Long-lost U.S. military satellite found by amateur radio operator | Hacker News Reader

Long-lost U.S. military satellite found by amateur radio operator

npr.org

321 pointswglb56 comments

I feel like "lost" is a bit of a misnomer here - this spacecraft was of course being tracked still, and it only took a couple seconds of googling to pull up the detailed info on the orbit from Celestrak[1]. There's even a nice visualization available at [2].

1: https://celestrak.com/satcat/tle.php?CATNR=02866

2: https://celestrak.com/cesium/orbit-viz.php?tle=/satcat/tle2....

For a somewhat cooler visualization, which also gives you a comparison to the GEO belt and other satellites but may be bad for browser performance, see http://stuffin.space/?intldes=1967-066E&search=1967-066e

This kind of visualisation is fascinating, but it’s also (for reasons I shall now explain) the root of a very serious misconception.

The misconception I speak of is the “junk in space” one. One sees images such as these and clearly reaches the conclusion that we’ve immersed ourselves in a thick fog of stuff which will soon become a barrier of fast-moving debris.

But... if one thinks about it, these objects are small, and if one were to lay them all out upon the surface of the earth, they’d actually cover a tiny fraction of it, and there’d be miles between each one. And furthermore, higher altitudes define a larger sphere, and surface area depends on the square of radius, so there’s actually far more distance available to these objects (alternatively, to repeat the experiment on earth, one would need to considerably scale down the already comparatively tiny objects and satellites).

And on top of that, we have a whole third dimension to deal with, so it’s not just one bigger sphere, but a continuum of spheres that all exist independently of each other.

Which leads to my core contention: even visualising satellites as the smallest graphical depiction possible (a single pixel) leads a viewer to vastly overestimate their size, and therefore the density of objects that exist in our sidereal neighbourhood.

And this irks me.

</rant>

What you did not consider is cascading collisions. If two high velocity objects collide, a large cloud of high velocity debris orbits Earth. The cloud expands and eventually parts of it collide with satellites, creating more debris that collides with other satellites, creating even more debris.

You may already be aware, but for others reading, the cascading collisions scenario is called the Kessler Syndrome.

https://en.wikipedia.org/wiki/Kessler_syndrome

Oh no I understand that very well, I’m well versed in statistical mechanics. The thing is that the cross-section of the targets remain low, and therefore the amplitude of the scattering matrix remains pretty low. It’s actually pretty unlikely to successfully trigger off a divergent chain reaction. To use a nuclear analogy, it’s the density is well below a critical density (or rather, it’s far from a critical geometry).

The nearly-perfectly-straight line of StarLink satellites is pretty fascinating.

The "no comment" is really "everybody who worked on that has long since retired and nobody is in the office to check the paper records, if they even wanted to and were allowed to."

The communication protocols used by that old bird are probably still classified.

A satellite of that age would have used a very simple analog repeater or linear transponder, meaning that there is no communications logic occurring on the satellite. Any digital modulation, and more so encryption, would be the responsibility of the ground stations. This is still a common design pattern for satellites, referred to as the "bent pipe" model since the space segment is merely a "bend" with no logic, but it is subject to abuse by unauthorized operators so there's usually some degree of at least authentication today.

Military satellites launched into the '80s continued to use analogue transponders and, to some extent to this day, see unauthorized use. The only real deterrent was the difficulty of obtaining inexpensive equipment for satellite bands but the widespread use of DVB and VSATs changed that during the '90s and '00s.

That said, all related documents may very well have been classified at the time (owing especially to the lack of any authentication!) and even when declassify-on dates pass there is often institutional resistance to going through the motions of releasing this material, especially since Lincoln Labs (a contractor) would not be authorized to do so and would have to forward the request on to someone else. A more formal FOIA request, followed by appeals if necessary, can often unstick these wheels since it creates a legal obligation that a more casual media request does not.

> A satellite of that age would have used a very simple analog repeater or linear transponder, meaning that there is no communications logic occurring on the satellite.

It's broadcasting telemetry, isn't there a chance it also accepts commands?

> Military satellites launched into the '80s continued to use analogue transponders and, to some extent to this day, see unauthorized use. The only real deterrent was the difficulty of obtaining inexpensive equipment for satellite bands but the widespread use of DVB and VSATs changed that during the '90s and '00s.

