SpaceX set for tenth Starship flight to test reusability milestones

Elon Musk's SpaceX is set to launch its massive Starship rocket for a tenth time from Texas on Sunday to achieve several long-sought development milestones missed due to past tests ending in early failures.

The 232-foot tall Super Heavy booster and its 171-feet (52 meters) tall Starship upper half sat stacked on a launch mount at SpaceX's Starbase rocket facilities ahead of an expected 7:30 p.m. ET liftoff time. Musk is expected to provide an update on Starship's development progress prior to the rocket's launch on Sunday.

Development of SpaceX's next-generation rocket, the center of the company's powerful launch business future and Musk's Mars ambitions, has faced repeated hiccups this year as NASA hopes to use the rocket as soon as 2027 for its first crewed moon landing since the Apollo program.

The future of SpaceX's Starlink satellite internet business, a major source of revenue for the company that has been deployed by SpaceX's workhorse Falcon 9, is also tied to Starship's success. Musk is keen on using Starship's greater lift strength to loft into orbit larger Starlink satellites designed to expand the constellation's bandwidth.

This year, two Starship testing failures early in flight, another failure in space on its ninth flight, and a massive test stand explosion in June that sent debris flying into nearby Mexican territory have tested SpaceX's test-to-failure development approach. Still, the company has continued to swiftly produce new Starships for test flights at its sprawling Starbase production facilities.

Those setbacks underscore the technical complexities of Starship's latest iteration, packed with far more capabilities such as increased thrust, a potentially more resilient heat shield and stronger steering flaps crucial to nailing its atmospheric reentry - key traits for Starship's rapid reusability that Musk has long pushed for.

Around sunset on Sunday, the stacked system will blast off from Texas before its Starship upper stage separates from the Super Heavy booster dozens of miles in altitude. Super Heavy, which has returned for a landing at its launch pad in giant mechanical arms in past tests, will instead target the Gulf of Mexico for a soft water landing in order to test a backup engine configuration.

Meanwhile, Starship will briefly ignite its own engines to blast further into space, where it will attempt to release its first batch of mock Starlink satellites and reignite an engine while on a suborbital path around the planet.

About an hour into the mission, the ship will then target an atmospheric reentry over the Indian Ocean, a crucial flight phase that will test a variety of prototypical heat shield tiles and engine flaps designed to endure a barrage of blazing heat that has largely shredded the rocket's exterior during past tests.

"Starship's reentry profile is designed to intentionally stress the structural limits of the upper stage's rear flaps while at the point of maximum entry dynamic pressure," SpaceX said on its website.