Hey, so I am trying to do chapter 3 of the Wasteland Survival Guide. I need to install some widget in RobotCo production however Moria never told me about the optional objective like there should be. 
 
How do I get the optional objective? 
 
Thanks.

Anyone?

It's been a while since I last played Fallout 3, but if memory serves me, it's possible to tamper with the mainframe within the RobCo factory. However, to do so, I think you need a high enough stat in a particular field (probably Science, but again, it's been a long time, so I'm not too sure). If you can disable the mainframe, you should complete the optional objective. 
 
If all this is bollocks (or even if it isn't), I'd recommend checking out the relevant page of the Fallout Wiki, or even Giant Bomb's Fallout 3 Mega Guide. Both are helpful resources. 
 
Hope this helps in some way :)

I don't know the answer to your question, but you might find this awkward bit of information helpful:  

There is a factory with a nearby small building. The small building is at the base of a cliff face, inside the small building is a hidden switch/computer, -I can't remember which one, but when you activate whatever it is the stairs are revealed. Down the stairs are a bunch of extremely powerful robots with high health levels, when you destroy them and get to the end there is a whole bunch of high-quality loot for you to collect.

Shall I recommend checking out the Fallout 3 Megaguide?

Did this yesterday. Gotta have Science skill at 50.

Try to get your skills to 50, 75 and 100 since numbers in between those don't matter and you can boost your intelligence skills temporarily by using mentats...

I started my character with 9 in intelligence which boosts some skills and gives you more points to distribute every time you level up.

" @NekuSakuraba:

Try to get your skills to 50, 75 and 100 since numbers in between those don't matter and you can boost your intelligence skills temporarily by using mentats...

I started my character with 9 in intelligence which boosts some skills and gives you more points to distribute every time you level up.

"

That depends... personally i cant stand not being able to hack or unlock stuff in rpg's... so those are the first skills i would do... and remember that with books and the raised level cap all your skills will be at or close to a hundred in the end... All my important skills where at a hundred before i hit level 20.

And try to find the intelligence bubblehead early on.

" @NekuSakuraba:

That depends... personally i cant stand not being able to hack or unlock stuff in rpg's... so those are the first skills i would do... and remember that with books and the raised level cap all your skills will be at or close to a hundred in the end... All my important skills where at a hundred before i hit level 20.

And try to find the intelligence bubblehead early on.

"

Its in Rivet City science lab... Which is part of the main quest. But as i said all your skills will end up at a hundred in the end. So its more a case of which skills you want to level up first...

For me it was science, lockpicking and repair, there are perks which significantly boost those skills which are worth taking early on as well.