NASA Heat Shield Experts Warn Starship Shielding Could Be a ‘Dead End’
A new expert analysis has bluntly questioned the viability of the SpaceX Starship program, particularly its ability to rapidly reset for “full” reuse. The culprit—Starship’s heat shielding—has long been known to be a challenge for SpaceX, but it has never been explicitly called out for its potential to tank the idea entirely.
When a spacecraft reenters the atmosphere, it uses drag against the increasingly thick gas to do most of its deceleration, usually from dozens of times the speed of sound. This creates the classic fireball we all associate with spaceships, satellites, and meteors descending toward Earth.
This obviously generates a great deal of heat and quickly burns away most materials that could be used to build a spaceship. NASA’s classic answer has been to plate spacecraft slated for reentry with small, specialized ceramic tiles that can withstand extreme temperatures and be cut and arranged to cover any surface shape.
The problem is that even though these tiles can keep a spacecraft intact, they are still stressed by the heat of reentry. NASA has had to painstakingly inspect thousands upon thousands of tiles for every launch of a retrievable vehicle—one of the many reasons the agency has opted for more disposable space tech in the past.
With SpaceX’s Starship program, that was supposed to change. Starship’s main claim to fame is that it can land vertically for re-use, but that’s not what has space engineers and investors most excited.
The real appeal comes from its promise to dramatically reduce the cost of launching to orbit, and that belief largely derives from Elon Musk’s claims that the Starship will be able to reset for successive launches in a matter of weeks, or eventually even days.
As Elon himself has admitted in several venues, that simply will not be possible if the heat shielding needs to be inspected tile by tile.
The experts quoted in this Ars Technica report include three former NASA officials, one of whom is a co-inventor of the substance used in the heat shield of SpaceX’s Crew Dragon capsule. They make it clear that they feel current technologies cannot realistically be advanced far enough to make Starship’s affordability promises a reality.
This origami-inspired heat shield design may never happen, but it sure looks cool.
Credit: ESA/Space Forge
“Starship’s current thermal protection system is a dead-end for all missions that require full and rapid reusability,” said Dan Rasky, a former NASA engineer who studied heat shield materials for nearly four decades at NASA Ames Research Center.
Other analysts quoted include Charles Miller and Charles Camarda, two former NASA employees who have recently been quite vocal about their criticisms of NASA. Miller called out what he characterized as NASA’s downplaying of the dangers to Artemis II astronauts, prompting Camarda to agree, saying that the heat shield, specifically, is a source of concern.
This is by no means the first time heat shielding has become an issue. NASA’s Orion spacecraft experienced damage to its heat shield just a couple of years ago, prompting an extensive search for the cause of the partial failure. All these years later, humanity is still using the same general type of solution that it started with in the 1950s.
There has been substantial research, of course, with many ideas that seem closer to science fiction than to real science, but some of that research has seemed quite promising. The problem is that no truly new idea is even close to ready for uses like those SpaceX has in mind for its Starships, and the current solutions have improved only slightly over the past several decades.
Perhaps this inflatable design will do the trick? (It didn’t.)
Credit: NASA
As mentioned, the experts quoted here have a long-standing axe to grind with NASA over the lack of investment in heat shield development; consequently, their ultimate recommendation is that NASA invest more in it.
The real issue isn’t that Starship might reduce cost-to-orbit by less than promised. It’s that, Elon being Elon, it would not be unreasonable to worry that he could stick with the tiles that already work while still pushing for re-use schedules that make proper tile inspections impossible.
In other words, this analysis reminds us that it is and always was entirely likely that the first human being killed by the private space industry will die upon reentry—not on the launch pad.
