Unfortunately the unsafe-ness of the shuttle isn't a small thing can be fixed, its a result of the side mounted configuration. With Apollo/Orion type capsules, or even a top mounted space plane, you can have an escape system that pulls the manned component off the top, and it's impossible to damage it with falling debris from other parts of the launch vehicle.
Also, the very idea of the reusable manned/cargo vehicle is inherently flawed. My personal favorite analogy is like deciding that you should buy a truck (instead of a truck and a small car) because you need to haul stuff around occasionally, with gas costing $1000 per gallon.
The new configuration, assuming it works as they say it will, is superior in l ways but one. The Ares V will have 130 m-T capability to LEO instead of the shuttles 24 m-T. The Orion capsule is in fact reusable, and while smaller than the shuttle, it doesn't make sense to launch the labs every time you go up. This goes with the idea that the ISS will become something useful. Having another tragedy like Columbia, while not only less likely, would also not cause a loss of our cargo capacity as well, which led to the current state of the ISS. The only real disadvantage is our inability to return things from orbit, and as far as I know we've never used that capability.
That is why I'm an engineer and not a more abstract scientist or science fiction writers. I think in a way along of how youd practically do something. We need people like me, we need people not like me.
I'd never much considered the nano-probe idea before simply because it didn't come to mind, but I think it's really interesting. That's why I'm here on slashdot, to discuss and learn things like this, not because I'm not doing anything better... well that and I have no class today. That's the beauty of society, academics, the internet, and all of this, that we can get together and consider ideas that we wouldn't think of individually, because we're all very different.
That said I hope we look at the possibilities of this in the near future for actual use, and would be interested in working on it myself if I got the chance.
True, but its still a nice reminder of the actual way it should be (I don't particularly like doing probabilities). Quick numbers say if there were so many of these advanced 'immortal'* species, you'd get:
Agreed, to some extent. Yes, we all hope theres something better than rocket technology. But right now theres nothing rigorously shown to be theoretical possible even. Certainly there are some promising ideas, but nothing for sure.
All I'm really saying is that 1/10 c seems reasonable for a highly advanced species, whether its done with advanced rocketry or something else entirely. Also you could make an argument similar to the Fermi Paradox (if they're out there exploring how come we havent met them yet), not necessarily that they're not there, but that something like this 1/10 c number is reasonable because if it were higher we'd likely have made contact by now.
Also, assuming they use some kind of rocket technology (that is, technology that shoots stuff out one side to propel the vehicle in the other), 1/10 c is much more realistic than something approaching c. Assuming a technology that has 100 times the specific impulse as our current vehicles (the best ion thrusters get ~4500 s,) I get using the rocket equation that the initial mass to move 1 ton of cargo is:
1/10 c: 3.263e29 tons.99 c: 1.534e292 tons
Even then this seems absolutely ridiculous. If you used a matter/antimatter reaction so that your propellant was pure electromagnetic radiation (thus your exit velocity is c), you'd get these results
1/10 c: 1.105 tons.99 c: 2.69 tons
Of course, these are not adjusted for relativity, since I don't know any simple equations to do that. I would imagine (as a wild-ass guess) that the 1/10 c estimates are close, but the.99 c results are off by thousands of orders of magnitude.
Basically all I'm saying is that 1/10 c seems fairly reasonable. It's not feasible given our current technology, but its within reason. If you start looking at things like space-time warpage, then we have no idea on any usage or capabilities, so any kind of theory based on it gets even further and further from reality.
By the way, I am a rocket scientist, but only a student, and not a physicist at all, only an interested amateur.
NASA and the rest are looking heavily at In-Situ Resource Utilization (ISRU) for other fuels, so if a future mission uses these engines, they will certainly look at taking the methane, and it will probably be easier than a lot of other messages.
However, looking at missions to the outer planets, chemical propellants won't cut it. Electric Propulsion, like ion thrusters or Hall thrusters have much higher specific impulse (basically fuel efficiency), with much lower thrust, but are ideal for long term missions like an outer planets exploration mission.
