Product design question
Design a datacenter on the moon for Google.
- Product design
- Hard
Practice this question out loud. An AI interviewer asks it, follows up like a real interviewer would, and scores your answer. Type or speak.
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What this question tests
Creative but grounded product design for an extreme-constraint scenario, testing whether the candidate reasons from real constraints rather than pure fantasy.
How to approach it
- Clarify the motivating value proposition: likely extreme cooling efficiency from permanent shadow craters near absolute zero, plus physical isolation from earth-based risks.
- Identify the target use case: cold storage or archival data tolerant of high latency, not latency-sensitive real-time services.
- Assess constraints: launch cost per kilogram, hardware servicing difficulty with no on-site repairs, radiation exposure, and solar power generation.
- Prioritize the cooling and isolation value proposition for archival storage, the use case where the moon's downsides matter least.
- Design the solution: a solar-powered facility in a permanently shadowed polar crater using passive cooling, with redundant hardware since repair visits are rare.
- Define success: cost per petabyte stored over the facility's lifetime versus an equivalent earth-based cold storage facility.
What a strong answer includes
- Grounds a whimsical prompt in real physical constraints, cooling, launch cost, latency, and radiation, rather than pure science fiction brainstorming.
- Picks a specific, defensible use case, cold archival storage, where the moon's downsides matter least, showing real product judgment.
- Names a genuine advantage, permanently shadowed craters near absolute zero, that a well-informed candidate would reason toward.
- Ends with a real business comparison, cost per petabyte versus earth-based storage, keeping the answer disciplined.
Common mistakes
- Treating this as pure creative brainstorming with no grounding in physical or economic constraints.
- Ignoring the earth-moon latency problem when picking a use case.
- Not comparing the idea against a simpler earth-based alternative to justify why it would ever make sense.
Likely follow-up questions
- How would you handle hardware failures without on-site repair capability?
- What is the realistic cost comparison against an equivalent earth-based facility?
- How would you get data to and from the moon efficiently?
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Learn the skill behind it
Chapters of the AI PM course that teach what this question tests.
- Chapter 4: Discovery and strategy for AI products
- Chapter 7: AI UX and human oversight: design for a system that is wrong sometimes
- Chapter 14: Get the job: the AI PM interview loop