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Voyager 2 to Switch to Backup Thruster Set
- iwwr 15y agoWhat are they using the thrusters for at this time? Just attitude adjustment to get the antenna pointed at the Earth?
- wglb 15y agoFirst sentence of linked article: NASA's Deep Space Network personnel sent commands to the Voyager 2 spacecraft Nov. 4 to switch to the backup set of thrusters that controls the roll of the spacecraft.
- InclinedPlane 15y agoThe Voyagers are 3-axis stabilized (vs spin stabilized) and they use the thrusters for attitude control. Without the thrusters the antenna would drift away from being pointed at Earth and we'd lose contact. More modern spacecraft use non-propulsive systems such as momentum wheels and gyrodines to maintain 3-axis attitude control and use thrusters to reset only when those systems become saturated.
- dquigley 15y agoThat these things still work is an amazing feat of engineering.
- hammock 15y agoReally cool to think we sent this guy out there which is now 9 billion miles away, and we are still in contact/command with it.
- ImprovedSilence 15y agoYeah, and the fact that it takes DAYS for a command to reach it.
- dalke 15y ago13.4 hours http://www.google.com/search?q=9+billion+miles+/+speed+of+light http://www.google.com/search?q=9+billion+miles+/+speed+of+li...
- InclinedPlane 15y agoConsider that there are almost certainly several undiscovered worlds as large as or larger than Pluto closer to us than Voyager 2 is now.
- ender7 15y agoFrom my wikipedia dive: the Voyager spacecraft are powered by "radioisotope thermoelectric generators", each of which is essentially a barrel full of plutonium spheres. As the plutonium decays, it generates heat. The resulting heat differential (one area is now hot, some other part of the craft remains cold) is then used to generate electricity via the Seebeck effect. http://en.wikipedia.org/wiki/Voyager_2#Power http://en.wikipedia.org/wiki/Voyager_2#Power http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator http://en.wikipedia.org/wiki/Radioisotope_thermoelectric_gen... Also known as "things we really hope the press never hears about".
- jparise 15y ago"Collectively, the RTGs supply the spacecraft with 470 watts at launch and will allow operations to continue until at least 2020."
- hammock 15y agoThat's interesting. I always thought it was a small nuclear reactor onboard. I don't see why the press/public would freak out to know that nuclear power is being used on a space probe 9 billion miles away.
- dalke 15y agoBecause it's launched from the earth, and rockets have an unfortunate tendency to blow up at times. That's why the RTG's are designed to re-enter safely even if there's an explosion. Even after it leaves orbit, the probes loop back to use the Earth for gravitational assist and there's a minuscule chance that it will crash; with odds something like 1:1000000. In the absolute let's-imagine-the-impossible worst case scenario, an additional few thousand people are expected to get cancer. Summarize that as "but if it crashes into the Earth, thousands of people will die!"
- InclinedPlane 15y agoEven the hugely improbable worst case scenario of an RTG powered spacecraft impacting the Earth during a flyby is unlikely to lead to any increased deaths per se. In such a scenario (again, astronomically unlikely) the RTGs fuel would vaporize in the upper atmosphere and ultimately add a very tiny additional contribution to the global background radiation level.
- MartinMond 15y agoDoes anyone know any details on what kind of software runs on Voyager 2 and how they program it from Earth? Is there just a list of predefined commands (activate this, deactivate that, send images) or do they overwrite the 'firmware' with each upload or ...
- hartror 15y agoFirmware, see: http://www.space-travel.com/reports/NASA_Fixes_Bug_On_Voyager_2_999.html http://www.space-travel.com/reports/NASA_Fixes_Bug_On_Voyage... In this case they downloaded the firmware from Voyager 2 and found a flipped bit.
- kmm 15y agoIt surprises me how little information about the Voyagers is on the internet. I'd love to know everything about what makes them tick.
- js2 15y agoTry exploring http://www.nasa.gov/mission_pages/voyager/index.html http://www.nasa.gov/mission_pages/voyager/index.html and http://voyager.jpl.nasa.gov/ http://voyager.jpl.nasa.gov/ The later has weekly mission reports all the way back to 1995. I also just submitted information about its onboard computers: http://news.ycombinator.com/item?id=3204224 http://news.ycombinator.com/item?id=3204224
- MartinMond 15y agoI found something: http://voyager.jpl.nasa.gov/faq.html http://voyager.jpl.nasa.gov/faq.html search for "What kind of computers are used on the Voyager spacecraft?"
- ericgearhart 15y agoWhat's the information security posture on these things like? What I mean is, what was considered "secure" in 1977 (DES based encryption was state of the art back then, right?) would be considered laughable today... I wonder what precautions are taken by NASA to prevent someone from intercepting and decoding NASA's commands to the probe and then beaming their own commands to Voyager 2.
- conover 15y agoFrom what I've read, the signals from these probes are so weak that you need large receivers coupled with extremely low temperature electronics to detect them. That puts it out of the reach of everyone except the extremely well funded. In the end, it would be a short list of suspects.
- mturmon 15y agoYes, you quite literally need one of these to communicate with Voyager: http://www2.jpl.nasa.gov/files/images/browse/jpl9020ac.gif http://www2.jpl.nasa.gov/files/images/browse/jpl9020ac.gif
- jtchang 15y agoDoes it blow anyone else's mind that we have a piece of technology 9 billion miles away and we are actually talking to it?!
- ajasmin 15y agoThe computer on that thing probably has the longest uptime in the solar system.
- thebigshane 15y ago"Slow to impulse, standard orbit, Mr. (Crusher|Sulu)"