Can *you* design a hinged joint that is:
- rigid enough to point constantly in one direction.
- but flexible enough for a geared stepper motor to move?
- able to survive large temperature extremes (at least a difference of 250 deg C on the outside of the craft)? (Remember not to use normal lubricants that will freeze solid or boil off in the vacuum of space.)
- it costs a lot of cash to get something into orbit, so it has to be very,very light.
Now mulitply that by however many hinged joints you need to deploy and accurately point your antenna. And that's just the hinged joints. You can also apply the same requirements to the stepper motors, drive electronics, feedback mechanisms and a whole lot of other stuff that likely makes up the antenna system.
It's not that easy, and I'll bet they didn't have an unlimited budget to design it either. And the thing's been up there , pointing its antenna about the place for 10 years now.
Sorry if this sounds like a bit of a rant, but casual comments like yours make me a little peeved;-)
ref : Cutnell, John D. & Johnson, Kenneth W. Physics, 3rd Edition. New York: Wiley, 1995: 441. "In certain regions of outer space the temperature is about 3 K, and there are approximately 5 x 10E6 molecules per cubic meter."
What they should have done 5 years ago is make a new music CD format with 24-bit 96khz sampling rate and 5.1 Dolby sound.
They did - it's called DVD audio. Still not too many about yet. Why? Because not too many people have DVD-Audio players.
Contrast this to CD's which can be played on hardware dating back to 1985 for crying out loud. Basically, CD's are good enough for the general public to listen to at home, in their cars, on their crappy PC "multimedia" speakers, and that's pretty much it.
No-one will buy the next "big thing" unless it really makes a quantum leap over the old. I haven't seen the next big thing appear yet.... maybe a few more years of CD's yet.
There's a commercial packet radio system around for long-distance trucking fleets that uses the meteor trail to do just that. It listens for a signal from home base then quickly sends a packet or two back. Good for digital store-and-forward of truck info etc.
Maybe it was on slashdot? was a year or two ago now tho'
Re:More environmentally friendly
on
42-Volt Autos
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· Score: 1
I used to drive 350 ton haul trucks for a living - they have fully-hydraliuc steering and if the engine stops, you've got about 3/4 of a turn (from lock to lock) before the hydraulic accumulator empties and that's it - your wheels (5 tons apiece) ain't gonna move, no matter how much you swing off the steering wheel.
They did have a electric-hydraulic backup pump but you could only turn the wheels r-e-a-l-l-y s-l-o-w-l-y.
Re:More environmentally friendly
on
42-Volt Autos
·
· Score: 1
Hmm - I thought that's what the electromagnetic clutch in an A/C compressor was for - when that's off, all it is is another idler pulley.
But still , a decent electrical system would mean that you don't have to dangle half your A/C system off the side of your engine, and could replace the rubber hoses (which leak) with something metal (that doesn't leak). Then you'd have systems that would last 10 years before a regas.
I've seen designs for things like electrically-assisted power steering that do away with the hydraulic pump etc... that's supposed to save 5% in fuel or so.
Accidents Involving U.S. Space Nuclear Power Sources
The United States has launched 22 missions with RTG power sources. Three accidents have occurred, though only one has resulted in release of radioactive materials. The U.S. has launched only one experimental space reactor, the SNAP 10-A in 1965. This reactor is currently in a nuclear-safe storage orbit with an estimated life of three-thousand years. The eventual re-entry of SNAP-10A will not occur until the level of radioactivity has decayed to a very low level.
In the single instance of radiological release from a U.S. NPS, the RTG performed as designed. The SNAP 9-A RTG (Space Nuclear Auxiliary Power) was launched in 1964 aboard a Department of Defense weather satellite that failed to achieve polar orbit. The SNAP 9-A, designed to burn up and disperse its nuclear inventory in the upper atmosphere during re-entry, performed as planned. The release of radioactive materials was measured by scientists from the Atomic Energy Commission in air and soil sampling efforts. The objective of current U.S. RTG design philosophy is for full fuel containment; that is, in the event of an abort during the launch or on-orbit phase of a mission, the RTGs are designed to retain the fuel material. In two subsequent unplanned incidents involving U.S. RTGs, the new design philosophy successfully prevented the fuel from being released. The first involved two SNAP 19 RTGs in a 1968 meteorological satellite while the other involved one SNAP 27 RTG in the Apollo Lunar Scientific Experiment Package (ALSEP) aboard Apollo XIII in 1970. Neither of these incidents caused release of radioactive materials. The two SNAP 19's were recovered from Santa Barbara Channel five months after the range destruct of the launch vehicle. The nuclear fuel was reprocessed and later re-launched in new RTGs. No release of the fuel was detected. The mission abort maneuver of Apollo XIII separated the Command Service Module from the Lunar Module. The Lunar Module containing the SNAP 27 RTG (as part of the ALSEP) re-entered the atmosphere and impacted in the South Pacific Ocean in the region of the Tonga Trench, where it remains today. Air and water samples taken by the U.S. in the vicinity of the re-entry found no evidence of fuel release.