WIRED had an article about this awhile back: https://www.wired.com/2009/04/fleetcom/

Oh, this is fascinating. Just a bit disappointing that the article doesn't mention at all why it's possible for random people in Brazil to access these satellites.

These specific satellites have no security. They just retransmit any signal that comes at them. Makes me wonder who else is using them...

Seems weird to me. They made these things when they were at war with Eurasia. Seems like it'd be a good idea to ensure only you could use them.

Right? Might as well open it up to the public. Brazilians hueing it up in their satellite is really the least of their problems. If a bunch of civilians can cobble together enough equipment to use the satellite, gotta wonder what nation states with real resources can manage.

So how insecure is this stuff, really? Radio security seems to be based on "authorities really, really don't want you to do this".

> Oh, this is fascinating. Just a bit disappointing that the article doesn't mention at all why it's possible for random people in Brazil to access these satellites.

This is my question as well.

From the article, to answer the hardware side of your question, which was mine as well.

> To use the satellite, pirates typically take an ordinary ham radio transmitter, which operates in the 144- to 148-MHZ range, and add a frequency doubler cobbled from coils and a varactor diode. That lets the radio stretch into the lower end of FLTSATCOM's 292- to 317-MHz uplink range. All the gear can be bought near any truck stop for less than $500. Ads on specialized websites offer to perform the conversion for less than $100. Taught the ropes, even rough electricians can make Bolinha-ware.

The Fleetcom satellites are, if I recall, just “bent pipe” satellites. There receive on one frequency and retransmit on another with zero logic onboard. Analog, digital, whatever. If you wanted them to encrypt their broadcasts, you’d just encrypt the signal before transmitting on the ground and it would happily rebroadcast your encrypted signal back to earth.

It's an experimental satellite, it's downlinking data rather than just being a bent-pipe relay. This is right before SGLS and the mass adoption of S-band (USB) so it's going to likely be a basic VHF BPSK kind of signal. This is also before encryption was easy so it's likely going to be in the clear.

Yeah, most geostationary communications birds use analog transponders, even to this day. There's a lot of fancy command and control, but the actual payload is just analog RF circuitry, even using tube-based power amplifiers.

I have no idea about these older satellites, but on modern stuff there's a separate Telemetry, Command, and Control (TT&C) link. Maybe this bird is only transmitting telemetry though?

I'd assume "sending commands to the satellite" would involve some sort of digital encoding. If you just want to bounce signals off of it then you probably just need to figure out the frequency and polarization (trial and error?), but if you wanted to issue a command I'd assume you need some sort of protocol.

>> This is still a common design pattern for satellites, referred to as the "bent pipe" model since

If it is a communications satellite. It is also a common design pattern for military satellites to be mislabeled as "communications" when they actually do other things. So too is it common for "communications" to also cover intercept of enemy communications.

Old secrets can still be embarrassing.

Dude out of curiosity who are you and how can I learn all the things you know.

I knew a guy that was part of the beginnings of the cable frontier running numerous cable headends. Any time he needs to align a new dish, he does it by hand. He knows where a specific satellite is, and a particular signal coming from it. Once he finds it, he pans the dish across the line of satellites until he gets to the one needed. As you pan across the sky, you can use a scope to see each of the birds come in and out of alignment. The constellations are known, so you map out which ones are which. Some of the signals are scrambled, but there's a lot to be learned, and if it is TV broadcast, decoders are available. A lot of this gear is available second/third/fourth hand now. With the right gear, it is possible to learn a lot of this stuff on your own with some google searches. Learning to decode what's already coming down is just a step on the way to learning about what goes up.

Useless satellite trivia: from time to time, it becomes necessary to adjust the orbit of the satellites (like a wandering disabled satellite). They do not fire boosters to raise/lower the orbit directly as that requires too much fuel. Instead, they speed up/slow down the horizontal speed to increase/decrease altitude. With enough notice, they can do this very incrementally and fuel efficiently.

The necessary equipment is also crazy cheap at this point. You could easily start listening to satellites with a $20 USB SDR dongle and a DIY antenna.

If someone wants a cheap way to learn orbital mechanics (like why you accelerate/decelerate to raise/lower your orbit), pick up a copy of Kerbal Space Program.

