Given that it's about as abundant as platinum (which trades at ~$50000/kg), tellurium is pretty cheap right now (~120$/kg, about 10 times the price of copper).

Since it's an almost free byproduct of copper electrorefining (>1% concentration in copper anode slime, but low annual production of ~800 tons, limiting CdTe panel production to ~100GW/year short term [1]), I don't think that mining it in space is ever gonna pay off for terrestrial panel production, because if it was priced somewhat comparably to platinum group metals you could never ever justify any demand for it (panels would be much too expensive compared to alternatives, tellurium is already a relevant cost factor for them despite being cheap-ish) => and you'd obviously use all interplanetary mining/transport capability on platinum and its ilk instead.

[1]: https://www.pv-magazine.com/2026/02/10/global-cadmium-tellur...