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Decoding James Webb Space Telescope

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Re: Decoding James Webb Space Telescope

#11

Post by ixfo »

andruby wrote: post #3
gjsman-1000 wrote: post #2

One would wish that for budget-exponentially-overrun taxpayer-funded infrastructure, there would be open-source decoding information available.

I actually don’t know if they want to protect the data. I can imagine they might not want China or other countries listening in and potentially sending commands to the craft. Does anyone know if there is typically encryption on the downlink? How about uplink commands? I guess we want those to be secured so only authenticated control can send commands

Yes, CCSDS Magenta and Blue reference books mandate AES-256-GCM as a minimum for data encryption and mandate that encryption and authentication should be used, particularly for commands/uplink. Sliding scale of requirements based on application of course - your cubesat's imaging system is less critical than the flight termination system on a manned mission, for instance.

Re: Decoding James Webb Space Telescope

#12

Post by jcims »

andruby wrote: post #3
gjsman-1000 wrote: post #2

One would wish that for budget-exponentially-overrun taxpayer-funded infrastructure, there would be open-source decoding information available.

I actually don’t know if they want to protect the data. I can imagine they might not want China or other countries listening in and potentially sending commands to the craft. Does anyone know if there is typically encryption on the downlink? How about uplink commands? I guess we want those to be secured so only authenticated control can send commands

I don't have any inside information but in my experience lurking in the amateur radio community the answer is 'it depends' and there is a lot of downlink that is not encrypted. This will get you into the graph:

https://twitter.com/usa_satcom

https://twitter.com/uhf_satcom

https://twitter.com/r2x0t

Re: Decoding James Webb Space Telescope

#13

Post by dylan604 »

gjsman-1000 wrote: post #4
andruby wrote: post #3

Earlier quoted context omitted.

I actually don’t know if they want to protect the data. I can imagine they might not want China or other countries listening in and potentially sending commands to the craft. Does anyone know if there is typically encryption on the downlink? How about uplink commands? I guess we want those to be secured so only authenticated control can send commands

There would have to be some sort of encryption or passkey or digital signature on commands, for sure. Otherwise some hobbyist in the middle of the Ocean on his yacht could be messing with the craft and taking pictures and there'd be no easy way to shut him down.

"Torpedo in the water!" would probably be sufficient.

Re: Decoding James Webb Space Telescope

#14

Post by dylan604 »

colechristensen wrote: post #9
gjsman-1000 wrote: post #2

One would wish that for budget-exponentially-overrun taxpayer-funded infrastructure, there would be open-source decoding information available.

This is just telemetry data which doesn’t have much general or scientific interest, i guess they could publish the protocol spec (honestly it probably is aquirable) but most of the fun for the kinds of people who want this data is going to be doing this reverse engineering themselves. The real imaging data would require a much more significant dish to even receive (i can’t immediately find what it’s going to use, but…

Aren't they using the Deep Space Network for this?

Re: Decoding James Webb Space Telescope

#15

Post by londons_explore »

colechristensen wrote: post #9
gjsman-1000 wrote: post #2

One would wish that for budget-exponentially-overrun taxpayer-funded infrastructure, there would be open-source decoding information available.

This is just telemetry data which doesn’t have much general or scientific interest, i guess they could publish the protocol spec (honestly it probably is aquirable) but most of the fun for the kinds of people who want this data is going to be doing this reverse engineering themselves. The real imaging data would require a much more significant dish to even receive (i can’t immediately find what it’s going to use, but…

But in a really open project, the design of the whole lot would be on the web, and the data sent back would be sitting on an FTP server somewhere for anyone to download and use.

In many ways, an open project is cheaper to do than a behind-closed-doors project where every new contractor needs to get access to only the bits of the project they need access to, and misunderstandings happen because not everyone has enough of the big picture.

The only bit that needs to be secret is one private key used to sign the commands sent to the satellite, just so one random Mallory can't 'steal' it.

Re: Decoding James Webb Space Telescope

#16

Post by manquer »

gjsman-1000 wrote: post #4
andruby wrote: post #3

Earlier quoted context omitted.

