
After 37 years, Voyager has fired up its trajectory thrusters - lisper
https://arstechnica.com/science/2017/12/after-37-years-voyager-has-fired-up-its-trajectory-thrusters/
======
botskonet
Voyager is probably the _most_ badass awesome thing ever.

Every single aspect of space travel is an engineering/mathematic/scientific
marvel. Not only did we plan, build, launch these, (before I was born) but
we're still communicating (until we can't).

I'm reading links people have posted here, trying to understand _how_ we
communicate with these probes. It's fascinating.

~~~
userbinator
What I find more amazing is the fact that a lot of what could be referred to
as "space-age technology" is actually many decades old, and thus was
accomplished with a fraction of the processing power and knowledge we have
today. Voyager was launched in the late 70s, but based on technology of the
50s and 60s. We visited the Moon almost 50 years ago, using that technology.

If you look at old spacecraft hardware, one thing that stands out is its
apparent simplicity and down-to-earth (no pun intended) design --- and I'd
argue that this is at least partially responsible for its extreme reliability.

From that perspective, I feel as though developments in modern technology just
can't compete for impact; we constantly search for new ways of designing
things, wrapping ourselves in endless layers of abstraction and high-level
thought, yet aren't really "getting off the ground" and _accomplishing
something concrete_ , so to speak.

~~~
matthewmacleod
_From that perspective, I feel as though developments in modern technology
just can 't compete for impact; we constantly search for new ways of designing
things, wrapping ourselves in endless layers of abstraction and high-level
thought, yet aren't really "getting off the ground" and accomplishing
something concrete, so to speak._

I’m not really sure this is true, though I understand why it might feel that
way sometimes.

I’m currently travelling at about 180mph on board a high-speed train in Japan.
I flew here on a jet which is something like 20% more efficient than the
equivalent from a few years ago. Using the ubiquitous LTE network, I can make
a real-time HD video call to my family back in the UK, using my palm-sized,
battery-powered computer. I used the same device earlier to do some research
about cities as we passed through them, and also to check the CCTV system at
home. Over the past couple of weeks I’ve used a similar technology stack to
locate my position to meter-level accuracy, to read and translate foreign
language text from images in real time, and to record hours of 4K video.

Modern technology is _astonishingly_ powerful - and in some ways, the examples
I described above are even more impactful to me on a day-to-day basis than
space exploration is. Don’t get me wrong - the latter is still important and
exciting! But it’s sometimes too easy to forget the impact of the somewhat
more mundane technology that’s all around us.

~~~
Teichopsia
You may have missed the last word of his previous sentence. _reliability_.
Which is at least to me, the way I understood it.

Something built back then _and_ still works.

Edit: fix markdown syntax.

~~~
djsumdog
But they're different systems, designed very differently. A high speed train
and a space craft are both designed carefully to maximize their possible life.
A cellphone is, unfortunately, been phased into the economy of consumption and
planned obsolescence.

Consumer electronics from a few decades are not quite cellphones, but not
quite high speed trains or nuclear reactors or space rockets. Many old C64
systems still work or can be restored, and I bet most of our current high end
laptops will continue to work a decade from now (you might need to replace the
battery).

The OP might have been talking about efficiency, and we have gotten a bit
sloppy with that in the consumer world (why does Slack/Atom/Discord need to be
a 100MB+ app bundled with its entire web browser and framework? It's like
we're in the 2000s with 15 copies of the JDK on your system again!), but once
again .. different uses.

A modern SpaceX craft is going to have custom real time operating systems
designed specifically to preform much more complex calculations than we've
done in previous space missions, hopefully increasing reliability and the
amount of sensors we can read, record and transmit data for. The software
engineers might be less space efficient in their code than the previous
generation, but if the hardware is cheaper and we can increase readability at
the expense of memory, why not do it?

In Kim Stanley Robinson's Mars trilogy (highly recommend; best Sci-Fi I've
ever read), humans eventually create AI so complex it can manage space
factories designed to build from asteroids. The most advanced AI ever created
is used to maneuver an asteroid into orbit of Mars while also mining the
interior and constructing the cable that would eventually turn into the space
elevator over the course of a decade.

~~~
nojvek
Will deffo check the book out.

Electronics aside, voyagers nuclear energy supply fascinates me.

I'm still very optimistic that someday we'll figure out safe micro nuclear
reactors.

The energy density of nuclear fuel is just amazing.

