How are scientific research projects planned? In particular computer science, but possibly there exists processes for all research? Possibly some context:
Take any research endeavor. Finding a vaccine. Going to the moon. Clean energy. I don't have a background in these scientific areas so picking one closer to home (Comp Sci) might be better. But the idea is how to battle the Unknowns? How to do it economically? How to make progress while not getting analysis paralysis?

Some might suggest a scrum, or an agile process try to solve these questions.  I'm not certain that they address the same level or kinds of Unknowns.

Are there previous experiences that work, and those that don't work?  And why?  The questions grows on the way forward through unknowns, and by definition the Unknown doesn't exactly have a road map, and new context is developed regularly.

This maybe simply the question of the 'meta' variety: Is there research on comp sci research?  If so does Comp Sci research have approaches or techniques that they rely on?
Scrum, Agile: sound like necromantic spells to evoke the spirits of the netherworld [yes, I know what these are]. This type of stuff is perhaps useful once you know what you want. 

But in science, that's usually not the case. You do not know what you want, when you do, you do not know how to get there, and if you think you know how to get there, you may be quite off estimating how long it will take and which obstacles you will stumble into.

So, the way to proceed is to ask/do the following: 


what is out there?
what are the techniques?
What am I interested in?
What do I enjoy doing? [No, it's not the same as 3!]
Acquire knowledge. (what's out there, what's known? Literature!)
Acquire skills. (how do I do stuff)
Acquire expertise (i.e. knowledge how to use skills, not the same
as skills)
Play around. 
Find loopholes, open issues, improvements, gaps, etc.
Can you fill them?


And the most important one: talk to people who are good in the field.

As you acquire expertise, you will be able to plan further into the future.