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SpaceX data scientist interview: SQL + case + stats, here's what the loop actually looked like

de_derek · 6 replies

Went through the SpaceX data scientist interview process earlier this year. Five rounds total, spread across about three weeks. Sharing the breakdown because I couldn't find much specific info when I was prepping.

The recruiter screen was pretty standard. 30 minutes, walk through your background, why SpaceX, what kind of problems you've worked on. No technical content yet.

SQL round: This was the meatiest technical screen. Two medium-hard SQL problems. One involved window functions, specifically ranking launches by some metric within groups. The other was a join-heavy query across a few tables to pull a time-series aggregation. They weren't trick questions but you need to be fluent with CTEs and window functions. Stumbling on syntax costs you.

Stats + case study: One round that blended both. First half was classical statistics: A/B testing setup, sample size estimation, what to do when your assignment mechanism isn't perfectly random. Second half was a product case. They give you a scenario (think: you have sensor data from a test, something's off, how do you investigate). It's more about structured thinking than a specific answer.

Data take-home: About 4 hours of work. Real telemetry-style dataset. They want you to explore it, surface findings, build one or two visualizations, and communicate recommendations clearly. Python or R, your choice. I used pandas + matplotlib.

Hiring manager interview: Mostly behavioral but also dug into my past work. Heavy on "tell me about a time you had imperfect data" and "how did you communicate results to non-technical stakeholders." STAR format. Be specific.

For prep: SQL on LeetCode or StrataScratch (medium level), brush up on experiment design, and practice explaining your project work to someone who isn't a data scientist. That last one gets people more than the coding.

6 replies

analyst_ana

thank you for writing this out. did they specify pandas vs SQL for the take-home or could you use whatever? also was the dataset provided or did you have to source something?

ops_omar

They provided the dataset, which was a relief. And yeah no constraint on tooling, I just had to deliver a Jupyter notebook with clear explanations. Some people on my loop apparently used R, no issue.

alex_design

The case study piece at SpaceX is genuinely different from most DS loops I've placed candidates into. They care a lot about whether you can think like an engineer even though the role is analytical. More "how would you debug this" than "design a metrics dashboard." Good prep advice.

frontend_fran

did you get any machine learning questions at all or was it mostly the stats + SQL path?

ux_uma

Very little ML, honestly. A couple of high-level questions in the HM round like "have you deployed a model to production" but nothing algorithmic. This felt more like a data analytics / DS-generalist role than an MLE-adjacent one. If the role is closer to MLE they probably go deeper on that.

quietquit_quincy

good write-up. the window functions question sounds pretty standard but I've been surprised at how many people bomb basic ranking queries. seriously just do 10 window function problems and you're fine for most companies