---
type: source
title: "An Orbital Data Center of a Million Satellites is Not Practical — Avi Loeb"
author: "Avi Loeb (@aviloeb), Harvard/Smithsonian"
url: https://avi-loeb.medium.com/an-orbital-data-center-of-a-million-satellites-is-not-practical-72c2e9665983
date: 2026-04-01
domain: space-development
secondary_domains: [energy]
format: article
status: null-result
priority: medium
tags: [orbital-data-centers, SpaceX, feasibility, physics-critique, thermal-management, power-density, refrigeration]
extraction_model: "anthropic/claude-sonnet-4.5"
---

## Content

Harvard astrophysicist Avi Loeb's April 2026 critique of SpaceX's orbital data center proposal, focusing on physics-based infeasibility.

**Key technical objections:**

**Power requirements:**
- Solar flux at orbital distances: ~1 kW/sq meter
- SpaceX's claimed total system power: 100 GW
- Required solar panel area: 100 million square meters (100 km²)
- Loeb's framing: "The envisioned total system power of 100 gigawatts requires an effective area of 100 million square meters in solar panels"
- This is not impossible in principle but requires a deployment scale 10,000x anything currently in orbit

**Refrigeration/cooling:**
- Standard refrigeration systems rely on gravity to manage liquids and gases
- In microgravity, lubricating oil in compressors can clog the system
- Heat cannot rise via natural convection — all cooling must be radiative
- The physics "makes little sense" from a practical standpoint given current technology

**Loeb's conclusion:** The SpaceX proposal "makes little sense" from a practical engineering standpoint. "Apart from the physics challenges, the constellation would cause devastating light pollution to astronomical observatories worldwide."

## Agent Notes
**Why this matters:** Loeb is a credentialed physics critic, not an industry competitor (Amazon is a competitor). His critique focuses on the physics — specifically the 100 million sq meter solar panel requirement — which is harder to dismiss than Amazon's business critique.

**What surprised me:** The 100 GW total claim from SpaceX's filing. If accurate, this is roughly equivalent to the current US nuclear fleet's total capacity. SpaceX is proposing an orbital power generation system equivalent to the entire US nuclear fleet, spread across a million tiny satellites.

**What I expected but didn't find:** Loeb's piece focuses on physics but doesn't address whether the correct comparison is to 100 GW in a first deployment vs. starting small (Starcloud-3's 200 kW first, scaling over decades). The critique is against the stated vision, not the early stages.

**KB connections:** Connects to power is the binding constraint on all space operations — for ODC, power generation and thermal dissipation are inseparably linked binding constraints.

**Extraction hints:**
- The 100 GW / 100 million sq meter solar array requirement is the clearest physics-based evidence that SpaceX's 1M satellite ODC vision is in the "science fiction" category for the foreseeable future.
- However: this critique applies to the full vision, not to the near-term small-scale deployment (Starcloud-3 at 200 kW).

## Curator Notes
PRIMARY CONNECTION: [[power is the binding constraint on all space operations because every capability from ISRU to manufacturing to life support is power-limited]] — ODC's power constraint is the same binding variable, just applied to compute instead of life support.
WHY ARCHIVED: Most prominent physics-based critique of the SpaceX 1M satellite plan. Provides the solar panel area math.
EXTRACTION HINT: Extract the solar panel area calculation as a falsifiability test for the 1M satellite vision.
