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back to article Voyager 2 finally agrees to a long hard thrust

Voyager 2 has finally gotten back to NASA to let engineers know that its switch to back-up thrusters was successful. Artist's impression of Voyager 1 and 2 in the heliosheath Credit: NASA/JPL-Caltech Artist's impression of Voyager 1 and 2 in the heliosheath Credit: NASA/JPL-Caltech The space agency sent the signal last week …

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TRT
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F*ck me. Impressive. Way better than that modern Russian job.

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Because...

The Voyagers are not running millions of lines of software.

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Joke

Voyager's code:

10 keep going

20 goto 10

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TRT
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Ah!

Well, that explains it.

How many hardware engineers does it take to change a lightbulb? None, we'll fix it in software.

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Anonymous Coward

One question

Why doesn't the fuel line to the backup thrusters need a heater??

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Anonymous Coward

It does.

and both heaters have been permanently on. now only one is on.

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Happy

I am

constantly in awe of the Voyager space craft. Its just a mind boggling feat and the distance they have traveled

.

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"Both Voyagers 1 and 2 are currently at the outer limits of our solar system, in the region of space known as the heliosheath, the outer shell of the bubble of charged particles around our Sun. They will soon reach interstellar space, the space between the stars."

'Wow' is all I can say to that.

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Anonymous Coward

This is wrong - its like a tabloid simplification.

"the ship took all this time to do the swap and then let the space boffins know it had managed the change."

The ship did not take that long to execute the command! the reason it took so long is that many commands and hence many send and receives are required in sequence to complete the task.

for example:

Send command to startup auxiliary system

Receive echo command

Send command to execute (if correctly received)

Receive Ack

Send command to Report status

Receive Status

Send command to transfer control to auxiliary system

Receive echo command

Send command to execute (if correctly received)

Receive Ack

Send command to Report status

Receive Status

Send command to shutdown primary system

Receive echo command

Send command to execute (if correctly received)

Receive Ack

Send command to Report status

Receive Status

Send command to shut down primary system support services

Receive echo command

Send command to execute (if correctly received)

Receive Ack

Send command to Report status

Receive Status

Many, Many send and receives, each taking 24+ hrs..

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Mushroom

@AC - This is wrong - its like a tabloid simplification.

You've clearly never made love to a woman. Have you.

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FAIL

Simpler

Just upload a bit of code (oh yes, code...silly command line person you) that do all the if (fail) then exit() checking on the craft. Then it's a simple bit of sending the commands all at once and let the craft fail out if any commands do not successfully execute or have a status failure. This includes the code to revert to original state if required.

See? A bit of a burst, but surely not requiring the 28hr round-trip per command line.

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Childcatcher

Communicating with a distant spacecraft is very much like making love to a beautiful woman

Read that post back through as if you're 14, making every third word or so a double-entendre and several of the steps are strikingly similar...

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FAIL

You seem to completely forget that the voyager crafts are getting on to being 40 years old. They simply do not have the processing power to parse any type of command script. I would presume that the commands are simple short single byte chains. Hence the repeated round robin of messages.

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Anonymous Coward

fail^2

I've got a 1Mhz 6502 that says old, slow hardware can too process scripts.

More than a few years ago I worked at/for JPL and spent considerable time in "mission control". RTLT (Round Trip Light Time) to talk to one of the Pioneer spacecraft, which was at that time nearing the fringes of our solar system, was on the order of 24 hours. I.e. twelve hours out, then twelve hours for the ack to return.

The scenario of one command, wait for an ack, next command, would take months to do anything complex, and doesn't jive with my experience at JPL.

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Paris Hilton

Phone sex at 9 billion miles distance

"All probes out that far (including Mars), use fault protection systems that can 'safe' the craft when an anomaly is detected." https://twitter.com/#!/NASAVoyager2/status/136821567106719745

"~ 7 seconds to transmit a 140 character tweet in EBCDIC" https://twitter.com/#!/NASAVoyager2/status/135781481812463616

You've clearly never had a hyster*e*cal paroxysm

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http://voyager.jpl.nasa.gov/mission/weekly-reports/index.htm

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Wow indeed

Almost 30 years ago I did a course on Error Correcting Codes as part of my Maths degree and sure I recall the lecturer talking about communications with the Voyager probes (which were then in between Saturn and Uranus) as being an example of how communications were being pushed to their limits - a tranmission of less power than a dim light bulb from millions of miles away.... and to think they are still in contact when Voyage is ~4x further away is amazing!

