NASA building network cables that can survive supersonic flight - could this finally deliver unbreakable RJ45 latching tabs? NASA has revealed it’s building network cables capable of surviving supersonic flight. The cables are needed for a project called “SCHAMROQ” – aka Schlieren, Airborne Measurements, and Range Operations for QueSST. Keen-minded Reg readers will recall that QueSST is NASA’s attempt to create a new supersonic jetliner, code-named …
Breakable latching tabs are the best invention.
Break it where the narrow part widens then the wankers cant remove them. Reduced the number of times a thousand fold when I had to go out and patch back in IP phones (despite them having a pass through port with attached cable), projectors, conference phones, digital displays, av equipment and on and on.
Apparently breaking tabs was a good idea, but breaking the fingers of those that kept unpatching this was not an acceptable, although preferred, option
"so fast they can survive supersonic flight"
[1] What has data rate ("so fast"?) got to do with surviving the stresses of a sonic boom?
[2] What's special about these cables (apart from a supposition about latching tabs)?
It would be really nice if both these questions were actually answered.
[2] What's special about these cables (apart from a supposition about latching tabs)?
Well, as the article says, they're used for special instruments:
Those instruments will fly on an F-15 aircraft that follows X-59 test flights so will need to survive supersonic flight and the X-59’s shockwave.
Me, I'd just have used WiFi between the planes.
Fair cop. I saw NASA's odd mention of networking, though to myself what's the most vulnerable part of a cable and tried to turn that into something amusing. Sorry if it ended up a little frustrating instead. FWIW I did look for the contract notice that would offer that detail (and maybe a $10k toilet kind of angle), but it was nowhere to be found - presumably either below the spend threshold for notification or not a new award.
I suspect that we are only talking about manually assembling cables out of COTS parts. There are numerous mil-spec / aviation grade solutions for Ethernet.
The most reliable would probably be to utilize an existing connector syystem with machined pins (which can be reliably hand-crimped. If RJ45 compatibility is required, then there are numerous rugged solutions that maintain pin compatibility. https://www.amphenol-socapex.com/en/products/connectors/rugged-ethernet-usb-display/rugged-ethernet-connectors
Just do not ask what a single connection costs. Prices tend to go beyond eye-watering. However, if a broken off retaining tab can cost you the aircraft, then this is an investment workh considering.
..mine is the one with a de-pinning tool and a wire harness plan in the left pocket..
Airplane part and MilSpec intermingle. Just do not mistake UltraLight part or General Aviation part for "real" aircraft part. Automotive Part is interesting. High part numbers press the part cost down. Quality is often very good. However, purchasing can be difficult (unless you plan to buy 10.000 units), and the part-specific installation tools can be eye-wateringly expensive, non-reusable and unobtainable.
Hand-assembly (crimping etc.) can negate the quality advantage of Automotive Parts.
"If RJ45 compatibility is required, then there are numerous rugged solutions that maintain pin compatibility. https://www.amphenol-socapex.com/en/products/connectors/rugged-ethernet-usb-display/rugged-ethernet-connectors"
Or... you can buy mil-grade Ethernet switches that use MIL-DTL-38999 connectors without the special RJ45 inserts. I'm sure with NASA money available, one of those suppliers would gladly rework the firmware to whatever data protocols necessary.
well, when I was in the Navy I went to a soldering school where they taught soldering techniques according to NASA specs. You had to visually QA your work under a lighted magnifier, no 'pits' no 'tits' etc.. You had to use solder with mildly activated flux that was 63:37 (Pb:Sn) which has the tightest thermal range for the plastic region [meaning that you're way less likely to have a cold solder joint] and you used specific types of crimp connections when making cables, crimped with the correct tool, through-hole leads were bent in specific ways before inserting into the circuit board, yotta yotta.
In short, it restricts you procedurally to constructing and repairing things in a manner that gets the highest possible reliability. In this case, it was for equipment used to control nuclear reactors, which had to stay running on a warship that might get hit by things that explode and send massive vibrations throughout the ship, potentially causing electronics to 'jitter' or even fail. The last thing you want is to have a nearby depth charge cause a reactor safety shutdown, leaving you without propulsion for a short period of time, and then NOT being able to start it back up again because it keeps shutting down when the system is shocked.
anyway, similar requirements here for handling in-flight vibration and supersonic shock waves.
