Amen to that. Thankfully, many of the missions I know of that are in development are baselining RAD750s. Of course, byt the time some of them launch (2010-2012 timeframe) I'm sure there'll be some newer, deeply cooler chip available. Such is life in the space industry...:-)
you'd think they could at least send up some more hardware with these little critters. The extra weight would pan out, when things go bad...case in point see what they are dealing with now
There's a limit to how much mass we can send to Mars, driven by the throw capability of our launch vehicles. MER was launched on a cheaper (read less throw capability) launch vehicle (the Delta II), and was pretty tight on mass from the get-go. There simply wasn't room for an extra computer. In fact there was barely any room for redundancy at all, so most of the design is single-string. The argument was that they had "system-level redundancy" (i.e. two rovers), but that only works if the problem isn't a design flaw...
The processors in MER are RAD6000's, which are radiation-hardened versions of the RS/6000, the predecessor to the PowerPC (see this for details). The RAD6000's younger brother, the RAD750, is indeed a rad-hardened PowerPC.
As an aside, there is a big difference between a radiation-shielded processor and a radiation-hardened processor. Shielding implies just sticking some kind of rad-absorbent material between the processor and the environment. A rad-hardened processor is actually manufactured in a different way - different gate layout, different design rules, often different materials (Silicon-on-Insulator is popular). These things are done to minimize or prevent the effects of single-event upsets (when a bit is flipped by high-energy particles) and single-event latchups (which basically turn a couple of gates into a glorified short-to-ground). The materials changes may also improve the overall total dose tolerance of the processor. The work required for redesign is one of the reasons that space-qualified rad-hard processors lag the commercial market. The NASA Office of Logic Design has some good papers on space processors available online if you're interested in learning more.
Sure, VBA is not anything you'd use for a major project...
Probably depends on what you mean by "major project":-) I've seen Excel VBA used as the indispensable core component of an industry-leading spacecraft design center. JPL's Project Design Center used to run on an Excel/VBA platform (although I believe that they may have migrated to something else recently).
The problem had nothing to do with eglish->metric conversion.
I never claimed it did. Perhaps you should re-read my post. My gripe is that the use of two different systems of units leads to lots of communications problems, and inevitably leads to errors when those communications channels fail. Now in the case of the Space Mountain mishap it seems that the problem was mostly related to poor configuration management, but it was exacerbated by the transition from one system of units to another which was poorly handled - i.e. a broken communications channel.
I don't want to get into a (pointless) argument about which is the "better" system. I happen to find metric easier to work with, and it seems to be the global standard system for science and engineering (except for some American throwbacks in fields like rocket engineering). So I'd like to see us standardize on metric. But frankly, I don't think it really matters whether we standardize on Imperial or on metric. I just wish we'd standardize on something.
Sigh. When is America going to ditch its archaic measurement system and use the same standard as everyone else? I work in the space industry, and I see this idiocy going on all the time: half the team works in metric, the other half in english. Most of the time everyone manages to keep it straight. But every now and then, a mistake happens. Scientists all use metric. Most engineers are trained in metric. Let's just switch to metric for everything and be done with it.
A side note: in New Zealand (and possibly other Commonwealth countries - I haven't checked) they don't even refer to "English units". Their term is "Imperial units". Which tells you how long it's been since they made the switch...
Not sure if the budget includes operations. I believe that it may well include development of the ground systems, but that will be a fraction of the cost of the spacecraft & launch. Even if the budget does include ops, that's only 90 days per rover, with a 2 month overlap (i.e. a total of around 120 days). They cannot go far beyond that due to design life limits on the rovers (mostly as a result of solar array degradation IIRC). So I doubt the ops cost will dominate the budget.
Satellite lifetime is also determined by the amount of degradation suffered by the solar arrays. Over time the arrays lose efficiency due to radiation damage. Satellite designers know this, and thus design the arrays to initially be bigger than is necessary to support the payload so that the capability of the degraded arrays at the end of life is still sufficient to power everything. Longer lifetimes mean larger solar arrays, which means more mass, more complicated attitude control, greater propellant usage, and a host of other problems. Plus, as another poster pointed out, the technology becomes obsolete after a while. 12-15 years seems to be an optimal spacecraft lifetime (the actual duration being dependent on the type of mission), although some missions are better off with even shorter lifetimes.
