Actually I like to think I'm a decently intelligent person. Not perfect, and certainly capable of being wrong, but decently intelligent. As far as I know the basis of the laws are based on old diesel engines that were particularly dirty. However, as you mention, in the past few years they have cleaned up a lot, and I would argue that the fact that they are going to be cheaper (and relatedly use less energy) to produce than a hybrid shifts the ultimate balance in their favor. If you have some useful information rather than personal attacks to demonstrate your point, please let me know. I really do want to know as I'm an engineer and really enjoy integrating new things that I haven't learned yet into my way of thinking. I never claimed diesels were a whole lot better, just that they have a nice combination of low(er) carbon emissions +low end torque that sounds fun, plus some modability. Personally, I'm excited that the apartment I found makes it easy to take the bus to work and minimize the whole issue, plus have a really short commute if I do drive. To be fair you can only go so far if you still rely on personal vehicles the size and mass of current passenger vehicles, and rely a largely carbon-powered utility grid.
And I don't expect the whole state to change overnight, but a number of years to simply remove a law that no longer holds up to common reason is not unreasonable. As far as cancer concerns go... I find it hard to take it seriously when both my workplace and my hotel inform me as I walk in that there a materials present that are known to the State of California to cause cancer. Genetically, we don't have much need to live past the point where we see our grandchildren grow up, so the fact that cancer has a habit of getting us in the end doesn't seem especially due to diesel engines. It seems more like a result of that pesky second law of thermodynamics than any particular materiel we encounter. Surprise! If people keep away from the outside world then they're less likely to encounter things that cause abnormal mutations and develop cancer... unfortunately whats the point of life then?
Again, not perfect, but decently intelligent. Please avoid unfounded attacks on other people on the internet, just because you can't see them doesn't mean you have free reign to insult someone. I appreciate well-reasoned discourse and correction however... I've been wrong more times than I care to admit.
I'd always just taken the general more power per stroke, less energy required to produce the fuel, and better mileage as the main reasons. Always assumed they had more carbon output than a non-plugin hybrid, but I figure thats probably offset by the reduced energy required for manufacturing. Thanks for that tip though, I'll have to look into that 20% and revise my thoughts.
Unfortunately I don't think the California standard is based on anything that reasonable, but probably 20-year old ideas of particulate emissions and slow, smelly engines that have been largely mitigated by modern technology.
California and green have little to do with each other. I just moved out here to take a job, and I was thinking I'd like to buy a diesel as my next vehicle, since to my way of thinking a diesel is far greener than a moderate hybrid like the Prius (the Volt is a different animal). Plus the low-end torque is great, as is the possibility of converting it to alternative fuels. Much to my surprise, I learned that you can't even buy a diesel car out here.
From what I can tell, California is about regulations that make people who don't know much feel good.
People forget this. In the rest of the country (for me Oklahoma, Texas, DC and LA) I've never had coverage issues with AT&T. In terms of customer service and policies, they're not particularly worse than any of the other nationals, except maybe T-Mobile. I can't say I'm happy with AT&T, but I don't think I'd change to anything else.
If you wrap your hand around the external antenna, you're going to block the signal. Of course an external antenna is going to get better reception, but it can still be attenuated.
And most phones don't have an exposed antenna. Thats what I'm trying to point out is a particular problem with the iPhone 4. Every phone can be attenuated by your hand blocking it, though some are more susceptible to it than others. However, the iPhone 4 has a problem where the antenna has an exposed conductor, which causes the biggest issues and is basically unique to the iPhone despite Jobs' attempt to conflate it with the other problem.
I think he's pretty happy still. His initial business plan was not dependent on NASA. COTS is a great opportunity for them, but thats not under threat -- they didn't get anything concrete out of the new NASA budget. And at any rate, the Iridium contract is a bigger deal right now.
Besides, this Boeing craft is being conceptualized under the CCDev contract, which is under threat from congress's revision. Dragon is in much better shape.
Which was the bigger innovation -- the first expensive gas-powered cars, or the first Model T?
Its nice to figure out how to do something new. Still, what really makes a difference is when you can reduce the cost and make it more accessible. Business practices and production methods are as important as the final product.