It would be great for a lander however, because if we land something on the surface and want to get it back up, a methane chemical rocket sounds like it might be a good idea in such an environment.
The other difference is that, at least in theory, a 'resistance' would refer to a group trying to drive the invaders out, as is the case with the European resistances in WWII.
However in Iraq, the US and UK would like nothing better than to leave, but feel a responsibility to insure stability after the mess we caused (in one set of rhetoric), or to secure freedom for the people (in another set of rhetoric.) The insurgent forces are not fighting to remove a foreign dictatorship, or if they think they are they're doing a really bad job of it. What they're doing, at least as best as I can tell, is to insure that the new government is their groups government, or, at risk of sounding self important, to stick it to US because they don't like us and our policies on Israel and other various issues.
Obviously it's a much more complex issue, we are trying to impose our own idea of order, and put up people in power that we can at least stand. However, it seems to me, though I'm biased, that the basic differences are there and important.
These are suborbital flights, and I'd imagine they'll be close to the same price as Virgin's (~$200,000). Not exactly cheap, but a couple of order of magnitudes smaller, and admittedly at least an order of magnitude less cool. I'm very interested to see how this suborbital space tourism thing goes. I know some people going up on the first few virgin flights, but I'm still not wholly optimistic about it.
If a kid is able to sneak out on abusive parents to report them, I imagine they can sneak out without their cell phone, or do it someplace they should be anyway (e.g. School.)
Parental controls are completely different from governmental controls. Firstly, children are by definition immature and therefore unlikely to be able to completely handle themeselves and make good decisions. This can change in the 15-18 year old range, although thats fairly unlikely, and it seems reasonable to give their parents the benefit of the doubt here. Secondly, parents are much more likely to behave beneficially toward their children than a government toward its people. Genetically we want to protect our children and try and do our best for them, while doing good in government probably comes from a higher part of the mind. Also, there is very little to be gained by abusing power in a family, when compared with what can be gained by abusing governmental power.
With younger and younger children having cell phones, particularly these little ones that can only call 6 numbers or something like that for the younger ones, this seems like a great thing. Keeps you from having to track down which house the pack of neighborhood kids went to now, makes it easier to pick up the kids from soccer practice when it ends early, and generally gives parents better peace of mind. Seems like an overall good thing to me. Surely there will be some problems, but I'm betting we can figure them out.
(Note: I'm not a parent, but have much younger siblings, so take my comments with a grain of salt)
While robots are great for initial exploration, and that for current manned work that isn't actually research on the people themselves, robots would provide more results per dollar (the human experience is still more useful, but I doubt as much as the cost.
Anyway, this is about colonization (I hope), rather than exploration. I really hope that the current NASA plan goes towards true colonization, although like most people I have become jaded. I just always fear that people don't realize that colonization is critical in the long term, and colonization, by definition, depends on manned flight.
I'd also argue that this problem really has its roots in middle and high school. I had great science teachers in high school. However, I was in one of the best public schools in the state, and even then, my physics teacher left during my last semester because his wifes business failed and he had to support the family. Our good chemistry and physics teachers left in the following years, and as far as I know they weren't replaced by equally well qualified teachers.
Programs like IBMs funding for those close to retirement to go into teaching seem to me the best solution, and I'd like to see more serious efforts like this by other companies or even (shockingly) the government.
Yes, its easy to get weeded out in college (I'm finishing up an engineering degree this year,) but I'd argue that a significant portion of the problem is that they're not prepared for college because its too easy. I probably would have had much more problems if not for AP Physics (Calculus-Based) class that I took in high school.
I'd say this is the exact problem with the space program. Yes, the ISS is a steaming pile of crap.
Spending our the to make the planet we will all live and die on a better place is a noble goal, however, its not the only goal. I think we already have a large number of people concentrating on that. That is I know people involved in Amnesty International, developing new hybrid vehicle systems, Engineers Without Borders, and the best of organized religion (mission trips concentrated on helping people as opposed to simple evangelism). I hear of even more here on slashdot, the Bill and Melinda Gates Foundation, the One Laptop Per Child Project, and the endless watch for Big Brother-ism and the tyranny of monopoly. I personally do some work with regards to the improvement of the educational system within the US, which is one of my main personal cause du jours.