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Obligatory NASA gee-whizzery

By the time Voyager 2 reached Neptune the strength of the radio signal received on Earth was already 1/20 billionth the power of that produced by a watch battery.

These machines are incredible.

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Coat

Let me be the first to say...

.. at least for this article...

They Don't Make them Like They Used too....

Mines the one with the Clovis point in the pocket :)

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Outer Limits of the Solar System

We control the vertical (thrusters...)

We control the horizontal (thrusters...)

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IT Angle

Bandwidth

I've got to ask - how many bits/second can they send to Voyager and how many can it send back to us?

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Bandwidth

According to Wikipedia it's 115.2 kilobits per second with the high-gain antenna. However I think that's the rate on the radio. The Voyager probes use constitutional codes halving the usable bandwidth.

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THIS is why I elected to do science.......

....... back in the middle of the last century.

You never know what amazing things can happen until you try.

I am in awe that this thing is still working.

Anyone remember the Star Trek movie where Voyager 1 "V----ger" was the co-star?

As for AC - "This is wrong - its like a tabloid simplification"

@AC Unless you were writing Fortran or the like back in the 1970s just fuck off you ignorant cretin.

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Anonymous Coward

Fortran 77 Was part of my engineering degree.

Do you really think "the ship took all this time to do the swap and then let the space boffins know it had managed the change" is accurate? I don't. You may not like my example, fair enough.

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Headmaster

@Bugsman

<Trekkie Geek Mode>

V'ger was Voyager 6, lost into a Black hole

</Trekkie Geek Mode>

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40 years...?

http://www.theregister.co.uk/2011/11/15/the_first_forty_years_of_intel_microprocessors/

?

Wonder if the time to do something might have do something with the ground station using directed huge amounts of power saying.

<font size="HUGE">FUCKING DO THIS</font>

Before the Voyager repeatedly meeps

<font size="tiny>ok</font>

and the return message via HUGE aerial arrays on Earth cross-correlate the repetitive weeny signal enough times to believe Voyager has done as asked.

Perhaps Intelligent life might have replied.

"PLEASE SHUT THE FUCK UP with your irritating transmissions.... We have done it for you. OK!"

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"Both Voyagers 1 and 2 are currently at the outer limits of our solar system, in the region of space known as the heliosheath, the outer shell of the bubble of charged particles around our Sun. They will soon reach interstellar space, the space between the stars."

I can't recall...are the Voyager craft capable of transmitting pictures back to us still? I'd love to see the view of our little corner of the galaxy from interstellar space in something other than an artists' rendition.

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Boffin

Just look for "Pale Blue Dot"

Voyager 1 took a "Family Portrait" back in 1990.

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Unhappy

Artists impression or Impressionist art ?

Unfortunately for us, the cameras have been powered down. However at the range they are at now, the resolution probably won't be much better than an old 640x480 slow-scan image. Now if only NASA could work out how to mix Hubble optics with Voyager reliability & Vasimir engineering we might get that image in our lifetimes.

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Anonymous Coward

signs point to yes.

http://en.wikipedia.org/wiki/File:Family_portrait_%28Voyager_1%29.png

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Anonymous Coward

oops

my bad, that was in 1990.

They have since essentially switched to radio science only...

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@Bandwidth

Ohh another source is saying it's currently transmitting at 160 bits per second.

Here's the data.

http://voyager.jpl.nasa.gov/mission/weekly-reports/index.htm

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Pictures

From that distance the view behind will look a lot like the view ahead. The Sun is just another, somewhat bright, star, and the planets are dim dots.

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Unhappy

Dim dots...

Looking around us, it might be safe to suggest on of those dots is getting dimmer by the minute...