While its absolutely true that a 'death grip' can cause signal loss on any phone, just as sticking it in a Faraday cage can, Apple is currently conflating two different problems. The first, where your hand blocks some signal is common to all phones.
However, there is a second problem with the iPhone 4. When you touch it in the wrong place, you, a conductor, connect two different antennae that each are designed to work at a specific wavelength. When you bring the two together, and throw your body into the mix too, the antenna geometry is decidedly sub-optimal, and this can damage reception significantly. This second problem is why bumpers/cases are suitable correction to the majority of the problem.
And I say this as someone who still plans to get an iPhone 4, because even while they hem and haw and obfuscate on the fact that there is a design flaw, they've taken appropriate actions to help those troubled by it, and if it really bothers me some tape or some clear nail polish should fix it.
Its pretty easy to move something bigger, given enough time. Potential mitigation of Apophis, among other asteroids, has been extensively studied. Note that its approximately 270 meters and 2.7e10 kg, enough to cause significant regional destruction, wiping out a continent.
As an example case study that I worked on, a 500 kg spacecraft hovering a few hundred meters away from an asteroid for a year is enough to move it 10s of Earth radii. Note that you'd need similar behavior to get a good track. The key is to make the move early. This particular plan was intended to eliminate the threat of a 2036 impact, which is well known to correspond with a 600-meter wide 'keyhole' during the 2029 approach. By moving the asteroid a few meters forward or backwards in 2022, the threat is mitigated -- you move it by kilometers and in 2029, and 10s of Earth radii in 2036.
Closed orbits over many revolutions are incredibly sensitive to very small changes, and close flybys, which are likely for a potential threat, increase the sensitivity by orders of magnitude. The key ingredients are time, tracking, and high fidelity trajectory models.
The problem with that analysis is that the effort required to tag an asteroid with a transponder isn't much different than the effort required to move an asteroid using something like a gravity tractor -- so long as its a relatively small asteroid. But if its not a relatively small one, then it will have global impact and will require a substantial mitigation effort anyway.
Another nasty political problem is what happens when we find out its going to hit the US, manage to change the trajectory about half an Earth diameter, and it magically ends up heading for Russia instead... It might not be through malice but rather technical failure, but its certainly not a pleasant concept.
Scaling back Constellation was not against congressional ban. What happened was that Bolden demanded that they take into account an accounting law that people had been ignoring, one that requires them to keep some cash on hand to help handle potential shutdowns.
This action was not against the law, but was in fact enforcing the law.
And how do the centennial challenges fit into this? $5 Million is pretty small compared to the questions around shuttle/Ares/CCDev.
Unfortunately that 'prototype' shouldn't be called that. The Ares 1 was designed as a J-2X engine on top of a 5-segment SRB.
The Ares 1-X however was intended solely as a test of the aerodynamics of the launch vehicle. As such, none of the other components had to be anything like the final one. The first stage was merely a 4-segment SRB, the same type we use on the shuttle, with a dummy 5th segment. That may not sound like much, but changing the length of the engine chamber means they have to completely redesign the fuel grain and that won't be done till 2017ish. The second stage is still completely non-existant - the one on that launch is a dead mass. Even the control system is just one they stole from a Titan missile.
And all of that cost more than $500M. While I dislike bringing up SpaceX in this sense, because Falcon 9/Dragon is not as capable as Ares 1/Orion, this is comparable to all of the money that SpaceX has spent so far.
Sadly you've been fooled by a publicity stunt meant to convince people that a program that was way behind schedule and over budget was actually making progress.
Actually, SpaceX is developing a human rated vehicle without any NASA funding to do so. The only NASA funding they have is a series of pay-for-performance contracts with NASA for delivering cargo to the ISS. Giving some of the money in advance has helped lend SpaceX some credibility, and also made it easier for them to complete their goals, but at this point there biggest contract is with Iridium, not NASA.
And Armadillo is doing something entirely different -- the markets they're in are the suborbital passenger market (e.g. Virgin Galactic), and as a potential contractor for things like a lunar lander. They're not trying to build huge rockets, they're trying to develop their technology on a reasonable scale and see what it can do.
