[HN Gopher] Old software keeping space missions alive
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Old software keeping space missions alive
Author : alex1212
Score : 71 points
Date : 2023-08-17 06:58 UTC (1 days ago)
(HTM) web link (www.bbc.com)
(TXT) w3m dump (www.bbc.com)
| h2odragon wrote:
| From rumors I heard, for a while there before 2005, NASA was one
| of the biggest buyers of salvage sun4 hardware. they had multiple
| missions running on it and there were some particular high rate
| data input cards on mbus that were hard to duplicate on other
| platforms.
|
| "we have a closet full of sparc 10s, we figure that'll be enough
| to last as long as the satellite"
| snickerbockers wrote:
| jesus christ, i dont think ive ever seen an article that beats
| around the bush for as long as this one does before finally
| getting to the point.
|
| anyways, for those who don't have the patience, the title is
| misleading. it's just some old software from the 90s. It's only
| ancient if you're one of those people who completely rewrites
| their entire code base from the ground up every two years because
| to pad out your resume with whatever bullshit new "framework" is
| in vogue. Contrary to popular belief you actually can just keep
| using the same software indefinitely, it doesn't degrade with
| age, and for the most part the hardware lasts pretty long too as
| long as you take care of it (with a few exceptions like optical
| drives and SSDs).
| weinzierl wrote:
| The article is bad but the premise is not wrong. The things
| that fly and a lot of the things that stay on the ground are
| analyzed with NASTRAN whose solver kernel dates back to 1964.
| At its heart it is still the old FORTRAN code because
| reproducibility is king.
| peraspera wrote:
| Not to mention that they confuse RAM with storage. The iPhone
| 14 certainly doesn't have a minimum of 128 GB of RAM.
| CoastalCoder wrote:
| Depending on context and the audience, it could be fair to
| use "RAM" to refer to SSD storage.
|
| SSDs are random access, just not volatile like DRAM.
| ComputerGuru wrote:
| The only context in which the technical difference between
| memory and disk can be glossed over is one where the
| audience is made of laypersons that wouldn't understand the
| first thing about seekable vs random-access memory in the
| first place.
|
| A tech-illiterate author/editor is the much more plausible
| explanation.
| jychang wrote:
| On the other hand, a modern SSD is probably faster than
| RAM on a spaceship from the 90s. (Don't quote me on this,
| I didn't double check).
|
| All of a sudden I had an urge to get MS-DOS to run with a
| SSD as memory. Unfortunately I know DOS can't address 1TB
| of memory, but the mental image of it is hilarious.
| dang wrote:
| Ok, I've taken the ancient technology out and replaced it with
| old software in the title above. Thanks!
| cryptoz wrote:
| Software does degrade with age, though. Simply the fact that
| vulnerabilities are found over time means that our
| understanding of a piece of software and how it works changes.
| But it's not just vulnerabilities being found, it's protocols
| used that may be unsupported etc. That change is a kind of a
| rot like people call 'bit rot' but it's a specific software rot
| that does happen. Systems are complicated.
| z3t4 wrote:
| An example is SSL root certificates, which expire by design.
| Also ABI. But if you use containers or virtual machines you
| can basically have a program run forever.
| arter4 wrote:
| You can, but you shouldn't, because at some point you
| should patch the vulnerabilities you inevitably find on any
| non-trivial piece of code after a while.
| bombcar wrote:
| Certain code can run with bugs forever, even
| vulnerabilities, because it will never interact with
| anything (see the famous "the missile" bug - a counter
| would overflow at some point, but by then the warhead
| would have detonated, so who cares?).
| JohnFen wrote:
| Sure, but none of that applies to non-networked embedded
| systems.
| kwhitefoot wrote:
| Most software used not to be connected to the outside world.
| It wasn't vulnerable at all unless the attacker already had
| control of the host.
|
| In the thirty years I spent developing software I spent
| hardly any time on anything that was accessible through the
| network and I'm confident that I'm not the only one. The
| embedded control software that I wrote for 6502s would still
| work today and would be completely invulnerable to attacks
| other than from someone standing right in front of the
| machine pushing buttons.
|
| Of course now that everything has to be networked so that
| your fridge can advertise special offers to you the situation
| is changing for the worse.
