Source Review: NASA OTPS — Space-Based Solar Power (Jan 2024)

Summary

Claim 1: SBSP not competitive vs terrestrial under reference assumptions

Quote: Baseline LCOE $610-1,590/MWh vs terrestrial PV ~$84/MWh; optimistic-scenario $40-80/MWh.

Verdict: Consistent

Why: This is the authoritative skeptical position on SBSP commercial viability under current launch-cost regime. q6.c4 BAU 5 GW deployment is conditional on strategic-autonomy demand (non-LCOE) rather than commercial competitiveness, consistent with NASA's finding. The TAI-C 100 GW deployment requires the "optimistic scenario" of $40-80/MWh + sub-$200/kg launch + mass-production scaling — explicitly NASA's optimistic-corner case.

Claim 2: $100-200/kg launch threshold for SBSP viability

Verdict: Consistent

Why: This couples directly to q1's Starship cost-curve projection. Per q1's reviewed answer, $100-200/kg LEO is in the optimistic-late-2030s corner under partial-reuse, and is fully attainable only under TAI-grade compression. The launch-cost threshold IS the BAU-vs-TAI-C regime distinction for SBSP.

Claim 3: Capability-gap inventory (on-orbit assembly, autonomous

operation, beam-power hardware, GEO operations)

Verdict: Consistent

Why: These are the engineering bottlenecks that spaceambition-2026-sbsp also identifies (km-scale phased arrays as "hardest unsolved engineering risk"). Cross-corroborated.

Claim 4: Lifecycle emissions parity with terrestrial sustainable

Verdict: Different conclusion

Why: Where NASA OTPS finds emissions parity with terrestrial sustainables, scientificamerican-2026-sdc cites Saarland University researchers finding orbital DC could be "order of magnitude greater emissions" once launch and reentry are factored. The discrepancy is SBSP-vs-SDC scope (NASA is SBSP specifically; Saarland is broader orbital infrastructure including SDC). For q6 the emissions question is tangential to the mass-demand question, but flag for synthesis: emissions-driven regulatory regimes could cap orbital deployment volume regardless of launch cost.

Claim 5: Capability-gap closure path

Verdict: Merits investigation

Why: NASA OTPS identifies the gaps but does not endorse a closure path. Where does TAI-grade automation enter the closure? q3-isru already establishes a framework for acceleration-regime-dependent TRL progression; q6 should adopt the same framework for SBSP TRL. Cross-leaf consistency: q3's TAI-C / BAU / stall regimes map directly onto q6's SBSP deployment scenarios. Flag for synthesis.

Anti-hallucination check

• The LCOE ranges and $100-200/kg threshold are widely cited NASA OTPS figures, cross-validated via the spaceambition-2026-sbsp extract.
• Direct PDF not parseable via WebFetch; figures attributed via multiple secondary aggregators citing the report.
• Flag: future iteration should hand-extract the LCOE sensitivity tables for direct primary-source review.

Notes

NASA OTPS is the tier-S authoritative source on SBSP economic viability under reference assumptions. The skeptical finding is itself load-bearing for q6.c4's BAU-vs-TAI-C regime distinction. The optimistic-scenario LCOE $40-80/MWh creates the conditional under which 100 GW TAI-C deployment becomes commercially viable.

Abstract

NASA's January 2024 OTPS report evaluates whether space-based solar power (SBSP) is a competitive option for U.S. net-zero emissions by 2050. The headline finding is that SBSP is more expensive than terrestrial sustainable alternatives under reference cost assumptions (LCOE $610-1,590/MWh baseline, $40-80/MWh optimistic; cf. terrestrial PV at ~$84/MWh). The report identifies capability gaps including: large-scale on-orbit assembly and maintenance, autonomous operation, efficient power-beaming hardware, GEO operations, and bulk launch and manufacturing cost reduction. Lifecycle emissions are similar to other sustainable alternatives but the levelized cost remains uncompetitive without substantial launch-cost reductions below $100-200/kg.

Key claims

• competitive-conditions: SBSP becomes competitive against terrestrial alternatives only under aggressive launch-cost and manufacturing-efficiency improvements.
• baseline-lcoe: Baseline LCOE $610-1,590/MWh; optimistic-scenario $40-80/MWh. Terrestrial PV ~$84/MWh (current).
• launch-cost-threshold: $100-200/kg LEO is the launch-cost regime required for SBSP economic viability.
• capability-gaps: Large-scale on-orbit assembly, autonomous operation, efficient power-beaming, GEO operations, and bulk launch+manufacturing cost are the binding gaps.
• emissions-parity: Lifecycle emissions of SBSP are comparable to other sustainable alternatives, not a comparative advantage.

Reviewer notes

Authoritative government technical assessment, tier S by virtue of NASA OTPS commissioning. Direct sectoral demand driver for q6: SBSP mass demand is conditional on the launch-cost regime. If Starship delivers $100-200/kg per q1, SBSP could become a major mass-demand sink; if not, SBSP stays demonstration-scale only. Direct PDF text not parseable via WebFetch; key numbers extracted from the NASA OTPS announcement page and secondary aggregators citing the report. Future iteration should hand-extract from the source PDF for full claim inventory.