How hard is it to build orbital data centers, actually? “The ISS radiators are expensive and heavy. We’re focu

• Short answer: very hard. The main show-stoppers are throwing huge mass into orbit repeatedly, rejecting waste heat in vacuum (large, heavy radiators), radiation hardening, and enormous cost and manufacturing scale [arstechnica].

• Launch/mass: a single orbital “data center” node likely needs multiple tons (estimates ~3.5–7.5 t including 1–2 t of radiators). That demands super‑heavy‑lift, massive reuse, and orders-of-magnitude more launch cadence than today [arstechnica].

• Thermal: onboard compute generates lots of waste heat that must be radiated away; radiators add significant mass/volume and are costly and heavy—this is a primary engineering constraint [arstechnica].

• Radiation and reliability: commercial GPUs/CPUs are vulnerable to space radiation; mitigation (shielding, redundancy, rad-hard designs) raises mass, complexity, and cost [arstechnica].

• Economics and scale: building, launching, and operating a useful constellation requires industrial-scale manufacturing, logistics, and likely multi‑billion to trillion-dollar investment—not a near-term consumer product [arstechnica].

Follow-up Questions:

1. How much would radiators for a single orbital data node actually weigh and size-wise look?

2. What spacecraft buses or rockets today could realistically lift such a node?

3. How do radiation‑hardening strategies change power, mass, and performance budgets?

4. Could in‑orbit assembly or manufacturing make this feasible sooner?

5. What latency and network-topology tradeoffs come from moving data centers to LEO?