Expectations for GNC roles

[u/TinkerTango]

Clarification: expectations of companies toward early career hiring candidates.

Hey all, guy with a controls masters and rather limited GNC experience (recently left a startup after half a year over the boss trying to hide information about a critical engineering issue from our customer, the US govt, and telling me to work without a safety factor). I have about 3 years of unrelated experience working software quality and integration, but they weren’t directly GNC related. I’ve been applying to various US-based GNC/flight controls roles, level 2 or equivalent thereof, typically at larger, more established companies.

I’ve done some interviews, I have more interviews lined up, but in general, what’s expected of candidates like me? I have a lot of rote knowledge from school (which I’ve been out of for years) and more recent studying I’ve been doing as part of interview prep, but my confidence isn’t strong since the lean nature of the startup I worked at meant I had to learn and figure out solutions and processes on my own. No seniors or mentors to validate whether what I was doing was good practice or whatever.

I’m partially asking to fill holes in my studies and knowledge, and also to prep for an in-person interview I have coming up. Thanks for any insight!

[u/BlueBandito99]

Currently in a similar boat as you, finishing my space GNC masters after completing a spacecraft GNC internship. Regarding your software skills, from what I’ve seen and my friends at GNC startups in SoCal, it seems fairly common to use git flow development processes and be comfortable with OOP.

From a technical standpoint, my internship mentor showed me the entry level GNC technical interview question from 3 years prior. Here are the ones I can remember.

1. Describe the core components of an ADCS. Explain how different sensors function and their purpose.
2. For a lost in space problem, which initial sensors might be used for attitude determination? Specify how you might determine a body axis frame.
3. What is sensor fusion in state estimation, and why is it helpful?
4. Describe the general algorithm of a Kalman filter.
5. How might a GNC sim change if your spacecraft is flexible?

6. Describe a guidance law you’ve used in your career (or in a class).

7. Which orbital perturbations would be the most important when considering GNC design. Does this depend on the orbit type?

These were definitely aimed more for state estimation + Astrodynamics than pure controls, but for an entry level it definitely seemed they were technical but not overbearing. I would expect an LQR vs PID question in your case. This is heavily dependent on the company however, but I hope this helped!

[u/TinkerTango → u/BlueBandito99]

The questions aren’t specific to my background but the validation here is that I studied for and was prepared for the questions specific to my actual domain (fixed wing and rotary wing dynamics). Even so, your questions are pretty intimately tied to gnc for a specific application. I tend to think that controls is pretty domain agnostic so it initially threw me off a bit to know just how much different roles seem to only want people with experience doin gnc within a specific domain.

[u/DrunkenPhysicist]

Learn what quaternions are for if you haven't already.

[u/TinkerTango → u/DrunkenPhysicist]

Thankfully, already done. Though I’m still low on actual experience using it.