Parent's (correct) point is that it isn't a matter of the ascent trajectory. They can't leave the Starship up in orbit, and where it reenters needs to be controlled.

> They can't leave the Starship up in orbit, and where it reenters needs to be controlled.

Why? Plenty of boosters re-enter uncontrolled and burn up all the time.

Typically American policy is to have a controlled reentry option for as much as possible. The disposable first stages of all rockets don't need a controlled reentry because they are always suborbital and thus their splashdown location is relatively well known ahead of time. The second stages are typically supposed to deorbit and burn up over water after a launch to LEO. There are occasional cases where something goes wrong and they fail to deorbit, which is when we sometimes hear of the burn up due to gradual orbit decay being witnessed over land.

Afaik, when talking about objects large enough that some debris will actually hit the ground, only China intentionally lets their final stage re-enter uncontrolled. Everyone else at least has a plan for controlling re-entry. SpaceX has lost control of some of their Falcon 9 second stages before, but that's the exception not the rule.

Starship is huge and heavy and made of steel, it will not burn up on reentry, if it falls on a populated area it will kill people. They will not be allowed orbital trajectories until they demonstrate they can control the deorbit burn.

Of course it will not maintain its shape, but the pieces that land will be large.

It's made of 4mm thick steel sheets, and the FAA disagrees with you.

Columbia was torn apart by the atmosphere... and dropped huge chunks that were a danger to people on the ground-- some as large as a VW Beetle.

Non-reusable boosters don't go into orbit and perform calculated crash into ocean soon after launch.

Small second stages and spacecrafts can be allowed uncontrolled orbital reentries because they usually burn-up. Starship is too big for that, debris would rain like when Space Shuttle Columbia disintegrated over land. They most likely will need to show engine relight capability to control reentry point before going orbital.

First thing that comes to mind: Starship has a lot of protection against burning up, so huge chunks of it could survive and cause damage.

Ok so they could leave Starship in orbit and launch payloads like that. The idea however is to launch payloads WHILE testing reentry and landing. This requires an engine relight in orbit.

> WHILE testing reentry and landing.

> This requires an engine relight in orbit.

The latter is part of the test at this point of development

Stated simply: zero-thrust "orbits" repeat the same trajectory again and again. So if you end your burn in the outer atmosphere near your launch pad, the next time around you will be back in the outer atmosphere (near where the the launch pad "was", ignoring the rotation of the planet). And since there's air there providing resistance, you'll re-enter and crash.

Getting to orbit requires at least one more burn near the apogee of the original orbit to circularize it and ensure the spacecraft doesn't approach the atmosphere again. Starship didn't do the apogee burn they intended to do, so didn't demonstrate this capability.

> Getting to orbit requires at least one more burn near the apogee of the original orbit to circularize it and ensure the spacecraft doesn't approach the atmosphere again

The Saturn V went direct to Earth orbit without requiring relighting the third stage engine.

Singe burn to orbit is pretty common though in reality, with the dynamics of staging, engine throttling, and precision insertion capabilities most modern rockets can hit the mark.