retrac 5 days ago | next |

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 hook up a really powerful transmitter, aim it in the probe's direction, and start issuing commands. There's no cryptography, of course. The resources required to hijack like that in the 1970s would have been much greater, and I doubt being hacked was much on the designer's minds.

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.

A bit closer to home, there's a tremendous amount of semi-functional orbital junk with a similar lack of security, decades-old computers still waiting for telecommands.

Denvercoder9 4 days ago | root | parent | next |

> 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 roughly 15000 m^2, so a small dish of 1 m^2 will catch roughly 1 photon per second. Given that the datarate is 40 bits/second, it's physically plain impossible to receive the signal with a small dish.

Voyager's security is that it's really far away and you need a big, expensive dish to talk with it.

DonHopkins 4 days ago | root | parent | next |

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).

lr1970 4 days ago | root | parent | prev | next |

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

sandworm101 4 days ago | root | parent | prev | next |

But you dont need to hear voyager in order to hack it. It just needs to hear you. Nasa needs the big dish to hear voyager's tiny transmitters. Someone wanting to send a disruptive message to voyager could use a massive transmitter and a relatively smaller dish.

But you dont even need that. You need just enough outbound signal to jam the legitimate uplink, enough that voyager can no longer tell you from the real signal. That is likely much less than the power needed to send a command.

Or you could jam the nasa ground stations. A one-watt transmitter on a carefully positioned cubesat in low orbit would be enough to nullify voyager's real signal. (Setup the orbit to be over the deep space network stations every day as voyager comes into view.)

manquer 4 days ago | root | parent | next |

Even then you need a fairly large transmitter. It is quite easy to detect EM transmissions even when they are low energy. This would be incredibly easy to detect. There are plenty of regulations already by FCC, ITU and equivalent on what is allowed on what wavelength which most nations are signatories too.

Violating these is already solved by law enforcement, even if a rogue nation state is protecting you it will be handled with big gun diplomacy, America after all has the biggest guns.

As xkcd put it, $5 wrench is all it takes no matter how strong your encryption, that works both ways, if a government can find a malicious actor all it takes is $5 wrench to stop you. There is limited value for nation state to protect you from hacking voyager, there is no military or strategic value in it. Dormant satellites in LEO or GEO can be used as kinetic weapons so are lot more valuable.

There are also tech solutions like active jamming that could easily be deployed to counteract you that civilized world can use first even if they don't/can't blow you up without risking retaliation from your state sponsor.

tivert 4 days ago | root | parent |

> Violating these is already solved by law enforcement, even if a rogue nation state is protecting you it will be handled with big gun diplomacy, America after all has the biggest guns.

No one is going to war over ITU regulations or Voyager.

manquer 3 days ago | root | parent | next |

ITU regulations or more precisely spectrum they regulate is one of the most valuable and scarce resources today . Nations would will go to war if they are threatened .

Voyager itself is not economically valuable, but it a cultural symbol of American achievement like say Eiffel Tower in itself does not have value economically (apart from tourism ) but it is very big part of their identity so yeah plausible it would start a war .

tivert 2 days ago | root | parent |

> ITU regulations or more precisely spectrum they regulate is one of the most valuable and scarce resources today . Nations would will go to war if they are threatened.

They'd go to war if they're threatened, but a violation is ITU regulations isn't a sufficient threat. I mean, North Korea and South Korea occasionally shell each other (much worse, https://en.wikipedia.org/wiki/2010_Yeonpyeong_bombardment), and no hot war has resulted.

> Voyager itself is not economically valuable but it a cultural symbol of American achievement...it is very big part of their identity so yeah plausible it would start a war.

I'm sorry, if you think that, you're in a bubble. Voyager is not a "very big part of [American] identity," it's a nearly-kaput space probe that science and science-adjacent geeks (a tiny minority) occasionally get enthusiastic about.

The absolute worst that would happen if a nation state sabotaged it at this point, is the American government would send a strongly worded letter, and the saboteur's ambassador would be summoned for a tongue lashing.

No one's would start a war over the sabotage, and if they did such a war would go down as one of the stupidest casus belli ever. FFS, no one would even have died.