As far as the money actually devoted to commercial crewed transport (CCDev), the money isn't there to fund development, its there to guarantee a customer if someone develops the capabilities. The US government did the same thing at the beginning of the 20th century, guaranteeing airmail contracts that helped get the commercial aviation field standing on its own.
It's easy to complain about politics getting in the way. However, very few people actually propose solutions. Hoping that politics ceases to be a hotbed of petty competition and small-minded short-term thinking isn't a viable solution (reminds me of a Churchill quote...). NASA uses public money, and as long as it does, politics will be a necessary (and proper) part of its operations.
Quite frankly, 5 years is as long as a program can go without producing concrete results. The new budget proposal has the advantage of actually taking this into account -- parallel commercial development of Gemini-class spacecraft, along with technology development are exactly what are required to break the gridlock of NASA. With new technology and a cheap way to get to orbit, heavy lift vehicles can be developed more quickly. With heavy lift and cheap manned access to orbit, moon missions can be done more easily. Constantly building up an actual infrastructure instead of relying on all-in-one architectures that take 20-30 years to build is the only way to deal with this.
I think that oversimplifies it. It was also good geopolitics. We were trying to prove that the American way was superior to the Soviet way. If we could demonstrate our technical prowess, and project that magical thing called soft power, it would give us an advantage in winning over other countries to our side.
The challenge from a popular president made it a bit easier to get past the voters (although I've heard it wasn't actually as popular as we imagine it was,) but the reason behind it stood regardless of whether Kennedy lived or died.
Yes, thank you. The issue is that filling some liquid (even cryogens) isn't nearly the hassle that shipping the case to Utah, waiting for most of a new engine to be made, and shipping it back is. In liquid engines all the complexity is in the engines, while in solids a great deal is in the fuel grain itself.
Thus, if you're making a disposable stage, then solids can be pretty reasonable, but the costs shift dramatically when you discuss reusability.
What portion of Apollo was done on solid boosters? Solids have some big advantages, particularly the ability to store them for long periods (great for military applications or a crew escape vehicle), they also have huge disadvantages for a manned system:
- More difficult to eliminate vibrations, which affect human payloads far more than unmanned payloads - Less reusable. To reuse a liquid stage you refill it. To reuse a solid stage you have to make a new fuel grain, so all you actually reuse is the case. - Can't turn it off. A liquid booster can abort on the pad. On top of a solid booster you have to eject the payload. - Not throttleable, which makes it more difficult to achieve a precise orbit -- the more solid stages you have, the more the liquid stages have to do to correct the errors.
Saturn V was all liquid for a reason. Jobs in Utah and a military desire to have NASA share some of the costs of keeping solid fuel in production are the reasons STS uses solids, and why Ares 1 used solids, not sound engineering.
State of the art solar aircraft look a lot like gliders. Huge wings, tiny fuselages, and slow speeds. And these are using top of the line, 25-30% efficient cells. On first glance, this tells me without a drastic improvement efficiency a cost effective passenger liner is out of the question for now.
However, there's one caveat to that. Most of those planes are concentrating on extremely long-duration flight, and a major component of the weight is the battery mass required to store all the energy for the night portion. So that means two things: short-haul flights that go during the day could be a bit more reasonable -- not commercially feasible yet, but not as bad as comparisons to these research planes might suggest. Second: battery technology is another avenue to improving the feasibility of solar aircraft, and is something under heavy research right now.
Given that, still, I think a better idea for sustainable aviation is going to be biofuels or hydrogen for large aircraft, and pure electric for small Cessna-type craft. If you charge the batteries and make the hydrogen from renewable sources its just as green in the end. The main place for solar power is extremely long duration unmanned observation platforms (civilian or military).
However, they can still exhibit some odd motion due to things like the Yarkovsky effect. Those are more important in the long term though, so aren't going to affect short term nav too much.
They are trying to stop funding for Constellation. Manned space missions like the ISS would be extended under the administrations plan. And when you can get to LEO with people for something a lot cheaper than Ares 1 (what commercialization promises), you open a lot of possibilities for impressive missions that can be completed within 5-10 years on a modest budget.