However, I think with all this effort spent to improve our earthly existence, theres a little room to get us off this planet and help to provide some relief that way. Obviously it won't have immediate effect. The early colonist's to America didn't immediately stem Europe's problems even directly related to population growth, however in the end its impossible to deny its effects. And with space we dont have the genocidal side effects that are such a stain on that period in history. The future of humanity (in my own very humble opinion) depends on us establishing offworld settlements, and whether thats in the next 20 years, the next 200, or the next 2000, I plan on doing my damndest to push us forward, and supporting others who do, because some people need to do it. And there's nothing wrong with a small portion of the national budget going that way too (and it is a small portion, look it up.)
Find your own way to save the world, improve it, or keep it going. All of those things are vital.
I actually finished a presentation today with Johnson Space Center (JSC) about resupplying a Moon Base for a university class today, and I'm planning on going and helping run a booth at the SEC conference (where I assume this plan was announced) tomorrow. Needless to say I'm very excited about these plans and am very much a space exploration advocate. Look at my previous posts and I think that will show it.
NASA at times does a great job of innovation and exploration. Anything unmanned, JPL and Ames do a great job with. Not to deride anyone at JPL, but its very hard to not be a little cyncical about this. I am very afraid of what the next administration may bring, whether it's Democrat or Republican, and am afraid that whoever is next may help put the axe on Bush's best initiative (though its been a bit bastardized lately.)
Here's hoping we get a moon base like the antarctic base, and can move on to Mars (although I don't believe that the one is necessarily dependent on the other.)
Exactly... some rough math gives me that an asteroid about a tenth the size of Ceres would be about 10^20 kg, or 10^17 metric-tons. In order to move that from the moons orbit to LEO (I'm working on a similar problem right now) in 2 decades would require about 10^12 Newtons, which would require 10^13 kW, which would require a similar order of magnitude of solar array area with a good estimate of future capabilities (Solar array efficience is improving only incrementally.) This, with the prices scaling linearly (which they wouldn't, you'd start having economies of scale), would cost 10^13 million dollars.
Note, these are very rough order of magnitude numbers scaled from a ~4 month journey to the moon with ~30 m-T, ~100 m^2 of solar arrays for ~100 kW of power. These things tend to scale linearly (solar array area to power, power to thrust, thrust to time, etc.)
Ion engines probably aren't the best choice for this. They require a lot of power (100s of kW to get a few newtons of thrust), and the material you'll find on the asteroid probably won't be ideal propellants (heavy noble gases like xenon are ideal.)
However, doing the same thing with a traditional chemical rocket and in-situ propellant production (currently in the works for moon and Mars missions) could be very productive, and in fact would hope that somewhere in JPL theres a case study looking at that possibility.
I'd say thats definitely a valid point (I actually considered saying something about it but decided to make the post short instead.) However, my impressions of the man are that he is good at knowing what he doesnt know and will be much more likely to listen to the generals and others. Also, I'd imagine that he has a good grasp on military matters from his days as a Soviet analyst (unfortunately nothing I've come across says whether his experience was more military or political, just that his PhD was in Soviet history, which could be either.)
Of course I could be wrong, I just hope I'm not (for our country and Iraq, not for my ego... well, maybe a little.)
I'm a student at Texas A&M (where Dr. Gates is currently university president,) and I'd have to say I disagree with this assesment of the man. He has done a great job here of seeing problems, finding a solution, and forcing it through even with strong opposition on some things. He has improved our faculty, decreased class sizes, and worked to change our image, all without ruining what many of us like about the university.
Yes, the CIA has gotten a bad rep of late, however, judge the man for himself, not for what you think of an agency that by its nature doesnt really defend itself from a bad reputation. (Note, I'm a republican, but not a Bush supporter, and am very glad to see Rumsfield gone.)