~~~
branko_d
Marry such a nuclear reactor to something like VASIMR engine, and suddenly the
entire Solar System opens-up to us.

------
Reason077
For anyone with an interest in Voyager, I highly recommend Emer Reynolds film,
"The Farthest". This documentary is brilliant, beautiful, and funny - and I
guarantee that you will learn something that you didn't know about Voyager!

For those in the UK, it's currently streaming on iPlayer - though it should
ideally be seen in cinemas to be fully appreciated.

[http://www.imdb.com/title/tt6223974/](http://www.imdb.com/title/tt6223974/)

~~~
sbmthakur
Torrent link for where it's not available:
[https://1337x.to/torrent/2379692/The-Farthest-2017-WEB-
DL-x2...](https://1337x.to/torrent/2379692/The-Farthest-2017-WEB-
DL-x264-RARBG/)

~~~
teddyh
.onion link to torrent:

[http://uj3wazyk5u4hnvtk.onion/torrent/18374376/The.Farthest....](http://uj3wazyk5u4hnvtk.onion/torrent/18374376/The.Farthest.2017.DOCU.1080p.WEB-
DL.AAC2.0.H264-PreBS)

Magnet link:

    
    
      magnet:?xt=urn:btih:cb7b9a2f7f318c9f84da467e3963c0fd8a31eb3d&dn=The.Farthest.2017.DOCU.1080p.WEB-DL.AAC2.0.H264-PreBS&tr=udp%3A%2F%2Ftracker.leechers-paradise.org%3A6969&tr=udp%3A%2F%2Fzer0day.ch%3A1337&tr=udp%3A%2F%2Fopen.demonii.com%3A1337&tr=udp%3A%2F%2Ftracker.coppersurfer.tk%3A6969&tr=udp%3A%2F%2Fexodus.desync.com%3A6969

------
ramshanker
So, they have all the codes and manuals to be able to control the probe after
37 years. More than that people able to operate those manuals.

DOCUMENTATION FTW.

~~~
DerfNet
Meanwhile, after two years my Android phone will brick itself.

~~~
Florin_Andrei
> _Meanwhile, after two years my Android phone will brick itself._

I understand the sentiment, but your phone was not made to exit the solar
system.

~~~
djsumdog
But they should be .. or at least last as long as an old C64. You can put
newer Windows on pretty old hardware, and for really old hardware you can
always slap Linux on and it will still be useful. There are still Kernel forks
to support 386 processors!

Cellphones are a mess because we can't even have a nice base hardware
platform. ARM isn't a platform. It's a SoC spec with random shit soldered to
random pins by different vendors with completely non-upstreamable kernels.
Google could just mandate UEFI on OHA phones like Microsoft did with theirs,
but instead we're just getting this /vendor partition in the next release.

I don't think it's unintentional either. It's an aspect of planned
obsolescence. The cellphone industry wants you to upgrade every two years,
when we should not be destroying the planet and creating gear that lasts 10
years. Fewer factories, less pollution, longer life .. but we're in a
consumerist economy hardwired the opposite direction, where any type of profit
shortfall or lack of growth is seen as a problem, not the result of a good
product.

~~~
pbhjpbhj
Agreed, but if a public company makes stuff to last 10 (why not 20) years then
they'll go bust because capitalism requires profit and sustainable ideals are
contrary to profit.

What we need is a privately held cellphone company that will forgo profit in
favour of creating long lasting, repairable, maintainable devices. [I've been
working on this thesis for the transition from capitalism to communism]

Meanwhile I'm wearing a 25 year old tshirt, whilst tshirts bought much more
recently wear out and get holes in.

