Which of these speculative stocks has a better shot at generating massive gains?AST SpaceMobile (ASTS 13.65%) and IonQ (IONQ 4.56%) are both speculative growth stocks that trade at sky-high valuations. AST, a developer of satellites for cellular communications, trades at 175 times this year's estimated sales. IonQ, a developer of quantum computing systems, trades at 36 times this year's sales. Both companies are expected to remain unprofitable for the foreseeable future.AST SpaceMobile and IonQ both seem li ...