Accidents Involving Soviet Nuclear Power Systems
There have been two accidents involving Soviet RTG's, and at least three incidents involving Soviet space nuclear reactors (Ref. 1).
In January of 1969, the launch failure of COSMOS 305 lunar mission with a lunar rover presumably powered by RTGs created detectable amounts of radioactivity in the upper atmosphere (Ref. 2, Ref. 3). In the fall of that year, another lunar probe failed to make a translunar injection from Earth orbit. The atmospheric burnup of this RTG also created detectable amounts of radioactivity in the upper atmosphere. Any surviving debris from these incidents is presumed to be on the floor of the ocean (Ref. 3).
Soviet incidents of accidental re-entry of nuclear reactors involved COSMOS-series radar ocean reconnaissance satellites (referred to as RORSATs by U.S. analysts) (Ref. 2, Ref. 4).
In April 1973, a Soviet RORSAT mission launch failure resulted in the return of the power source in the Pacific Ocean, North of Japan. Radioactive release consistent with the RORSAT mission profile was detected by U.S. air sampling planes (Ref. 2).
In 1978, COSMOS 954 failed to boost into a nuclear-safe storage orbit as planned. Nuclear materials survived the fall through the atmosphere and spread over a wide area of Canada's Northwest Territory. A search and recovery effort coordinated by the Canadian government with U.S. help was undertaken after this accident. Since the cleanup operations, no detectable contamination has been found in samples of air, water, or food supplies (Ref. 5, Ref. 6, Ref. 7, Ref. 8).
God, I must be showing my age , but I remember getting up early as a kid and having nothing but test patterns on until 6am. One station used to just have teletext pages broadcast at random from station close (just after midnight) until they started up again in the morning... at least that was mildly interesting.
Still, that were probably better than the 6 hour infomercials selling crap products that you get these days... and test patterns can be handy when you're fiddling with the guns and convergence on your TV.
And who knows, with their current "elevated" threat advisory, what the current non-military accuracy is?
I'd guess quite a few surveyors would. "Hmmm. The GPS co-ordinates don't match the ones for this datum set in concrete beside the road here.... damn GPS"
Besides, differential GPS is good for plus or minus a few cm once you put your own GPS beacon (over a known datum) nearby. Again, surveyors do this a lot.
I vaguely remember the japanese had some sort of thing like that - it was a device that you program with your likes/dislikes, and it'd beep and blink a bit if it got near someone with matching interests.
Don't think it really caught on... not enough market penetration.
But , don't you remember? They sold off telstra not "for the children!" , but "for the environment!"
So they got a few billion dollars for half of Telstra. Great. What happens in ten years time when than money's gone? Why, sell the other half! And then? Ooops, no more assets to sell. Telstra pretty much was the last major valuable asset the Australian Gov't had.
Once they sell them, there's no buying them back. Soon after they'll say "No, you can't have a phone in outer BumFuck, it's too far away from any regional centres of note and it's just not *cost effective* for us. Sorry. Here, try a HF radiotelephone instead."
As far as I'm concerned, certain things should be government owned simply because they provide a service to the people that is too important to worry about the cost, which is what private companies do.
a short kids cartoon I remember seeing a long time ago:
A race lives for thousands of years, becomes super-advanced (and so on), and one of it's scientists while doing tests realises that they are living in a dream.
So he holds a meeting with all the leaders,showing a display with the "real world" in it, with a man asleep in bed. Problem is the alarm clock's set to 8am and it's 5 to 8. They've lived 10,000 years of history overnight, but the clock's ticking towords the end of the world! What to do?