Even from a less IT-oriented perspective, many engineering firms would have trouble operating with the internet out. Some CAD software (ProEngineer comes to mind) requires you to connect to the internet and register with the server and confirm that you're a real customer and not a criminal in order to use it. So even at previous jobs where I wouldn't have *needed* the internet, I would have been stopped from doing my work anyway.
Of course whether its proper for a company to do this is a separate question, but given that companies are going to treat users like they're criminals, we're dependent on internet connections in much less obvious ways.
To be more specific, NASA already cancelled a mission designed to do exactly that: Mars Sample Return (MSR).
It was supposed to be the next mission after the Pheonix lander (which would be stationary and bring much more scientific equipment than the wonder rovers.)
I worked on a an alternate baseline for this mission with a school class, with the assistance of NASA Jet Propulsion Labs, and it's a very interesting and challenging project, with the size of everything being determined that you have to bring a rocket capable of reaching Martian orbit all the way to the surface of Mars. I'm very curious to see what their plan is, whether they take NASA's simple approach, or our student projects more complex approach, or something else entirely.
If only we could get rid of it. They've got those pesky international obligations to finish the ISS in the way. Those modules (some russian ones, maybe some european ones, I know theres a Japanese module), had been designed specifically for the shuttle payload bay and we are simply unable to launch them in any other vehicle. I'm not sure on all the details on that, maybe the new shuttle-derived heavy lift vehicle would be capable, but I think if it were the shuttle would be cut now.
If most NASA engineers had their way, and certainly most students who are likely to be going to NASA our their contractors (I'm a Aerospace Engineering students), would prefer to scrap the shuttle now, accelerate the CEV, and keep more JPL projects on the table. Particularly since the ISS doesnt seem too useful, even if its finished. It's in a bad orbit for support of other missions (too high an inclination, in order to accomodate the high latitude of Baikonur), and it remains to be seen if its a valid scientific platform, since right now they only have enough people on board to keep it running.
Programming is still important for many professions and schooling that don't seem related at all. I'm an Aerospace Engineering student (Senior), and I've been programming since middle school (Basic, C++, VB), and I'm glad I did because most people struggle with it for classes.
Some codes I've had to write/design are specialized CFD simulations, finite element solutions, burn rate simulations, data retrieval, storage, and control onboard a rocket, etc...(all in FORTRAN). Working on these, most of my peers are lost with regard to proper programming, because its not taught. It seems to me that most technical fields, no matter how removed from normal CS areas, still require this kind of programming.
Granted, its not OO or scripting or dealing with crazy data structures and compiling your kernel from source, but basic structural programming still seems vital to many fields, where specific problems required specialized solutions for which there would never be any GUI-ified programs.
It's not just a question of how much thrust you get (chemical rockets are still at the top for that), its a question of specific impulse, which is basically a measure of how much propellant mass is used to attain a certain velocity change.
A chemical rocket has a specific impulse of about 300 s-400 s, while a typical ion thruster has something closer to 3000 s. This new design should be 12,000s I guess
Obviously for a larger mission than DS1 or this ESA probe, doubling them up to get more thrust is definitely a necessity, although there are limits, because each new thruster adds to the mass signficantly.
Not really, what the extra grids are doing are focusing the beams more so that they actually proceed through the grid rather than hitting it. Ions hitting the grids and causing them to collapse over time is the primary failure mode for an ion thruster, so being able to focus it more seems to allow more power to be pumped into it so that the stream is accelerated faster. I guess more grids might allow you to focus it more, but I'd guess that its a diminishing returns thing.
I'm doing research with these thrusters (trying to show a particular fluid simulation, which is particularly good with parallel processing, is valid), especially for the reasons the article talks about with the testing. I think im going to try this multiple grid situation and see how it acts later.
Slashdot Mirror
Unfortunately the unsafe-ness of the shuttle isn't a small thing can be fixed, its a result of the side mounted configuration. With Apollo/Orion type capsules, or even a top mounted space plane, you can have an escape system that pulls the manned component off the top, and it's impossible to damage it with falling debris from other parts of the launch vehicle.
