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Somebody moved the UK's oldest satellite in the mid 1970s, but no one knows who

bbc.co.uk

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Re: Somebody moved the UK's oldest satellite in the mid 1970s, but no one knows who

#81

Post by chiph »

emchammer wrote: post #32
retrac wrote: post #9

There was remarkably little in the way of security for early satellites (or space probes). I recently encountered here on HN the suggestion that, the main reason you can't find particularly in-depth details on the Voyager space probes, is project security. Security through obscurity, mostly. If amateurs can detect the signal from the Voyager probes with a small dish antenna, it's at least conceivable someone might ho…

Documentation and logs of the Voyager and Apollo projects are public, comprehensive, and fascinating reading. They do use authentication and keep the keys secret. They are literally rocket scientists.

CuriousMarc, kens, and crew have been recreating the up & downlinks for Apollo using vintage NASA hardware. They recently were able to send commands to their AGC[0][1] remotely. No encryption used, just a hefty investment in RF engineering.

The techniques were probably closely held at the time to prevent Soviet interference, but these days you can just download the circuit diagram PDFs.

[0] Simulated, since the owner of the original AGC wanted it back.

[1] https://www.youtube.com/watch?v=tBy1j9cTYKc

Re: Somebody moved the UK's oldest satellite in the mid 1970s, but no one knows who

#82

Post by lr1970 »

Denvercoder9 wrote: post #29
retrac wrote: post #9

There was remarkably little in the way of security for early satellites (or space probes). I recently encountered here on HN the suggestion that, the main reason you can't find particularly in-depth details on the Voyager space probes, is project security. Security through obscurity, mostly. If amateurs can detect the signal from the Voyager probes with a small dish antenna, it's at least conceivable someone might ho…

> If amateurs can detect the signal from the Voyager probes with a small dish antenna They can't, at least not for any reasonable definition of small. As I'm writing this, NASA is listening to Voyager using the DSS-14 antenna of the Deep Space Network, a dish with a 70 meter diameter, and the signal it receives is 10^-19 Watt. That's only 15000 photons per second. Coincidentally the area of that 70 meter dish is also…

There is fundamental limit (Shannon limit) on decoding a signal Eb/No = -1.6dB [0]

where Eb is energy received per bit of information and No is noise spectral density.

This makes it paramount to collect as much energy per bit (Eb) as possible which in turn requires large antennas for far away objects such as Voyager probe.

[0] https://en.wikipedia.org/wiki/Eb/N0#Shannon_limit

Re: Somebody moved the UK's oldest satellite in the mid 1970s, but no one knows who

#83

Post by DonHopkins »

Denvercoder9 wrote: post #29
retrac wrote: post #9

There was remarkably little in the way of security for early satellites (or space probes). I recently encountered here on HN the suggestion that, the main reason you can't find particularly in-depth details on the Voyager space probes, is project security. Security through obscurity, mostly. If amateurs can detect the signal from the Voyager probes with a small dish antenna, it's at least conceivable someone might ho…

> If amateurs can detect the signal from the Voyager probes with a small dish antenna They can't, at least not for any reasonable definition of small. As I'm writing this, NASA is listening to Voyager using the DSS-14 antenna of the Deep Space Network, a dish with a 70 meter diameter, and the signal it receives is 10^-19 Watt. That's only 15000 photons per second. Coincidentally the area of that 70 meter dish is also…

https://news.ycombinator.com/item?id=34227604

DonHopkins on Jan 3, 2023 | root | parent | next [–]

John McCarthy trolled me once!

When I met him, we were chatting about Stanford, and I mentioned that I really admired that huge radio telescope that you could see around 280 and Page Mill Road in the hills above Stanford.

He looked puzzled and confused, and asked "Which huge radio telescope?"

I was flustered and explained how you couldn't miss it, right by 280 and Page Mill Road, it's out there in a field, its huge, it's enormous, gigantic I tell you, there's no way you can miss it, bla bla bla...

He let me go on and on, describing it, and acted like he had absolutely no idea what I was talking about, like I was crazy for hallucinating a gigantic radio telescope that both of us must have passed zillions of times.

Finally he let on and said, "Oh, you mean that SMALL radio telescope???"

inamberclad on Jan 3, 2023 | root | parent | next [–]

It's just called The Dish, and I mean, it's only medium sized (46 meters) compared to the main antenna at a DSN site (70 meters).

Re: Somebody moved the UK's oldest satellite in the mid 1970s, but no one knows who

#84

Post by DonHopkins »

lukeck wrote: post #54
dgfitz wrote: post #51

Earlier quoted context omitted.

I was trying to frame the numbers for people who don’t have an engineering background. My mistake.

And they provided an interesting tidbit of information about some of the units mentioned. I didn’t read it as anything negative towards your comment at all. Both your’s and their’s added to the conversation.

