A solar smelter in space might be one way to reuse metals in space.

Q. Could a solar smelter work in space

Google AI

Yes, a solar smelter in space could work from a strict physics standpoint, but it faces massive practical and economic hurdles.

How It Would Work

• Concentrated Solar Thermal Energy: Instead of using solar panels to make electricity, a space smelter would use large curved mirrors or heliostats to focus direct, unfiltered sunlight onto a single focal point.

• Extreme Heat in a Vacuum: Without an atmosphere to diffuse light or absorb heat, concentrated orbital sunlight can easily reach temperatures above 3,000°C—more than enough to melt iron, aluminum, or silicate rocks.

• No Oxygen/Gravity Advantages: Smelting in a vacuum prevents unwanted chemical oxidation with air, and microgravity could allow for unique foam-metal or alloy casting processes without settling or convection currents.

Major Challenges

• The Launch Cost Barrier: Lifting heavy raw ores or massive smelting apparatuses out of Earth’s gravity well is currently too expensive to make commercial space manufacturing profitable.

• Thermal Management: While gathering heat is easy in direct sunlight, getting rid of waste heat in a vacuum is notoriously difficult because there is no air to cool things down via convection; everything relies on slow thermal radiation.

• The Need for Extraterrestrial Materials: For a space smelter to make economic sense, it would have to process asteroidal or lunar regolith rather than materials launched from Earth.

Explore:

• Using lunar in-situ resource utilization (ISRU) to feed the smelter

• How radiative cooling works in the vacuum of space

• Comparing solar thermal smelting to electric arc furnaces powered by space solar panels

Cooling metal in space can be achieved by moving heat shields in front of the metal to be cooled.

Moving heat shields could be achieved using ion drives. The power for the ion drives comes from solar arrays.

Why have a solar space smelter?

1 To help clean up the space debris field, rocket casings and defunct satellites on an on going basis.

2 To smelt metal asteroids into ingots or bars on an on going basis.

I’ve given a rough estimate of 20 years, but if China, America, Europe and other space manufacturing countries become interested that number could be reduced. Further Reduced if AI is doing shared work.

Sell the idea to Elon. $5m and a 1% carried interest.

Tau.Neutrino said:

Why have a solar space smelter?

1 To help clean up the space debris field, rocket casings and defunct satellites on an on going basis.

2 To smelt metal asteroids into ingots or bars on an on going basis.

Rocket casings, defunct satellites can be smelted down and reused for building larger rockets for space mining.

Tau.Neutrino said:

Tau.Neutrino said:

Why have a solar space smelter?

1 To help clean up the space debris field, rocket casings and defunct satellites on an on going basis.

2 To smelt metal asteroids into ingots or bars on an on going basis.

Rocket casings, defunct satellites can be smelted down and reused for building larger rockets for space mining.

This should help towards efficient use of materials in space, that can be reused after first use.

Future space stations could stay in a higher orbit and continually recycle older sections of the space station to the smelter which are then returned as new sections to the space station ready for refitting.

I don’t think this will be a useful technology in my lifetime.

dv said:

I don’t think this will be a useful technology in my lifetime.

Same for me I would think.

Google AI

Space mining is expected to reach early commercial and robotic operations within 10 to 20 years (around 2030 to 2045), though full-scale industrial mining will likely take 30 to 100+ years.

Key Timelines by Sector

• Lunar Civil Engineering & Robotic Operations: Robotic and preliminary civil engineering on the Moon is projected to begin around 2027 to 2030, focusing on extracting lunar ice (water) for in-space refuelling and life support.

• Near-Earth Asteroid (NEA) Prospecting & Commercial Tests: Private companies like AstroForge are actively testing deep-space mining tech and planning commercial asteroid missions through the mid-2020s.

• Small-Scale / Initial Extraction: Industry analysts estimate that small-scale or pilot asteroid and lunar resource extraction could become viable within 20 years under optimal technological progress and funding.

• Industrial-Scale Mining: Operating a mature, high-yield, multi-tonne commercial supply chain that ships minerals back to Earth (or scales massive off-Earth manufacturing) is a multi-decade project expected to span 50 to over 100 years due to extreme transport and refining hurdles.

Space sample returns: Space agencies have successfully retrieved tiny amounts of asteroid material via missions like Hayabusa2 and OSIRIS-REx, totaling roughly 127 grams of returned material to date.

Commercial missions: Private firms like AstroForge are developing low-cost autonomous spacecraft to target and test extraction methods on near-Earth metallic asteroids.

Is Space Mining Worth It? Luxembourg’s Law, Lunar Water, and Psyche @PureScienceDocs