Also, the very idea of the reusable manned/cargo vehicle is inherently flawed. My personal favorite analogy is like deciding that you should buy a truck (instead of a truck and a small car) because you need to haul stuff around occasionally, with gas costing $1000 per gallon.
The new configuration, assuming it works as they say it will, is superior in l ways but one. The Ares V will have 130 m-T capability to LEO instead of the shuttles 24 m-T. The Orion capsule is in fact reusable, and while smaller than the shuttle, it doesn't make sense to launch the labs every time you go up. This goes with the idea that the ISS will become something useful. Having another tragedy like Columbia, while not only less likely, would also not cause a loss of our cargo capacity as well, which led to the current state of the ISS. The only real disadvantage is our inability to return things from orbit, and as far as I know we've never used that capability.
That is why I'm an engineer and not a more abstract scientist or science fiction writers. I think in a way along of how youd practically do something. We need people like me, we need people not like me.
I'd never much considered the nano-probe idea before simply because it didn't come to mind, but I think it's really interesting. That's why I'm here on slashdot, to discuss and learn things like this, not because I'm not doing anything better... well that and I have no class today. That's the beauty of society, academics, the internet, and all of this, that we can get together and consider ideas that we wouldn't think of individually, because we're all very different.
That said I hope we look at the possibilities of this in the near future for actual use, and would be interested in working on it myself if I got the chance.
True, but its still a nice reminder of the actual way it should be (I don't particularly like doing probabilities). Quick numbers say if there were so many of these advanced 'immortal'* species, you'd get:
1: 4%
2: 7.84%
5: 18.4%
10: 33.5%
50: 87%
100: 98.3%
* By 'immortal' I mean species that have moved off planet and gotten past the point where accidentally killing themselves is a serious threat.
Agreed, to some extent. Yes, we all hope theres something better than rocket technology. But right now theres nothing rigorously shown to be theoretical possible even. Certainly there are some promising ideas, but nothing for sure.
All I'm really saying is that 1/10 c seems reasonable for a highly advanced species, whether its done with advanced rocketry or something else entirely. Also you could make an argument similar to the Fermi Paradox (if they're out there exploring how come we havent met them yet), not necessarily that they're not there, but that something like this 1/10 c number is reasonable because if it were higher we'd likely have made contact by now.
Also, assuming they use some kind of rocket technology (that is, technology that shoots stuff out one side to propel the vehicle in the other), 1/10 c is much more realistic than something approaching c. Assuming a technology that has 100 times the specific impulse as our current vehicles (the best ion thrusters get ~4500 s,) I get using the rocket equation that the initial mass to move 1 ton of cargo is:
.99 c: 1.534e292 tons
.99 c: 2.69 tons
.99 c results are off by thousands of orders of magnitude.
1/10 c: 3.263e29 tons
Even then this seems absolutely ridiculous. If you used a matter/antimatter reaction so that your propellant was pure electromagnetic radiation (thus your exit velocity is c), you'd get these results
1/10 c: 1.105 tons
Of course, these are not adjusted for relativity, since I don't know any simple equations to do that. I would imagine (as a wild-ass guess) that the 1/10 c estimates are close, but the
Basically all I'm saying is that 1/10 c seems fairly reasonable. It's not feasible given our current technology, but its within reason. If you start looking at things like space-time warpage, then we have no idea on any usage or capabilities, so any kind of theory based on it gets even further and further from reality.
By the way, I am a rocket scientist, but only a student, and not a physicist at all, only an interested amateur.
NASA and the rest are looking heavily at In-Situ Resource Utilization (ISRU) for other fuels, so if a future mission uses these engines, they will certainly look at taking the methane, and it will probably be easier than a lot of other messages.
However, looking at missions to the outer planets, chemical propellants won't cut it. Electric Propulsion, like ion thrusters or Hall thrusters have much higher specific impulse (basically fuel efficiency), with much lower thrust, but are ideal for long term missions like an outer planets exploration mission.
It would be great for a lander however, because if we land something on the surface and want to get it back up, a methane chemical rocket sounds like it might be a good idea in such an environment.