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Joke

I can't help but think they will move from the heliosphere and into an interstellar spaceway, causing a major pile up that results in the human species being enslaved to an interstellar freight company.

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A sort of interstellar Eddie Stobart if you will.

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TRT
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We’re heading out into intergalactic space! I feel cold, all alone in this infinite void.

Apart from the fleet of black battle cruisers behind us. There are about a hundred-thousand. Is that wrong?

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Go Voyager!

Brings a tear to my eye to hear about that old hardware still voyaging. What utterly brilliant engineering!

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IBEX

If you think the Voyagers are cool have a look at <a href="http://www.ibex.swri.edu/index.shtml">IBEX</a>. Launched from a Boeing jet liner it goes round the Earth and its data (recording neutral hydrogen atoms) complements the data from the Voyagers.

If you are interested in the heliopause (and all things helio...) there's some good info here.

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Anonymous Coward

What I don't understand is - if the power source is nuclear, then surely use/non-use of available power won't affect the longevity of the power source, since it's half-life based, and not something you can increase/decrease the rate of use.

Unless they mean that the power output is so low that using both heaters would soon leave insufficient leccy to run other instruments/radios/CPUs.

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Correct

The available power has fallen to the stage that they have to prioritise instruments. I mean, it's not like you want to launch with a lot more isotopes than you actually need for the primary mission....

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Pictures from space...

The last pictures from Voyager 1 were sent a while ago. The sun was but a faint dot, and earth was only a pixel.

As for turning off thrusters, there is a finite amount of reaction fuel, and you don't want to use too much (as I understand it). As for power, the nuclear battery does have a finite life, and being that it was "started" about 35 years ago. The RTG uses Pu-228 because it is easy to shield (it is an alpha emitter), which has a half life of 88 years. While not yet there, the power is reduced a bit, thus the conservation.

Life (spacecraft) goes on.

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and on and

Its fascinating and at the same time mind boggling,if you consider that these man-made contraptions originated from Earth and will keep on going and going across the vastness of the cosmos long after everyone is gone. Imagine those who have worked and built on probes like these, hell even touched them when mounting them on their fairings, knowing that their work will outlive everyone. Every now and then I read the Sagan text on the Voyager picture to remind myself that we keep wasting our time here with wars and the ultimate quest of getting richer & richer so that we can have an extra car. That picture sure puts things into perspective.

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A Little out of date but gives the details

Power was provided to the spacecraft systems and instruments through the use of three radioisotope thermoelectric generators. The RTG's were assembled in tandem on a deployable boom hinged on an outrigger arrangement of struts attached to the basic structure.

Each RTG unit, contained in a beryllium outer case, was 40.6 cm in diameter, 50.8 cm in length, and weighed 39 kg. The RTG's used a radioactive source (Plutonium-238 in the form of plutonium oxide, or PuO2, in this case) which, as it decayed, gave off heat. A bi-metallic thermoelectric device was used to convert the heat to electric power for the spacecraft. The total output of RTG's slowly decreases with time as the radioactive material is expended. Therefore, although the initial output of the RTG's on Voyager was approximately 470 W of 30 V DC power at launch, it had fallen off to approximately 335 W by the beginning of 1997 (about 19.5 years post-launch). As power continues to decrease, power loads on the spacecraft must also decrease. Current estimates (1998) are that increasingly limited instrument operations can be carried out at least until 2020.

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Nearly there...

"Both Voyagers 1 and 2 are currently at the outer limits of our solar system, in the region of space known as the heliosheath, the outer shell of the bubble of charged particles around our Sun. They will soon reach interstellar space, the space between the stars".

So they'll hit the glass sphere soon...

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Anonymous Coward

Glass sphere?

Glass sphere? What utter nonsense!

Clearly what will happen next is that God will eat them.

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Any follow up?

I'm all for a fast Voyager III - take pics if you can on the way but boost for interstellar space as fast as you can, with as many swing bys to speed it up as possible. I'm sure there's lots of interesting science which could be done outside the heliosheath.

Any planned?

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