Well, that's probably the silliest thing in this entire thread, including the original article. You are driving down a highway at a reasonable speed for the existing conditions, then the conditions unexpectedly change (someone steps out on the highway). It takes a finite time to react. Is your proposed solution that everyone drive down the interstate at 5 mph on the off chance that someone walks into traffic?
And the first one that goes in the drink, blows up, or otherwise fails, people will jump all over them for wasting millions of dollars on some pie-in-the-sky experiment instead of using proven approaches.
Well, that's part of it. Just ignore the cleaning events and other factors. They probably figured on 3-sigma dust accumulation rates. That means that 99.73% of the time it's going to be less than that. Meaning that they could launch 1000 of them, and you would expect that 3 of them would run out of power in 90 days. So it is not in any way surprising that they didn't get excess dust accumulation.
Same thing with everything else. All the.9973 from every identified part/subassembly multipled together is total reliability, and so it's not in any way surprising that these things generally last *much much longer* than the specified mission duration.
This sort of analysis, of course, presupposes that statistically significant measures are applicable. For one-off or very short-run parts, of course there are no statistics so the methodology can tend to the bullshit end of the plausibility scale.
But in the USA, if you proposed adding another $2/gallon tax on gasoline, it would be political suicide. (Hell, just suggesting it on/. risks karma suicide.)
Well, it's funny, but a lot of people are *against* killing the economy and going broke. And worst of all, a gas tax is exceptionally regressive.
All due respect but I must jest: Tell us a story grandpa!
Are you one of those kids I chased off my lawn last night?!
What did you do for NASA?./ is curious!
I was an MCC console analyst on the mission control team for the payload. So I didn't work for NASA, but a contractor working for our governmental customer.
A lot of people don't realize this, but NASA is not the biggest player in the space business. Some individual DOD and other government customer *programs* have budgets rivaling NASA, and there are a pretty good number of programs.
Since the satellite runs in 'bent pipe' mode, amplifying wide bands of RF that are beamed up to it, it is likely to interfere with other satellites as it crosses their orbital slots on its way to an earth-sun Lagrange point, the natural final destination of a geostationary satellite without maneuvering power."
LAGRANGE POINTS? Good God almighty? What in the holy heck are you talking about? That's just ridiculous. It's not going to go to the Lagrange points (any of them). If nothing else there's no maneuvering and so the semi-major axis is FIXED at essentially geosynchronous period. What will happen is that that it will drift at varying speeds on the order of fractions of degrees a day, speeding up as it goes towards the gravity wells, passing through at pretty high speeds, then climbing back out, slowing all the time. I haven't checked the TLEs but it will either oscillate back and forth in one of wells or pass from one to the other. Just like dozens of other "died in place" spacecraft that had exactly the same problem. Eventually as the inclination changes it might go over the side of the hill (since the wells are 3-dimensional) like Skynet II/9354. Look that one up, or DSCS II/Flight II/9432 TLEs and history, that's what it's going to do.
I have a fair bit of experience with spacecraft of this era, and they tended to have pretty similar architecture. This is speculation of course since I haven't seen the data, but typically, the telemetry from the bus (everything but the intruments) is formed by the main telemetry unit. Data from user systems (like the intruments) is generally collected and put into a data stream by a secondary encoder. Periodically, the main telemetry unit sends a sync pulse to the payload encoder to trigger it to spew out the stream, conveniently timed to align itself with the rest of the downlink, Given thereport the bus telemetry seems OK, so there's probably something wrong with the payload encoder, or the generation of the sync pulse. I have seen anomalies where the sync pulse was generated at the wrong time, generated at random, or generated more-or-less continuosly. Of course a simple failure of a multiplexer in the encoder, or the serial data interface to the encoder in the main TLM unit would cause similar problems. It might be possible to recover from the spurious sync pulse issue if some of the data is sufficiently repeatable to use an an alternate way of determining where in the encoder stream the data got to when the window in the downlink frame came around. You might lose some of it but might be able to retrieve the rest. That should be pretty easy since a lot of the instruments are turned off (which they are) - that will create a very distinct pattern of valid data an all zeros that would let you know where in the encoder stream you are. If there's off-time sync pulse what will happen is that you will get all the data but it will be rolled around so that what you thought was the "bus voltage" is actually showing up in the downlink as the "tank pressure" or something like that. That would probably work for a "continuously rolling" encoder stream as well, where it never receives any sync pulses.
Of course they probably figured it out themselves, but I have had a lot of luck working these sorts of issues so if anyone from JPL thinks they need a hand, I will happy to consult. Given that I use my REAL NAME it shouldn't be difficult to contact me.
"It's a piece of crap, but every yuppie retard will still buy one."
In other news, Slashdot posters also declared with authority that "dating supermodels is a real pain in the ass, they are too high-maintenance" and "being rich doesn't make you happy!"
I guess I am not following the issue - I have been running various versions of Safari since it first appeared, and it has crashed, at most, 2-3 times in however many years it has been. What is it that people are doing that causes it to crash? I am not doing anything special, and I haven't even bothered to block any plugins, or Javascript. Flash seems to be fine - an abomination, to be sure - but functionally fine.
Well, if you crash a bunch of asteroids into it, it will likely become molten, creating a new phase of differentiation, and there is a reasonable chance that a new dynamo will form and create a new magnetosphere. It's at least as plausible that that would happen as you could crash a bunch of asteroids into it in the first place. It wouldn't likely last all that long in geological terms given the likely lack of useful radionuclides.
Slashdot Mirror
You left off "you insensitive clod!!"