And no one's signing up to die in a war to avenge it. Would you volunteer to be sent to something like the meat-grinder of Eastern Ukraine, because a Voyager became incommunicado a few years early?

dtgriscom 4 days ago | root | parent | prev |

A satellite could jam the signal for a minute or two every ninety minutes, which isn't a lot, although it might be enough to be annoying.

sandworm101 4 days ago | root | parent |

Not if put into an eccentric orbit designed to have it hover in place. A tundra orbit could keep it in the way for many hours each day. Three sats could probably manage 24/7 coverage.

zamadatix 4 days ago | root | parent | prev | next |

If 70 m is the diameter, not radius, that area is a factor of 4 too high. Should be more like ~3850 m^2. Still physically impossible at that size but it does make the required size a bit more tenable.

justsomehnguy 4 days ago | root | parent | next | 

        Antennas at Goldstone Deep Space Communications Complex 
        Name                       Diameter  Description
        DSS 12: "Echo"             34m       Decommissioned in 2012.
        DSS 13: "Venus"            34m       Beam waveguide antenna (BWG) on altazimuth mount, located in Venus, California. ~910 m2 aperture.
    ->  DSS 14: "Mars"             70m       Cassegrain reflector on Alt/Az mount. ~3850 m2 aperture.
        DSS 15: "Uranus"           34m       "High Efficiency" reflector on Alt/Az mount
        DSS 24, 25, 26: "Apollo"   34 m      BWG reflector on Alt/Az mount
        DSS 27, 28: "Gemini"       34 m      BWG reflector on "High Speed" Alt/Az mount
https://en.wikipedia.org/wiki/Goldstone_Deep_Space_Communica...

dgfitz 4 days ago | root | parent | prev |

For those using freedom units that is about 200ft diameter, or about 31,000 square feet.

This works out to roughly 0.7 acres.

vdvsvwvwvwvwv 4 days ago | root | parent | next |

Funny enough the foot was restandardized to .3048m in 1959. So it is a metric-derived unit. Before that it was a feifdom unit, set by kings.

dgfitz 4 days ago | root | parent |

Was a tongue-in-check turn-of-phrase. This place is wound tight apparently.

Brian_K_White 4 days ago | root | parent | next |

Your tangential remark is ok but anyone else's is wound up too tight. OK.

dgfitz 4 days ago | root | parent |

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

lukeck 4 days ago | root | parent | next |

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.

47282847 3 days ago | root | parent | prev |

And it made sense for you to then call it “freedom units“ why, of all possibilities?

wiml 3 days ago | root | parent |

Eh, it's a pretty common tongue-in-cheek way to refer to America's love of a slightly old fashioned system. I wouldn't read much into it.

47282847 2 days ago | root | parent |

Words matter.

47282847 2 days ago | root | parent |

At least half of the world has been violently invaded by this so-called “freedom“ and will take offense by this framing. Rightly so. Freedom by force is simply violence, with the additional violence of deliberate newspeak. Anyone repeating this joins the perpetrators, consciously or out of ignorance, and anyone not speaking out against it supports them by inaction and avoidance of their own responsibility and power.

vdvsvwvwvwvwv 4 days ago | root | parent | prev |

Hey just having fun. Transatlantic banter and fun facts.

I had to look it up to check: my mental model was that a foot is some king's foot but there is more of a storied history.

tzs 4 days ago | root | parent | prev |

> […] a small dish of 1 m^2 will catch roughly 1 photon per second. Given that the datarate is 40 bits/second, it's physically plain impossible to receive the signal with a small dish.

Do you just mean plain impossible with the specific type of system used with Voyager, or are making a general argument that all systems that have a 1 photon/second rate cannot carry 40 bits/second of data?

CableNinja 4 days ago | root | parent | prev | next |

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

emchammer 4 days ago | root | parent | prev | next |

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.

chiph 4 days ago | root | parent | next |

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

tivert 4 days ago | root | parent | prev | next |

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

Can you link to the documentation for the authentication mechanism?

dingaling 4 days ago | root | parent | prev | next |

> They are literally rocket scientists.

Literally they are not. The rockets used to launch the Voyagers were built by Martin and General Dynamics.

echoangle 4 days ago | root | parent |

There’s some overlap though, space probes have (rocket) engines too. Much simpler than on a proper lifting rocket but I would still count it as a rocket engine.

retrac 4 days ago | root | parent | prev | next |

I've looked hard for details and specs on the computers for the Voyagers and it's just not online, beyond high-level descriptions. Almost nothing when compared to Apollo (which has assembly source code for the software, and circuit diagrams for the computers, available).

gloflo 4 days ago | root | parent | prev | next |

Was there authentication right from the beginning or was it patched in later?

Kon-Peki 4 days ago | root | parent |

The space communication network was ~15 years old by the time of the Apollo program and under constant expansion to meet needs. For the moon landing, it was a few dozen ground stations all over the world and 2 million miles of cable linking them together.

"from the beginning" doesn't really mean much of anything, and the system would need to be pretty sophisticated just to work, even if 100% of the users were operating in good faith 100% of the time.

gertop 4 days ago | root | parent |

"from the beginning" means exactly that; did Voyager launch with authentication support or was the authentication added later on?

Kon-Peki 3 days ago | root | parent |

Oh man, I thought this was in reference to Apollo, not Voyager!

I'd say that it almost certain that by the time Voyager was launched, there would have been robust authentication just out of necessity. By that time they'd have decades of experience dealing with software bugs, to say nothing of bad actors.

