NASA engineers make progress toward understanding Voyager 1 issue

Shouldn’t this software archeology have been done decades ago?

I have found that even the group I'm in being documentation-heavy, it's hard to read through everything and build the same context that another engineer has all stuffed into their head.

As you mention:

> available and searchable digitally.

Even with 100% everything written down, it takes a while to build up that context, and even carefully written documentation can have subtleties which send a consumer the wrong way.

Things are a lot easier than they used to be, but still not easy-easy.

>The project was not really designed to reach interstellar space originally.

Not only that, Voyager 2's flyby of Uranus and Neptune in the late 1980's was originally not intended either. As an aside, to this day Voyager 2 remains the only spacecraft to ever have visited either planet, and there are no firm plans for a followup, just some loose ideas about maybe launching something in the mid 2030's. Anyway, doing the Uranus/Neptune part of the mission required extensive software upgrades, which introduced Reed-Solomon error correction and image compression capabilities, among other things - the software as launched would not have been capable of a meaningful mission to Uranus and Neptune.

These days the Voyager program is lauded as an astonishing feat of engineering and one of the most inspiring science and engineering achievements of all time, but in the early 1970's the entire idea was NASA's red-headed stepchild and ended up cut down to a bare minimum. The Grand Tour mission concept (taking advantage of the extremely rare opportunity to visit Jupiter, Saturn, Uranus and Neptune in a single mission) was pitched as early as 1965, and by the early 1970's there were plans for launching four spacecraft, two bound for Jupiter-Saturn-Pluto and two bound for Jupiter-Uranus-Neptune. These were referred to as TOPS, Thermoelectric Outer Planets Spacecraft. But then people started complaining that it might cost a billion dollars (Apollo had cost $25 billion) and the whole thing became intensely political. Quoting from Voyager: The Grand Tour of Big Science (https://www.nasa.gov/history/SP-4219/Chapter11.html) by Andrew J. Butrica:

> Further complicating matters was Senator Clinton P. Anderson (D-NM), champion of the Los Alamos nuclear weapons laboratories and an enthusiast, until his retirement in 1973, of the development of a nuclear rocket engine called NERVA. As chair of both the Senate Aeronautical and Space Sciences Committee and the joint Atomic Energy Committee, Anderson provided NASA and the Atomic Energy Commission over $1.4 billion, about $500 million of which was spent in Los Alamos, for the development of the NERVA engine, which, Anderson held, was ideally suited for exploration of the outer planets, as well as for more advanced missions. Anderson worried that NASA and the OMB were shifting money from NERVA to fund Grand Tour. When the NASA budget came before Anderson's Aeronautical and Space Sciences Committee on May 12, 1971, his committee voted five to two to reduce Grand Tour's budget, while an amendment to increase NERVA funding passed. Werner von Braun worried that ardent congressional interest in NERVA would force a loss of Grand Tour in favor of a NERVA that had "no place to go."

> Meanwhile, NASA was trying to include Grand Tour as a new start in its 1972 fiscal budget. The Friedman report moved the Office of Management and Budget (OMB), in March 1971, to ask NASA to study simpler, less costly spacecraft alternatives to TOPS. The OMB also attempted to delay the Grand Tour start-up to fiscal 1973.

> (...)

> As NASA prepared its fiscal 1973 budget, rumors spread that the "budget pinch" was going to affect planetary programs deeply and that the reduction of the Grand Tour payload from 205 to 130 pounds was "a likely fact of life." Furthermore, Grand Tour now began to compete for funding with the latest NASA human program: the Space Shuttle. The fiscal 1973 budget request NASA submitted to the OMB on September 30, 1971 included both Grand Tour and the Space Shuttle. Throughout the autumn of 1971, several press reports presciently reported Grand Tour's vulnerability to a possible elimination or reduction. On December 11, 1971, James Fletcher, NASA administrator since April 27, 1971, learned from White House officials that Nixon was prepared to approve the shuttle program and that Nixon would not let NASA simultaneously fund the shuttle and the full TOPS Grand Tour in the 1973 budget or in subsequent fiscal years. Fletcher had to decide which was more important: Grand Tour or human flight.

Fletcher chose the shuttle, and what could be squeezed into the budget was an extension of the Mariner program to visit Jupiter and Saturn only. For budget reasons the spacecraft development was kept in-house at JPL rather than contracted out, and at JPL the dream of the full Grand Tour was still alive:

> Despite the limited aim of the Mariner Jupiter-Saturn, the mission had the Grand Tour launch window, that rare planetary alignment, and the engineers at JPL still had every intention of building a spacecraft that would last long enough to visit Uranus and Neptune. This intention was not emphasized; however, it was stated that a Mariner Jupiter-Saturn spacecraft might continue to Uranus if its mission at Saturn proved successful. The scientists working on the project knew that Mariner Jupiter-Saturn was going to go to Uranus and Neptune, too. As Bradford Smith, Leader of the Imaging Team, explained: "We understood at the time the enormous potential of this mission, that it could very well be one of the truly outstanding if not the most outstanding mission in the whole planetary exploration program."

Also for budget reasons, the spacecraft were limited to mostly reusing existing technology. Getting reprogrammable computers (without which they could never have been kept alive in the way they have) required a separate budget grant from Congress:

> Despite the reliance on extant technology, some money was set aside to develop new technology. Congress and the OMB approved an additional $7 million to the Mariner Jupiter-Saturn appropriation for scientific and technological enhancements. Part of that appropriation went to develop a reprogrammable onboard computer, which proved vital to maintaining Voyager 2 as a functioning observatory in space. Without properly functioning hardware, no science could be conducted.