Well, that's probably the silliest thing in this entire thread, including the original article. You are driving down a highway at a reasonable speed for the existing conditions, then the conditions unexpectedly change (someone steps out on the highway). It takes a finite time to react. Is your proposed solution that everyone drive down the interstate at 5 mph on the off chance that someone walks into traffic?
Answered your own question, there, didn't you? Besides, a *computer* told them to, can't argue with that.
Brett
And the first one that goes in the drink, blows up, or otherwise fails, people will jump all over them for wasting millions of dollars on some pie-in-the-sky experiment instead of using proven approaches.
Well, that's part of it. Just ignore the cleaning events and other factors. They probably figured on 3-sigma dust accumulation rates. That means that 99.73% of the time it's going to be less than that. Meaning that they could launch 1000 of them, and you would expect that 3 of them would run out of power in 90 days. So it is not in any way surprising that they didn't get excess dust accumulation.
Same thing with everything else. All the .9973 from every identified part/subassembly multipled together is total reliability, and so it's not in any way surprising that these things generally last *much much longer* than the specified mission duration.
This sort of analysis, of course, presupposes that statistically significant measures are applicable. For one-off or very short-run parts, of course there are no statistics so the methodology can tend to the bullshit end of the plausibility scale.
Well, it's funny, but a lot of people are *against* killing the economy and going broke. And worst of all, a gas tax is exceptionally regressive.
Brett
Because sometimes it doesn't come back on again.
Brett
Obviously, it's in "key.doc"
Absolutely correct, and good analogy
Are you one of those kids I chased off my lawn last night?!
I was an MCC console analyst on the mission control team for the payload. So I didn't work for NASA, but a contractor working for our governmental customer.
A lot of people don't realize this, but NASA is not the biggest player in the space business. Some individual DOD and other government customer *programs* have budgets rivaling NASA, and there are a pretty good number of programs.
Brett
"We used to have a way to move things without robots. What was that again? - Ruth Gordon had one....Oh, The Wheel!"
I worked on mission 51J (first Atlantis flight) and now it's done. Man, I am old...
I suggest unicorns on a treadmill.
Brett
LAGRANGE POINTS? Good God almighty? What in the holy heck are you talking about? That's just ridiculous. It's not going to go to the Lagrange points (any of them). If nothing else there's no maneuvering and so the semi-major axis is FIXED at essentially geosynchronous period. What will happen is that that it will drift at varying speeds on the order of fractions of degrees a day, speeding up as it goes towards the gravity wells, passing through at pretty high speeds, then climbing back out, slowing all the time. I haven't checked the TLEs but it will either oscillate back and forth in one of wells or pass from one to the other. Just like dozens of other "died in place" spacecraft that had exactly the same problem. Eventually as the inclination changes it might go over the side of the hill (since the wells are 3-dimensional) like Skynet II/9354. Look that one up, or DSCS II/Flight II/9432 TLEs and history, that's what it's going to do.
Brett
A few?
Damn straight! Why should I have to pay for it? The government has a lot of money, they should pay!
I have a fair bit of experience with spacecraft of this era, and they tended to have pretty similar architecture. This is speculation of course since I haven't seen the data, but typically, the telemetry from the bus (everything but the intruments) is formed by the main telemetry unit. Data from user systems (like the intruments) is generally collected and put into a data stream by a secondary encoder. Periodically, the main telemetry unit sends a sync pulse to the payload encoder to trigger it to spew out the stream, conveniently timed to align itself with the rest of the downlink, Given thereport the bus telemetry seems OK, so there's probably something wrong with the payload encoder, or the generation of the sync pulse. I have seen anomalies where the sync pulse was generated at the wrong time, generated at random, or generated more-or-less continuosly. Of course a simple failure of a multiplexer in the encoder, or the serial data interface to the encoder in the main TLM unit would cause similar problems. It might be possible to recover from the spurious sync pulse issue if some of the data is sufficiently repeatable to use an an alternate way of determining where in the encoder stream the data got to when the window in the downlink frame came around. You might lose some of it but might be able to retrieve the rest. That should be pretty easy since a lot of the instruments are turned off (which they are) - that will create a very distinct pattern of valid data an all zeros that would let you know where in the encoder stream you are. If there's off-time sync pulse what will happen is that you will get all the data but it will be rolled around so that what you thought was the "bus voltage" is actually showing up in the downlink as the "tank pressure" or something like that. That would probably work for a "continuously rolling" encoder stream as well, where it never receives any sync pulses.
Of course they probably figured it out themselves, but I have had a lot of luck working these sorts of issues so if anyone from JPL thinks they need a hand, I will happy to consult. Given that I use my REAL NAME it shouldn't be difficult to contact me.
A turtleneck sweater would not be amiss, either.
Yeah, all that frequent sex with gorgeous women really gets you down after a while. I had to tell Salma to *stop calling*!
In other news, Slashdot posters also declared with authority that "dating supermodels is a real pain in the ass, they are too high-maintenance" and "being rich doesn't make you happy!"
Its cheap (free) and easy. Even if there is *one* sale, its worth it.
I guess I am not following the issue - I have been running various versions of Safari since it first appeared, and it has crashed, at most, 2-3 times in however many years it has been. What is it that people are doing that causes it to crash? I am not doing anything special, and I haven't even bothered to block any plugins, or Javascript. Flash seems to be fine - an abomination, to be sure - but functionally fine.
Well, if you crash a bunch of asteroids into it, it will likely become molten, creating a new phase of differentiation, and there is a reasonable chance that a new dynamo will form and create a new magnetosphere. It's at least as plausible that that would happen as you could crash a bunch of asteroids into it in the first place. It wouldn't likely last all that long in geological terms given the likely lack of useful radionuclides.
There are still some people who believe that human achievement is a zero-sum game. Idiots, we call them.