Streaming Sunshine: Space Based Solar Power, Minus the Sci-Fi - Martin Soltau, CEO Space Solar

Jul 15, 2025

36:05

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Space Solar has a revolutionary vision to enable Net Zero and global energy security with Space-Based Solar Power.

An 80 × 80 m satellite in low-Earth orbit, continuously exporting one megawatt of electricity to a ground station, is not science fiction. According to Martin Soltau, co-CEO of Space Solar, that first-of-its-kind demonstrator will fly within five years.

In this conversation Mark and Jeremy Think On Paper about the engineering reality and the policy headaches behind space-based solar power (SBSP):

Cassiopeia’s solar array converts sunlight to 5.8 GHz microwaves at up to 85 % efficiency
The down-link beam peaks at ≈230 W m⁻², less than a quarter of midday sunlight, so it warms rather than cooks anything it touches.
A rectenna two-to-three-kilometres wide re-converts the RF to DC with ≥ 85 % efficiency delivering “plug-ready” power around the clock.
Today’s launch prices already model to < $30/MWh levelised cost of electricity; a further order-of-magnitude drop could push SBSP below $10/MWh—one-tenth the cost of nuclear baseload today.
Sun-to-plug efficiency is about 18 %, versus 1–5 % for ground solar once night-time and weather are included.

Regulatory and diplomatic knots

Spectrum allocation through the ITU, debris-safe autonomous assembly, and international rectenna standards are the next gating items—not new physics.

Why AI cares

Data-centre power demand is “asymptotic,” with forecasts that AI workloads could swallow > 90 % of U.S. electricity this century. Off-grid rectennas over a server farm could bypass decade-long grid-connection queues.

Failure modes worth losing sleep over

Beam divergence, spectrum crowding, orbital debris and the inevitable “Death-Star” headlines—all solvable, but only with transparent public engagement. A Royal Society survey found strong public support once safety was explained.

Soltau also outlines the mid-2030s scale-up to tens of gigawatts per year and why modular, robot-assembled satellites could deliver that pace faster than any terrestrial baseload technology.

Please enjoy the show. And share with a curious friend.

Learn More: https://www.spacesolar.co.uk/

Timestamps

(00:00) Disruptors And Curious Minds

(01:34) Space Based Solar Satellites

(05:10) The Ground Infrastructure

(07:37) SBSP V Nuclear, Coal & Gas

(12:05) Launch Costs

(13:55) Data Centers In Space

(15:36) Scaling Space Based Solar Power

(18:08) Manufacturing In Space

(20:25) The Eisenhower Of SBSP