Which one is veeger?
V1 or V2?
NASA has switched off a heater on a part of the Voyager 1 probe, plunging the temperature of its one functioning instrument to below minus 110° Fahrenheit (minus 79°C) – well below the minimum temps of minus 31° Fahrenheit (minus 35° C) at which it was designed to operate. Space boffins took the decision in order to conserve …
Eh? There's no "bubble" as such related to the Sun's gravity; gravity's strength fades smoothly away with distance, and there's no point at which it stops or has any change in behaviour.
Do you mean the heliopause, perhaps, which is related to where the solar wind loses its influence?
This is pretty amazing stuff. Voyager 1 was launched in 1977. Good Old Conservative NASA (as it definitely was then) built stuff using well tried and tested technology, so this tech is much earlier, like the use of an 8-track digital recorder. It takes 33 hours for a round trip message to get from Earth to Voyager. So NASA sends a signal, and waits a day and half to see if the space craft has responded.
And today, how long can we keep an "advanced" computer running for (my record is 287 days for the home server- YMMV).
Like I say - built to last.
Your home computer was really built for a price, and was built with the idea that someone could always "turn it off and on again".
A telecoms satellite built today would be expected to work for 15 years, and the main computer will be allowed up to 1 restart over that time. It would probably keep going longer too, but the solar panels won't output as much after 15 years of the crap in space, and by then there will be no fuel left to keep it in the same place in the sky so that the dish on your house is still pointing at it.
I know I'm nitpicking here, but since we're talking about highly professional equipment I'd like to pick up on that...
Even a not so advanced computer should have no big problems with being left turned on. In fact; in many cases its actually more healthy because it doesn't have to deal with power surges (even though most of it gets handled by your power supply unit) and more importantly your hard disks won't have to cope with drastic physical changes.
If on the other hand you're referring to the OS and as such uptime then I think its a very bad indicator. To me very high uptimes only make me think of insecure or maybe even unmaintained computer environments. Which by itself is no problem, but it gets a bit shakey when we're talking about stuff hooked onto the Internet.
I'll take low uptimes with recent kernels and software (Linux, Windows, BSD*) over high uptimes any day of the week.
"Even a not so advanced computer should have no big problems with being left turned on. In fact; in many cases its actually more healthy because it doesn't have to deal with power surges (even though most of it gets handled by your power supply unit) and more importantly your hard disks won't have to cope with drastic physical changes."
Not quite. The reason why leaving computers running is usually much healthier for them is simply the abundance of mechanical stress that occurs when components heat up and cool down. It has nothing to do with power surges (which btw also do occur when computers are running). Switching computers on and off means a lot of heating up and cooling down, and thus a lot of mechanical stress.
For hard drives an additional problem is that the spin-up phase is the one that stresses components most, which (depending on the designed-in margins) may lead to overstressing and therefore life reduction of electrical components on the PCB. However, with modern (aka less than 10 years old) hard drives this isn't a issue any more, but it has been for older fast-rotating SCSI drives and 5.25" and full height 3.5" drives of the past.
"If on the other hand you're referring to the OS and as such uptime then I think its a very bad indicator. To me very high uptimes only make me think of insecure or maybe even unmaintained computer environments. Which by itself is no problem, but it gets a bit shakey when we're talking about stuff hooked onto the Internet."
I agree 100%. Long uptime is key for certain areas like production control systems and similar stuff, but for general purpose computers it's just a sign that the system hasn't been properly updated for a long time.
I think a better factor than uptime to look at is how much unwanted downtime (which doesn't include updates) a system has accumulated.
"I'll take low uptimes with recent kernels and software (Linux, Windows, BSD*) over high uptimes any day of the week."
I agree with your main argument. The main problem is that people do not distinguish between planned and forced reboots. I like to reboot customer machines when a new kernel is installed, this takes a few minutes and is done when is convenient.
The machine at which I am typing is 10 years old, but runs an up to date kernel. I leave it on 24x7 andhave had few hardware problems over the years, just: CPU fans and hard disks.
mostly because they were launched at a time when the planets were in a sort of alignment that meant they could use each one as stepping stone on their path out of the galaxy, each planet they visted gave the probes a gravitational slingshot boost on the way past.