Plus the parent post was discussing unmanned missions, which do quite well under the new proposed budget, given that Constellation was so budget-hungry it was threatening everything else NASA does.
You can't forget that gravity either. Its small, but its significant. Because asteroids tend to have awkward shapes too, you can't depend on orbits or any of the other tools you'd use for a real planet. If you're not keeping a kilometer or more away, you have to have a really good gravity map to avoid smashing into the thing.
But like you said, you can't depend on that gravity to actually hold you down, which makes it all harder still. Operations near asteroids are definitely one of the hardest things we do in deep space right now.
Its doubtful you'd find anything life-like there, except maybe some building blocks. (And by life I mean life as we know it.) Also, no new elements, since the only new ones that could exist don't form from supernovae or anything like that. Its not like there are any missing, we just can't get stable ones higher than a certain atomic number. The real advances come from understanding the mineral content and its implications on how the solar system formed, as well as potentially opening up the long term possibility of mining.
And you do realize that NASA's budget has been increased, and unmanned missions such as this are doing just fine, with many new ones on the docket. What Obama did do is attempt to shut down Constellation, an expensive and unnecessarily complex manned program that tried to reconstruct the past glories of Apollo with no real purpose, and that was sucking the money out of unmanned missions. Commercialization is simply about finding an inexpensive way to get people to orbit so that NASA can get back to doing real exploration without having to find unsustainable amounts of money.
As I pointed out before: this isn't comparing SpaceX of the present to NASA of the 1960s, which would be a very unfair comparison for the reasons you're saying. Its comparing SpaceX to the NASA of now -- which can use exactly the same developed technologies. Somehow NASA has ended up doing things that cost 10x as much and are destined to be cancelled due to the realities of a system that is rooted in politics.
Many of us involved with the space program are simply fed up and want to try something, anything, different that might make things work better than the failure of the past 30 years to develop a viable launch vehicle using cost-plus contracts. This isn't gov't vs. corporations. Its behemoths that suckle at the gov't teat and profit off of the taxpayer vs. smaller entrepreneurial ventures. The people who get the most out of the current system are the higher-ups at Boeing, Lockheed and ATK, and the politicians who get the votes from bringing the pork home.
You can have good and bad gov't programs: the unmanned programs and aeronautical research are astounding at NASA. Its just that in manned spaceflight, the JSC/MSFC way of doing things has demonstrated itself as insufficient. For basic launch services, things that don't require new research and insane amounts of risk, we're better off going with a more standard contracting method: the government purchases a service for a fixed-price rather than paying for development and paying for overruns as well. Its not idealogical, its practical.
Then why isn't NASA simply using existing techniques and systems? Ares is unnecessarily complicated and poorly designed because Congress got involved in the design -- no one would want to continue to use solid boosters on a manned system if it didn't keep jobs in Utah. It isn't market-fundamentalist, its just simply logical.
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Actually I like to think I'm a decently intelligent person. Not perfect, and certainly capable of being wrong, but decently intelligent. As far as I know the basis of the laws are based on old diesel engines that were particularly dirty. However, as you mention, in the past few years they have cleaned up a lot, and I would argue that the fact that they are going to be cheaper (and relatedly use less energy) to produce than a hybrid shifts the ultimate balance in their favor. If you have some useful information rather than personal attacks to demonstrate your point, please let me know. I really do want to know as I'm an engineer and really enjoy integrating new things that I haven't learned yet into my way of thinking. I never claimed diesels were a whole lot better, just that they have a nice combination of low(er) carbon emissions +low end torque that sounds fun, plus some modability. Personally, I'm excited that the apartment I found makes it easy to take the bus to work and minimize the whole issue, plus have a really short commute if I do drive. To be fair you can only go so far if you still rely on personal vehicles the size and mass of current passenger vehicles, and rely a largely carbon-powered utility grid. And I don't expect the whole state to change overnight, but a number of years to simply remove a law that no longer holds up to common reason is not unreasonable. As far as cancer concerns go... I find it hard to take it seriously when both my workplace and my hotel inform me as I walk in that there a materials present that are known to the State of California to cause cancer. Genetically, we don't have much need to live past the point where we see our grandchildren grow up, so the fact that cancer has a habit of getting us in the end doesn't seem especially due to diesel engines. It seems more like a result of that pesky second law of thermodynamics than any particular materiel we encounter. Surprise! If people keep away from the outside world then they're less likely to encounter things that cause abnormal mutations and develop cancer... unfortunately whats the point of life then? Again, not perfect, but decently intelligent. Please avoid unfounded attacks on other people on the internet, just because you can't see them doesn't mean you have free reign to insult someone. I appreciate well-reasoned discourse and correction however... I've been wrong more times than I care to admit.
