[NRVR-Members] Decoding the video cam stream from INSIDE the SapceX LOX Tank! Super Interesting!

[Weeks, Thomas]

Correction... Nitrogen is often used to displace or pressurize liquid fuels, but n the case of spaceX it sounds like they use helium. Hmm..

Tweeks

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-------- Original Message --------
From: Thomas Tweeks Weeks <tom at theweeks.org>
Sent: Sunday, April 4, 2021 10:56 AM
To: NRV Rocketry Members <nrvr-members at server2.nrvr.org>
Subject: [NRVR-Members] Decoding the video cam stream from INSIDE the SapceX LOX Tank! Super Interesting!


Hey all...



So Bob and I are auditing Pat Artis' space launch vehicle design class.. and of late we've been talking about how LOX and other fuels slosh around in large liquid /oxidizer & fuel tanks.. and I thought they would find this super interesting.



RF/SDR hackers have aimed dishes as various SpaceX space craft, and used SDR to get the raw data streams to look at their system logs, and what's super cool.. decode the H264 mp4 video streams from all the on board cameras!

https://www.youtube.com/watch?v=74_N163HyhA<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D74_N163HyhA&data=04%7C01%7Ct.weeks%40vt.edu%7C52dbab5494764aa3235708d8f779b991%7C6095688410ad40fa863d4f32c1e3a37a%7C0%7C0%7C637531449902054836%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=LmDbWtpw5SIC7YdenxBK%2FDZTnxoy27v24RpHM2uA4R8%3D&reserved=0>



A couple of videos show the live stream from, INSIDE the LOX tanks and you can SEE the liquid Oxygen doing some pretty cool stuff..

https://twitter.com/r2x0t/status/1375232102887780356<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftwitter.com%2Fr2x0t%2Fstatus%2F1375232102887780356&data=04%7C01%7Ct.weeks%40vt.edu%7C52dbab5494764aa3235708d8f779b991%7C6095688410ad40fa863d4f32c1e3a37a%7C0%7C0%7C637531449902054836%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=890Pe4uky1LqzrkJg1SQf4YdoX%2BhvDaTuavA9L5gSBE%3D&reserved=0>



At one point it is "clinging" to the aft end of the tank by surface tension, and at another time, where various maneuvers have agitated it and you can see bubbles of LOX floating around the tank:

https://twitter.com/r2x0t/status/1375252976625979393<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftwitter.com%2Fr2x0t%2Fstatus%2F1375252976625979393&data=04%7C01%7Ct.weeks%40vt.edu%7C52dbab5494764aa3235708d8f779b991%7C6095688410ad40fa863d4f32c1e3a37a%7C0%7C0%7C637531449902064826%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=QRytrPPwO2jxXyYaEtdnkGaYHS6T%2Boll2NWFS6Ndpsg%3D&reserved=0>



UsingLOX is like trying to drink liquid from a container in zero-G with a straw. As you can imagine, with the liquid floating around.. you get more "air" (nitrogen gas) than liquid.  You have to get the LOX to shift  back to the aft end of the tank so that it can be "sucked out" to sustain a solid "bubble-less burn".  This is normally done with a small preburn of forward thrust to gently nudge the liquid fuel toward the business end.



Really cool to see the raw footage of all this book and theory information in practice.  Something you don't get to see on mass produced live streams.



Here's some weekend fun:

SDR Radio Hacking of SpaceX - https://www.r00t.cz/Sats/Falcon9<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.r00t.cz%2FSats%2FFalcon9&data=04%7C01%7Ct.weeks%40vt.edu%7C52dbab5494764aa3235708d8f779b991%7C6095688410ad40fa863d4f32c1e3a37a%7C0%7C0%7C637531449902064826%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=rA%2B6qjnmlZGKl%2BTrkEaYp28iJMQr%2BY8QWFK6%2FNdgi44%3D&reserved=0><https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.r00t.cz%2FSats%2FFalcon9&data=04%7C01%7Ct.weeks%40vt.edu%7C52dbab5494764aa3235708d8f779b991%7C6095688410ad40fa863d4f32c1e3a37a%7C0%7C0%7C637531449902074821%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=vph4MP8sgAc2aLFQ9vXpyn8Eeuf8vaeXyR0IiH%2FJugc%3D&reserved=0>

Cool LOX Videos & Theory - https://www.youtube.com/watch?v=tAh5P-bozM8<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DtAh5P-bozM8&data=04%7C01%7Ct.weeks%40vt.edu%7C52dbab5494764aa3235708d8f779b991%7C6095688410ad40fa863d4f32c1e3a37a%7C0%7C0%7C637531449902074821%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=42jz3rGdyflsSmO7idavDUgHDnSkEslCcqVahOCevGk%3D&reserved=0>



T.Weeks






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