The closed-ended fund will invest in an international portfolio of early and growth-stage space tech businesses, targeting an annualised net asset value of at least 20% over the long term, it said in a statement.
Seraphim will issue ordinary shares at 100 pence per share.
JPMorgan Cazenove and Deutsche Bank are joint bookrunners, the company said.
(Reporting by Carolyn Cohn; Editing by Dhara Ranasinghe)