WASHINGTON, Aug 4 (Reuters) - SpaceX is increasingly reserving space on its rockets to launch its own Starlink satellites, crowding out rival space companies that have long depended on Elon Musk's company to get their payloads into orbit. ‌They added that the bottleneck is driven by SpaceX's plans to transition to the new Starship rocket, designed to be fully reusable and cheaper than Falcon 9. The unit is critical to SpaceX's success, accounting for 60% of its revenue last year. Even as SpaceX transitions to the Starship rocket, the company's NASA obligations and its plans for Starlink are likely to occupy most of its launches. The company has said it is targeting late 2026 for Starship's first orbital mission, which will deploy a batch of SpaceX's next-generation Starlink satellites.