[HN Gopher] Long-lost U.S. military satellite found by amateur r...
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Long-lost U.S. military satellite found by amateur radio operator
Author : wglb
Score : 152 points
Date : 2020-04-24 17:34 UTC (5 hours ago)
(HTM) web link (www.npr.org)
(TXT) w3m dump (www.npr.org)
| wrigby wrote:
| 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....
| imjustsaying wrote:
| 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.
| codewritinfool wrote:
| I was wondering the same thing!
| Florin_Andrei wrote:
| 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.
| [deleted]
| colordrops wrote:
| 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.
| wglb wrote:
| 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.
| teraflop wrote:
| 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.
| dcassett wrote:
| That is one of Heinrich Dorrie's 100 Great Problems of
| Elementary Mathematics:
|
| https://www2.washjeff.edu/users/mwoltermann/Dorrie/MaxMinPro.
| ..
| 8bitsrule wrote:
| 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....
| emptybits wrote:
| 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.
| Rebelgecko wrote:
| 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.
| CraigJPerry wrote:
| I got interested in rf spectrum in 2014 and haven't looked back.
| There's just so much fascinating stuff out there.
| 3fe9a03ccd14ca5 wrote:
| 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??
| kjs3 wrote:
| 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".
| tectonic wrote:
| See also: https://www.rtl-sdr.com/receiving-dead-satellites-rtl-
| sdr/
| jplayer01 wrote:
| > "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?
| merlincorey wrote:
| 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.
| themodelplumber wrote:
| 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. ;-)
| raginalix wrote:
| 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.
| CalChris wrote:
| 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...
| sciurus wrote:
| If you're intrigued by tracking satellites and their
| transmissions more generally, check out https://satnogs.org/
| callesgg wrote:
| The people at MIT that built that piece of junk are long gone.
| What the current people at MIT be able say.
| jandrese wrote:
| 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.
| jcrawfordor wrote:
| 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.
| wrigby wrote:
| 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?
| unixhero wrote:
| Dude out of curiosity who are you and how can I learn all the
| things you know.
| dylan604 wrote:
| 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.
| jandrese wrote:
| 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.
| moftz wrote:
| 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.
| tlrobinson wrote:
| > 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/
| jplayer01 wrote:
| 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.
| oyebenny wrote:
| > 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.
| ColanR wrote:
| 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.
| tonyarkles wrote:
| 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.
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(page generated 2020-04-24 23:00 UTC)