| justinator wrote:
| There's a little more to it. If your original team retires
| because of old age, that's a lot of wisdom lost. Not everyone
| wants to learn COBOL to keep planes in the air and the IRS
| running, imagine needing to figure out the low level code on
| something millions of miles away with half the hardware broken,
| the battery cracked and leaking - and if the software update
| doesn't work, the entire mission is over?
|
| It's altogether amazing.
| deepspace wrote:
| The article calls software from the 90s "old". Nobody used
| COBOL for mission-critical software at that time. There is
| embedded software I wrote in the 80s and 90s still running in
| the field, mostly written in C.
| ericbarrett wrote:
| COBOL is really quite straightforward and readable. I don't
| think a developer who's already familiar with a modern
| language or two would have a hard time picking it up. The
| system it's operating is domain-specific knowledge anyway,
| and would be something a newcomer would have to learn (or be
| familiar with) regardless of language.
| JohnFen wrote:
| > Not everyone wants to learn COBOL to keep planes in the air
| and the IRS running
|
| But there's _excellent_ money in being a COBOL programmer.
| Some might be interested in that.
| hn_throwaway_99 wrote:
| Agreed. The older I get, the saltier I get when I read anything
| that refers to something from the 90s as "ancient".
| KineticLensman wrote:
| > Agreed. The older I get, the saltier I get when I read
| anything that refers to something from the 90s as "ancient"
|
| As someone who started programming in 1980, I feel your pain.
| My oldest spreadsheet goes back to 1995.
| JohnFen wrote:
| > it's just some old software from the 90s.
|
| What nonsense. the 90s is recent, not ancient.
| contingencies wrote:
| _The spacecraft doesn 't have a fuel gauge_ ...
|
| _Zoom call with 100 Airbus engineers_ ...
|
| _The original software for part of the onboard navigation system
| was running on a Windows 98 PC that no-one could find the
| password to and ended up using bolt cutters to extract the hard
| drives._
|
| Talk about a deep space horror story!
| dr_orpheus wrote:
| No spacecraft has a "fuel gauge" in the traditional sense. You
| don't have gravity to for a float to work like any fuel gauge
| in a car or airplane. Fuel is driven by surface tension and
| pressure rather than any buoyancy/gravity forces. These leads
| to the development of diaphragm type tanks where the
| pressurized bladder pushes fuel out of the tank or propellant
| management device (PMD) type tanks [0/1] that use the surface
| tension to guide pressurant-free fuel to the thrusters.
|
| So determining how much fuel you have left is done by a
| combination of integrating how much time you had thrusters
| firing, coupled with what pressure the tanks/lines were at
| while the thrusters were firing. Errors in these measurements
| accumulate over time which is why there is a lot of effort in
| to determining how much fuel is left in a spacecraft.
| Especially critical for things like big comm birds in GEO where
| fuel can be limiting in operation and the more fuel you have
| the longer you can keep station and get revenue from the
| satellite. But you need to still be conservative enough to have
| enough fuel to get out of the GEO belt for decommissioning your
| satellite.
|
| [0] https://en.wikipedia.org/wiki/Propellant_management_device
| [1] https://www.northropgrumman.com/space/pmd-tanks/
| RugnirViking wrote:
| I'm sure we'll get there eventually. But there is a fun idea
| in there somewhere about a future where the only need for
| manned spaceflight is so we can get pinged by the computer
| once every few days and go and hug/wrap a tape measure around
| the fuel bladder
| WalterBright wrote:
| The Apollo capsule didn't have a fuel gauge, either, because
| nobody could figure out how to make a fuel gauge work in
| weightless conditions. Various schemes failed. The solution
| turned out to be to have a reserve tank with enough propellant
| in it to do reentry. Then when the main tank ran dry, you knew
| just what you could do with what was left.
| barelyauser wrote:
| Since you know how much fuel you start with, can't you
| integrate something like the time spent firing the engine and
| use that as gauge?
| WalterBright wrote:
| I'm sure they thought of that, so there must be some reason
| why it is inaccurate.
| dr_orpheus wrote:
| Yes, and that is what most satellites due to estimate fuel.
| But any errors in that measurement can accumulate. See my
| other response on this thread for more details.
| WalterBright wrote:
| Why would anyone need bolt cutters to extract the drives? I
| have a couple Win98 PCs in the basement, and you just unscrew
| the drives. The password on it didn't encrypt the drives,
| either.
|
| As for the password, this is the old days. Could probably
| google how to crack the password for it. Or just try the
| classic 123456, querty, password, or letmein.