I dont think that kind of alignement is due to happen again for quite some time
I would add that modern ground based detection systems have advanced so much that sending probes to fly passed planets is really not a requirement any more.
when you add to the mix satellite based detection systems, the only way you are going to get better data is to place a probe on the surface of the planets.
the only point in sending probes outside of the solar system would be to try and intercept interstellar transportation that's passing us by without dropping in to say hello.
if you was to try and send a probe (or maybe people) to the nearest star then you are looking at a journey time of of around 18,500 years (travelling at the same speed as voyager), Why take on that expense for the benefit of the future generations, when in probably a hundred or so years time that journey time could be cut by a half. That is if something nasty doest happen on the way like and os needing a upgrade, or a reboot....
"Why take on that expense for the benefit of the future generations, when in probably a hundred or so years time that journey time could be cut by a half."
Can you imagine how pissed off the great*260-or-so grandchildren of the first ever interstellar explorers would be when they finally arrive at their destination, only to discover that the place has already been all screwed up by 9000-odd years of humanity?
Fly-by craft are the way you do a first survey of a planet/object/thingy. That let's you get a good idea of the environment (magnetic fields, temperatures, atmosphere's density and composition, etc). That gives you good specs for an orbiter, which gives you good info and specs for a lander, etc.
Recall that Mars had Mariners 3 & 4 fly by, had Mariner 9 orbit (finding shocking things like mountains, caldera, evidence of flowing water, etc), which allowed NASA to find sites and design instruments for Viking, which has allowed us to make better roving instruments, ... and so on
Voyagers 1&2 followed two Pioneer craft to Jupiter and one to Saturn. (The one that went to both also allowed NASA to try a gravity-assist path that would be crucial to Voyager.) Uranus, Neptune and (largely) Titan were unknown and needed flyby missions first.
The flyby missions are important, but we've done that for all the planets and until we design a mission to search the heliopause or Oort cloud, I doubt we'll have a reason to send anything out that far again.
(Of couse, having said that, something new will be discovered within a year ...)
"Why are we not building more of these probes to fling out of the solar system?"
True, we are not doing fly-bys, but we have take a long look at Jupiter (Galileo), Juno(??) is next for that, Cassini is doing wonders at Saturn, having landed on Titan and observed equinox up close, discovered the relationship between Encelidus and the F-ring, etc.
We are also doing good stuff with Kepler and related probes. I would really like to see an exploration of Europa's ocean :) So, there is a lot of exploration happening.
My great-grandma had a refrigerator that's been working since the 50's, except that the thermal relay welded closed some 30 years ago. Yes, working non-stop, you won't hear the fridge clacking-in and clacking-out in the middle of the night.
Except for a paint job on the handle, new sealing gaskets on the door frame and occasional de-icing every odd month, the bugger kept going. My 2nd degree uncle GAVE it away to charity, still fully functional.
Well NASA did all that, with something running on batteries. Top that.
PS. My car won't even start if parked for a straight month without new batteries. sigh.
And I can't forget the remark: "If someone built a washing machine that could fly...."
About 10 years ago an art gallery in London were selling big (2 metre) photographs (taken from original), mounted on aluminium, as art. There were Hubble shots, etc., but I bought a close up of Saturn -- part of the planet and rings, and two moons, that was taken by Voyager I. It is incredibly lovely and is better art than most things I can think of. When I hear of Voyager's continuing journeys, and continuing value, I feel like I am part of its family.
Yes... a big fucker with proper nuclear power source that could last 100+ years powering a vast array of instruments and multiple redundant comms channels. Should cost less than a Mars rover since there's no fancy re-entry mechanisms needed, just find a nice spot in the galaxy to point it at and send it off
I second that e motion, James Micallef, and would suggest it is carried already and accepted and currently HyperRadioProActive in Advanced Personalised Perception/Virtual Reality Fields in Live Operational Virtual Environments.
* Answers in a comment on this thread, please, is AI Start.
A member since 2008 and you’ve never seen AMFM post!!!!!!!!!!!!!!!!!!!!!!!
FYI, I put AMFM's post through a English-Yoda translator and I still can't make sense of it.
That e motion, I second james micallef and would suggest, carried already and accepted and currently hyperradioproactive in advanced personalised perception/virtual reality fields in live operational virtual environments, is it. Herh herh herh.
"Voyager 1's ultraviolet spectrometer (UVS), a light meter which is its only working instrument"
I thought that there were a few instruments still working? Perhaps this is the last optical sensor? I though that they were still detecting charged particles and magnetic fields?
The last update I've seen on the Voyager logs is from October last year. For anyone really bored, you can read it all here: http://voyager.jpl.nasa.gov/mission/weekly-reports/
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