Source: The Conversation – USA
SpaceX’s Starship, the most powerful launch vehicle ever developed, reached Earth orbit for the first time on Sept. 28, 2026. This mission, the rocket’s 14th test flight, also marked the first time that Starship deployed Starlink internet satellites into the existing larger constellation: 26 new next-generation nodes in total.
But not all went as planned. An engine went out, though SpaceX quickly determined Starship could still reach orbit without it. While SpaceX had planned for Starship to orbit the Earth six times, it changed gears and had Starship return after only two orbits. And the splashdown in the Pacific Ocean ended in a huge bang, rather than the soft landing the company had hoped for.
This flight can still be viewed as a success. It was an important step toward putting the enormous rocket to work by sending it into orbit. Starship is a key part of SpaceX’s vision. The company wants Starship to be a fully and rapidly reusable transport system that slashes the cost of spaceflight.
To realize this vision of extremely low-cost launches, SpaceX needs to be able to bring these spacecraft back from orbit, refurbish them and launch them again in short order.
Whether that all becomes quick and routine largely depends on dark ceramic tiles covering Starship’s underside. These tiles make up Starship’s heat shield.
I’m an engineer and professor who has researched the way heat shields respond when reentering the atmosphere, a process that is extremely harsh on a spacecraft. I see Starship’s heat shield as a technical challenge that also drives the company’s economics. Elon Musk has agreed.
A spacecraft that survives its return has passed an essential test. Next, engineers must establish how much work it will take to repair or replace the heat shield before its next launch.
Why is reentry so difficult?
A spacecraft in low Earth orbit travels at roughly 17,500 miles per hour (28,000 kilometers per hour). Returning to Earth means shedding an enormous amount of energy to slow down. Some shedding happens higher up by igniting the engine, but a lot of it happens lower down as the spacecraft reenters through the atmosphere. During reentry, strong shock waves form and heat up the surrounding atmosphere. Much of that heat transfers to the spacecraft.
If you’ve ever experienced a rug burn, you understand what is happening. You trip and your arm slides to a stop on a rug, with your bare skin experiencing a painful burn. If you were wearing a long-sleeved shirt, you might still feel the heat, but you would likely escape a severe burn.
The role of a spacecraft’s heat shield is similar to the protection that the shirt provides: It limits how much of that heat reaches the spacecraft structure underneath it. Starship’s heat shield is composed of approximately 18,000 hexagonal tiles made of silica ceramic. You can think of them like the ceramic lining of a furnace: The fire in the furnace is extremely hot, but the tiles contain that heat.
AP Photo/Eric Gay
To be reusable, the heat shield must withstand the mechanical demands of launch, such as pressure and vibrations, as well as the challenges of space, such as exposure to a vacuum. It should also withstand the repeated cycles of heating and cooling that the rocket experiences during flight.
How the tiles are attached and the spaces between them matter as much as the material itself. A tile that tolerates the heat does little good if it falls off. A gap that lets hot gas reach the structure underneath can lead to catastrophe, as in the space shuttle Columbia accident in 2003.
Before the flight, SpaceX engineers made some changes they wanted to test. They attached the tiles more securely in vulnerable areas. They also added measures that stop hot plasma from traveling behind tiles and added curved tiles to reduce heating in the gaps.
SpaceX also reflew two tiles recovered from a previous Starship. Repeating a flight with previously exposed material can test how the protection holds up over time. Two tiles, however, cannot establish how many flights an entire heat shield will last.
What exactly does a successful return mean?
SpaceX equipped three of the Starlink satellites released on Monday with cameras to inspect Starship’s heat shield after deployment.
Their images could tell engineers about any damage the ship took as it launched and entered orbit. This way, they can compare the photos to the tiles after reentry to learn about the heat shield’s performance. Engineers will look at where the damage occurred, what caused it and whether the same hardware could fly again safely.
AP Photo/Eric Gay
The business case requires reusability
The logic behind reusable rockets is straightforward: Spreading the cost of building a vehicle over many missions lowers the hardware cost for each launch.
But the accounting also includes inspection, replacement parts, labor, propellant, ground facilities and the risk of losing a vehicle. A rocket waiting for repairs ties up capital.
My engineering assessment is that heat shield improvements can produce two kinds of savings: First, better heat shields require fewer repairs after each mission. And a more rapid turnaround time would allow each vehicle to fly more missions. This achievement could make reuse more valuable than simply recovering the expensive hardware from a used Starship, to be reinstalled on a new spacecraft.
SpaceX’s own investor disclosures make this connection explicit. They warn that failing to achieve full reuse and quick turnaround times between flights could increase launch costs. Delays could also stall the deployment of satellites in the Starlink constellation, which is a major source of revenue growth.
Satellites, the Moon and data centers
NASA also plans to use Starship on future missions to the Moon, which will require Starship to be ready for a sequence of launches.
A March 2026 report from NASA’s inspector general described a plan requiring more than 10 Starship tanker flights. These Starship tankers would carry propellant to lunar orbit, where each would rendezvous with, dock to and transfer propellant to a storage depot. However, NASA’s timeline for returning to the Moon is already facing delays, and any delays with Starship could add further delay.
SpaceX has also proposed building orbital data centers, which would use Starship to launch the heavy computing satellites to orbit. But SpaceX’s prospectus says it will need Starship to be fully reusable for these plans to be economically attractive.
For me, the next telling milestone will be recovering a Starship and then inspecting it and preparing it to launch again. To date, SpaceX has successfully reused only its first-stage Super Heavy booster, not the Starship vehicle itself. SpaceX will need to show that this process is becoming predictable and routine. That feat would require a heat shield that protects both the spacecraft and the economics behind Starship.
Sven Bilén does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.