The other difference is that, at least in theory, a 'resistance' would refer to a group trying to drive the invaders out, as is the case with the European resistances in WWII.
However in Iraq, the US and UK would like nothing better than to leave, but feel a responsibility to insure stability after the mess we caused (in one set of rhetoric), or to secure freedom for the people (in another set of rhetoric.) The insurgent forces are not fighting to remove a foreign dictatorship, or if they think they are they're doing a really bad job of it. What they're doing, at least as best as I can tell, is to insure that the new government is their groups government, or, at risk of sounding self important, to stick it to US because they don't like us and our policies on Israel and other various issues.
Obviously it's a much more complex issue, we are trying to impose our own idea of order, and put up people in power that we can at least stand. However, it seems to me, though I'm biased, that the basic differences are there and important.
Armadillo's stuff is pretty cool. I guess that's a bit off-topic though.
These are suborbital flights, and I'd imagine they'll be close to the same price as Virgin's (~$200,000). Not exactly cheap, but a couple of order of magnitudes smaller, and admittedly at least an order of magnitude less cool. I'm very interested to see how this suborbital space tourism thing goes. I know some people going up on the first few virgin flights, but I'm still not wholly optimistic about it.
This is something that I care about a lot, and all I have to say is that if it matters to you, do something about it:
http://www.seds.org/ - Students for the Exploration and Development of Space
http://www.nss.org/ - National Space Society
http://www.yurisnight.net/ - Yuri's Night, the international space party
http://www.xprize.com/ -X-Prize Foundation
just to name a few...
or of course if you're young enough and willing to work a civil servants salary:
http://www.nasa.gov/about/career/index.html
-Brian
If a kid is able to sneak out on abusive parents to report them, I imagine they can sneak out without their cell phone, or do it someplace they should be anyway (e.g. School.)
Parental controls are completely different from governmental controls. Firstly, children are by definition immature and therefore unlikely to be able to completely handle themeselves and make good decisions. This can change in the 15-18 year old range, although thats fairly unlikely, and it seems reasonable to give their parents the benefit of the doubt here. Secondly, parents are much more likely to behave beneficially toward their children than a government toward its people. Genetically we want to protect our children and try and do our best for them, while doing good in government probably comes from a higher part of the mind. Also, there is very little to be gained by abusing power in a family, when compared with what can be gained by abusing governmental power.
With younger and younger children having cell phones, particularly these little ones that can only call 6 numbers or something like that for the younger ones, this seems like a great thing. Keeps you from having to track down which house the pack of neighborhood kids went to now, makes it easier to pick up the kids from soccer practice when it ends early, and generally gives parents better peace of mind. Seems like an overall good thing to me. Surely there will be some problems, but I'm betting we can figure them out.
(Note: I'm not a parent, but have much younger siblings, so take my comments with a grain of salt)
While robots are great for initial exploration, and that for current manned work that isn't actually research on the people themselves, robots would provide more results per dollar (the human experience is still more useful, but I doubt as much as the cost.
Anyway, this is about colonization (I hope), rather than exploration. I really hope that the current NASA plan goes towards true colonization, although like most people I have become jaded. I just always fear that people don't realize that colonization is critical in the long term, and colonization, by definition, depends on manned flight.
I'd also argue that this problem really has its roots in middle and high school. I had great science teachers in high school. However, I was in one of the best public schools in the state, and even then, my physics teacher left during my last semester because his wifes business failed and he had to support the family. Our good chemistry and physics teachers left in the following years, and as far as I know they weren't replaced by equally well qualified teachers.
Programs like IBMs funding for those close to retirement to go into teaching seem to me the best solution, and I'd like to see more serious efforts like this by other companies or even (shockingly) the government.
Yes, its easy to get weeded out in college (I'm finishing up an engineering degree this year,) but I'd argue that a significant portion of the problem is that they're not prepared for college because its too easy. I probably would have had much more problems if not for AP Physics (Calculus-Based) class that I took in high school.
