IIRC it’s a custom process using wide-bandgap silicon (part of the whole rad-hardening thing) that no-one else needs or wants, so you have to pay the full costs

IIRC it’s a custom process using wide-bandgap silicon (part of the whole rad-hardening thing) that no-one else needs or wants, so you have to pay the full costs of a fab run for a relatively small number of chips. Hence the cost per chip is huge.