I'm not the person you're replying to, but my answer would be "stay curious, and don't be afraid to follow that curiosity down a lot of rabbit holes".

Space Force is accepting enlistments and commissions.

I wonder if anyone's ever heard from SNAP-10. It was the first fission reactor in orbit (1965). It had, uh, problems and was shut down after 43 days. In late November 1979 it had a 'anomalous event', and it had 6 more in the next 6 years... releasing '50 trackable pieces'.

[0] https://web.archive.org/web/20170503083646/https://ston.jsc....

Great document. One of many eye-openers:

"The West German government sponsors a meeting called Safety Aspects of Nuclear Reactors in Space, in Cologne. Nietrich Rex predicts that Soviet space nuclear reactors will undergo 2-3 on-orbit collisions in the next 300 years. Each will result in world-wide reentry of radioactive debris."

That's a prediction from November 1989.

I can't find a source after a cursory search, but IIRC the Soviet RORSATs are still the second or third biggest source of space junk today (#1 being the 2007 Chinese test of an antisatellite weapon). A few of them had nuclear reactors fail in dramatic ways, although a lot of their debris is just from leaking coolant.

Per this document it appears that (frequent) Delta second stage explosions were one of the most significant contributors. By 1981 27% of all tracked debris (of orbital period under 225 minutes) were from Delta second stage explosions. (I'm guessing these are considered high velocity debris). It's quite interesting that NASA was surprised by this (asking McDonnell-Douglas to find out why in May of 1981) considering how long they had been launching the Delta rockets and tracking debris. From the document, NASA officials continually approved work to track orbital debris, but often didn't give the reports administrative attention.

1965. Wow. Watching and listening to that waterfall was fantastic. And by the way, great use of links in the NPR article. I found a new blog to follow, a lab I've never heard of, a Twitter account to check out, and _Gunter's Space Page_, which we hopefully all know via intuition is a quality work to be saved for later in-depth review. ;-)

When I got my first rtlsdr dongle I spent hours just surfing the frequencies looking for interesting signals and trying to decide them. It's a great hobby!

SDR has opened up a new frontier for me, it gives me the same excitement I got when I discovered BBSs and then the internet.

I was lucky enough to have a project come up last year that required gsm/4G and GPS simulation. I got budget to buy a bladerf and a nice SBC and built a box that could simulate a GSM, 3G/4G basestation and simulate GPS.

That's awesome! Especially since your work experience seems to integrate with your hobby, and a very cool hobby at that.

Just to re-balance the universe a bit here, I almost stepped on my RTL-SDR the other day, in a neglected corner of my workspace, and felt pretty guilty about it ;-)

(Tangentially, I gave a cheap portable SW radio to my son the other day, after not using it for a while. I was trying to find a favorite FM radio station to demonstrate to him, and stumbled across one of the local emergency services instead, in the 150 MHz range. Haha, no wonder the dial markings don't match up at all. Now he's telling me what kind of makes & models he's hearing about over the air...)

This reminds me of another thing a lot of people have been noticing lately with more time to look up.

What's been up with Venus? It's been really bright for weeks if not months now.

Venus is only a few weeks away from its inferior solar conjunction, which is approximately the point in its orbit (recurring about every 19 months) where it most closely approaches Earth: https://in-the-sky.org/news.php?id=20200603_11_100

Interestingly, Venus' brightness is currently near its peak, even though the conjunction itself is still several weeks away. At the point of closest approach, the planet will be almost 3x bigger in angular area than it is today, but we will be seeing a much smaller fraction of its sunlit side.

That is one of Heinrich Dorrie's 100 Great Problems of Elementary Mathematics:

https://www2.washjeff.edu/users/mwoltermann/Dorrie/MaxMinPro...

Venus is currently very close to us. See:

https://theskylive.com

Also the air is a lot cleaner these days with everyone staying at home.

Actually, it was extremely bright here even before anyone ws in lockdown. I particularly remember when it was in the western sky near the moon several moons ago.

I was wondering the same thing!

They just have more time now to actually look up. Venus is same as ever, the brightest object in the sky besides the Sun and the Moon. It was at its greatest elongation from the Sun in late March, so of course it's very visible.

I got interested in rf spectrum in 2014 and haven’t looked back. There’s just so much fascinating stuff out there.

