Stocks in rocket launch and satellite companies have surged over the past year, as SpaceX’s soaring private valuation and steps toward what could be a record-smashing initial public offering drums up enthusiasm for all things outer space.

But most of the companies whose stocks have been rocketing are at risk if SpaceX solidifies its lead in launches and satellite-powered communications. Those include rocket maker Rocket Lab and AST SpaceMobile, a rival to SpaceX’s Starlink satellite internet service.