Castelion, a nearly four-year-old startup that makes hypersonic missiles, is aiming to raise a new funding round at a valuation of $12 billion or more, including the money raised, according to two people with knowledge of the fundraising efforts.

The company’s target would be at least four times the valuation of its last funding round in December, reflecting heightened investor interest in defense tech startups that the SpaceX initial public offering has supercharged. Castelion’s three co-founders previously worked at SpaceX.