I'd say this is the exact problem with the space program. Yes, the ISS is a steaming pile of crap. Spending our the to make the planet we will all live and die on a better place is a noble goal, however, its not the only goal. I think we already have a large number of people concentrating on that. That is I know people involved in Amnesty International, developing new hybrid vehicle systems, Engineers Without Borders, and the best of organized religion (mission trips concentrated on helping people as opposed to simple evangelism). I hear of even more here on slashdot, the Bill and Melinda Gates Foundation, the One Laptop Per Child Project, and the endless watch for Big Brother-ism and the tyranny of monopoly. I personally do some work with regards to the improvement of the educational system within the US, which is one of my main personal cause du jours. However, I think with all this effort spent to improve our earthly existence, theres a little room to get us off this planet and help to provide some relief that way. Obviously it won't have immediate effect. The early colonist's to America didn't immediately stem Europe's problems even directly related to population growth, however in the end its impossible to deny its effects. And with space we dont have the genocidal side effects that are such a stain on that period in history. The future of humanity (in my own very humble opinion) depends on us establishing offworld settlements, and whether thats in the next 20 years, the next 200, or the next 2000, I plan on doing my damndest to push us forward, and supporting others who do, because some people need to do it. And there's nothing wrong with a small portion of the national budget going that way too (and it is a small portion, look it up.) Find your own way to save the world, improve it, or keep it going. All of those things are vital.
I actually finished a presentation today with Johnson Space Center (JSC) about resupplying a Moon Base for a university class today, and I'm planning on going and helping run a booth at the SEC conference (where I assume this plan was announced) tomorrow. Needless to say I'm very excited about these plans and am very much a space exploration advocate. Look at my previous posts and I think that will show it.
NASA at times does a great job of innovation and exploration. Anything unmanned, JPL and Ames do a great job with. Not to deride anyone at JPL, but its very hard to not be a little cyncical about this. I am very afraid of what the next administration may bring, whether it's Democrat or Republican, and am afraid that whoever is next may help put the axe on Bush's best initiative (though its been a bit bastardized lately.)
Here's hoping we get a moon base like the antarctic base, and can move on to Mars (although I don't believe that the one is necessarily dependent on the other.)
Exactly... some rough math gives me that an asteroid about a tenth the size of Ceres would be about 10^20 kg, or 10^17 metric-tons. In order to move that from the moons orbit to LEO (I'm working on a similar problem right now) in 2 decades would require about 10^12 Newtons, which would require 10^13 kW, which would require a similar order of magnitude of solar array area with a good estimate of future capabilities (Solar array efficience is improving only incrementally.) This, with the prices scaling linearly (which they wouldn't, you'd start having economies of scale), would cost 10^13 million dollars. Note, these are very rough order of magnitude numbers scaled from a ~4 month journey to the moon with ~30 m-T, ~100 m^2 of solar arrays for ~100 kW of power. These things tend to scale linearly (solar array area to power, power to thrust, thrust to time, etc.)
Ion engines probably aren't the best choice for this. They require a lot of power (100s of kW to get a few newtons of thrust), and the material you'll find on the asteroid probably won't be ideal propellants (heavy noble gases like xenon are ideal.)
However, doing the same thing with a traditional chemical rocket and in-situ propellant production (currently in the works for moon and Mars missions) could be very productive, and in fact would hope that somewhere in JPL theres a case study looking at that possibility.
I'd say thats definitely a valid point (I actually considered saying something about it but decided to make the post short instead.) However, my impressions of the man are that he is good at knowing what he doesnt know and will be much more likely to listen to the generals and others. Also, I'd imagine that he has a good grasp on military matters from his days as a Soviet analyst (unfortunately nothing I've come across says whether his experience was more military or political, just that his PhD was in Soviet history, which could be either.) Of course I could be wrong, I just hope I'm not (for our country and Iraq, not for my ego... well, maybe a little.)
I'm a student at Texas A&M (where Dr. Gates is currently university president,) and I'd have to say I disagree with this assesment of the man. He has done a great job here of seeing problems, finding a solution, and forcing it through even with strong opposition on some things. He has improved our faculty, decreased class sizes, and worked to change our image, all without ruining what many of us like about the university.
