Lunar settlement connectivity: sizing the data link and choosing an Earth-Moon network

A settlement of 1,000 people lives on the Moon. You are asked two connected questions: how much internet bandwidth does the settlement need, and how would you get internet service to it? Answer them in order, stating every assumption you make. ### Clarifying Questions - What do the residents do: is this a working research base, or a settlement with families, children and schools that expects work, study and entertainment online? - Where on the Moon is the settlement: on the side that always faces Earth, on the far side, or near a pole? - Should the estimate cover only traffic exchanged with Earth, or the settlement's internal network as well? - Is the target an Earth-like internet experience, or is a slower, delayed service acceptable for most uses? ### Part 1 — Estimate the bandwidth Estimate the bandwidth the settlement needs. Show the equation you use, label each assumption with a round number, do the arithmetic, and check the result for plausibility. ```hint Size for the busiest hour A network is built for its peak, so decide how many residents are online at the same moment and what each of them is doing, rather than spreading a day's usage evenly. ``` #### What This Part Should Cover - A clear equation broken down by activity or resident type, with a peak-concurrency factor. - Explicit, adjustable assumptions and correct arithmetic. - A sanity check against a familiar reference and a sense of how sensitive the answer is. - A split between traffic that must cross to Earth and traffic that can stay on the Moon. ### Part 2 — Deliver internet to the settlement Propose how you would provide internet service to the settlement, and compare the main alternatives. ```hint What is different from a remote town List what makes this harder than connecting an isolated town on Earth, starting with the distance, and let each difference shape the design. ``` #### What This Part Should Cover - Link options (radio versus laser, direct to Earth versus through relay satellites) and their trade-offs. - How the design copes with the Earth–Moon delay and with periods when one end cannot see the other. - Redundancy, the settlement's local network, and what keeps working if the link to Earth fails. ### What a Strong Answer Covers - A transparent estimate whose assumptions an interviewer can challenge and change. - How the Earth–Moon signal delay affects which applications work, and how much traffic can be served on the Moon instead of crossing to Earth. - Resilience: what happens when any single link, terminal or ground station fails. - A clear connection between the bandwidth number from Part 1 and the infrastructure chosen in Part 2. ### Follow-up Questions - How would your design scale as the settlement grows, and which part would become the bottleneck first? - Which everyday apps would feel broken because of the delay, and how would you adapt them for residents? - If the main link to Earth fails for a week, what must keep working, and how?