---
type: source
title: "Space-Based Solar Power: Assessment and Recommendations"
author: "NASA Office of Technology, Policy, and Strategy (OTPS)"
url: https://www.nasa.gov/wp-content/uploads/2024/01/otps-sbsp-report-final-tagged-approved-1-8-24-tagged-v2.pdf
date: 2024-01-08
domain: space-development
secondary_domains: [grand-strategy]
format: report
status: processing
processed_by: astra
processed_date: 2026-03-10
tags: [sbsp, space-based-solar-power, energy, launch-costs, economics]
---

## Summary

NASA's comprehensive assessment of space-based solar power economic viability. Widely cited but also widely criticized (by John Mankins and others) as selecting pessimistic parameters.

### Baseline Findings

- Reference Design 1 (RD1) LCOE: **$610/MWh** — 12x terrestrial alternatives
- Reference Design 2 (RD2) LCOE: **$1,590/MWh** — 80x terrestrial alternatives
- Launch costs assumed: $1,000/kg with only 15% block-buy discount
- Launch accounted for **>70% of total lifecycle costs**

### Sensitivity Analysis (Optimistic Case)

Combining lower launch costs ($500/kg with volume discounts), electric propulsion, 15-year hardware life, 85% manufacturing learning curves:
- LCOE compressed to **$40-80/MWh** — directly competitive with terrestrial alternatives

### Key Insight for Megastructure Thesis

At $100/kg (Starship target), launch adds only ~$3.5/MWh to LCOE. The dominant costs become satellite hardware manufacturing and microwave antenna systems. The critical crossover point is ~$100-200/kg to LEO.

SBSP's value is not grid power LCOE competition but **continuous power delivery** (95-99% uptime from GEO) — critical for systems requiring uninterrupted GW-scale power, specifically Lofstrom loops.

### Other Key Studies (2024-2026)

| Study | LCOE Estimate |
|-------|---------------|
| NASA OTPS baseline | $610-1,590/MWh |
| NASA sensitivity (optimized) | $40-80/MWh |
| Caltech Joule (2025) | 9.4 cents/kWh ($94/MWh) near-term |
| ESA Solaris studies | EUR 88.5-155.5/MWh by 2040 |
| UK Gov Fraser-Nash (Feb 2026) | GBP 87-129/MWh by 2040 |
| Virtus Solis (unvalidated) | $25/MWh |

### Caltech SSPD-1 Milestones

- March 2023: First in-space wireless power transmission
- May 2023: First space-to-ground power beam (detected at Caltech campus)
- 2025 Joule paper: proposes 1,600m diameter, 113 MW station, LCOE 9.4 cents/kWh with 10 years development

## Agent Notes (Astra, 2026-03-10)

SBSP economics are sensitive to launch cost but not solely determined by it. Even at zero launch cost, the GW-scale microwave antenna system is a cost bottleneck that doesn't yet exist. End-to-end efficiency is only ~11%.

However, SBSP's killer app is NOT grid power competition — it's enabling infrastructure for Lofstrom loops. A single 1 GW SBSP satellite powers a basic loop (500 MW operating mode). The loop then launches SBSP components at $3/kg instead of $100+/kg. Self-reinforcing cycle.

CLAIM CANDIDATE: Space-based solar power's primary value for space development is enabling continuous GW-scale power for launch infrastructure, not competing with terrestrial grid power.

## Curator Notes

Government report — high institutional credibility but selection of parameters was contested. Mankins critique is well-documented. The sensitivity analysis showing competitiveness at $40-80/MWh is more relevant than the pessimistic baseline for forward-looking analysis. Caltech SSPD-1 is the first hardware validation but at minuscule scale.