's a reason why intergalactic travel (presumably Faster Than Light) exists.
Perhaps it's not an intergalactic invasion, but an interplanetary one? We have no idea what's under Europa's ice crust, after all...
But putting that aside, one still does not need FTL for long-distance space travel, only patience, determination, and some degree of longevity. They could simply be wedding desperation and a zen attitude.
I'll hide your name inside a word and paint your eyes with false perception.^^ All spacecraft have their own computers for their navigation and other systems. In 1970 at the height of the Apollo landings, the combined computing power of an entire ship (lunar lander included) is beaten by a 15 dollar calculator today.
The mainframes at base are used for calculating everything else ahead of time. Fuel burn times, total course duration and destinations, expected travel time (including radio blackouts), and other things. The ship aboard can calculate those things but it's better to have that information on hand ahead of time and leave the ship's computers doing stuff that requires immediate attention.
If in this setting above there is Faster-Than-Light Travel we can assume there's FTL Radio to convey advanced computing needs to the vacuum tube built computer systems aboard each ship.
The only way I could see this working is through Organic Technology acting both as a means of transportation and as a weapon. (Varja, anyone)? This would also require an intuitive understanding of the structure of spacetime, which would make ANYBODY a total nutjob anyway, so them not caring about less evolved organic life makes sense. ;)
My original thought for the aliens' interstellar travels (which would be slower-than-light) was having one ship that was basically a 'computer' and observatory crewed by mostly mathematical savants, which acted as a pathfinder, which would contain not only all of the equipment to plot a course afresh, but a couple of decades worth of calculated courses from back home.
Their military hardware would be mostly physically better than ours, but would be limited - by their lack of electronics - to either line-of-sight or pre-calculated targets. Not that that would give us too much of an advantage of course, since they'd smash most of the satellites, but we'd at least still have the advantage of laser-guided weapons and such. They'd also use compact nuclear-fission plants rather than petrol.
I've also come up with an enemy for them, aliens who've developed shields that can deflect bullets and bombs. Of course, with that, they've thrown their guns away and got lasers, but haven't realised that while their shields are good at stopping bullets, they're not good enough to stop anything travelling at less than about 150 km/h, like grenades, and that while carbon - which forms the majority of their armour - is good at heat dissipation, it's not so good at stopping physical explosions. They'd use advanced hydrogen cells for power.
edited 13th Mar '11 3:24:57 PM by MattII
Well to be fair, you don't need semiconductor computers to perform space travel, or even travelling to another solar system. Some good mathematicians are good enough. It's not actually that hard.
Your real issue is precision weapons and high-speed warfare. Mobility and precision DOES require better computers, so these aliens could have giant death particle beams but have manual aiming. That would be fairly schizo but it would give humans a chance anyway. We have IR missiles and they have doom cannons that are manually aimed.
it's not them who have the death-rays, its the other guys. Precision Weapons, as far as the first invaders go is developments of the Fritz X
, or actual dive-bombers. They might well freak out when they start taking losses from our 'self-thinking' munitions.
^^ The first guided missiles such as the original AIM-9 Sidewinder heatseeking missile and the SA-2 Guideline (NATO Reporting Name for the S-75 Dvina) SAM were not transistor technology. They were 1950s guided weapons (and for the era remarkably effective).
Fair enough, you can have rudimentary precision with just tubes. I was thinking more like our current 250 lb laser guided bombs.
So anyway, how many invasions are there?
Humans are on earth. Then Aliens invade who are computerless. And then computerised aliens invade?
edited 14th Mar '11 7:02:02 PM by breadloaf
Humans are on earth. Then Aliens invade who are computerless. And then computerised aliens invade?
Basically, the first lot comes, and tries but fails to take over. Nor can they go home either, since we manage to slag their pathfinder ships, and so we force them to hand over most of their stuff and settle down in the, to us, less hospitable areas of the world like the sahara desert.
Years later, the second lot come, and as it turns out, the first lot tried to conquer them as well a couple of centuries back, but it didn't work out to well, and now they're trying genocide against the first lot, and aren't too picky about who gets caught in the crossfire.
are the computer-less invaders adverse to organically guided bombs, missiles, or projectiles? you could go the rout of Project Pigeon
, Project X-ray
, or suicide aviators.
Okay so it's something of the sort where interstellar space travel's biggest problem then in your setting is social psychology, rather than technology. In the case of humans, we're too concerned with the "here and now" to get off our rock whereas with them, they're highly patient and fully willing to wait the length of time it takes to invade people across vast stellar distances.
Then the second aliens come in and have a "nuke em all" attitude. Other than humans getting killed in the crossfire, what capabilities do they have over humans? If they could just wipe out the first aliens, are humans capable of just stepping back, take the losses and hope the second aliens go away?
edited 15th Mar '11 9:17:27 PM by MattII
As for why they actually come, well, the news of our defeat of the first aliens made them think that either we'd wiped them out, and so they'd come to congratulate us, or that we'd hand them over willingly since we'd hate them.
edited 15th Mar '11 11:35:13 PM by MattII

Okay, I was just reading one of H. Turtledove's World War novels tonight, and IMO, in comparison to most of the movies in the genre the story was actually damned good, but unfortunately couldn't really be remade for the modern-day the same way that The War Of The Worlds could because of all the period equipment (valves are still in use, jets, nukes and rockets are just coming of age etc.). So that got me thinking, now to write a believable, modern Alien Invasion story where the aliens' equipment is much better on its own, even given the sort of 10+ - 1 numerical odds its going to be facing, yet not so powerful that the aliens can just walk over humans. What I eventually came up with was that the aliens never discovered the semiconductor, but instead continued to make valves better and better until they could at least rival 60s era computers.
So, discuss, how do you think an alien invasion would go if the aliens hadn't invented transistors?