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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

#41

Post by myself248 »

mikepurvis wrote: post #26
verelo wrote: post #9

Earlier quoted context omitted.

Encryption takes time, and energy. I suspect they are trying to avoid adding latency to anything that’s not super sensitive.

Those final gasps of data while a vehicle is breaking up could be critical for understanding what went wrong with it. I can definitely see how missing out on the final milliseconds of telemetry because some encryption buffer wasn't full enough to trigger a frame or something would be unacceptable.

I think this is the true reason that telemetry is as raw as possible.

The happy-path telemetry tells you very little you didn't already know, but when something goes wrong, those last few bits before the transmitter went silent can make or break your analysis. Sitting on bits until you have enough to run a block through the cipher seems like a terrible idea, even if that's only a few microseconds.

Things happen mighty fast when you're trying to get data that might represent the structural collapse or propagation of a blast wave through the body of a hypersonic vehicle.

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

#42

Post by myself248 »

shmerl wrote: post #35
mastax wrote: post #21

Earlier quoted context omitted.

No, but you can add it if you want a lower noise floor.

I mean how critical is it? Just an improvement in quality or it's bad without it?

Yes, both. It depends on what you're doing. Tractors don't need to be aerodynamic.

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

#43

Post by vardump »

mikepurvis wrote: post #26
verelo wrote: post #9

Earlier quoted context omitted.

Encryption takes time, and energy. I suspect they are trying to avoid adding latency to anything that’s not super sensitive.

Those final gasps of data while a vehicle is breaking up could be critical for understanding what went wrong with it. I can definitely see how missing out on the final milliseconds of telemetry because some encryption buffer wasn't full enough to trigger a frame or something would be unacceptable.

You don't need any buffering if you pick your encryption mode correctly. That is, use a stream cipher.

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

#44

Post by sandworm101 »

coder543 wrote: post #33
sandworm101 wrote: post #31

Earlier quoted context omitted.

>> commands the other way do have some kind of encryption. I'm betting that they don't. The reason that this stuff isn't encrypted is likely the same reason that fighter jets and airliners don't have keys. Yes, someone could jump in and do something bad, but the greater danger is the encryption/lock system causing an accident by getting in the way of legitimate commands. This is the launch vehicle, not the spy satell…

> Yes, someone could jump in and do something bad, but the greater danger is the encryption/lock system causing an accident by getting in the way of legitimate commands. That's just not how encryption works... Also, a malicious actor being able to point a multi-ton rocket filled with explosive fuel the wrong direction would be far worse than the system continuing the mission autonomously. Now imagine human spacefligh…

>> spaceflight missions where the command stream can be hijacked by anyone with an SDR. Yeah, not happening.

An SDR attached to some serious antenna hardware, enough to get into the sidelobe of an antenna pointed at the legitimate command network. As for rockets rolling, that isn't handled by ground commands. That sort of stuff it totally within the rocket's internal systems. The ground staff have very little control until the second stage has done its thing.

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

#45

Post by zelon88 »

coder543 wrote: post #33
sandworm101 wrote: post #31

Earlier quoted context omitted.

>> commands the other way do have some kind of encryption. I'm betting that they don't. The reason that this stuff isn't encrypted is likely the same reason that fighter jets and airliners don't have keys. Yes, someone could jump in and do something bad, but the greater danger is the encryption/lock system causing an accident by getting in the way of legitimate commands. This is the launch vehicle, not the spy satell…

> Yes, someone could jump in and do something bad, but the greater danger is the encryption/lock system causing an accident by getting in the way of legitimate commands. That's just not how encryption works... Also, a malicious actor being able to point a multi-ton rocket filled with explosive fuel the wrong direction would be far worse than the system continuing the mission autonomously. Now imagine human spacefligh…

> Now imagine human spaceflight missions where the command stream can be hijacked by anyone with an SDR. Yeah, not happening.

I am no expert on spacecraft command channels but I would highly doubt that a lot of non military US spacecraft use encrypted command signals until extremely recently.

He is right. Space engineers are extremely adverse to trying new technology and technique. They are even more adverse to adding code to things that work without adding more code.

In order to talk to one of these things you have to have one of the satellites in the NASA DTN. Technically the DTN protocol supports authentication and encryption but remember that everything about DTN must maintain perfect backwards compatibility with space assets that are made with decades old technology. Security is not it's primary goal like with terrestrial communications. Connectivity is far more important.

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

#46

Post by sandworm101 »

zelon88 wrote: post #45
coder543 wrote: post #33

Earlier quoted context omitted.

> Yes, someone could jump in and do something bad, but the greater danger is the encryption/lock system causing an accident by getting in the way of legitimate commands. That's just not how encryption works... Also, a malicious actor being able to point a multi-ton rocket filled with explosive fuel the wrong direction would be far worse than the system continuing the mission autonomously. Now imagine human spacefligh…

> Now imagine human spaceflight missions where the command stream can be hijacked by anyone with an SDR. Yeah, not happening. I am no expert on spacecraft command channels but I would highly doubt that a lot of non military US spacecraft use encrypted command signals until extremely recently. He is right. Space engineers are extremely adverse to trying new technology and technique. They are even more adverse to addin…

Some US hardware also operates on frequencies that do not penetrate the atmosphere, an old failsafe against ground-based interference/spying. So, even if totally unencrypted, the attackers SDR would have to be in orbit. That's a high barrier for the average hacker.

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

#47

Post by NikolaeVarius »

ClumsyPilot wrote: post #39
Denvercoder9 wrote: post #36

Earlier quoted context omitted.

> that commands the other way Does Falcon 9 even have a command channel anymore? The trajectory is preprogrammed, guidance and control is automatic, and the flight termination system is automatic as well.

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

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

#48

Post by darknavi »

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.

There was a reddit thread from a guest lecture a few years ago that said that around T-1 they turn off all receivers on Falcon 9.

https://www.reddit.com/r/spacex/comments/lw6yk1/notes_from_a...

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

#49

Post by kchr »

ceejayoz wrote: post #29
Cthulhu_ wrote: post #20

Earlier quoted context omitted.

And if amateur astronomers can do it, a well-funded national space agency can do it even better. I'm 100% sure that any launch is picked up via radar and sattelites and the like when they happen, and various properties extracted and extrapolated to determine their target orbit. That said, I wouldn't be surprised if some known launches also contained some unknown payloads. Stealth technology on a satellite would proba…

> Stealth technology on a satellite would probably thwart detection in space well enough. Stealth is great for radar, but even the B-2 can be spotted pretty easily via the Mk 1 eyeball. Satellites also have to have radiators, which limits what you can manage.

> Mk 1 eyeball

I giggled.

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

#50

Post by darknavi »

londons_explore wrote: post #4
robin_reala wrote: post #3

Serbia and Siberia are substantially different places. Let’s hope it’s just a typo and not a bug :)

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

South Africia is really pretty this time of year!
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