------
nebulus
In the Epilogue of "Murmurs of Earth" (1978), Sagan writes:

"It is a difficult computer task to calculate what stars might by chance be
along the Voyager spacecraft trajectories 50,000 or 100,000 years from now.
Mike Helton of the Jet Propulsion Laboratory has attempted to make such a
calculation. He calls attention in particular to an obscure star called AC+79
3888, which is now in the constellation of Ursa Minor -- the Little Bear, or
Little Dipper. It is now seventeen light-years from the Sun. But in 40,000
years it will by chance be within three light-years of the Sun, closer than
Alpha Centauri is to us now. Within that period, Voyager 1 will come within
1.7 light-years of AC+79 3888, and Voyager 2 within 1.1 light-years. Two other
candidate stars are DM+21 652 in the constellation Taurus and AC-24 2833 183
in the constellation Sagittarius. However, neither Voyager 1 nor Voyager 2
will come as close to these stars as to AC+79 3888.

"Our ability to detect planetary systems around other stars is at present
extremely limited, although it is rapidly improving. Some preliminary evidence
suggest that there are one or more planets of about the mass of Jupiter and
Saturn orbiting Barnard's star, and general theoretical considerations suggest
that planets ought to be a frequent component of most such stars.

"If future studies of AC+79 3888 demonstrate that it indeed has a planetary
system, then we might wish to do something to beat the odds set by the
haunting and dreadful emptiness of space -- the near certainty that, left to
themselves, neither Voyager spacecraft would ever plummet into the planet-rich
interior of another solar system. For it might be possible -- after the
Voyager scientific missions are completed -- to make one final firing of the
onboard rocket propulsion system and redirect the the spacecraft as closely as
we possibly can so that they will make a true encounter with AC+79 3888. If
such a maneuver can be effected, then some 60,000 years from now one or two
tiny hurtling messengers from the strange and distant planet Earth may
penetrate into the planetary system of AC+79 3888."

We know so much more about exoplanets today than we did in Sagan's time, and
have so much more computing power to bring to bear. Knowing the trajectory
thrusters still work, it would be a fitting tribute to try one last
interstellar bank shot into the corner pocket, and see if we couldn't honor
Sagan's last wishes, and give the Voyagers a destination worthy of their
journey and their cargo.

~~~
kgilpin
60,000 years ago, humans were just leaving Africa. So I would be impressed if
60,000 years from now, anyone remembers that Voyager is still out there!

~~~
MarkMc
I really wish I could see the progress humans make over the next 60,000 years.
Shout out to all my ancestors in 62017!

~~~
Narishma
I think you mean descendants.

~~~
rezwrrd
There was an accident involving a contraceptive and a time machine.

------
ridgeguy
Kudos to Aerojet Rocketdyne on their thrusters lighting up after 37 years.
That's genuinely impressive engineering.

Certain Volkswagen models apparently have an even more amazing MTBF. It's a
real sleeper. [1]

[1]
[https://www.youtube.com/watch?v=Xo2kSu6O8cU](https://www.youtube.com/watch?v=Xo2kSu6O8cU)

But Voyager's got it beat on mileage...

~~~
oh_sigh
Not just 37 years, but 37 years in near absolute temperature.

------
monster_group
Can somebody with knowledge of radio communication explain how we are able to
send a radio signal to a destination that is 21 billion Kms away? How powerful
does the signal need to be? What kind of technology is used to generate such a
powerful signal?

~~~
InclinedPlane
There are high gain antennas on both ends, and use of error correcting codes,
as well as _extremely_ high grade low noise amplifiers on the Earth side.

The Voyagers have a 3.7m diameter parabolic radio dish, larger than the Hubble
space telescope's mirror even. That alone provides a huge amount of gain on
communications. Additionally, the spacecraft have 10s of watts of power
available for transmitting signals, which is a fair bit considering (while on
the other end the ground stations have up to hundreds of thousands of watts to
transmit). The ground-stations in the deep space network (DSN) are tens of
meters across, a small antenna is 34m, the biggest ones are 70m across. That
also provides a _huge_ amount of gain alone. It means that there is more area
to collect signals from the spacecraft and it means that the beam from the
ground station to the spacecraft is much tighter, concentrating the total
transmission power into a smaller cross-sectional area at the distance of the
spacecraft.

