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Receiving SpaceX Falcon 9 Telemetry with a HackRF and 1.2m Satellite Dish

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Re: Receiving SpaceX Falcon 9 Telemetry with a HackRF and 1.2m Satellite Dish

#81

Post by bumby »

jccooper wrote: post #37
Cthulhu_ wrote: post #18

Earlier quoted context omitted.

I'm kinda hoping they'll publish some specs about at least part of their transmission data, I mean given that it's not encrypted either means it's not critical, or encryption is too costly. I can imagine that commands the other way do have some kind of encryption.

There are no commands the other way. F9 flies entirely autonomous, including termination. Based on the FCC filings, I'm pretty sure it doesn't even have receivers.

I know the Air Force claims this makes it safer by avoiding the need for a range officer to make a time sensitive safety call but it’s not like there isn’t a precedent of software goofs in this area of software controlled termination

https://apnews.com/article/1d85f290e31cad8532636fcb576f4788

Re: Receiving SpaceX Falcon 9 Telemetry with a HackRF and 1.2m Satellite Dish

#82

Post by NikolaeVarius »

matmatmatmat wrote: post #77
NikolaeVarius wrote: post #47

Earlier quoted context omitted.

The override is missing the droneship or blowing itself up. Why the hell does there "got" to be an override. Humans are generally not good at doing hypersonic/supersonic aerodynamic modeling in their heads, especially remotely

`The override is missing the droneship or blowing itself up.` Disagree, that's not an override. That's a program written by a human programmer (who makes mistakes) that autonomously decides that something went wrong. I would argue there has "got" to be an override precisely because humans make mistakes all the time and so there's no reason to think that an autonomous failsafe should work in all possible situations. I…

>> I don't know much about rocketry

There you go.

You are welcome to try and disagree with decades of rocket launch practices.

The range safety officer can blow up the rocket if the rocket veers off and is in danger of overshooting the safe area.

Otherwise, you know the reason why we launch over water? Since it doesn't goddamn matter after it clears the tower and clears the danger zone. It either blows up over water, and who cares, it lands in the water, who cares, or it blows up in the upper atmosphere, and who cares.

Also, the rocket blowing itself up is a reference to the fact that if it is going off course, there is damn good chance it will destroy itself since aerodynamic forces are calculated to a specific launch window with upper weather. If not following a calculated path, good chance it will rip itself apart.

Also many abort modes are disabled for the first few seconds in flight so a dumb human or computer wont accidentally trigger a abort after flight starts and blow up the launch pad

Re: Receiving SpaceX Falcon 9 Telemetry with a HackRF and 1.2m Satellite Dish

#83

Post by function_seven »

Lev1a wrote: post #8
londons_explore wrote: post #4

Earlier quoted context omitted.

I really want to visit /S.*ia/ sometime!

I personally don't have the kind of time to visit all of /S.*ia/, I'll have to make to do with just /S\w+ia/. Shame, really...

Not sure what you have against Sia, Cypress. I, for one, will try to make it to /S\w*ia/.

Re: Receiving SpaceX Falcon 9 Telemetry with a HackRF and 1.2m Satellite Dish

#84

Post by gbrown »

jccooper wrote: post #37
Cthulhu_ wrote: post #18

Earlier quoted context omitted.

I'm kinda hoping they'll publish some specs about at least part of their transmission data, I mean given that it's not encrypted either means it's not critical, or encryption is too costly. I can imagine that commands the other way do have some kind of encryption.

There are no commands the other way. F9 flies entirely autonomous, including termination. Based on the FCC filings, I'm pretty sure it doesn't even have receivers.

The launch termination system at least needs a receiver

Re: Receiving SpaceX Falcon 9 Telemetry with a HackRF and 1.2m Satellite Dish

#85

Post by jcims »

drmpeg wrote: post #71
_Microft wrote: post #6

Some sleuths repaired/decoded a corrupted video file from (the first?) splashdown of a Falcon 9 in the ocean a few years ago [0], so maybe someone is able to tease out some information from the recorded binary data as well? They only searched for obvious string data so far. It's a different beast of course, as the structure and meaning of the data is basically unknown in contrast to the known format of a video file.…

Video decoded here. https://twitter.com/r2x0t/status/1370030702633312259

Not sure about @r2x0t but @uhf_satcom is involved in some pretty amazing space rf projects, poke around their tweet history. Some crazy smart folks out there.

Re: Receiving SpaceX Falcon 9 Telemetry with a HackRF and 1.2m Satellite Dish

#86

Post by bumby »

gbrown wrote: post #84
jccooper wrote: post #37

Earlier quoted context omitted.

There are no commands the other way. F9 flies entirely autonomous, including termination. Based on the FCC filings, I'm pretty sure it doesn't even have receivers.

The launch termination system at least needs a receiver

Isn’t this only the case if the intent is for a range officer to abort? I.e., if this system is fully autonomous and on-board, a receiver wouldn’t be necessary?

Re: Receiving SpaceX Falcon 9 Telemetry with a HackRF and 1.2m Satellite Dish

#87

Post by soapboxrocket »

drmpeg wrote: post #71
_Microft wrote: post #6

Some sleuths repaired/decoded a corrupted video file from (the first?) splashdown of a Falcon 9 in the ocean a few years ago [0], so maybe someone is able to tease out some information from the recorded binary data as well? They only searched for obvious string data so far. It's a different beast of course, as the structure and meaning of the data is basically unknown in contrast to the known format of a video file.…

Video decoded here. https://twitter.com/r2x0t/status/1370030702633312259

I'm interested in the ITAR implications here of the video. When asked about seeing the inside of the fuel tank during the crew demo mission Shotwell said no because it was covered by ITAR. This video clearly shows inside a tank.

Re: Receiving SpaceX Falcon 9 Telemetry with a HackRF and 1.2m Satellite Dish

#89

Post by SEJeff »

gbrown wrote: post #84
jccooper wrote: post #37

Earlier quoted context omitted.

There are no commands the other way. F9 flies entirely autonomous, including termination. Based on the FCC filings, I'm pretty sure it doesn't even have receivers.

The launch termination system at least needs a receiver

The way the automated FTS works is essentially that the USAF blasts a "DO NOT BLOW UP" signal with a very high power transmitter to the FTS. If the FTS doesn't receive that signal, it triggers and then you have a RUD.

Re: Receiving SpaceX Falcon 9 Telemetry with a HackRF and 1.2m Satellite Dish

#90

Post by ric2b »

NikolaeVarius wrote: post #47
ClumsyPilot wrote: post #39

Earlier quoted context omitted.

People who code still make mistakes. There's got to be an override of some sort

The override is missing the droneship or blowing itself up. Why the hell does there "got" to be an override. Humans are generally not good at doing hypersonic/supersonic aerodynamic modeling in their heads, especially remotely

I don't know, if it launches sideways and starts heading for a crowd they might want to force it to blow itself up or something like that.
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