Been working 3 years out of undergrad, who should I pick?

[eruwaedhiel]

Hello everyone!  This is my first post here, so I apologize if I could have made this better/more clear:

I graduated from undergrad 3 years ago and have been working/getting my MS since then.  Since PhD programs require 3 recs, and they prefer tenured faculty, I am having a tough time deciding who to ask for LORs.  Here is who I'm deciding between:

1. Undergrad senior project research advisor: She was a new professor when I did my research project.  The project was 3 years ago and with a partner (so it wasn't just me alone), and it was in human factors (not exactly the subfield I'm going into), but I think she can write a decent letter for me.
2. Undergrad summer research advisor: He is a NASA employee (no PhD, not faculty), but the research I did was more closely related to what I want to study and was entirely my own (I also elaborate more on it in my SOP than any other research I've done).  It was also 3.5 years ago, though.
3. Grad professor: Okay, I did a distance-learning MS (not a for-profit degree, it is exactly the same as the on-campus program but instead of having myself physically in the classroom I had to watch the lectures online a couple of hours after they occurred in real-life).  I had the same assignments and requirements as on-campus students, and did a research project in the end.  This particular professor taught my favorite class, which, based on his comments, I did better than most on the assignments and exams.  I had decent email interaction with him, but never face-to-face, and I didn't do any research under him.
4. Grad research advisor: This would seem like a sure choice since it was recent and, while the project was not as related as #2 for what I want to do, it is more closely related than #1.  However, my advisor was really hands-off on my project, and he never responded to my request for comments on my rough draft, so I honestly don't know his opinion on my work (other than the fact he gave me an A for the final report - I don't know what he liked/didn't, what to improve, etc.).  Since I was a distance student, most of my communication with him was through weekly email updates I would send him, which he frequently did not reply to unless I explicitly asked for a reply in the subject line.
5. Work supervisor: I work for a research organization that is tied to a good engineering university (the same one I got my MS from), and I have had the same boss since I started.  He's worked really closely with me, so he can write a great rec and possibly go into even more detail about my grad research than my advisor (I did my MS while working, so I frequently discussed my plans and progress with him and also used the model I created for that project at work for a customer).  However, he is research faculty like me (so no PhD), and my job is not directly related to what I want to study (it's modelling and simulation, which is related, but in electronic warfare, so not close to aerodynamics).

In my situation, I believe the best LORs would be from 1, 2, and 5, but that set completely removes anyone from my MS program and only has 1 PhD.  However, that group would give the best picture of what I can do in terms of research, which I feel would be more valuable to the application than the unknown elements of 3 and 4.  I'm also worried that my distance-learning degree will be looked at negatively (it's from a top-5 aero program, and the distance aspect is not actually mentioned anywhere since the work is equivalent, but the committee will know because I don't work in the state the university is in....).  Any advice?

[horrificmodernist]

I think it might be kind of strange if you don't have any letters from your MS program. I agree that 1, 2, and 5 seem like good choices, but maybe try emailing your grad research advisor and seeing what kind of response you get (if you're not in a time crunch for your LOR)? Maybe see if you can get 1, 4, and 5 and work from there - if you feel like you can't get a solid recommendation from 4, get one from 2. Just my two cents!

[rising_star]

You definitely need a letter from your MS program. You might try talking to your MS advisor about what he thinks the best LOR strategy for you is.

[TakeruK]

In my opinion, I think your best choice is 1, 4, 5 and I agree with rising_star that you should talk to #4 and see what their advice is.

Also, #2 can be a good option for some schools. For example, if #2 is a NASA employee that is close to (or regularly collaborates with) a university, then #2 might be a good choice when you apply to that university.

I don't think #3 is a good choice for a letter at all, especially if you have all of these other options.

[eruwaedhiel]

Thanks everyone for the advice!  As a distance student, I didn't have a regular academic advisor (I picked classes on my own and didn't have anyone to talk to about planning my program), my research advisor was only selected automatically for me during my last semester based on what I stated my research interests were, so he's only known me for the 3 months I worked on the project.  I'm not in a rush to get the letters (I'm putting in applications during fall 2016 for starting fall 2017 - I think I missunderstood the "application season" profile setting), so I will email my MS research advisor and get his opinion before I officially ask for LORs.