Starship’s sixth flight revealed two key findings. Ditching carbon fiber for a stainless steel fuselage was essential for creating a relatively inexpensive and easy-to-assemble rocket capable of surviving atmospheric re-entry in one piece. However, the heat shield meant to protect the fuselage from extreme plasma temperatures is underperforming.
“The biggest technology challenge remaining for Starship is a fully & immediately reusable heat shield. Being able to land the ship, refill propellant & launch right away with no refurbishment or laborious inspection. That is the acid test,” SpaceX CEO Elon Musk said.
Yet, SpaceX still has a long way to go, as shown in images of the spacecraft’s first daylight splashdown over the Indian Ocean. A camera on a buoy captured Starship 31 turning upright after returning from space, its fuselage visibly scorched. Unlike the Super Heavy booster, which is designed primarily for liftoff, Starship—the spacecraft responsible for carrying satellites and astronauts—needs significant improvements to be reused without repairs.
Back to Active Cooling
Acknowledging that the heat shield is the program’s biggest technical hurdle, Musk revealed on X that SpaceX is reconsidering an earlier heat shield design. This design, previously shelved due to its complexity, involves adding active cooling to Starship’s exterior by circulating cryogenic propellants—either as a liquid or gas—through a thin outer film.
The spacecraft’s existing heat shield, made of thousands of ceramic tiles, would work alongside this liquid or gaseous film cooling system in critical areas. However, this approach adds complexity, weight, and cost to the rocket. SpaceX may have underestimated the challenges of creating a heat shield simple enough to meet its reusability goals.
While this represents a step back, it aligns with SpaceX’s trial-and-error philosophy in Starship development. No spacecraft to date has achieved a fully reusable heat shield. For instance, SpaceX partially replaces the shield on the Crew Dragon capsule before reusing it for missions to the International Space Station. NASA’s space shuttle had a reusable heat shield but required months of restoration between flights.
Starship’s sixth flight also marked the last of the current generation of spacecraft. Ship 33, set to fly on the seventh test flight, will introduce the V2—or Block 2—design. This iteration includes larger tanks, an improved heat shield, and redesigned front flaps for better re-entry protection. For the eighth flight, SpaceX plans to land Starship using the same method as the Super Heavy booster: catching the spacecraft with the arms of the Mechazilla tower.
Image | SpaceX
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