Big comm birds aren't going to LEO, they're going to GEO. That said, your conclusions are dead on.
Launch costs are somewhere between US $50M-$100M these days, depending on exactly how big a satellite we're talking about. The standard rule-of-thumb is that launch costs are roughly the same as spacecraft costs. So the average "big comm bird" is probably somewhere around US $100M.
Just to put the ridiculousness of the grandparent's assertion about comm sats costing $1B into further perspective: the current Mars Exploration Rover mission cost (officially anyway) under $1B. For that cost they developed a brand new and very complex rover design, as well as a complete lander and cruise-stage system, then actually built and launched two of them (Spirit and Opportunity). So claiming that a single satellite doing a fairly standard mission, and launching only to GEO, cost ~$1B seems fairly absurd.
Yeah, but an RTG is a whole different beast to a reactor. An RTG is basically just a chunk of plutonium that radioactively decays, generating heat that is then converted to electricity via the Peltier effect. A reactor involves an actual fission reaction (not just decay), and therefore all of the complexity that creating and controlling that reaction entails. Not saying that we couldn't build a robust reactor, just that the comparison with RTGs is not really a very good one.
...Somethings, like the invention/development of first computers, and aircraft that pretty much cannot be done with private dollars alone...
Except that the first aircraft were done with private dollars. At a fraction (~1/10) the cost of the contemporaneous government efforts (which failed).
Or perhaps its that they haven't actually calibrated the color filters yet. That comes later in the mission. AFAIK the current images are coming from the hazcams and navcams, which don't have any color capability. The pancam does have color filters, but they're fairly useless until calibrated against the onboard color wheel. Bandwidth may also be playing a part (the high gain antenna has only just been deployed), but transmitting the three images required to generate a color-composite, at the resolution presently being used, wouldn't be that much of a bandwidth hog.
Just wanted to point out that there where many other groups involved in producing MER aside from NASA, including scientists at Cornell (and elsewhere), engineers at Lockheed Martin and Ball Aerospace, and engineers and technicians at a variety of smaller contractors. Yes, the team was led by NASA/JPL, but it was composed of folks from all over the place.
Actually, the RAD6000 is derived from an RS/6000 (predecessor to the PowerPC). Its newer cousin, the RAD750 rad-hardened processor, is based on one of the older PowerPC models, but has not actually (AFAIK) been flown in space yet.
Space flight is a huge *waste* of valueable research dollars.
You forgot the "IMHO" part...
You may think that space flight is a huge waste of dollars. Many others do not. So long as it's not your money being spent, why should you care? "Ah" you say, "but it *is* my money, 'cos NASA is taxpayer funded." But that's the beauty of the X-prize competition that the grandparent post was referring to - it's purely privately funded. So it really doens't matter what you think about space flight. They're going to do it anyway. Who knows, maybe you'll even derive some benefit from it at some point.
We have basic space filight now. Its fairly safe and the costs are resonable.
Uh, in a word, bullshit. Especially on the "costs are reasonable" part. It costs on the order of $500 Million for a single shuttle launch, and they only happen a few times a year (and require a standing army of several thousand to support them). The whole point of the X-prize is to develop cheap, reliable, regular space launch. Everyone in the space industry (and I speak here as someone in the space industry) views launch costs as one of the greatest impediments to doing more in space. That applies to unmanned as well as manned missions.
There is simple no return on investment in continued research.
I won't even bother to debate the stupidity of that comment. The fact that people are investing would tend to imply that there is at least some perception of an ROI. Although it may depend on what exactly you consider an adequate ROI, and what time scales you are operating on.
We have a space station or will very soon, we have the shuttle which works well enough.
