---
type: claim
domain: space-development
description: "At 1366 W/m² with no atmosphere, clouds, or night cycle in sun-synchronous orbits, space solar eliminates the power constraint that gates terrestrial data center expansion"
confidence: proven
source: "Astra, space data centers feasibility analysis February 2026; Google Project Suncatcher feasibility study"
created: 2026-02-17
secondary_domains:
  - energy
depends_on:
  - "space-based computing at datacenter scale is blocked by thermal physics because radiative cooling in vacuum requires surface areas that grow faster than compute density"
  - "power is the binding constraint on all space operations because every capability from ISRU to manufacturing to life support is power-limited"
---

# Solar irradiance in LEO delivers 8-10x ground-based solar power with near-continuous availability in sun-synchronous orbits making orbital compute power-abundant where terrestrial facilities are power-starved

Solar irradiance in low Earth orbit is approximately 1,366 watts per square meter -- the full output of the sun unattenuated by atmosphere. After accounting for atmospheric absorption, weather, day/night cycles, and panel orientation losses, ground-based solar panels achieve roughly 150-200 W/m² of average output. The orbital advantage is therefore 7-10x in raw power density per unit area.

In sun-synchronous orbits (approximately 600-800 km altitude), satellites maintain a nearly constant angle to the sun, achieving near-continuous illumination. Eclipse periods still occur but are short (roughly 30 minutes per 90-minute orbit in some configurations), manageable with battery buffering. There are no grid interconnection queues, no utility contracts, no transmission losses, no permitting delays, and no competition with other users for the same electrical infrastructure.

This is the strongest genuine advantage of orbital compute. Power generation in space is not a speculative technology -- it is mature, well-characterized physics exploited by every satellite in orbit since the dawn of the space age. The solar panels themselves are the most cost-effective component of the orbital compute stack. The irony is that while power generation is essentially solved in orbit, dissipating the waste heat from using that power is the unsolved showstopper. Power-abundant and cooling-constrained is the exact inverse of the terrestrial situation (cooling-abundant, power-constrained), which is why the orbital data center thesis is seductive but the physics do not cooperate at scale.

## Evidence
- Solar constant: 1,366 W/m² in LEO vs 150-200 W/m² average ground-based
- Sun-synchronous orbit mechanics providing near-continuous illumination
- Every satellite in orbit validates space solar power generation

## Challenges
[[space-based computing at datacenter scale is blocked by thermal physics because radiative cooling in vacuum requires surface areas that grow faster than compute density]] — the fatal irony: orbital power is abundant but dissipating waste heat is the binding constraint.

---

Relevant Notes:
- [[space-based solar power economics depend almost entirely on launch cost reduction with viability threshold near 10 dollars per kg to orbit]] — the alternative: beam orbital solar to terrestrial data centers
- [[power is the binding constraint on all space operations because every capability from ISRU to manufacturing to life support is power-limited]] — for compute, the constraint shifts from power to thermal management

Topics:
- [[space exploration and development]]
