I'll need a basegame friendly solution for this as I don't have whatever pack gives you Geekcon (City Living?). I've already invested nearly a week into a sim who's been working on Tech Head since toddlerhood.
I haven't tried to build a rocket yet as she's only on stage 2 of nerd brain (and her teen grades/job take priority right now) but if I do end up having this bug with the rocket when I get to that point, what should I do?
A base game player will also run into trouble maxing 3 skills required for tech head until this bug is fixed - books can only take you to rocket science level 9. I have DU so I'll be able to have her do robotics though it's pretty annoying to have wasted all those hours that she spent on getting to level 3 with the first rocket science book.
Edited to add: I'm also going to have a problem with one requirement from Soulmate and one from Foodie, assuming I have this bug with the rocket. (As soon as we can afford a rocket, I'll try to check if I have the bug. Someone in the bug thread says it's related to a cottage living festival so maybe I'll be alright as I don't have that either just the free patch.)
I went back to check your earliest post and note that you don't mention owning Cottage Living. Did you buy and install it since then?
The rocket ship bug only occurs if you have Cottage Living, so you should be fine since you don't have it.
For those who also own Eco Lifestyle, I read about another workaround in EA Answers HQ which involves voting in the Tech Support NAP.
This will encourage NPCs to build your rocket. You could make a group which includes NPCs and one or more will autonomously start building the rockesthip.
Someone else in the same thread (the one posted by Nandarelle) recommended storing or locking away 'fun' objects on the lot to prevent sims from preferring other activities over your rocketship.
Once an NPC starts building the rocketship, your sim will be able to continue building & interacting with it.
Frankly, however, I've only tried the GeekCon approach myself.
The bug didn't manifest in my tournament save and I realized it's because my sim started building the rocketship before the Day 7 (the first Saturday = the first Finchwick Fair).