Headscratchers / Starship Girl Yamamoto Yohko

• Lawson is designated not only the inventor but as the sole individual in control of the Chronos System. So how can other characters, who aren't affiliated with Estrantech, travel to the 1999 Earth? Be it Rouge, Tensa or Yousuke - all of them and several more 2999 people appeared in Yohko's era.
• Why did Sara/Sakura Taurus think that hyper-jumping into a comet's path would be the most effective way of commiting planetary suicide? Wouldn't plummeting into its sun be easier?
• Why is Old-Timer so hell-bent on eradicating Yohko considering that she's not the only person from different timeline affecting the universe and without Lawson building the Chronos System she wouldn't ever be able to. It's basically all Lawson's fault and simply destroying his Chronos while the heroines are in their home era, or even preventing him to build it would be more effective. Not only that, none of the troble the galaxy goes through the course of the series would've ever occured. Sakura Taurus would never be awoken and Zenga wouldn't get his hands on the Old-Timer's legacy and attempt to restart the universe.

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