Oh, now you're just trolling the Apostrophe Nazis! ;)

Re: Somebody moved the UK's oldest satellite in the mid 1970s, but no one knows who

#86

Post by CableNinja »

retrac wrote: post #9

There was remarkably little in the way of security for early satellites (or space probes). I recently encountered here on HN the suggestion that, the main reason you can't find particularly in-depth details on the Voyager space probes, is project security. Security through obscurity, mostly. If amateurs can detect the signal from the Voyager probes with a small dish antenna, it's at least conceivable someone might ho…

CuriousMarc on Youtube has a very large playlist of him and a few others restoring the apollo systems they have been able to get their hands on, and youre absolutely correct on the hacky possibilities. There was no authentication, just lock on and issue commands. They were not only able to restore pretty much everything to a working apollo comms and control system, they were even able to use lab equipment to communicate with apollo outright. I linked the first part of the series. Its a long one but very worth the watch even if you arent into everything they cover.

Many sats were and are similar, theres not much security. Newer ones with specific uses are most definitely encrypted.

The only real saving grace is that the size of dish/antenna and power you need to do anything with stuff actually in space at long distances is beyond what most people could do (not saying a very dedicated nerd couldnt, look at SaveItForParts for example).

https://www.youtube.com/watch?v=2KSahAoOLdU

Re: Somebody moved the UK's oldest satellite in the mid 1970s, but no one knows who

#87

Post by trollied »

Denvercoder9 wrote: post #29
retrac wrote: post #9

There was remarkably little in the way of security for early satellites (or space probes). I recently encountered here on HN the suggestion that, the main reason you can't find particularly in-depth details on the Voyager space probes, is project security. Security through obscurity, mostly. If amateurs can detect the signal from the Voyager probes with a small dish antenna, it's at least conceivable someone might ho…

> If amateurs can detect the signal from the Voyager probes with a small dish antenna They can't, at least not for any reasonable definition of small. As I'm writing this, NASA is listening to Voyager using the DSS-14 antenna of the Deep Space Network, a dish with a 70 meter diameter, and the signal it receives is 10^-19 Watt. That's only 15000 photons per second. Coincidentally the area of that 70 meter dish is also…

At the current rate of progress, when will it become physically impossibe to receive signals from it?

Re: Somebody moved the UK's oldest satellite in the mid 1970s, but no one knows who

#88

Post by CableNinja »

chiph wrote: post #81
emchammer wrote: post #32

Earlier quoted context omitted.

Documentation and logs of the Voyager and Apollo projects are public, comprehensive, and fascinating reading. They do use authentication and keep the keys secret. They are literally rocket scientists.

CuriousMarc, kens, and crew have been recreating the up & downlinks for Apollo using vintage NASA hardware. They recently were able to send commands to their AGC[0][1] remotely. No encryption used, just a hefty investment in RF engineering. The techniques were probably closely held at the time to prevent Soviet interference, but these days you can just download the circuit diagram PDFs. [0] Simulated, since the owner…

Hah i just linked the same series in the root comment too before i saw this

Re: Somebody moved the UK's oldest satellite in the mid 1970s, but no one knows who

#89

Post by CableNinja »

mulmen wrote: post #58
retrac wrote: post #9

There was remarkably little in the way of security for early satellites (or space probes). I recently encountered here on HN the suggestion that, the main reason you can't find particularly in-depth details on the Voyager space probes, is project security. Security through obscurity, mostly. If amateurs can detect the signal from the Voyager probes with a small dish antenna, it's at least conceivable someone might ho…

> The Apollo Program was the same; today anyone with the documentation, a small dish antenna, a software radio, and some nerd dedication, would be able to hack Apollo midflight via its radio link. It was the equivalent of a root prompt with no password on an exposed port. Is this right? In a recent curiosmarc video I got the impression the astronauts on board had to enable remote commands. This was frequently done bu…

Yeah that was basically the only thing the apollo astronauts had to prevent remote control by anyone. Comms wasnt encrypted or anything, just a simple switch that completed the command circuit.

Strangely from that series, iirc, ground commands were "king", meaning if that switch was enabled, whatever ground wanted the ship to do, it did, no matter the input from astronauts

Re: Somebody moved the UK's oldest satellite in the mid 1970s, but no one knows who

#90

Post by treflop »

retrac wrote: post #9

There was remarkably little in the way of security for early satellites (or space probes). I recently encountered here on HN the suggestion that, the main reason you can't find particularly in-depth details on the Voyager space probes, is project security. Security through obscurity, mostly. If amateurs can detect the signal from the Voyager probes with a small dish antenna, it's at least conceivable someone might ho…

The US Navy has has a problem with people hijacking their old FLTSATCOM comm satellites as a walkie-talkie.

https://www.wired.com/2009/04/fleetcom/

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