See above for the shuttle. It costs a crapload. Far more than it needs to. Mostly as a result of a piss-poor design that was more political compromise than anything else. The station is a nice idea but appears to be a bit of a white elephant. Right now it can only deal with a crew of up to 3, which is not a sufficient number to allow any science to take place (too busy just maintaining the station). And my understanding from talking to folks in the science community is that the station is essentially useless for it purported primary purpose, microgravity research, because astronaut induced vibrations screw up the "microgravity" environment in all but a very small part of the station.
There is nothing valueable in space within our grasp as far as anyone knows if that changes so does my thesis but untill then the status quo is best left to persist.
It's a cost/benefit thing - there's lots of stuff in space that's be nice to make use of, but it costs too much to get it right now. Why? Well, launch costs have a lot to do with that (see above). Highly recommend that you check out a report called "LEO on the Cheap" by Lt. Col. Jack London that discusses that cascading effects of high launch costs, and how to fix them (should be available in PDF form on line - google is your friend).
I read in some physics journal once that even if you could travel faster then the speed of light you probably need around 1 1/3 times the sqare of the mass you will be moving in fule.
Depends a lot on the efficiency of your engine. Alternatively, you could make use of something like a laser sail to accelerate - then you don't need to carry any fuel. A third alternative is not to accelerate to the speed of light, but to bypass it, i.e. use one of the various (somewhat flaky at this point) "warp drives" that have been proposed. All are at least as plausible (or more plausible) than a time travel machine. Incidentally, did it occur to you that time travel is equivalent to faster than light travel in the Einsteinian universe?
...or the one-sided archetypes that plagued most of B5's run...
Are we thinking of the same series? Babylon 5, right? The one where Londo Molari intially appeared to be the archtypal comic foil for Garibaldi, but was gradually revealed to be a far more complex, "shades of grey" character. Where G'kar slowly moved from his intial appearance as the archetypal villain to someone philosopphical, noble, and worthy of trust and respect. Where even bad guy Bester can be seen to have something sympathetic about him in at least a few of the episodes. I mean, ok, Sheridan was kind of wooden and cardboard cut-out. But the supporting characters were excellent (IMHO).
Also, space flight doesn't work like that... but every other series I've seen has portrayed space flight as far too similar to atmospheric flight, so I guess I shouldn't bother complaining.
Some of the space battle scenes in Babylon 5 were handled in a physically realistic manner (not all - scenes involving the White Star tended to get out of hand). In particular, their handling of the Star Fury fighters was very good. The fighters were depicted as having full 3-axis attitude control, and it wasn't uncommon to see them flying "sideways" relative to their velocity vector, changing attitude to track a target without changing trajectory.
And there is the propect that the next Mars landings will do some good science....Stick with KISS -- Keep It Simple, Stupid.
I wouldn't exactly be banking on MER if you're a believer in the KISS philosophy. While it's marketed as being "just like Pathfinder, but a little bigger", it's actually radically different in a number of ways. And those ways all add complexity and risk to the mission. For example, cramming such a large rover into a Pathfinder-sized lander means that the number of successful mechanical deployments necessary for the rover to get up and running is... uh... unusually high, to say the least.
Pretty much all spacecraft are manufactured in clean rooms, in roder to avoid picking up contaminating particles that might damage electronics or optics.
On the sterilization issue, believe it or not a lot of it comes down to alcohol wipes. (no joke)
I think you'll find that your questions will be answered by a look at this site. It's all about Mini-Magnetospheric Plasma Propulsion (M2P2). They do exactly what you are asking for (create an artificial magnetosphere), and supply some nifty propulsion to boot. And no, it doesn't require megatons of molten iron, as some other posters have suggested...
I suspect that you will see SuSE get some namebrand notice in the near future, since they've just become part of Novell. Novell has extremely good name recognition, and they're very keen to get into Linux in a big way. Something to keep an eye on...
And maybe you'll think differently when you end up being accidentally profiled as a terrorist, like all the "Dave Nelson"s out there...
