Voyager 2’s Discoveries from Interstellar Space (opens in new tab)

I know a person who worked on voyager. He is a very smart person who has contributed to a wide range of technologies over a long period of time. I have talked to him and the reality is that by the time that project was being done, the people who ran it had a lot of experience, and they applied the hell out of it to the project.

I've spent a lot of time since then looking into how to build reliable systems that operate for decades and... there are no easy answers. You have to have an amazing amount of knowledge about the engineering context (what's it like to run a computer in space), the scientific mission (IE, given this payload mass, what instruments can we fit), judicious software engineering skills (just updating the firmware on a machine that's millions of miles away is a challenging problem, worse yet if updating the firmware bricks your control plane), project management skills (to ensure you make your launch date), and the dedication to keep things going long after most people got bored of them.

After a long time playing with complicated systems I went back and played with 8-bit microcontrollers and they were actually really fun because it forces you to build systems that are reliable without a terminal and resource constrained (you'd have a hard time fitting a program as large as this comment into an arduino...)

Voyager 1 is 0.00234 light years from Earth, Voyager 2 is 0.00194 ly. Or in more useful units: 20.5 and 17 light hours.

Also we do not receive images any more (the cameras were made for planetary encounters and have been turned off long ago).

But yes, getting data (at 160 bits per second) from man made objects that are the better part of a light day away is impressive. Even more so because they have been working for 42 years now, 30 years past the initial planetary mission.

I used to have it in my head that the Voyager probes were about as powerful as an Apple II computer. But it's hard to make a direct comparison as the probes have three computers made of two processors each, running at 1/20th or 1/6th the speed of an Apple. So it's not a one-on-one comparison in any way, but for discussion purposes:

An original Apple II used a MOS 6502 8-bit word CPU clocked at 1.023 MHz and typically had 4Kb to 48Kb of RAM. It ran about 500,000 instructions per second [1].

Computer Command System (CCS) - two 18-bit word interrupt-type processors with 4096 words each of plated wire memory. It ran about 25,000 instructions per second. [2]

Flight Data System (FDS) - two 16-bit word machine with modular memories and 8198 words each of memory. It ran about 25,000 instructions per second. [2]

Attitude and Articulation Control System (AACS) - two 18-bit word machines with 4096 words each of memory. The AACS ran about 80,000 instructions per second. [2]

So maybe the total amount of computing power is equal? The total memory on a Voyager was about 32K [3], and since the word sizes were bigger, theoretically they could access larger chunks of memory in a single instruction? What's for sure is that a single CCS is at least an of magnitude less powerful than an Apple II.

More info:

1) http://www.classiccmp.org/cini/pdf/Apple/Apple%20II%20Refere...

2) http://www.cpushack.com/space-craft-cpu.html

3) https://web.archive.org/web/20110721050617/http://voyager.jp...

Just FYI nothing man made is even close to light years away from the Earth.

EDIT: I don't understand the downvotes. Isn't this just fact?

EDIT 2: I see the OP changed his original comment, so I can understand the confusion. Thanks all :)

Imagine the systems that they worked with.

In the 1970s, dealing with primitive electronic systems, often without screen and most definitely without a full OS.

Goosebumps. To imagine that the tech phenomenon that we can only regard as recent (2000-) but there are people from as far as 30 years back before that, working on things that have lasting impact to us.

I recently read bwk's Unix history and memoir, it's a great read, to see many of these pioneers being old and passed away is a great sadness.

My favorite part is how everyone is jumping down your throat over a simple mistake in what was meant to be an expression of awe and admiration.

Voyager 1 is about 0,0023409 lightyears away from earth (voyager 2 is a bit closer than that).

https://voyager.jpl.nasa.gov/mission/status/

Related, and relevant: https://en.wikipedia.org/wiki/Pale_Blue_Dot

Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there--on a mote of dust suspended in a sunbeam.

The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds.

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand.

It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known.

— Carl Sagan

Yes, the notion of engineers knowing what they are doing and actually creating a reliable system seems to be largely alien to the HN crowd.

Anyone has any details of how its implemented ? Arch diagram of some sort ?

Voyager 1, the most distant probe, is about 0.002 light years away from the earth.

FYI Voyager 1 is about 20 light hours away.

Yeah but did they use Agile methods and have good team velocity as they burned down the backlog? If not, how can we really be sure the project was a success?

The irony is that without the practical experience of those intermediate steps, you might never reach the point where the diminishing returns become negligible.

You're basically describing the reverse of Zeno's paradox - the "why bother" paradox.

This is a fairly common trope in SciFi settings which have Generation Ships.

