SpaceX’s massive Starship rocket may take to the skies for a fourth time on June 5, primarily to evaluate the second stage’s reusable heat shield as the vehicle attempts to safely re-enter the atmosphere for the first time.
CEO Elon Musk said on his social media platform X that “There are a lot of hard problems to solve with this vehicle, but the biggest remaining problem is creating a reusable orbital heat shield, which has never been done before.”
His post echoed comments he made earlier this month when he noted that the primary goal of Starship’s next test was to “go through maximum reheat.”
This means that the new heat shield of the second stage, made up of around 18,000 ceramic hexagonal tiles, will be put to the test. These tiles are designed to protect the second stage (which is also called the Starship) from the extreme temperatures experienced upon re-entry into the Earth’s atmosphere. One of the biggest problems, Musk suggested, is the vulnerability of the system as a whole: “we’re not immune to losing one tile in most places,” he said. This means that a damaged or defective circuit board can cause a crash.
As Musk noted in his post, surviving re-entry is only one piece of the puzzle. The company will also have to create an “entirely new supply chain” for the high-performance thermal insulation tiles and produce them in very high volume.
It’s a tough problem, but solving it will bring them closer to the holy grail of launch vehicles: full reusability. SpaceX has made great progress in reusability with its workhorse Falcon 9 rocket — which has flown 56 times so far this year alone — but although the company is recovering the booster, the second stage is spent in its target orbit. By reusing both rocket stages, SpaceX hopes to reduce costs to a fraction of what they are today, while delivering many orders of magnitude more mass into orbit in a single launch. (SpaceX’s Transporter ride-sharing missions cost $6,000 per kilogram.)
If all goes according to plan, the company will demonstrate the ability to return the Starship to Earth through a controlled re-entry and soft splash in the Indian Ocean. SpaceX is also looking to return the booster, called the Super Heavy, also by dispersing it into the ocean. And it will be one step closer to bringing the largest and most powerful launch system ever built online, ready to transport cargo and possibly crew to Earth orbit and beyond.
This next Starship launch will be the fourth in a series of orbital flights that began last April. Before the launch can proceed, SpaceX must obtain a commercial launch license from the US Federal Aviation Administration, the agency responsible for regulating commercial launch operations. The FAA also oversees investigations into rocket launches that fail for whatever reason, and so it worked closely with SpaceX during the Starship test campaign.
And previous Starship launches have certainly failed: the first two ended in fiery explosions in mid-air, and the third ended with the Super Heavy and Starship presumably disintegrating before hitting the ocean. But for SpaceX, which takes an iterative approach to hardware development, each test was ultimately successful because they provided engineers with data about the rocket in a real-world flight environment. And it’s true that each mission went further than the last: on the third flight, the engines pulled a full burn as the vehicle ascended, and the Starship eventually reached orbit for the first time.
Ultimately, SpaceX aims to land both the Super Heavy booster and the Starship second stage at its launch facility in southeast Texas, where they can be quickly refurbished and returned to the pad.