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About PakledHostage

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  1. Speaking of nerds... I went back and refined my estimate of Perseverance's entry trajectory. I initially went with the simplifying assumption that the path between data points was linear (rather than hyperbolic) and that the speed over that distance was just the average of the speeds at the two data points. Unfortunately, the solution is quite sensitive to the angular distance between the data points used in the system of equations, so the small error introduced with that assumption turns out to be significant. That assumption did provide a good seed value for a couple of rounds of iterations
  2. I recall that Bombardier tried active noise cancellation in the cabin of the Dash-8 Q400 aircraft, but it struck me more as a gimmick... and we're getting off topic.
  3. That thing really is going down like a greased piano... no messing around.
  4. And admittedly not a planet, but I recall that Huygens recorded audio on Titan?
  5. So I nerded out yesterday evening and attemped to compute the hyperbolic trajectory that Perseverance followed to the entry interface. I used the data that was shown on mission control's readouts in the mission control livestream. I ended up having to make some simplifying assumptions but I arrived at an eccentricity of about 1.3 and a periapsis point about 130km below the Martian surface. The entry interface angle worked out to about 18 degrees. That's a bit steeper than the value of ~15 degrees that I heard quoted during the livestream. The data from the early part of the entry in the livest
  6. Post landing briefing going live shortly (they seem to be running late):
  7. Livestream starts in just over 5 minutes. Already over 1/2 million people waiting.
  8. Interestingly, Al Chen, JPL's Entry Descent and Landing team lead said yesterday during the news conference that it is a misconception that the sky crane hovers. He said that it only actually hovers for about a second. Edit: I should add that I'm really excited to eventually see the footage from the EDL cameras. We're all probably imagining how the landing looks, but I expect that the real thing is a lot more dynamic and scary. For example, I didn't realize what a "sucide burn" landing the Apollo landings were until I watched the documentary "Apollo 11" with it's overlaid altitude
  9. Interestingly, Perseverance's atmospheric entry speed, direct from its transfer orbit, will be on the order of 5 km/s, which is substantially less than atmospheric entry speed from LEO. Of course that doesn't mean Mars atmospheric entry is easy... ----------------------------------------------------- I'm not just here to be pedantic, though... Does anyone know how they're acquiring the video data from the cameras on the backshell and sky crane? I understand that the video will be stored on Perseverance until they have the bandwidth to downlink it to Earth some weeks or months af
  10. I'll revive this thread with my image from this evening of the Jupiter/Saturn conjunction, rather than start a new one. (Just because there's a lot of good stuff in here that deserves another look.) I shot it through a 600mm lense at 1/200, f6.3,ISO200. I then brightened Saturn by about a stop and dimmed Jupiter by about a stop using a linear gradient in Lightroom.
  11. https://www.cnn.com/2020/12/07/us/chuck-yeager-death/index.html Another legend leaves us.
  12. On another note, I just discovered that the Tesla Roadster with Starman is included in NASA's Eyes On The Solar System application. It currently shows as being about 70 million km from Earth and 11 million km from Mars.
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