In the end only Voyager 2 was launched on the full Grand Tour trajectory that would allow visiting all of Jupiter, Saturn, Uranus and Neptune; Voyager 1 was launched on an easier and much faster trajectory that would take it only to Jupiter and Saturn. Even then, the official decision to extend the Voyager 2 mission to Uranus was only approved in 1980.

Human spaceflight and its enormous appetite for money has always been a huge threat to actually exploring the solar system beyond Earth orbit, and we should be very glad we got even the very diminished Voyager program that exists today.

Haha look at this guy, thinking you can trust the docs. ;)

The Voyager software was updated repeatedly and significantly in flight while the spacecraft were still in their early years. They were very intentionally designed to be patched over the course of the mission. The software as launched was not capable of a meaningful mission beyond Saturn, because for budget reasons that was officially not on the cards at launch (the Voyager name came very late; the program was officially "Mariner Jupiter-Saturn" for a long time). Features like image compression were added in the early 1980's, after Voyager 2's mission extension to Uranus and Neptune had been approved.

Without any inside information on the program, I would expect that a lot of development has been done more or less ad-hoc over the decades, as budgets have allowed and operational requirements demanded.

> they didn't know how to do software engineering like we do.

Yes, luckily. If they did, it would have broken after four years, and would have needed a second nuclear battery due to the inefficient code.

Oh Nooooo! Bezos won't be able to make his yacht payments now!! Won't you think of the starving billionaires before making your kneejerk reactions. Nobody wants to be humiliated and drop out of the 3 commas club

It has to start somewhere, and for many of us, that somewhere is in individual decisions.

Interacting with Amazon is increasingly feeling like being worked over by a seedy breed of con artist. I just missed a good price (circa 25% off the normal price) because -- best guess -- a driver failed to deliver and now my order is stuck in their "running late" limbo that will see it eventually cancelled. It's hardly the first time, exactly this scenario of an abnormally good price effectively lost, and no call to customer service can fix it. In fact, the driver missed the delivery story is the explanation I've read somewhere, but the unerring correspondence with very favorable pricing leaves me feeling suspicious.

I commend your decision, and your awareness of its impact.

It's a shame we probably live too early for cryogenic freezing to work, either.

In reality, they would wake up to find themselves in a landfill as everyone just forgot what those funny boxes were for and got rid of them.

The HTC is the opposite of the cryogenic freezer or relativistic chamber - it accelerates time for people inside it, allowing you to meet external deadlines while the world passes by slowly outside. A cryo freezer or relativistic spaceship decelerates time for people inside, allowing external activities to be accomplished while you don't age.

This is about a time chamber that works in the opposite direction.

It'll be a good year for planetary astronomy anyhow.

From my perspective microprocessor grew up around the general purpose computing model. Now the microprocessor power has far outpaced the the actual human needs the focus on general purpose is inefficient.

I see efficiencies to be gained in the overall integration of very task specific computers in common network.

I don't think a key fob is a good example. I think if you look at what goes into word processing for the average office or almost any other office task would be my example.

My point is that early on general purpose computing was needed to drive the cost of computing down. I think we are past that stage and it is now time to look at making everything as simple and efficient as possible.

I could see them being impressed with the human achievements. I have doubts if they would be impressed by the engineering. Everything I see looks more like the results of human hours spent.

Consider giving those old timers the same problem with todays resources and I think we would get great results.

Compared to voyager I see that as more of the same and almost disposable.

I have a large collection of technical documentation and physical artifacts of the same computer implemented as discreet components amd integrated circuits. The company had to invent the lithographic process to print circuits.

So ASML is very impressive but could also be seen as a derivative idea.

I'm going to just outright dismiss this comment the way you're dismissing people talking about capitalism, a very real economic system we're all living under, since it's ridiculous on its face.

Why do companies do that? Shouldn't it be enough that you have experience contributing to a large project long-term and you can program decently? Is it that modern programming just requires different/additional programming skills compared to most old codebases, like writing asynchronous code?

I don't hire, but that story would make me want to hire you. It takes certain skills and pig-headedness to successfully work on old software!

I once asked a company to rehire me saying that I only wanted to do software maintenance work (I wanted low stress). I am good at it, and it's hard to find people that want to do that work. They didn't rehire because although the manager really wanted me back, his idiot boss had taken it personally when I had quit. Idiot boss later got ousted to their dismay: I shouldn't enjoy that but I did!

It is known as error handling. Some languages renamed the practice to try/catch. Others added a Result type.

I would love to read the full story on this.

Any details? We have people work on a dead moon lander…why not a live v1/2. If sadly one is dead, the other still has some life left ?

As far as I can tell the HDC-402 wasn't even the Viking computer that got reused on Voyager anyway - it was something NASA developed in-house from the orbiter side of the Viking mission and that presumably has even less documentation available.

I’m not sure why that would be the case. If anything, I’d expect earlier code to be easier to hack.

One of the Best Practices for maintaining software that you expect to support for decades involves archiving the development tools used.

Of course, finding a platform to run it on could be a problem. Also, the License Server that so many proprietary tools need before they'll run.

The timeframe described would work for something written for a System/370, no? That stuff, along with the tooling, will run all day long on a current Z Series.

Well, my grandpa didn’t know jack about computers, so I very well could have maintained code he’s written based on the disquality of stuff I’ve had to work on in the past.

But yeah. In “A Fire Upon the Deep”, Vinge talked about archaeological programmers. There’s no doubt in my mind we’ll reach that point. “Tell me again why time_t is only 64 bits?” “Pull up a chair while I dig out the LKML archive. You know, this was originally stored in electric fields, if you can believe it!”

Probably, but why’s that spar here? Why did they route that wire around the screw, and why doesn’t the 1960s bomb sight work right if the wire’s only twisted 3 times instead of 4?

Yes, but I don't get your point.