I'd always just taken the general more power per stroke, less energy required to produce the fuel, and better mileage as the main reasons. Always assumed they had more carbon output than a non-plugin hybrid, but I figure thats probably offset by the reduced energy required for manufacturing. Thanks for that tip though, I'll have to look into that 20% and revise my thoughts.
Unfortunately I don't think the California standard is based on anything that reasonable, but probably 20-year old ideas of particulate emissions and slow, smelly engines that have been largely mitigated by modern technology.
California and green have little to do with each other. I just moved out here to take a job, and I was thinking I'd like to buy a diesel as my next vehicle, since to my way of thinking a diesel is far greener than a moderate hybrid like the Prius (the Volt is a different animal). Plus the low-end torque is great, as is the possibility of converting it to alternative fuels. Much to my surprise, I learned that you can't even buy a diesel car out here.
From what I can tell, California is about regulations that make people who don't know much feel good.
People forget this. In the rest of the country (for me Oklahoma, Texas, DC and LA) I've never had coverage issues with AT&T. In terms of customer service and policies, they're not particularly worse than any of the other nationals, except maybe T-Mobile. I can't say I'm happy with AT&T, but I don't think I'd change to anything else.
If you wrap your hand around the external antenna, you're going to block the signal. Of course an external antenna is going to get better reception, but it can still be attenuated.
And most phones don't have an exposed antenna. Thats what I'm trying to point out is a particular problem with the iPhone 4. Every phone can be attenuated by your hand blocking it, though some are more susceptible to it than others. However, the iPhone 4 has a problem where the antenna has an exposed conductor, which causes the biggest issues and is basically unique to the iPhone despite Jobs' attempt to conflate it with the other problem.
I think he's pretty happy still. His initial business plan was not dependent on NASA. COTS is a great opportunity for them, but thats not under threat -- they didn't get anything concrete out of the new NASA budget. And at any rate, the Iridium contract is a bigger deal right now.
Besides, this Boeing craft is being conceptualized under the CCDev contract, which is under threat from congress's revision. Dragon is in much better shape.
Which was the bigger innovation -- the first expensive gas-powered cars, or the first Model T?
Its nice to figure out how to do something new. Still, what really makes a difference is when you can reduce the cost and make it more accessible. Business practices and production methods are as important as the final product.
While its absolutely true that a 'death grip' can cause signal loss on any phone, just as sticking it in a Faraday cage can, Apple is currently conflating two different problems. The first, where your hand blocks some signal is common to all phones.
However, there is a second problem with the iPhone 4. When you touch it in the wrong place, you, a conductor, connect two different antennae that each are designed to work at a specific wavelength. When you bring the two together, and throw your body into the mix too, the antenna geometry is decidedly sub-optimal, and this can damage reception significantly. This second problem is why bumpers/cases are suitable correction to the majority of the problem.
And I say this as someone who still plans to get an iPhone 4, because even while they hem and haw and obfuscate on the fact that there is a design flaw, they've taken appropriate actions to help those troubled by it, and if it really bothers me some tape or some clear nail polish should fix it.
Its pretty easy to move something bigger, given enough time. Potential mitigation of Apophis, among other asteroids, has been extensively studied. Note that its approximately 270 meters and 2.7e10 kg, enough to cause significant regional destruction, wiping out a continent.
