| ▲ | derriz 3 hours ago | ||||||||||||||||||||||
Capacity factor of orbital solar PV panel: 97% Capacity factor of terrestrial solar panel: 23% Retail cost per watt for terrestrial panel: under 45c Manufacturing cost per watt of space grade solar panel: up to $450 Annual performance degradation of terrestrial solar panel: under 0.5% That of space-grade solar panel: up to 2% Life span of terrestrial panel: about 2x that of space panel. Total difference in cost per watt feeding a DC load in space vs on land: about x400 And that's ignoring launch costs. It makes absolutely zero sense. And given the scale of production and investment in manufacturing, terrestrial is likely to stretch even further ahead in the cost stakes. | |||||||||||||||||||||||
| ▲ | philipkglass 2 hours ago | parent | next [-] | ||||||||||||||||||||||
The idea is still a real stretch, but according to Google's paper in Joule [1] they're putting satellites in low Earth orbit and only targeting a service lifetime of 5 years. Over that short time, with the correspondingly modest radiation exposure, you can use inexpensive silicon solar cells like you would use for terrestrial solar farms. The expensive space grade solar cells from e.g. Boeing Spectrolab are more resistant to radiation, and achieve higher conversion efficiencies, but silicon cells are fine for satellites like these. Starlink satellites already use silicon solar cells, since they too are cost sensitive and don't have long lifespans: https://starlink.com/public-files/Starlink_Approach_to_Satel... On the Starlink V2 mini satellite, we predict that approximately 5% of the mass of the entire satellite could survive reentry. The biggest contributor (~90% of the surviving mass) is silicon from the solar cells, which has a high melting point... [1] https://www.cell.com/joule/fulltext/S2542-4351(26)00362-4 | |||||||||||||||||||||||
| ▲ | 0cf8612b2e1e 2 hours ago | parent | prev [-] | ||||||||||||||||||||||
Just on a mass basis it falls apart. Best cost to orbit I am seeing is $1500/kg. A GPU rack is ~1500kg. Let’s imagine you can take a terrestrial data center rack, no scaffolding, solar panels, radiators, radios, propellant, or propulsion. Fly it into orbit, kick it out the airlock, and let it work through magic. That’s $2.2 million to get into position. Industrial power rates are cheap, say $.10/kwh, but pretend you sign terrible deals, and it costs you $.30/kwh to run and cool a terrestrial GPU rack. A 150kw unit will then be (150x24x365x.3) =$394k/year. You can operate the terrestrial version for 5.7 years before the two hit parity. | |||||||||||||||||||||||
| |||||||||||||||||||||||