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About Tullius

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  1. Tullius

    JWST: it's done!

    Yes, interferometry is possible for optical telescopes. For example, it is one of the nice features of the VLT. (cf. https://en.wikipedia.org/wiki/Interferometry) However, even down here on Earth combining optical telescopes is incredibly hard (Guess why ESO is building the Extremely Large Telescope with its nearly 40m mirror?!). The biggest problem is the fact that you need to actually combine the light from the participating telescopes to a very high degree of precision, unlike for radio waves, for which computationally combining the data from multiple telescopes is enough (cf. Event Horizon Telescope). So, I would say that it is incredibly unlikely that one could do the same thing as the JWST with multiple space telescopes, while reducing costs.
  2. Tullius

    Unity Analytics and the GDPR

    Ehm, yes they do: https://blog.redshell.io/gdpr-and-red-shell-57f9c03b5769 For their fingerprint, they use the IP-adress and an user ID (Steam ID, Xbox ID, etc.), even though they scramble them them using SHA-256. They are hoping that hashing these personal information makes them not personally identifiable anymore, and that therefore the GDPR doesn't apply anymore. This is a rather interesting interpretation of GDPR.
  3. Tullius

    SpaceX Discussion Thread

    Is Elon Musk CEO of a rocket building company or a sci-fi author?
  4. Tullius

    Unity Analytics and the GDPR

    Looking at Red Shell's homepage: https://redshell.io/home The problem is the fingerprint, as it allows to identify the user. More specifically, it allows game developers to identify which of their players has clicked on which links (after all Steam games have access to your user name and Steam itself even to your real name, if you bought anything). This makes this fingerprint personal data and therefore is covered by GDPR, i.e. Squad or any other developer needs explicit consent from the user to be able to use this fingerprinting technique on them. Just think of the fingerprint as an extreme version of a browser cookie, as you cannot delete it and it works across applications.
  5. That happens only if we are speaking of "relativistic mass". E=mc^2 only holds for a mass at rest, for moving masses the formula is E=gamma*mc^2, where gamma = 1/sqrt(1-v^2/c^2), where v is the speed of the object. The kinetic energy of the object is therefore E=(gamma-1)*mc^2, which in first order approximation leads to the classical formula of kinetic energy E=1/2*mv^2 (This works fine up to about 10% of the speed of light).
  6. Curiosity's RTG produces only about 100-125 W, amounting to about 3000 Wh per sol (Martian day). The solar panels on the MER rovers are usually capable of producing 300 to 900 Wh per sol. Considering the size difference, the solar panels on the MER are actually not that bad in comparison to Curiosity.
  7. There are probably two main reasons for it: The Russians believe that it brings bad luck to have women on spacecraft. Quoting from the wikipedia article on Soyuz TMA-11 (which had 1 man and 2 women on board for the landing): Also, normally astronauts are chosen to be the best of the best. However, when comparing men and women in terms of physical strength on equal grounds, usually the men come out ahead. This might in part explain why men are overrepresented in the astronaut lists.
  8. Tullius

    Adeline concept for Ariane 6

    Even if recovery is easy, it is also a problem of cost. Arianespace was expecting at the start of development of Ariane 6 a launch cadence of 10-20 per year. If one rocket can fly 10 times, it means you only need to produce 1-2 rockets per year, i.e. you need to keep production lines open for a ridiculously low number of products produced. Therefore, instead of developing booster recovery, Arianespace decided to put their development money into designing the booster to be as cheap as possible. It is only now becoming clear that these launch cadence estimates were way too low, as extremely large satellite constellations have been announced (OneWeb wants to launch nearly 700 satellites for a single constellation and SpaceX wants to launch as many as 12000, which need dozens or hundreds of launches themselves).
  9. Tullius

    Adeline concept for Ariane 6

    On wikipedia, one paragraph is dedicated to Ariane vs Space Shuttle: Designing Ariane 1 to be reusable would have also been a pretty pointless endeavour, as it only ever flew 11 times (including 2 failures).
  10. Someone needs to pay for New Armstrong and it is certainly useful if you already have a paying customer.
  11. Tullius

    Want I want to see....

    If there is no crew on board, I would guess none. After all, it is YOUR rocket that blows up, if YOUR drone misbehaves.
  12. Tullius

    SpaceX Discussion Thread

    A few hours. For the Space Shuttle (https://en.wikipedia.org/wiki/Space_shuttle_launch_countdown), the propellant loading took 2 hours, which meant that fueling started about 11 hours before launch, while the crew started boarding the shuttle about 4 hours before launch. Also during the propellant loading, nobody was at the pad. So in case of STS, NASA was expecting the propellant loading process to be one of the more dangerous parts of the countdown. Also one should not forget that it was during the propellant loading for the static fire that the Falcon 9 for Amos-6 exploded (although one can hope that the problem that caused this is now solved). It is clear that SpaceX wants to shorten the countdown of any launch as much as possible (the Space Shuttle countdown started nearly 3 days before launch), but that will of course mean that they will have to take additional risks. It all depends on how much risks you are able to mitigate and how much risks you are willing to take.
  13. Tullius

    Link Space

    This new rocket looks a bit like their CEO saw Falcon 9 and told his designers and engineers to build something similar, especially considering the timing. However, Buran was also a 'ripoff' of the Space Shuttle, but at the same time a completely independent development.
  14. Tullius

    Agreement for Mars Sample Return

    This is something of category, where you just don't want to find out afterwards that you have been wrong, no matter how low the risk. It is the same with the quarantine measures for Apollo 11, 12 and 14. If it is really necessary to do the quarantine measures and first tests of the samples in lunar orbit, I don't know, but having some protection in place is necessary. After all, it is better to be safe than sorry. Planetary protection is more about protecting our future scientific results than the planet. After all, when did the humanity ever give a f*** about protecting a place when colonising?
  15. Tullius

    Two-launch scheme for manned Lunar mission

    Saturn V was at the time the largest American rocket by quite some margin. Choosing a two-launch scheme would have meant building a half-size Saturn V, which would have still been the largest American rocket. Only problem now is that you need to build and launch twice as many rockets.