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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

#91

Post by pavel_lishin »

Iulioh wrote: post #14
perihelions wrote: post #8

- "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" )

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

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.

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

#92

Post by another4578 »

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...

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

#93

Post by thebruce87m »

iancmceachern wrote: post #59
Denvercoder9 wrote: post #29

Earlier quoted context omitted.

> 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…

It's an air gapped system effectively

There is some air in the gap, I suppose.

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

#94

Post by Andrex »

garaetjjte wrote: post #13
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…

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 b…

> 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.

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

#95

Post by iancmceachern »

thebruce87m wrote: post #93
iancmceachern wrote: post #59

Earlier quoted context omitted.

It's an air gapped system effectively

There is some air in the gap, I suppose.

Thank you. Indeed, it's more accurate to say it is space gapped

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

#96

Post by tim333 »

tim333 wrote: post #79
Denvercoder9 wrote: post #29

Earlier quoted context omitted.

> 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…

pic of the dish for those curious https://www.planetary.org/space-images/the-70-meter-dss-14-a...

Also as seen from Google maps satellite view https://www.google.co.uk/maps/search/+goldstone+dss-14+/@35....

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

#97

Post by 47282847 »

dgfitz wrote: post #51
Brian_K_White wrote: post #44

Earlier quoted context omitted.

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

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

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

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

#98

Post by wiml »

47282847 wrote: post #97
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 it made sense for you to then call it “freedom units“ why, of all possibilities?

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.

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

#99

Post by manquer »

tivert wrote: post #60
manquer wrote: post #39

Earlier quoted context omitted.

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…

> 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.

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 .

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

#100

Post by alex-moon »

perihelions wrote: post #8

- "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" )

This was also the premise of the 2013 film Gravity starring Sandra Bullock and George Clooney.

https://en.wikipedia.org/wiki/Gravity_(2013_film)#Plot

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