The spacecraft also uses error correcting codes, which involve transmitting
many more bits than the underlying data, but in such a way that errors due to
noise are not only detectable but correctable.

On top of all of that you have the state of the art low noise amplifiers in
the DSN antennae. A typical low noise amplifier is a carefully built
electronics assembly made by experts. The DSN amplifiers? They use 99.95%
purity ruby rods chilled to 4 degrees above absolute zero to form microwave
MASER based amplifiers.

There's a neat little video (series) here on the DSN and contacting the
Voyagers:
[https://www.youtube.com/watch?v=FzRP1qdwPKw](https://www.youtube.com/watch?v=FzRP1qdwPKw)

~~~
femto
There's also a neat book for those interested in the engineering details of
their receivers:

"Low-Noise Systems in the Deep Space Network" Edited by Macgregor S. Reid

[https://descanso.jpl.nasa.gov/monograph/series10/Reid_DESCAN...](https://descanso.jpl.nasa.gov/monograph/series10/Reid_DESCANSO_sml-110804.pdf)

It's published by the JPL as part of the "Deep Space Communictions and
Navigation Series". The rest of the books in the series, listed in the book's
front matter, have some fascinating titles.

------
sohkamyung
Remarkable. I'm vividly reminded of that scene in the movie, Apollo 13, where
this is said: _[Gene Kranz:] I want you guys to find every engineer who
designed every switch, every circuit, every transistor and every light bulb
that 's up there. Then I want you to talk to the guy in the assembly line who
actually built the thing. Find out how to squeeze every amp out of both of
these goddamn machines._

NASA has a remarkble group of engineers who know how to get every last erg of
energy out of that machine.

~~~
botskonet
I think Apollo 13 did a lot to show what talented engineering teams can do.
They also didn't shy away from real terminology and rarely stopped to explain
it. No other movie has done that in my experience.

------
jacquesm
Very impressive. Every day still the envelope of what mankind has touched is
still expanding because of this craft. It's a tiny mark on a vast universe but
for some unspecified reason it makes me feel very happy to know that it is out
there and still ticking, I am not looking forward to the day that it
eventually will shut down but even as an inert man-made mass that far out it
will be an amazing accomplishment.

~~~
lvspiff
I am not looking forward to the day when it somehow returns, starts blowing up
star ships, ultimately taking over one of them, and tries to seduce the crew

~~~
hota_mazi
That's actually the plot of the first Star Trek movie (without the seduction
part).

[Spoiler below, hopefully not a huge deal for an almost forty year old movie)

Voyager returns under the name v-ger.

~~~
jcims
Back in the early 90's I wondered why so many Unix boxes had 'vger' in their
name. Not until this year, when I watched the original Star Trek with my
youngest, did I realize what it was all about.

Sad thing is I saw the movie in the theater when it was first released...just
didn't put the two together.

~~~
noir_lord
The first two Linux machines I ever had to admin back in the 90's where called
Picard and Kirk (Picard was the primary, Kirk the secondary (no guessing which
series I preferred)).

The NT machine was called Locutus.

~~~
ajmurmann
The "Locutus" is so perfect!

------
emptybits
The round-trip request/response time for a command is 39 hours (!) ... I guess
the team has normalized to that latency, but when asking a system to fire with
paths of execution plus hardware plus propellant/etc that haven't been used
for 37 years ... I can only imagine the tension and celebration.

Related question ... can an easily amateur listen to response transmissions
like this that come back from probes?

~~~
ohazi
I had a chance to visit the Deep Space Network facility at Goldstone several
years ago (definitely worth a visit if you can arrange one). The antennas they
use vary in size from 26 to 70 meters in diameter, and even then they need to
use lots of process gain because the signal is still several dB below the
noise floor. Amateur tracking would probably be incredibly difficult.

~~~
PoachedSausage
You will definitely want to be doing cryogenic cooling of your receiver front-
end to reduce the noise figure[0].

[0]
[https://en.wikipedia.org/wiki/Noise_figure](https://en.wikipedia.org/wiki/Noise_figure)

------
soheil
In the spirit of what this community's name suggests it's about, how hard
would it be for someone to hack into the spacecraft by sending it a signal to
turn on its thruster too soon given the technology is 40 years old?

Has anything like this been tried before with other spacecrafts?