One of the satellites found by this sleuth:

> Transit 5B5 was a US Navy navigation satellite launched by a Thor Able Star rocket. It carried a nuclear power source.

Wait what? Nuclear powered satellites? How do they safely dispose of these??

Yes, it's a thing. Most of the deep space probes were radio-nucleotide powered. Earth orbiting is less common for obvious reasons. One option is boost to a parking orbit where it'll be stable and out of the way for a couple of thousand years. But the stuff from the '60s was often "it'll burn up on reentry (cross fingers) and it's a cost of doing Cold War business if a little get's scattered around".

There are plenty of earth orbiting actual fission reactors, not like the RTGs you have heard about.

There were quite a few sent up by the Soviets (from 1967-1988) and at least one malfunctioned, failed to eject its reactor into a disposal orbit and scattered radioactive waste across northern Canada.

Even the Soviets didn't intend to send nuclear reactors to burn up on reentry; I'd be surprised if that was anyone's plan.

https://en.wikipedia.org/wiki/US-A

https://en.wikipedia.org/wiki/BES-5

https://en.wikipedia.org/wiki/Kosmos_954

https://en.wikipedia.org/wiki/Kosmos_1402

"...44 kg of uranium had been dispersed into the stratosphere after the incident..."

I've more than "heard about" RTGs, and I'm well aware of the kind of reactors that have been shot into space. We can argue the level of "intend", but in the Cold War, the reentry of a nuclear reactor was considered an acceptable cost of doing business.

If you're intrigued by tracking satellites and their transmissions more generally, check out https://satnogs.org/

I guess that was before we had responsible satellite disposal.

http://www.esa.int/ESA_Multimedia/Videos/2017/04/Space_debri...

Reconnecting with an old satellite has been done before. Perhaps it be done again.

The International Sun-Earth Explorer (ISEE-3) satellite was launched on August 12, 1978, and was originally meant to study the Earth's magnetosphere from the L1 Lagrangian point between the Sun and the Earth, where the gravity of both bodies cancel each other out.

https://www.vice.com/en_us/article/pga3m7/techno-archaeologi...

This has me puzzled:

>>> Confirmation will occur at ~0445 UTC this evening when the satellite should pass through eclipse.

Shouldn't it be stationary, if it's in geostationary orbit? Or is it just that the satellite has drifted out of that orbit over time?

The article says GEO, but actual quotes in the article say "GEO graveyard orbit". What this means is that, at the end of the satellite's service life, it was boosted into a lower (in this case [1]) or higher (also common) orbit out of the way of the GEO line. There isn't much space in GEO, as it's a one-dimensional space [2] - only true anomaly (position in the orbit) can be varied. So you want to free up the slot once you're not using it anymore.

[1] This particular satellite is http://stuffin.space/?intldes=1967-066E&search=1967-066e. Note the orbital period - it's shorter than a sidereal day of 1436 minutes, which means this is a lower orbit. It's also slightly inclined to GEO, which reduces the chance of collisions even further.

[2] By contrast, the set of Keplerian orbits is generally a six-dimensional space, with singularities at eccentricity = 0 and inclination = 0. Well, also technically at semi-major axis = 0, but that's not a physically possible "orbit".

Are lower-than-GEO graveyard orbits common? I mean, I guess they are, judging by stuffin.space, but my intuition would be that it wouldn't take any more fuel to put a satellite in a higher-than-GEO graveyard orbit (and thus further minimize the risk of collision), no?

No particular reason why a higher orbit is any better than a lower orbit. As long as you're a good 1000 kilometers away from the GEO belt at closest, and preferably a little inclined so that closest approach only happens ~2 times a day, both high and low graveyard orbits are equally good for avoiding collisions.

> "The reason this one is kind of intriguing is its telemetry beacon is still operating," Tilley says.

What exactly is a telemetry beacon, and what kind of data would it be broadcasting?

It's at a minimum simply a high signal on a certain frequency indicating the device is there and then you use math to gather telemetry data (position, speed, etc).

At most, it's packets of data that indicate telemetry data such as position, speed, temperature, and the current state of any instruments on board.

Telemetry data is typically pushed out at regular intervals to allow it to be recorded and graphed in a time series.

Rick Rhodes could really build ‘em!

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