The interview process was lengthy but thorough:

• 1-hour phone screening of your technical background with an engineer
• 1-hour phone technical/skill assessment with an engineer (material properties, general equation relationships, design challenge hypotheticals, etc.)
• 1-hour "on-site" presentation (virtual, due to COVID-19) with the team + approximately 6x 30-minute technical assessments with engineers and leadership.

The interviews with SpaceX were difficult but never unreasonable. It is clear from their approach that they seek engineers who have:

• A track record of technical solution/product development ownership (“cradle-to-grave”)
• Consistently applied the scientific method, performed FMEA/RCCA, and validated results to resolve design challenges
• An intuitive understanding of the fundamental physics (both breadth and job-relevant depth).

Because of the level of knowledge mastery required, it is difficult to study for these interviews in advance. My best advice is to spend your time preparing in two ways:

• (25% of your time) Brush up on mechanical engineering fundamentals (fluids, thermodynamics, heat and mass transfer, statics/dynamics, materials, and GD&T), especially where you know you have gaps.
• (75% of your time) Review your past projects and be sure you can discuss and defend your design decisions, plus any design flaws, both historically (by describing the physics as you applied them at the time) and currently (by describing what you could do better knowing what you know now).

For one of your given previous projects/designs, what is likely to fail mechanically first?

Explain in detail.

Describe how you would design a given component, given parameters XYZ.

How do you justify your decision?

Describe an instance during which you had to defend an unpopular design decision.

What made it unpopular?

Why and how did you defend it?

What was the outcome?