They decide to make a portal to the real world, and proceed to carry the sleeping man's bed back to their world... all is saved!
Until the man start's dreaming of something else, and things get a little trippy - they all turn to birds or something, but in the end they're still happy (hey, it was a kids cartoon)
Struck me at the time as being a little bit wild to present the concept of alternate realities to small children... but there you go.
It's in a server , and with the moving the data off it and the putting data back on the new one, and the warranty claim, and the sending away and all that.
I've a 6 month old 40GB WD drive and it's developing unrecoverable read errors on sectors already:-(.
As far as I'm concerned , big drives are good for the "Wow!" factor, but are pretty much useless for serious data storage work. What's the point of having all that space if the damn thing dies 6 months down the track? Hard drives have to be pretty much the last "unreliable" bit of gear there is in a PC.
Increasing areal density just to get the "Wow!" factor doesn't help their reputation one bit when the error rate goes up as well.
Slashdot Mirror
I found a link to the SOHO technical description - check out figure 5 (antenna assembly)
Looks like an alt-azimuth assembly... and man, there looks like there's a lot of parts to go wrong in there!
There's *plenty* of reasons for it to fail!
:
;-)
Can *you* design a hinged joint that is
- rigid enough to point constantly in one direction.
- but flexible enough for a geared stepper motor to move?
- able to survive large temperature extremes (at least a difference of 250 deg C on the outside of the craft)? (Remember not to use normal lubricants that will freeze solid or boil off in the vacuum of space.)
- it costs a lot of cash to get something into orbit, so it has to be very,very light.
Now mulitply that by however many hinged joints you need to deploy and accurately point your antenna. And that's just the hinged joints.
You can also apply the same requirements to the stepper motors, drive electronics, feedback mechanisms and a whole lot of other stuff that likely makes up the antenna system.
It's not that easy, and I'll bet they didn't have an unlimited budget to design it either. And the thing's been up there , pointing its antenna about the place for 10 years now.
Sorry if this sounds like a bit of a rant, but casual comments like yours make me a little peeved
5 atoms per cubic centimetre is hardly dusty.
ref : Cutnell, John D. & Johnson, Kenneth W. Physics, 3rd Edition. New York: Wiley, 1995: 441. "In certain regions of outer space the temperature is about 3 K, and there are approximately 5 x 10E6 molecules per cubic meter."
What they should have done 5 years ago is make a new music CD format with 24-bit 96khz sampling rate and 5.1 Dolby sound.
They did - it's called DVD audio. Still not too many about yet. Why? Because not too many people have DVD-Audio players.
Contrast this to CD's which can be played on hardware dating back to 1985 for crying out loud.
Basically, CD's are good enough for the general public to listen to at home, in their cars, on their crappy PC "multimedia" speakers, and that's pretty much it.
No-one will buy the next "big thing" unless it really makes a quantum leap over the old. I haven't seen the next big thing appear yet.... maybe a few more years of CD's yet.
You can't just half-ass write something that works most of the time when your name is all over it
:
Well, looking at most OSS projects, you can do that as long as
1) No-one else has done it yet.
2) You mention in the source that this is a "half-ass hack that I threw together to make something work"
That's fine , but when you downshift, your brake lights don't come on and a person daydreaming behind you will tend to rear-end you real quick.
Sounds like the *decent* thing to do is for them to release a txt/html/pdf converter to the general public for their soon-to-be-abandoned product.
Odds are they won't though. Bastards.
Sounds like a good chance to market a USB speed-sensing device. Spread a little FUD about USB speeds and then market your gadget.
I'm guessing 15 bucks could get you a dongle with LED's that light for each speed - red for 12Mb/s, green for 480Mb/s.
Then it's just a case of plugging it into every unit you check out at the store, and you can ignore the sales guy's rants.
Yes - Samba with NT ACL's works under Linux with the SGI XFS patches - I've been using it on a file server at work for the last few months.
With it we can use our XP computers to modify access permissions on files on the samba share like it was a NT server.
Or a little physical jumper on the motherboard that says "Read-Only BIOS"
There's a commercial packet radio system around for long-distance trucking fleets that uses the meteor trail to do just that. It listens for a signal from home base then quickly sends a packet or two back. Good for digital store-and-forward of truck info etc.