| mikestew wrote:
| _Why would anyone need bolt cutters to extract the drives?_
|
| I've had PC cases that had eyelets for a lock. You'd have to
| get through that before "unscrew(ing) the drives".
| WalterBright wrote:
| The drives aren't password protected. Why would one need to
| take the drives apart? Besides, the text was about
| extracting the drives, i.e. taking them out of the computer
| box.
| ubermonkey wrote:
| It's not immediatley on point, but the title reminds me that many
| here may enjoy the documentary about the Voyager team as it works
| today called It's Quieter in the Twilight.
| neilv wrote:
| > _Launched almost 46 years ago in 1977, the twin Voyager probes
| continue to send back data from beyond the Solar System._
|
| > _I checked with Nasa, which has assured me that the spacecraft
| are still being controlled from the same beige cubicle in an
| annex of its Jet Propulsion Laboratory (JPL) that I visited in
| 2017, marked with a homemade cardboard sign reading: "Mission
| critical hardware - PLEASE DO NOT TOUCH"._
|
| I throw around the term "mission critical" maybe too easily.
| Because that beige cubicle with the homemade cardboard sign
| sounds humbling.
| sillywalk wrote:
| Also NASA's infrastructure is crumbling, and 25% of workers are
| eligible for retirement.
|
| https://arstechnica.com/space/2023/08/nasas-buildings-are-ev...
| hilbert42 wrote:
| How about traveling-wave vacuum tubes from the pre-transistor
| era. Doesn't Voyager use them to generate its RF transmission
| power?
| 3pac wrote:
| It also has a vidicon tube for gathering images, although that
| can no longer be switched on.
| andyjohnson0 wrote:
| Yes, they're used in the rf power amplifiers. Both the X-band
| amps use tubes, and one of the pair of S-band amps does. The
| other is solid state. I don't know what drove this decision
| back then - they're presumably mission-critical so perhaps they
| were separately sourced.
| madengr wrote:
| [dead]
| AlanYx wrote:
| It does! But the really interesting thing is that travelling
| wave tubes are still being used for quite a few modern
| satellite designs. For example, SiriusXM used them in SXM-9/10,
| and is probably using them in SXM-11/12.
| dr_orpheus wrote:
| Yes travelling wave tubes are still very common on modern
| satellites. They tend to be used most on high power (>50W RF
| power)/high frequency (K-band and higher) systems. I don't
| know the exact rationale, but for space systems in the higher
| frequency and power regimes travelling wave tubes are still
| more reliable than solid state power amplifiers. Traveling
| wave tubes are still in the 40-50% efficiency range so
| they're not out of range with efficiency of some solid state
| devices as well.
| hilbert42 wrote:
| In recent years I've occasionally wondered what the type/part
| number of that TWT is. Given its history, its heater and
| cathode emission seems to have held up remarkably well.
|
| Another question I'd like answered, do the Voyagers cycle
| down or turn off the heater during TX downtime? Turning it
| off risks metal/cycling fatigue, leaving it on risks reducing
| the cathode life--or even poisoning it from stray ions.
|
| A final point, presumably the TWT's output has dropped over
| the decades, how is this monitored and do we know the
| percentage drop in power output (from the TWT not the Pu
| power source)?
|
| The fact the TWT is still working seems quite remarkable--but
| then perhaps I shouldn't be overly surprised, one of my TV
| sets, a 23" Sharp, is 43 years old and the CRT still works
| well (and it's switched on for several hours every day).
| CoastalCoder wrote:
| Slightly tangential, but if money were no object, do vacuum
| tubes or solid-state amps have a longer service life in this
| kind of application?
| dr_orpheus wrote:
| Theoretically, solid state amplifiers would have a longer
| service life. Vacuum tubes will always have cathode depletion
| causing them to degrade eventually (although this is pretty
| well controlled in most cases for long life). In space though
| the answer might become more complicated. Because the vacuum
| tubes are more tolerant of high voltages, they are probably
| also more tolerant of charge build-up and discharge from free
| electrons in space. Significant amounts of free electrons
| trapped in the second Van Allen belt that affects satellites
| in geosynchronous orbit (like a lot of comm satellites with
| big TWTAs). Less of an effect in deep space though.
| paulpauper wrote:
| space-x has taken over Nasa to some degree, i think
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