~~~
ewams
Know the big dish from James Bond? Used legit:
[http://observer.com/2014/08/civilians-in-abandoned-
mcdonalds...](http://observer.com/2014/08/civilians-in-abandoned-mcdonalds-
seize-control-of-wandering-space-satellite/)

~~~
rurban
Nope, Arecibo is not used for this. The Chinese FAST would be perfect for this
also.

~~~
ewams
You are correct this wasn't the article I was looking for, didn't read it to
verify. I can't find it now but 1-2 years ago some people used that dish to
reactivate a "lost" satellite that had not been used for several years.

------
muxator
Wild engineer's dream: where can I work on something of the same coolness
level? High scientific content, total quality, no compromises whatsoever.

~~~
ISL
I'll burst the quality bubble now:

There were absolutely compromises, and the engineers who shipped it knew
myriad ways in which it could be better.

To answer the question:

Find something you think is equally cool, learn what you can about the field,
be open to the possibility of a pay cut, and start knocking on doors.
Sometimes doors open. Work really hard when they do.

~~~
InclinedPlane
Two months before the Voyager probes were shipped for launch it was found out
that Jupiter's magnetic fields and radiation environment were a lot stronger
than anticipated, in excess of what the spacecraft were designed to tolerate.
They ended up wrapping many of the cables on the spacecraft with aluminum foil
bought from a local supermarket as a protective measure.

------
outside1234
I love that every time I read one of these articles it is extending the life
of the mission by 2-3 years. :)

My favorite use of tax dollars ever.

~~~
elliotec
What do you mean? Any context here?

------
mark-r
When you're far enough from the sun to avoid thermal cycles, in the vacuum of
space, what forces will cause things to deteriorate? If I wanted something to
last forever, deep space would be the perfect place for it.

~~~
ISL
\-- It is a tough radiation environment. Materials are embrittled and altered
over time.

\-- Many materials age on their own; plasticizers outgas from plastics. You're
probably familiar with how once-pliable but now old/aged plastics, even kept
sealed in a box, can become crunchy and brittle.

\-- Chemistry doesn't stop in space. The thrusters are likely to involve
chemically-reactive materials. Any little bit of corrosion, stress-corrosion
cracking, etcetera could cause anomalous performance.

It is wonderful when things still work.

~~~
jacquesm
And then there are vacuum welding and interstellar dust.

~~~
comstock
Interesting, I didn’t realize cold welding was a problem in space. I assume it
can be solved by applying a coating to surfaces that might come in contact
with each other.

------
manmal
How does Voyager know where Earth is, such that it can position the dish
correctly? Does it use inertia to keep track?

Also, at such an enormous distance, I’d expect very minor dish positioning
errors to result in the loss of the line. It’s awesome that they had the
skills to build something like that in the 80s.

~~~
jacquesm
It doesn't need to point its dish at Earth, it can simply aim for the Sun. It
is so far away they are as good as in the same position relative to itself.
And the Sun conveniently lights up making aiming a lot easier.

~~~
manmal
Did they have digital light detectors in the 70s? I mean, it’s trivial now to
aim something at the sun now, but they didn’t have image recognition then. A
primitive heat sensor perhaps?

~~~
jacquesm
Yes, CDS cells are much older than that, and Ge diodes are light sensitive
too.

------
acheron
Primary source here:
[https://www.jpl.nasa.gov/news/news.php?release=2017-310](https://www.jpl.nasa.gov/news/news.php?release=2017-310)

------
jhallenworld
Voyager's antenna is aimed at the sun (because at its distance, earth and sun
have close angular separation). So this means the command signal has to
overcome microwave noise from the sun.

So this is the same problem as SETI. I know for SETI they reduce stellar noise
by assuming that aliens are transmitting in very narrow bandwidths.

------
tempodox
Fascinating. Now, that's what I call Engineering. And +1 to the author for
using the metric system :)

------
oskarth
Lisping at JPL (Jet Propulsion Lab) is an interesting read:
[http://www.flownet.com/gat/jpl-lisp.html](http://www.flownet.com/gat/jpl-
lisp.html)

It is written by lisper at HN who submitted this article :)

------
byron_fast
The speed of light sucks. What patience.