Maybe it was on slashdot? was a year or two ago now tho'
I used to drive 350 ton haul trucks for a living - they have fully-hydraliuc steering and if the engine stops, you've got about 3/4 of a turn (from lock to lock) before the hydraulic accumulator empties and that's it - your wheels (5 tons apiece) ain't gonna move, no matter how much you swing off the steering wheel.
They did have a electric-hydraulic backup pump but you could only turn the wheels r-e-a-l-l-y s-l-o-w-l-y.
Hmm - I thought that's what the electromagnetic clutch in an A/C compressor was for - when that's off, all it is is another idler pulley.
But still , a decent electrical system would mean that you don't have to dangle half your A/C system off the side of your engine, and could replace the rubber hoses (which leak) with something metal (that doesn't leak). Then you'd have systems that would last 10 years before a regas.
I've seen designs for things like electrically-assisted power steering that do away with the hydraulic pump etc... that's supposed to save 5% in fuel or so.
God, I must be showing my age , but I remember getting up early as a kid and having nothing but test patterns on until 6am. One station used to just have teletext pages broadcast at random from station close (just after midnight) until they started up again in the morning... at least that was mildly interesting.
Still, that were probably better than the 6 hour infomercials selling crap products that you get these days... and test patterns can be handy when you're fiddling with the guns and convergence on your TV.
(Oh, and I'm 29.)
The eFork is made of the same Space Age material encapsulating the Astronauts!
eeeewww! skin?
And who knows, with their current "elevated" threat advisory, what the current non-military accuracy is?
I'd guess quite a few surveyors would.
"Hmmm. The GPS co-ordinates don't match the ones for this datum set in concrete beside the road here.... damn GPS"
Besides, differential GPS is good for plus or minus a few cm once you put your own GPS beacon (over a known datum) nearby. Again, surveyors do this a lot.
I vaguely remember the japanese had some sort of thing like that - it was a device that you program with your likes /dislikes, and it'd beep and blink a bit if it got near someone with matching interests.
Don't think it really caught on... not enough market penetration.
But , don't you remember?
They sold off telstra not "for the children!" , but "for the environment!"
So they got a few billion dollars for half of Telstra. Great. What happens in ten years time when than money's gone? Why, sell the other half! And then? Ooops, no more assets to sell. Telstra pretty much was the last major valuable asset the Australian Gov't had.
Once they sell them, there's no buying them back. Soon after they'll say "No, you can't have a phone in outer BumFuck, it's too far away from any regional centres of note and it's just not *cost effective* for us. Sorry. Here, try a HF radiotelephone instead."
As far as I'm concerned, certain things should be government owned simply because they provide a service to the people that is too important to worry about the cost, which is what private companies do.
Sadly,
If there are an infinite number of worlds, then there will (by the nature of infinity) be an infinite number of inhabited ones as well.
Sorry.
a short kids cartoon I remember seeing a long time ago :
,showing a display with the "real world" in it, with a man asleep in bed. Problem is the alarm clock's set to 8am and it's 5 to 8. They've lived 10,000 years of history overnight, but the clock's ticking towords the end of the world! What to do?
A race lives for thousands of years, becomes super-advanced (and so on), and one of it's scientists while doing tests realises that they are living in a dream.
So he holds a meeting with all the leaders
They decide to make a portal to the real world, and proceed to carry the sleeping man's bed back to their world... all is saved!
Until the man start's dreaming of something else, and things get a little trippy - they all turn to birds or something, but in the end they're still happy (hey, it was a kids cartoon)
Struck me at the time as being a little bit wild to present the concept of alternate realities to small children... but there you go.
one word: why? (it works)
They just run DOS for a PLC controller system. The software + DOS takes up about 8MB. Anything more is a waste really.
Maybe for you, fella - I live in Australia, its 11am Friday here :-)
I know, it's just my Rant For The Day ;-)
It's in a server , and with the moving the data off it and the putting data back on the new one, and the warranty claim, and the sending away and all that.
Thank God it's Friday, anyway.
I've a 6 month old 40GB WD drive and it's developing unrecoverable read errors on sectors already :-(.
As far as I'm concerned , big drives are good for the "Wow!" factor, but are pretty much useless for serious data storage work. What's the point of having all that space if the damn thing dies 6 months down the track? Hard drives have to be pretty much the last "unreliable" bit of gear there is in a PC.
Increasing areal density just to get the "Wow!" factor doesn't help their reputation one bit when the error rate goes up as well.