OJFord 4 days ago | root | parent | prev | next |

It hasn't been suddenly moved in 2024 and nobody knows why, it was left in an inconvenient place (now) decades ago and there's no (found) record of who/why.

cfraenkel 4 days ago | root | parent | prev | next |

Define early. And it does not include this vehicle. I can't personally speak for Skynet 1A, but the DSCS II satellites, first launched in 1971 (so developed at roughly the same time), most definitely had an encrypted command uplink.

mulmen 4 days ago | root | parent | prev | next |

> 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 but they did have a cutoff.

CableNinja 4 days ago | root | parent |

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

garaetjjte 4 days ago | root | parent | prev | next |

Voyagers are so far away that possibility of owning necessary antenna is probably limited to nation-states or mad billionaires. Also DSN-sized antenna is not exactly easy to hide. If you are hell-bent on breaking Voyager and have such resources I think you could acquire necessary information anyway (I guess you could get uplink data for reverse-engineer framing format by standing near DSN antenna with SDR?).

>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.

Indeed, but in that case it would be port opened with a switch: https://youtu.be/2Jt0PsxLM7k?t=1732

Andrex 3 days ago | root | parent |

> mad billionaires.

If one of them in particular were to happen upon this HN post, I honestly wouldn't put it past him to try messing with Voyager.

PittleyDunkin 4 days ago | root | parent | prev |

> There was remarkably little in the way of security for early satellites (or space probes).

Compared to what? What was (or is) worth securing? From what? Talking about security in abstract is nonsensical

ben_w 4 days ago | root | parent | next |

The early stuff was spy satellites, weather satellites, and communication satellites.

The earliest active communication satellites — e.g. Telstar 1 — was done with "take signal in from vaguely the right direction, amplify with pure circuitry, rebroadcast in vaguely the right direction", no encryption possible on the satellite itself, and the thing itself was so primitive it was spin-stabilised rather than having an actively maintained orientation.

Weather satellites won't have mattered too much. Spy satellites I'm not sure about (what with this stuff being somewhat secretive and all), but they're obviously a thing where security matters.

sandworm101 4 days ago | root | parent |

These were and are called "bent pipe" satalites as they deftly turn around an amplified signal. But their control circuits are different and are not so open.

For the airplane nerds, this was also how early radar jammers worked. They took an incomming radar signal, delayed it a little, and retransmitted. No processing required and no digital circuits. That worked very well once upon a time.

atoav 4 days ago | root | parent | prev |

You are aware of the historical fact that there was a cold war when these things were designed?

PittleyDunkin 4 days ago | root | parent |

Sure but that was so propaganda heavy nothing can be trusted from that era. What do people actually think today and why? Surely we live in such a free society now people are actually free to explain their viewpoints and reasoning.

Besides, invoking the cold war explains little (aside from invoking the propaganda of the time). The soviets live-streamed the moon landing. The idea that they were necessarily antagonistic is simply inaccurate. Not to mention what they would gain from fucking with satellites remains unexplained.

JumpCrisscross 4 days ago | root | parent | next |

> what they would gain from fucking with satellites remains unexplained

You don’t see what America might have gained if it could de-orbit the USSR’s early-warning satellites at will?

seabass-labrax 4 days ago | root | parent |

You might have chosen a bad example, as both sides had many early warning satellites, and such a catastrophic 'failure' in any tactically significant proportion of them would immediately put both sides on high alert. It would be much more valuable to target individual reconnaissance or communications satellites in order to make a 'blind spot' to support a particularly important secret project, but even this scenario would be scarcely credible.

atoav 4 days ago | root | parent | prev |

Does space race say anything to you? One way of winning a race is to become faster, another is to make others slower. You know sabotage isn't just spy novel stuff.

another4578 3 days ago | prev | next |

Satcom 3 was lost after launch in 1979 and wound up in a non-geosynchronous orbit.

On a tour of the satellite manufacturer, RCA Astro, years after the loss, we heard this story: during the transfer of control from NASA to RCA Astro contact was lost and not re-established. Eventually the U.S. military was asked, "Errrh, did you see where Satcom 3 went?". The answer came back "Yup, looks like isn't in the geosynchronous orbit you expected".

The thought was that during the handover a command to fire the apogee motor was inadvertently sent and obeyed!

The fix for FUTURE launches was a protocol of checksummed commands. Beyond that, the new, more cautious sequence, became:

  1. uplink dangerous command.

  2. spacecraft verifies checksum and downlinks a copy of the proposed dangerous command

  3. a keylock on the RCA  command console is turned on and the "execute that dangerous command" instruction is uplinked.

  4. upon verifying the execute command's checksum, the dangerous command is executed.
No further launches suffered a failure similar to Satcom 3.

