
F*ck me. Impressive. Way better than that modern Russian job.
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 …
"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.
"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..
"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
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.
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.
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!
....... 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.
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!"
"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.
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.
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.
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.
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.
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.
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.
"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...