I actually don’t know if they want to protect the data. I can imagine they might not want China or other countries listening in and potentially sending commands to the craft. Does anyone know if there is typically encryption on the downlink? How about uplink commands? I guess we want those to be secured so only authenticated control can send commands

There would have to be some sort of encryption or passkey or digital signature on commands, for sure. Otherwise some hobbyist in the middle of the Ocean on his yacht could be messing with the craft and taking pictures and there'd be no easy way to shut him down.

It is not necessary really.

There is unlikely any non-state actors[1] that has the ability to transmit signals to L2 . Just receiving signals even now (only 2 out of 30 days to l2) the OP used a 6 meter dish. Most of interplanetary mission signals are handled by the DSN.

Any sort of encryption will add both b/w requirements and compute requirements . The CPU/network budgets on such missions are very very limited. Every bit and cycle counts.

Finally standard encryption libraries, algorithms et al, are not likely suitable . I am no expert, but I have not read of any modern algorithms with very low network overhead + compute requirements designed for these kind of use cases, that is also secure from brute force or other attacks.

Mission risk is also a factor, even handshake failures can jeopardize the mission. It is one thing a website did not load because of TLS negotiation failures and $10 B mission overshot its orbit because handshake failures on the encryption layer.

[1] Threats from state actors for science missions is different category of concern, harder to quantify and with not much history of actual attacks. Collateral risks like from the ASAT Russian test to ISS, or in dual use missions would perhaps not apply here .Usually science teams collaborate well even if there is lot of tension in political sphere.

Re: Decoding James Webb Space Telescope

#17

Post by cycomanic »

andruby wrote: post #3
gjsman-1000 wrote: post #2

One would wish that for budget-exponentially-overrun taxpayer-funded infrastructure, there would be open-source decoding information available.

I actually don’t know if they want to protect the data. I can imagine they might not want China or other countries listening in and potentially sending commands to the craft. Does anyone know if there is typically encryption on the downlink? How about uplink commands? I guess we want those to be secured so only authenticated control can send commands

I highly suspect that China (and almost every other country) are not the issue. Chinese and the whole international scientific community will profit immensely from the data coming from James Webb, so I don't think the Chinese have any interest in sabotaging the project. More dangerous would be some average joe, somewhere who would try to mess with it for the lulz.

Re: Decoding James Webb Space Telescope

#19

Post by semi-extrinsic »

londons_explore wrote: post #15
colechristensen wrote: post #9

Earlier quoted context omitted.

This is just telemetry data which doesn’t have much general or scientific interest, i guess they could publish the protocol spec (honestly it probably is aquirable) but most of the fun for the kinds of people who want this data is going to be doing this reverse engineering themselves. The real imaging data would require a much more significant dish to even receive (i can’t immediately find what it’s going to use, but…

But in a really open project, the design of the whole lot would be on the web, and the data sent back would be sitting on an FTP server somewhere for anyone to download and use. In many ways, an open project is cheaper to do than a behind-closed-doors project where every new contractor needs to get access to only the bits of the project they need access to, and misunderstandings happen because not everyone has enough…

> the data sent back would be sitting on an FTP server somewhere for anyone to download and use

I'm sure they could actually do that without too much fuss. But it would require significant amounts of scientist time to document those datasets to enable others to use them for any arbitrary dataset. I'm sure we'll see fully open data sets from JWST appear, but lots of the stuff it collects isn't going to be interesting enough that it's reasonable to spend scientist time documenting it.

Re: Decoding James Webb Space Telescope

#20

Post by TedDoesntTalk »

cycomanic wrote: post #17
andruby wrote: post #3

Earlier quoted context omitted.

I actually don’t know if they want to protect the data. I can imagine they might not want China or other countries listening in and potentially sending commands to the craft. Does anyone know if there is typically encryption on the downlink? How about uplink commands? I guess we want those to be secured so only authenticated control can send commands

I highly suspect that China (and almost every other country) are not the issue. Chinese and the whole international scientific community will profit immensely from the data coming from James Webb, so I don't think the Chinese have any interest in sabotaging the project. More dangerous would be some average joe, somewhere who would try to mess with it for the lulz.

Or terrorist organizations with tech skills
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