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SpaceX moved beyond what they could test without the launch (and catch) tower. They've spent a lot of time and money developing the ground systems - in compari

SpaceX moved beyond what they could test without the launch (and catch) tower. They've spent a lot of time and money developing the ground systems - in comparison the early crude Starship prototypes were comparatively cheap and easily replaced - and I would imagine they really would prefer not to accidentally demolish the tower again.

ralfd 4y ago
If I recall correctly after this Methan explosion 9 month ago they got more cautious and slower: https://www.youtube.com/watch?v=PjbjXTomxqI https://www.youtube.com/watch?v=PjbjXTomxqI
- mhandley 4y ago
  And they also have previous painful experience of destroying a Falcon 9 pad. https://www.youtube.com/watch?v=_BgJEXQkjNQ https://www.youtube.com/watch?v=_BgJEXQkjNQ Really can't afford to repeat that if they are to make the timeline for using Starship as NASA's next lunar lander.
  - antoniuschan99 4y ago
    How much does Mechazilla cost? I read it's 1 billion. Also news is Elon said destroying nearby infrastructure would be a 9 month setback at the least.
    - brookst 4y ago
      Wow that’s like 2.5% of a Twitter.
      - throwaway60134 4y ago
        [dead]
usrusr 4y ago
Almost sounds like a bit chicken/egg, you can't try landing without a certain amount of confidence, you can't build confidence without trying. Considering the hover capability of the booster (can be throttled to <1G) we might see an unprecedented amount of touch and go testing before the first real attempt?
- Laremere 4y ago
  From the booster's point of view, the catch is a target location and speed. Plus a set of tolerances: however much the arm can swing to catch it, and horizontal speed has to be really low because it needs to drop down vertically into the arms. I would expect that the target on the ocean, even for the first test, is very specific. Once the booster can hit a phantom target, they can change the target to the tower and go for a catch attempt.
  - usrusr 4y ago
    I imagine that lack of stable reference points would be an issue on the ocean. Both for the algorithms under test and for validation. (I liberally use "algorithm" here as the superset of both algorithm and the hardware it runs on, I think in reality these tests are mostly for correcting parameters that are hard to determine with sufficient accuracy on paper) If you want to write off an entire booster, adding a dummy tower somewhere in the desert would not add much to the bill and could well be worth it. Or maybe even a not-quite-so-dummy tower, but off-site, where the booster would be scrapped on location (instead of reflown) even in the best case, no matter how hypothetical?
    - Laremere 4y ago
      Good GPS in ideal conditions (no trees or buildings blocking/bouncing signal) has accuracy on the centimeter scale: https://www.gps.gov/systems/gps/performance/accuracy/ https://www.gps.gov/systems/gps/performance/accuracy/
      - usrusr 4y ago

ralfd 4y ago

If I recall correctly after this Methan explosion 9 month ago they got more cautious and slower: https://www.youtube.com/watch?v=PjbjXTomxqI https://www.youtube.com/watch?v=PjbjXTomxqI

mhandley 4y ago
And they also have previous painful experience of destroying a Falcon 9 pad. https://www.youtube.com/watch?v=_BgJEXQkjNQ https://www.youtube.com/watch?v=_BgJEXQkjNQ Really can't afford to repeat that if they are to make the timeline for using Starship as NASA's next lunar lander.
- antoniuschan99 4y ago
  How much does Mechazilla cost? I read it's 1 billion. Also news is Elon said destroying nearby infrastructure would be a 9 month setback at the least.
  - brookst 4y ago
    Wow that’s like 2.5% of a Twitter.
    - throwaway60134 4y ago
      [dead]

usrusr 4y ago

Almost sounds like a bit chicken/egg, you can't try landing without a certain amount of confidence, you can't build confidence without trying. Considering the hover capability of the booster (can be throttled to <1G) we might see an unprecedented amount of touch and go testing before the first real attempt?

Laremere 4y ago
From the booster's point of view, the catch is a target location and speed. Plus a set of tolerances: however much the arm can swing to catch it, and horizontal speed has to be really low because it needs to drop down vertically into the arms. I would expect that the target on the ocean, even for the first test, is very specific. Once the booster can hit a phantom target, they can change the target to the tower and go for a catch attempt.
- usrusr 4y ago
  I imagine that lack of stable reference points would be an issue on the ocean. Both for the algorithms under test and for validation. (I liberally use "algorithm" here as the superset of both algorithm and the hardware it runs on, I think in reality these tests are mostly for correcting parameters that are hard to determine with sufficient accuracy on paper) If you want to write off an entire booster, adding a dummy tower somewhere in the desert would not add much to the bill and could well be worth it. Or maybe even a not-quite-so-dummy tower, but off-site, where the booster would be scrapped on location (instead of reflown) even in the best case, no matter how hypothetical?
  - Laremere 4y ago
    Good GPS in ideal conditions (no trees or buildings blocking/bouncing signal) has accuracy on the centimeter scale: https://www.gps.gov/systems/gps/performance/accuracy/ https://www.gps.gov/systems/gps/performance/accuracy/
    - usrusr 4y ago