We have suffered one (1) Islamist terrorist attack in the US. It was a wake-up call for everyone. The only reason it succeeded at all was that the terrorists exploited a loophole in the policy for dealing with hijackers. That loophole has been patched by virtue of the fact that people will not sit idly by and let a plane be hijacked now, as they would have in the past. Over-reacting to that single attack (no matter how devastating it was) will not make things better. Remake our society into a police state, and the terrorists will have won.
Incidentally, given the fact that the FBI and CIA were unable to catch the 9/11 group before they did anything not because they had no info, but because they had far too much info to process, doesn't it seem silly to deluge them with even more info - most of it useless?
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AFAIK the RAD6K is derived from the original POWER architecture.
Amen to that. Thankfully, many of the missions I know of that are in development are baselining RAD750s. Of course, byt the time some of them launch (2010-2012 timeframe) I'm sure there'll be some newer, deeply cooler chip available. Such is life in the space industry... :-)
There's a limit to how much mass we can send to Mars, driven by the throw capability of our launch vehicles. MER was launched on a cheaper (read less throw capability) launch vehicle (the Delta II), and was pretty tight on mass from the get-go. There simply wasn't room for an extra computer. In fact there was barely any room for redundancy at all, so most of the design is single-string. The argument was that they had "system-level redundancy" (i.e. two rovers), but that only works if the problem isn't a design flaw...
No, they're not.
The processors in MER are RAD6000's, which are radiation-hardened versions of the RS/6000, the predecessor to the PowerPC (see this for details). The RAD6000's younger brother, the RAD750, is indeed a rad-hardened PowerPC.
As an aside, there is a big difference between a radiation-shielded processor and a radiation-hardened processor. Shielding implies just sticking some kind of rad-absorbent material between the processor and the environment. A rad-hardened processor is actually manufactured in a different way - different gate layout, different design rules, often different materials (Silicon-on-Insulator is popular). These things are done to minimize or prevent the effects of single-event upsets (when a bit is flipped by high-energy particles) and single-event latchups (which basically turn a couple of gates into a glorified short-to-ground). The materials changes may also improve the overall total dose tolerance of the processor. The work required for redesign is one of the reasons that space-qualified rad-hard processors lag the commercial market. The NASA Office of Logic Design has some good papers on space processors available online if you're interested in learning more.
Probably depends on what you mean by "major project" :-) I've seen Excel VBA used as the indispensable core component of an industry-leading spacecraft design center. JPL's Project Design Center used to run on an Excel/VBA platform (although I believe that they may have migrated to something else recently).
I never claimed it did. Perhaps you should re-read my post. My gripe is that the use of two different systems of units leads to lots of communications problems, and inevitably leads to errors when those communications channels fail. Now in the case of the Space Mountain mishap it seems that the problem was mostly related to poor configuration management, but it was exacerbated by the transition from one system of units to another which was poorly handled - i.e. a broken communications channel.
I don't want to get into a (pointless) argument about which is the "better" system. I happen to find metric easier to work with, and it seems to be the global standard system for science and engineering (except for some American throwbacks in fields like rocket engineering). So I'd like to see us standardize on metric. But frankly, I don't think it really matters whether we standardize on Imperial or on metric. I just wish we'd standardize on something.
A side note: in New Zealand (and possibly other Commonwealth countries - I haven't checked) they don't even refer to "English units". Their term is "Imperial units". Which tells you how long it's been since they made the switch...
Not sure if the budget includes operations. I believe that it may well include development of the ground systems, but that will be a fraction of the cost of the spacecraft & launch. Even if the budget does include ops, that's only 90 days per rover, with a 2 month overlap (i.e. a total of around 120 days). They cannot go far beyond that due to design life limits on the rovers (mostly as a result of solar array degradation IIRC). So I doubt the ops cost will dominate the budget.