Yes, the CIA has gotten a bad rep of late, however, judge the man for himself, not for what you think of an agency that by its nature doesnt really defend itself from a bad reputation. (Note, I'm a republican, but not a Bush supporter, and am very glad to see Rumsfield gone.)
Even from a less IT-oriented perspective, many engineering firms would have trouble operating with the internet out. Some CAD software (ProEngineer comes to mind) requires you to connect to the internet and register with the server and confirm that you're a real customer and not a criminal in order to use it. So even at previous jobs where I wouldn't have *needed* the internet, I would have been stopped from doing my work anyway. Of course whether its proper for a company to do this is a separate question, but given that companies are going to treat users like they're criminals, we're dependent on internet connections in much less obvious ways.
To be more specific, NASA already cancelled a mission designed to do exactly that: Mars Sample Return (MSR).
It was supposed to be the next mission after the Pheonix lander (which would be stationary and bring much more scientific equipment than the wonder rovers.)
I worked on a an alternate baseline for this mission with a school class, with the assistance of NASA Jet Propulsion Labs, and it's a very interesting and challenging project, with the size of everything being determined that you have to bring a rocket capable of reaching Martian orbit all the way to the surface of Mars. I'm very curious to see what their plan is, whether they take NASA's simple approach, or our student projects more complex approach, or something else entirely.
If only we could get rid of it. They've got those pesky international obligations to finish the ISS in the way. Those modules (some russian ones, maybe some european ones, I know theres a Japanese module), had been designed specifically for the shuttle payload bay and we are simply unable to launch them in any other vehicle. I'm not sure on all the details on that, maybe the new shuttle-derived heavy lift vehicle would be capable, but I think if it were the shuttle would be cut now.
If most NASA engineers had their way, and certainly most students who are likely to be going to NASA our their contractors (I'm a Aerospace Engineering students), would prefer to scrap the shuttle now, accelerate the CEV, and keep more JPL projects on the table. Particularly since the ISS doesnt seem too useful, even if its finished. It's in a bad orbit for support of other missions (too high an inclination, in order to accomodate the high latitude of Baikonur), and it remains to be seen if its a valid scientific platform, since right now they only have enough people on board to keep it running.
Programming is still important for many professions and schooling that don't seem related at all. I'm an Aerospace Engineering student (Senior), and I've been programming since middle school (Basic, C++, VB), and I'm glad I did because most people struggle with it for classes.
Some codes I've had to write/design are specialized CFD simulations, finite element solutions, burn rate simulations, data retrieval, storage, and control onboard a rocket, etc...(all in FORTRAN). Working on these, most of my peers are lost with regard to proper programming, because its not taught. It seems to me that most technical fields, no matter how removed from normal CS areas, still require this kind of programming.
Granted, its not OO or scripting or dealing with crazy data structures and compiling your kernel from source, but basic structural programming still seems vital to many fields, where specific problems required specialized solutions for which there would never be any GUI-ified programs.
It's not just a question of how much thrust you get (chemical rockets are still at the top for that), its a question of specific impulse, which is basically a measure of how much propellant mass is used to attain a certain velocity change.
A chemical rocket has a specific impulse of about 300 s-400 s, while a typical ion thruster has something closer to 3000 s. This new design should be 12,000s I guess
Obviously for a larger mission than DS1 or this ESA probe, doubling them up to get more thrust is definitely a necessity, although there are limits, because each new thruster adds to the mass signficantly.
Not really, what the extra grids are doing are focusing the beams more so that they actually proceed through the grid rather than hitting it. Ions hitting the grids and causing them to collapse over time is the primary failure mode for an ion thruster, so being able to focus it more seems to allow more power to be pumped into it so that the stream is accelerated faster. I guess more grids might allow you to focus it more, but I'd guess that its a diminishing returns thing. I'm doing research with these thrusters (trying to show a particular fluid simulation, which is particularly good with parallel processing, is valid), especially for the reasons the article talks about with the testing. I think im going to try this multiple grid situation and see how it acts later.