Satcom 3's hulk is still in orbit.

See: https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id...

https://space.skyrocket.de/doc_sdat/satcom-1.htm#:~:text=Sat...

perihelions 5 days ago | prev | next |

- "We need to avoid what I call super-spreader events. When these things explode or something collides with them, it generates thousands of pieces of debris that then become a hazard to something else that we care about."

There was one of these just a couple weeks ago (and that was not the first),

https://news.ycombinator.com/item?id=41904346 ("Intelsat 33e breaks up in geostationary orbit")

Iulioh 4 days ago | root | parent | prev |

....is this really a problem in a geostationary orbit?

pavel_lishin 3 days ago | root | parent | next |

Yes, because the bits that come off satellites don't stay in a perfect orbit with them - inclination and other orbital elements may change, which means they may eventually collide with other satellites.

WJW 4 days ago | root | parent | prev |

Yes, because of the https://en.wikipedia.org/wiki/Kessler_syndrome

margalabargala 4 days ago | root | parent |

No, because of the https://en.wikipedia.org/wiki/Geostationary_orbit

schiffern 4 days ago | root | parent |

Actually GEO is one of the worse orbits for this, because

1) unlike LEO, there's so little drag that both large particles and small fragments are essentially up there forever

2) all the satellites are concentrated in a line, not spread out in a 2D plane or (even better) a 3D volume (collisional probability scales as number density squared)

3) despite that, the moon perturbs any uncontrolled debris into a slightly inclined orbit that nevertheless crosses GEO with >500 m/s relative velocity

If you want to intentionally rendezvous with and deorbit satellite debris, GEO is certainly one of the orbits to prioritize.

rep_lodsb 5 days ago | prev | next |

This didn't happen recently. From the article:

>Almost certainly, it was commanded to fire its thrusters in the mid-1970s to take it westwards.

adrian_b 5 days ago | prev | next |

TLDR:

While the title says that it is not known who has moved an abandoned UK satellite used for military telecommunications, the article very strongly implies that it was someone from USA, who does not want to acknowledge this.

The satellite had been built by USA and initially operated also by USA, before being handed down to the UK, so they had the capabilities to control it at any time.

Yeul 5 days ago | root | parent | next |

UKs nuclear deterrence is built by the USA.

It is a testament to deGaulle's genius that he never fell into that trap.

cenamus 4 days ago | root | parent | prev | next |

To be honest, most central Europeans would not have been too happy with France's early nuclear strategy. Basically just shooting a-bombs into a corridor along the Rhine to stop the Soviets

casefields 4 days ago | root | parent | prev |

I’ll never forget after de Gaulle ordered all American soldiers out of France, US Sec of State Dean Rusk retorted “Does your order include the bodies of American soldiers in France's cemeteries?"

rhplus 4 days ago | root | parent | prev |

Its current position above Central America would certainly have been useful to the US in the mid 1970s when it apparently moved, perhaps more useful than it would have been to the UK over post-colonial East Africa.

fy20 4 days ago | root | parent | next |

Right, and given the US-UK military relationship, it seems likely that it could have been moved with the UK having full knowledge - but they just didn't want to record or admit it.

Keysh 4 days ago | root | parent | prev |

The article says that it was no longer functional (in its communications abilities, at least) by that point

> Launched in 1969 ... the spacecraft ceased working a few years later ...

Also, what makes you think the US didn't already have their own satellites for that purpose?

Luc 4 days ago | prev | next |

A simple malfunction is not considered in the article. Is that so unlikely, e.g. a sticky relais or some-such?

cfraenkel 4 days ago | root | parent |

It was spin stabilized. A stuck relay would have just created equal thrust all the way around the spin - ie the thrust would cancel out to zero. This design required thrusters that fired for very short intervals at a given delay after the earth sensor saw the earth, so the thrust would line up in the desired vector. In other words, no a simple malfunction cannot result in an orbit change.

That said, it's an assumption in the article that the orbit change wasn't due to the cumulative effect of the normal gravitational perturbations the pull on all these vehicles. You'd need to dig up what orbit it was in 40 years ago and then calculate how the orbit would have drifted over those 40 yrs. Good luck.

euroderf 5 days ago | prev | next |

If satellite warfare will be like chess, this could be a preparatory move.

pram 4 days ago | prev | next |

Wild speculation with zero evidence since no one else is: it wasn't broken, and the US/CIA intentionally moved it so they could communicate with agents in SA/Chile (during Allende etc)

aaron695 4 days ago | prev | next |

This is literally a historian can't find paperwork from ~50 years ago.

A UK historian can't find in part classified paperwork that would be created by the U.S. Department of Defense who had control and moved a broken satellite in the 1970's

Re-framed as a puzzle, why was this location chosen it becomes interesting. But I get BBC are just chasing NPC clicks from sites like HN