SpaceX's massive Starship rocket could take to the skies for a fourth time on June 5, with the main purpose of evaluating the second stage's reusable heat shield as the vehicle attempts to safely enter the atmosphere for the first time.
CEO Elon Musk“ said on his social media platform X that “there are many tough problems to solve with this vehicle, but the biggest remaining problem is creating a reusable orbital return heat shield, which has never been done before.”
His message echoes comments he made earlier this month, when he noted that the primary goal of the next Starship test was “to pass maximum re-entry heating.”
This means that the new heat shield of the second phase, consisting of approximately 18,000 ceramic hexagonal tiles, will be put to the test. These tiles are designed to protect the second stage (also called Starship) from the extreme temperatures experienced upon re-entering Earth's atmosphere. One of the biggest problems, Musk suggested, is the fragility of the system in general: “we can't withstand the loss of a single tile in most places,” he said. That means a single damaged or defective tile can lead to a catastrophe.
As Musk noted in his post, surviving the return is only part of the puzzle. The company will also have to create an “entirely new supply chain” for the high-performance heat shield tiles and produce them in very high volume.
It's a tough problem, but solving it would bring them closer to the holy grail of launch vehicles: complete reusability. SpaceX has made great strides in reusability with its workhorse Falcon 9 rocket – which has flown 56 times so far this year – but even though the company has recovered the booster, the second stage is being used in its target orbit. By reusing both stages of the rocket, SpaceX hopes to reduce costs to a fraction of what they are today, while delivering many orders of magnitude more mass to orbit in a single launch. (SpaceX's Transporter ride-share missions cost $6,000 per kilogram.)
If all goes according to plan, the company will demonstrate the ability to return the Starship to Earth via a controlled reentry and soft splash in the Indian Ocean. SpaceX also aims to return the booster, called Super Heavy, via a splashdown in the ocean. And it will move one step closer to bringing the largest and most powerful launch system ever built online, ready to carry cargo and ultimately crew to Earth's orbit and beyond.
This next Starship launch will be the fourth in a series of orbital flight tests that began last April. Before the launch can proceed, SpaceX must obtain a commercial launch license from the U.S. Federal Aviation Administration, the agency responsible for regulating commercial launch operations. The FAA also oversees investigations into rocket launches that go wrong for any reason, and is therefore working closely with SpaceX during the Starship test campaign.
And the previous Starship launches have certainly failed: the first two ended in fiery explosions in the sky, and the third ended with both Super Heavy and Starship likely disintegrating before hitting the ocean. But for SpaceX, which takes an iterative approach to hardware development, each test was ultimately a success because they provided engineers with data about the rocket in a real flight environment. And it's true that each mission has gone further than the last: on the third flight, the engines caused complete burns as the vehicle took off, and Starship finally reached orbit for the first time.
Ultimately, SpaceX plans to land both the Super Heavy booster and the Starship second stage at its launch site in southeast Texas, where they can be quickly refurbished and returned to the pad.