Some time after the ship gets launched (centuries, even), FTL gets developed. Then they either arrive and find a civilization at their destination, or they are considered to be off-limits and not to be messed with, depending on the setting.

That assumes such improvements are even possible.

At least for non-magical propulsion, we don't really need "faster" engines. Take whatever engine you want, let's say it can accelerate at a constant 1g. In less than 4 years(from an observer standpoint), you are at 97% of lightspeed. From your point of view, that would take less than two years.

If you can have an engine that can accelerate at a constant 1g for years (fueling it is left as an exercise for the reader), then you are all set. You can go anywhere in the galaxy inside a human lifespan – of course, assuming you don't care for the people left behind.

If you want to accelerate at more than 1g, there may be physiological issues.

One fairly decent argument against waiting until we have the technology is that it cuts against how we develop the necessary technology in the first place. We can't improve our propulsion/spacefaring tech without designing, building and launching spacecraft. There's absolutely no reason to assume that we will have invented a faster engine if we've just been sitting around for 100 years not building anything. Hell, we're having trouble rebuilding a moon program fifty years after Apollo 11, inspite of all the advances that have happened in the meantime.

It is covered in this Wikipedia article. It is called 'the incessant obsolescence postulate'. https://en.wikipedia.org/wiki/Interstellar_travel

"It has been argued that an interstellar mission that cannot be completed within 50 years should not be started at all. Instead, assuming that a civilization is still on an increasing curve of propulsion system velocity and not yet having reached the limit, the resources should be invested in designing a better propulsion system. This is because a slow spacecraft would probably be passed by another mission sent later with more advanced propulsion (the incessant obsolescence postulate)"

You can't get faster engine without having slower one first.

How do they even know what to improve upon without building it and experiment with it?

Also simulation is not a replacement for real world testing. They should launch stuff into space to figure out if it works and their simulation is making the correct assumptions.

Also I'd imagine these launches are sending back valuable data that they can use to make adjustment and improvement for future engines.

"Why should I buy a computer today, when a computer in 10 years can do a ton more for less money?"

> Quite likely you can keep doing this until you can reach it in e.g. a year

Given that Alpha Centauri is 4 light-years away, this is a fairly bold speculation.

It has been 47 years since a person walked on the moon, so it might just be a good idea to do something when you can and not wait for it to be possibly easier to do in the future.

This is why I didn't invest in solar yet. Even with subsidies, it looked to me like they would take far more than double the time to pay for themselves than it would for the price to cut itself in half based on current trends. Might as well wait a few years.

I believe it's called the "wait calculation".

Unfortunately we have not sent any for 40 years ... the speed is not but the data collection power may be improved exponentially until recently.

We cant reach it in a year because it is more than 4 light years away.

Innovator’s dilemma

Thanks but only for American

Voyagers 1 and 2 took advantage of a fleeting phenomenon - an alignment of all the outer planets that allowed successive gravity assists, and so let us send probes out to those planets and then on to escape velocity with a very small launcher/budget. These come around every 175 years, so the next point at which solar system escape will be that easy is around 2150.

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

All the ideas thrown around for follow-on missions have relied either on very powerful boosters (on the scale of SLS), smaller probes (New Horizons, a bit over half the size of the Voyagers and on a much lower-energy trajectory, despite a more powerful launcher), or an Oberth maneuver close to the sun in a very challenging thermal and radiation environment.

The problem is we can't launch another Voyager mission. The Voyagers took advantage of the planets being aligned in just the right way to allow them slingshot through the outer solar system. This won't happen again for another 100 years or so.

Now we could design probes that are just for going into interstellar space but it would be a hard sell when you are competing against missions like sending a drone to Titan. Even the New Horizons mission to Pluto barely made it through NASA's project selection process and IMO expanding our knowledge of Pluto is more valuable (and sellable to the public) than a mission to literally nothing.

New Horizons can and may do exactly that.

http://pluto.jhuapl.edu/Mission/2019-Onward.php

"Future New Horizons extended missions, if funded by NASA, could explore even farther out. The spacecraft is on an escape trajectory from the Sun, traveling about three astronomical units per year. Moreover, New Horizons and its payload sensors are healthy and operating perfectly. The spacecraft has enough power and fuel to operate into the mid-2030s or longer, perhaps enough to reach the boundary of interstellar space."

The cynic in me thinks that there is little marketing value in throwing probes into the void, whereas landing and taking pictures of “the new frontier” can be sold to the (taxpaying) public more easily.

Keeping you alive for the kinds of durations that matter (that is decades) won't be technologically or economically possible for the present.

Is there a reason why the left side of the heliosphere is so elongated?

Is it simply because we haven't sent any probes there and so don't really know where it ends or is it really this oblong shaped?