No cadmium plating, no halogen-releasing PVC insulation, etc. Sounds like standard defense/aerospace design -- can't have similar issues in a hatches-closed armored vehicle either.
(And robust, because you don't want them having to fix it in the middle of a battle; they probably don't have the necessary tools on-hand.)
I have network switches that regularly go into space and on missiles, both go well over the speed of sound, both have 38999 connectors but only for density reasons.
In tests we use RJ45 versions without any problems. (They last about 4 weeks running 24/7 on a Level-5 vibration rig.)
One of the cheap and cheerful distributers of 'patch cables' were actually supplying something that did conform to the aerospace specs at normal prices until someone tipped them off! (We had about 5 years worth in stock by that point :-)
Pah, who are they trying to kid.
I got buzzed by a couple of pairs of F15s up in the Lakes a month or so ago. The noise sort of hits you like a sledge hammer and these ones weren't trying to go supersonic. The chance of hearing anything in the vicinity seems unlikely. Or maybe that's the point. This way they can claim the new toy is silent because they couldn't hear a thing.
Unlike the 'hogs, which are scarily silent. Saw them much earlier than I heard them (caught the movement when they came over some trees) - ouf course I would have been deader than dead by then if I were a tank, but usually they do not prey on hikers...
They still were rather loud when they passed, though.
I've had the experience of not hearing fast jets until they're on top of you many times, or sometimes even before they are underneath you, which is much more fun. This was at the western end of Wast Water so not on the Mach loop. and at close to sea level so they were going over head for us, but they came up the valley well below the top of Yewbarrow and Middle Fell. Again it's not unusual to see military jets there, but this is the first time I've seen F15s and they seemed much louder than anything else 'veI heard there. Hearing them before they arrive might be down the sound being reflected around the valley as they were subsonic. The noise level goes up massively once you're behind them, but they were loud before.
Fast jet low flying training...
https://en.wikipedia.org/wiki/Mach_Loop
https://www.youtube.com/watch?v=INcWJYFvSkQ
https://www.youtube.com/watch?v=3-7zHlOi4T4
"Star Wars Canyon" - Death Valley
https://www.youtube.com/watch?v=SiAW6u4Yt1w
The view from inside the cockpit...
Speed doesn't have any impact on a cable's performance. Acceleration does, but the shock of dropping a bunch of cables on the floor before starting an install will probably be more stressful than the acceleration to Mach whatever. As someone above points out, there are already plenty of specs for military applications which would cover this. From my experience, anything that can survive the UK navy's gunfire shock and vibration specs can probably survive anything a supersonic jet can chuck at it.
Mil-Spec connectors are very fine pieces of hardware.. Individually CNC machined parts etc..
Attemps to keep Mil-Spec pin compatibility while lowering cost often involve the introduction of stamped connectors.. ..which takes away from reliability if you have to hand-crimp the connector.
Automotive connectors, while able to withstand similarly rugged conditions (but not as low temperatures), often tend to lack sufficient mating cycles. Where Mil-Spec will give you 500 cycles, expect no more than 20-50 cycles in automotive (assembled once, never touched). Horses for courses..
As for field-survivability: Nothing is infantry-proof, except, maybe, for a steel ball, 2 meters in diameter, made out of hardened steel. However, this they will instead manage to loose.
Would seem to be a complete solution to the problem of vibration affecting the physical connector.
Else hot glue...
I would be more concerned that the little springs in the network switch which make contact might get bounced off their contacts for a moment, but again, a small plastic shim would likely suffice.
The problem with ethercon is that someone will inevitably need to plug it into a non ethercon hole, take the metal barrel off and then proceed break the plastic bit.
...Actually that hasn't happened to me for a while, since when I last worked with ethercon they could afford decent kit at both ends of the cable, but when I started out there was all to much of it.
You can just use a plain cable - although it does require that you have a cable of the appropriate length, and access to both ends. I don't imagine that's a problem here. Also - who cares about the little tab on ethercon? The whole barrel locks the connector in place - doesn't it? I haven't had to replace any of my ethercon kit in a while...
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