Difference between tenure-track/tenured positions in universities and research scientist positions in national labs I am trying to evaluate pros and cons for working at universities as tenure-track (and eventually, hopefully, tenured) and research scientist at national labs. I realize that not much is discussed on what it means by working at national labs (except a few specific questions such as Are faculty positions more competitive than government research lab positions?), unlike working at universities. I wish to start by asking about job security, salary (US universities usually pay 9-monthly and expect profs to cover the remaining 3 months from the prof's grants. Is there any such thing at national labs), any other things? Working with research students (all the way to completion of their degrees, as opposed to as your interns for a few months) is of course rewarding at universities. But probably too much teaching and administrative work may be negatives at universities too - any comparison with national lab jobs?

I know that this may be slightly broader question, and a bit subjective too, but I believe answers from different perspectives would help researchers like me who are at critical juncture at their career and need to decide one way or another.

Edit-1: I also came to know that some research labs in the US may have different classifications. e.g., is National Renewable Energy Laboratory same as NASA etc.?

Edit-2: How about 'redundancies'? Can these labs use 'lack of budget' or some other (non-disciplinary) excuse to remove the permanent staff?
My experience is purely through my work at NASA, so take that with a grain of salt. 

There are (roughly) two levels of employment at NASA Research Centers (not labs like JPL): civil servants and contractors. If you're looking to become a research scientist at NASA, you want to become a civil servant, though there are plenty of scientists on contract.

Contractors are just that, they work on a specific research project that has allocated in its budget a certain amount of money for a project. Usually these contracts are administered under huge omnibus corporations like Millennium Enterprise Integration, who take something like 200k in overhead, per contractor. 

What this means is contractors can be extremely expensive to a project, and that, as a result, contractors usually split their time (and cost) on two or three projects. If you're a contractor at a NASA center, you'll need to maintain a decent porfolio of projects that cover your salary. It can be stressful, but also less regulated than civil servantship

Civil Servantship is a pretty sweet gig if being a tenured professor was your reason to enter academia. If you get hired as a civil servant, it's virtually impossible to fire you unless you commit the equivalent of a felony (which is easier than tenured professorship, see below). Basically when you're hired congress agrees to pay your salary for the rest of your working life.

You can apply for money to do projects, including internal funding that academics won't have access to. With that you can hire contractors or buy equipment, but not pay yourself. Instead you have this new unit of labor called Full Time Equivalent (FTE), which is can also be part of a grant award, and represents your salary being paid for a full year. FTE vary depending on the center you're at, Alabama FTE is going to be cheaper than Bay Area FTE, but at some centers there's a significant surplus of FTE going around (no idea why). All not having FTE means as a civil servant is you might have to go ask someone for FTE, which means you're effectively working for them.

I said before it's easier to commit a felony when you're a civil servant, and that's because you're effectively a representative of the U.S. government. That means you can't take money from companies (gifts are limited to $20), and a whole host of other rules that have been put in place because essentially every form of graft and corruption that you can possibly imagine has already been done by someone in the government. It's actually pretty amazing. 

Also the pay for a civil servant isn't that great (still better than grad school!), and because of the rules you can't really supplement your income. That's why it's not unheard of for civil servants to actually switch to contractors sometimes- the caps for compensation are much higher for contractors, and can be influenced by a competing offer. 

oh and also you don't have to teach, but that's one of the few places where civil servants can make extra money (lecturing at local universities).

But in terms of an environment where 1) you can pitch research and it will get funded and 2) you'll have job security that tenure used to match, there is no better place, as far as I can tell, than NASA.