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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 contr

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.

DarmokJalad1701 3y ago
> 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.
- golol 3y ago
  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.
  - DarmokJalad1701 3y ago
    > WHILE testing reentry and landing. > This requires an engine relight in orbit. The latter is part of the test at this point of development
- ajross 3y ago
  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.
  - DiggyJohnson 3y ago
    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.
  - DarmokJalad1701 3y ago
    > 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.
- terramex 3y ago
  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.
- Toutouxc 3y ago
  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.
- Laremere 3y ago
  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.
- wolf550e 3y ago
  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.
  - dotancohen 3y ago
    An empty Starship has a very low ballistic coefficient, it will be torn apart by the atmosphere if not carefully controlled. Add to that the FTS and there is no real danger to population on the ground.
    - wolf550e 3y ago
      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.
    - mlyle 3y ago
      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.
- dotnet00 3y ago
  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.

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.

DarmokJalad1701 3y ago

> 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.

golol 3y ago
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.
- DarmokJalad1701 3y ago
  > WHILE testing reentry and landing. > This requires an engine relight in orbit. The latter is part of the test at this point of development
ajross 3y ago
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.
- DiggyJohnson 3y ago
  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.
- DarmokJalad1701 3y ago
  > 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.
terramex 3y ago
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.
Toutouxc 3y ago
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.
Laremere 3y ago
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.
wolf550e 3y ago
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.
- dotancohen 3y ago
  An empty Starship has a very low ballistic coefficient, it will be torn apart by the atmosphere if not carefully controlled. Add to that the FTS and there is no real danger to population on the ground.
  - wolf550e 3y ago
    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.
  - mlyle 3y ago
    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.
dotnet00 3y ago
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.