~~~
b3lvedere
It's way too slow :)

[https://www.youtube.com/watch?v=1AAU_btBN7s](https://www.youtube.com/watch?v=1AAU_btBN7s)

------
Retric
19 hours and 35 minutes * speed of light is a long way.

It's not pointed in the right direction, but it's interesting to think of this
as just over 1/2000th the distance to the nearest star.

------
Cshelton
Would it be possible to use these thrusters, or even the main thruster, to
speed Voyager or slingshot it around something right before it loses power to
communicate back to us?

It'd be cool if right before we lose contact of it for good, we got it to go
as fast as possible so that it will reach who knows where someday... just
slightly faster.

~~~
ceejayoz
> slingshot it around something

It's in interstellar space. Barring a really lucky encounter with another
interstellar body, it'll be another 40,000 years before it's close to
anything.

~~~
Cshelton
I mean, we are finding Pluto sized objects right outside our solar system all
the time now.

~~~
eesmith
It doesn't seem like it's all the time. Pluto is the largest, Eris is close.
Haumea, (225088) 2007 OR10 and Makemake are the only others at least 1/2 the
diameter of Pluto.

We are finding more trans-Neptunian objects. There's about 2,500 of them. But
as Adams said, "Space is big. Really big. You just won't believe how vastly,
hugely, mind-bogglingly big it is."

Voyager can only be angled a smidgen from it's current path. There's nothing
it can reach to do a slingshot.

If Voyager could change its path by 0.1 degree (which it can't), and if all of
the trans-Neptunian objects were equally distributed around the Sun (which
they aren't - and Voyager is going out of the plane of the ecliptic), then
that's still only a 0.2% chance of having something in its path.

Even if there were, Pluto gave New Horizons about 5-6 m/s boost. That's
effectively nothing compared to Voyager's 17 km/s speed.
[https://www.youtube.com/watch?v=Hm6ga-g9ACU](https://www.youtube.com/watch?v=Hm6ga-g9ACU)
via [https://space.stackexchange.com/questions/10087/did-the-
plut...](https://space.stackexchange.com/questions/10087/did-the-pluto-flyby-
give-new-horizons-any-significant-gravitational-boost) .

------
signa11
just as a scale, this distance is not even a light-day away ! i am just
_amazed_ that we can still "hear" it.

anyone have more info on the power with which the signal arrives here at earth
? and how do they make sure that ambient/thermal noise does corrupt it ? thank
you !

~~~
calgoo
You can normally see them communicating here:
[https://eyes.nasa.gov/dsn/dsn.html](https://eyes.nasa.gov/dsn/dsn.html)

------
keithflower
There's a wealth of fascinating information including book series on deep
space communication at the JPL DESCANSO Deep Space Communications and
Navigation Center of Excellence:

[https://descanso.jpl.nasa.gov](https://descanso.jpl.nasa.gov)

------
lordnacho
What does it fire out when firing the thrusters? How come there's propellant
left?

~~~
iaw
All the references I found Wikipedia said it used Hydrazine thrusters.

As to why there's propellant left: it's a sealed system and NASA has
intelligent engineering practices when it comes to resource planning.

~~~
garmaine
No seal is perfect, especially without standard pressure surrounding it.

~~~
mrguyorama
The fact that there is propellant left implies that the seals were good enough

------
cmsonger
I'm too old now: but I so wish I could have been a young engineer on such a
project. The title is literally "37 years later." (And that's not from
launch.)

Amazing.

------
make3
Those that make it humanity's farthest controlled object? literally,
humanity's furthest influence

------
joering2
> This week, the scientists and engineers on the Voyager team did something
> very special.

I would say if you still manage to run sophisticated system that is 37 years
old, even more challenging when its out in space, everything you do is
special.

------
verybadvoodoo
Everybody wept when they read this, right?

------
faragon
Voyager mission is so epic. A miracle.