As an example case study that I worked on, a 500 kg spacecraft hovering a few hundred meters away from an asteroid for a year is enough to move it 10s of Earth radii. Note that you'd need similar behavior to get a good track. The key is to make the move early. This particular plan was intended to eliminate the threat of a 2036 impact, which is well known to correspond with a 600-meter wide 'keyhole' during the 2029 approach. By moving the asteroid a few meters forward or backwards in 2022, the threat is mitigated -- you move it by kilometers and in 2029, and 10s of Earth radii in 2036.
Closed orbits over many revolutions are incredibly sensitive to very small changes, and close flybys, which are likely for a potential threat, increase the sensitivity by orders of magnitude. The key ingredients are time, tracking, and high fidelity trajectory models.
The problem with that analysis is that the effort required to tag an asteroid with a transponder isn't much different than the effort required to move an asteroid using something like a gravity tractor -- so long as its a relatively small asteroid. But if its not a relatively small one, then it will have global impact and will require a substantial mitigation effort anyway.
Another nasty political problem is what happens when we find out its going to hit the US, manage to change the trajectory about half an Earth diameter, and it magically ends up heading for Russia instead... It might not be through malice but rather technical failure, but its certainly not a pleasant concept.
Scaling back Constellation was not against congressional ban. What happened was that Bolden demanded that they take into account an accounting law that people had been ignoring, one that requires them to keep some cash on hand to help handle potential shutdowns.
This action was not against the law, but was in fact enforcing the law.
And how do the centennial challenges fit into this? $5 Million is pretty small compared to the questions around shuttle/Ares/CCDev.
Unfortunately that 'prototype' shouldn't be called that. The Ares 1 was designed as a J-2X engine on top of a 5-segment SRB.
The Ares 1-X however was intended solely as a test of the aerodynamics of the launch vehicle. As such, none of the other components had to be anything like the final one. The first stage was merely a 4-segment SRB, the same type we use on the shuttle, with a dummy 5th segment. That may not sound like much, but changing the length of the engine chamber means they have to completely redesign the fuel grain and that won't be done till 2017ish. The second stage is still completely non-existant - the one on that launch is a dead mass. Even the control system is just one they stole from a Titan missile.
And all of that cost more than $500M. While I dislike bringing up SpaceX in this sense, because Falcon 9/Dragon is not as capable as Ares 1/Orion, this is comparable to all of the money that SpaceX has spent so far.
Sadly you've been fooled by a publicity stunt meant to convince people that a program that was way behind schedule and over budget was actually making progress.
Actually, SpaceX is developing a human rated vehicle without any NASA funding to do so. The only NASA funding they have is a series of pay-for-performance contracts with NASA for delivering cargo to the ISS. Giving some of the money in advance has helped lend SpaceX some credibility, and also made it easier for them to complete their goals, but at this point there biggest contract is with Iridium, not NASA.
And Armadillo is doing something entirely different -- the markets they're in are the suborbital passenger market (e.g. Virgin Galactic), and as a potential contractor for things like a lunar lander. They're not trying to build huge rockets, they're trying to develop their technology on a reasonable scale and see what it can do.
As far as the money actually devoted to commercial crewed transport (CCDev), the money isn't there to fund development, its there to guarantee a customer if someone develops the capabilities. The US government did the same thing at the beginning of the 20th century, guaranteeing airmail contracts that helped get the commercial aviation field standing on its own.
It's easy to complain about politics getting in the way. However, very few people actually propose solutions. Hoping that politics ceases to be a hotbed of petty competition and small-minded short-term thinking isn't a viable solution (reminds me of a Churchill quote...). NASA uses public money, and as long as it does, politics will be a necessary (and proper) part of its operations.
Quite frankly, 5 years is as long as a program can go without producing concrete results. The new budget proposal has the advantage of actually taking this into account -- parallel commercial development of Gemini-class spacecraft, along with technology development are exactly what are required to break the gridlock of NASA. With new technology and a cheap way to get to orbit, heavy lift vehicles can be developed more quickly. With heavy lift and cheap manned access to orbit, moon missions can be done more easily. Constantly building up an actual infrastructure instead of relying on all-in-one architectures that take 20-30 years to build is the only way to deal with this.
