If Elon Musk’s SpaceX and T-Mobile are to have any hope of beating a wide range of rivals—including Amazon and potentially Apple—to the market for satellite-delivered cellphone services, they need to overcome an array of both regulatory and technological roadblocks. Musk and SpaceX engineers are racing to clear key engineering hurdles. But it will be much harder for Musk to quickly overcome the biggest regulatory challenge—getting approval from the Federal Communications Commission.

Despite Musk’s hyping the “profundity” of their venture when it was unveiled last month, the SpaceX-T-Mobile partnership is behind rivals. Globalstar, for instance, which sells existing bulky satellite phones, already has approval from the FCC to provide satellite-based mobile services using regular phones. And industry chatter suggests it is planning to partner with Apple on a service that could be announced as soon as Wednesday, when the iPhone maker has a new-product event scheduled. Satellite service provider AST SpaceMobile also has FCC approval to test a new satellite-based cellphone project.