Satellite lifetime is also determined by the amount of degradation suffered by the solar arrays. Over time the arrays lose efficiency due to radiation damage. Satellite designers know this, and thus design the arrays to initially be bigger than is necessary to support the payload so that the capability of the degraded arrays at the end of life is still sufficient to power everything. Longer lifetimes mean larger solar arrays, which means more mass, more complicated attitude control, greater propellant usage, and a host of other problems. Plus, as another poster pointed out, the technology becomes obsolete after a while. 12-15 years seems to be an optimal spacecraft lifetime (the actual duration being dependent on the type of mission), although some missions are better off with even shorter lifetimes.
Launch costs are somewhere between US $50M-$100M these days, depending on exactly how big a satellite we're talking about. The standard rule-of-thumb is that launch costs are roughly the same as spacecraft costs. So the average "big comm bird" is probably somewhere around US $100M.
Just to put the ridiculousness of the grandparent's assertion about comm sats costing $1B into further perspective: the current Mars Exploration Rover mission cost (officially anyway) under $1B. For that cost they developed a brand new and very complex rover design, as well as a complete lander and cruise-stage system, then actually built and launched two of them (Spirit and Opportunity). So claiming that a single satellite doing a fairly standard mission, and launching only to GEO, cost ~$1B seems fairly absurd.
Yeah, but an RTG is a whole different beast to a reactor. An RTG is basically just a chunk of plutonium that radioactively decays, generating heat that is then converted to electricity via the Peltier effect. A reactor involves an actual fission reaction (not just decay), and therefore all of the complexity that creating and controlling that reaction entails. Not saying that we couldn't build a robust reactor, just that the comparison with RTGs is not really a very good one.
Except that the first aircraft were done with private dollars. At a fraction (~1/10) the cost of the contemporaneous government efforts (which failed).
Or perhaps its that they haven't actually calibrated the color filters yet. That comes later in the mission. AFAIK the current images are coming from the hazcams and navcams, which don't have any color capability. The pancam does have color filters, but they're fairly useless until calibrated against the onboard color wheel. Bandwidth may also be playing a part (the high gain antenna has only just been deployed), but transmitting the three images required to generate a color-composite, at the resolution presently being used, wouldn't be that much of a bandwidth hog.
Just wanted to point out that there where many other groups involved in producing MER aside from NASA, including scientists at Cornell (and elsewhere), engineers at Lockheed Martin and Ball Aerospace, and engineers and technicians at a variety of smaller contractors. Yes, the team was led by NASA/JPL, but it was composed of folks from all over the place.
MER was mostly designed and manufactured at JPL. IIRC Lockmart only supplied the aeroshell (although they may have also done a few other components).
Actually, the RAD6000 is derived from an RS/6000 (predecessor to the PowerPC). Its newer cousin, the RAD750 rad-hardened processor, is based on one of the older PowerPC models, but has not actually (AFAIK) been flown in space yet.
You forgot the "IMHO" part...
You may think that space flight is a huge waste of dollars. Many others do not. So long as it's not your money being spent, why should you care? "Ah" you say, "but it *is* my money, 'cos NASA is taxpayer funded." But that's the beauty of the X-prize competition that the grandparent post was referring to - it's purely privately funded. So it really doens't matter what you think about space flight. They're going to do it anyway. Who knows, maybe you'll even derive some benefit from it at some point.
We have basic space filight now. Its fairly safe and the costs are resonable.
Uh, in a word, bullshit. Especially on the "costs are reasonable" part. It costs on the order of $500 Million for a single shuttle launch, and they only happen a few times a year (and require a standing army of several thousand to support them). The whole point of the X-prize is to develop cheap, reliable, regular space launch. Everyone in the space industry (and I speak here as someone in the space industry) views launch costs as one of the greatest impediments to doing more in space. That applies to unmanned as well as manned missions.
There is simple no return on investment in continued research.
I won't even bother to debate the stupidity of that comment. The fact that people are investing would tend to imply that there is at least some perception of an ROI. Although it may depend on what exactly you consider an adequate ROI, and what time scales you are operating on.
We have a space station or will very soon, we have the shuttle which works well enough.
See above for the shuttle. It costs a crapload. Far more than it needs to. Mostly as a result of a piss-poor design that was more political compromise than anything else. The station is a nice idea but appears to be a bit of a white elephant. Right now it can only deal with a crew of up to 3, which is not a sufficient number to allow any science to take place (too busy just maintaining the station). And my understanding from talking to folks in the science community is that the station is essentially useless for it purported primary purpose, microgravity research, because astronaut induced vibrations screw up the "microgravity" environment in all but a very small part of the station.
There is nothing valueable in space within our grasp as far as anyone knows if that changes so does my thesis but untill then the status quo is best left to persist.
It's a cost/benefit thing - there's lots of stuff in space that's be nice to make use of, but it costs too much to get it right now. Why? Well, launch costs have a lot to do with that (see above). Highly recommend that you check out a report called "LEO on the Cheap" by Lt. Col. Jack London that discusses that cascading effects of high launch costs, and how to fix them (should be available in PDF form on line - google is your friend).
I read in some physics journal once that even if you could travel faster then the speed of light you probably need around 1 1/3 times the sqare of the mass you will be moving in fule.
Depends a lot on the efficiency of your engine. Alternatively, you could make use of something like a laser sail to accelerate - then you don't need to carry any fuel. A third alternative is not to accelerate to the speed of light, but to bypass it, i.e. use one of the various (somewhat flaky at this point) "warp drives" that have been proposed. All are at least as plausible (or more plausible) than a time travel machine. Incidentally, did it occur to you that time travel is equivalent to faster than light travel in the Einsteinian universe?
Are we thinking of the same series? Babylon 5, right? The one where Londo Molari intially appeared to be the archtypal comic foil for Garibaldi, but was gradually revealed to be a far more complex, "shades of grey" character. Where G'kar slowly moved from his intial appearance as the archetypal villain to someone philosopphical, noble, and worthy of trust and respect. Where even bad guy Bester can be seen to have something sympathetic about him in at least a few of the episodes. I mean, ok, Sheridan was kind of wooden and cardboard cut-out. But the supporting characters were excellent (IMHO).
Some of the space battle scenes in Babylon 5 were handled in a physically realistic manner (not all - scenes involving the White Star tended to get out of hand). In particular, their handling of the Star Fury fighters was very good. The fighters were depicted as having full 3-axis attitude control, and it wasn't uncommon to see them flying "sideways" relative to their velocity vector, changing attitude to track a target without changing trajectory.
I wouldn't exactly be banking on MER if you're a believer in the KISS philosophy. While it's marketed as being "just like Pathfinder, but a little bigger", it's actually radically different in a number of ways. And those ways all add complexity and risk to the mission. For example, cramming such a large rover into a Pathfinder-sized lander means that the number of successful mechanical deployments necessary for the rover to get up and running is... uh... unusually high, to say the least.
On the sterilization issue, believe it or not a lot of it comes down to alcohol wipes. (no joke)
I think you'll find that your questions will be answered by a look at this site. It's all about Mini-Magnetospheric Plasma Propulsion (M2P2). They do exactly what you are asking for (create an artificial magnetosphere), and supply some nifty propulsion to boot. And no, it doesn't require megatons of molten iron, as some other posters have suggested...
Disclaimer: I like X, and don't happen to believe it suffers from "bloat".
I suspect that you will see SuSE get some namebrand notice in the near future, since they've just become part of Novell. Novell has extremely good name recognition, and they're very keen to get into Linux in a big way. Something to keep an eye on...
We have suffered one (1) Islamist terrorist attack in the US. It was a wake-up call for everyone. The only reason it succeeded at all was that the terrorists exploited a loophole in the policy for dealing with hijackers. That loophole has been patched by virtue of the fact that people will not sit idly by and let a plane be hijacked now, as they would have in the past. Over-reacting to that single attack (no matter how devastating it was) will not make things better. Remake our society into a police state, and the terrorists will have won.
Incidentally, given the fact that the FBI and CIA were unable to catch the 9/11 group before they did anything not because they had no info, but because they had far too much info to process, doesn't it seem silly to deluge them with even more info - most of it useless?