I think that oversimplifies it. It was also good geopolitics. We were trying to prove that the American way was superior to the Soviet way. If we could demonstrate our technical prowess, and project that magical thing called soft power, it would give us an advantage in winning over other countries to our side.
The challenge from a popular president made it a bit easier to get past the voters (although I've heard it wasn't actually as popular as we imagine it was,) but the reason behind it stood regardless of whether Kennedy lived or died.
Yes, thank you. The issue is that filling some liquid (even cryogens) isn't nearly the hassle that shipping the case to Utah, waiting for most of a new engine to be made, and shipping it back is. In liquid engines all the complexity is in the engines, while in solids a great deal is in the fuel grain itself.
Thus, if you're making a disposable stage, then solids can be pretty reasonable, but the costs shift dramatically when you discuss reusability.
What portion of Apollo was done on solid boosters? Solids have some big advantages, particularly the ability to store them for long periods (great for military applications or a crew escape vehicle), they also have huge disadvantages for a manned system:
- More difficult to eliminate vibrations, which affect human payloads far more than unmanned payloads
- Less reusable. To reuse a liquid stage you refill it. To reuse a solid stage you have to make a new fuel grain, so all you actually reuse is the case.
- Can't turn it off. A liquid booster can abort on the pad. On top of a solid booster you have to eject the payload.
- Not throttleable, which makes it more difficult to achieve a precise orbit -- the more solid stages you have, the more the liquid stages have to do to correct the errors.
Saturn V was all liquid for a reason. Jobs in Utah and a military desire to have NASA share some of the costs of keeping solid fuel in production are the reasons STS uses solids, and why Ares 1 used solids, not sound engineering.
State of the art solar aircraft look a lot like gliders. Huge wings, tiny fuselages, and slow speeds. And these are using top of the line, 25-30% efficient cells. On first glance, this tells me without a drastic improvement efficiency a cost effective passenger liner is out of the question for now.
However, there's one caveat to that. Most of those planes are concentrating on extremely long-duration flight, and a major component of the weight is the battery mass required to store all the energy for the night portion. So that means two things: short-haul flights that go during the day could be a bit more reasonable -- not commercially feasible yet, but not as bad as comparisons to these research planes might suggest. Second: battery technology is another avenue to improving the feasibility of solar aircraft, and is something under heavy research right now.
Given that, still, I think a better idea for sustainable aviation is going to be biofuels or hydrogen for large aircraft, and pure electric for small Cessna-type craft. If you charge the batteries and make the hydrogen from renewable sources its just as green in the end. The main place for solar power is extremely long duration unmanned observation platforms (civilian or military).
However, they can still exhibit some odd motion due to things like the Yarkovsky effect. Those are more important in the long term though, so aren't going to affect short term nav too much.
They are trying to stop funding for Constellation. Manned space missions like the ISS would be extended under the administrations plan. And when you can get to LEO with people for something a lot cheaper than Ares 1 (what commercialization promises), you open a lot of possibilities for impressive missions that can be completed within 5-10 years on a modest budget.
Plus the parent post was discussing unmanned missions, which do quite well under the new proposed budget, given that Constellation was so budget-hungry it was threatening everything else NASA does.
You can't forget that gravity either. Its small, but its significant. Because asteroids tend to have awkward shapes too, you can't depend on orbits or any of the other tools you'd use for a real planet. If you're not keeping a kilometer or more away, you have to have a really good gravity map to avoid smashing into the thing.
But like you said, you can't depend on that gravity to actually hold you down, which makes it all harder still. Operations near asteroids are definitely one of the hardest things we do in deep space right now.
Its doubtful you'd find anything life-like there, except maybe some building blocks. (And by life I mean life as we know it.) Also, no new elements, since the only new ones that could exist don't form from supernovae or anything like that. Its not like there are any missing, we just can't get stable ones higher than a certain atomic number. The real advances come from understanding the mineral content and its implications on how the solar system formed, as well as potentially opening up the long term possibility of mining.
And you do realize that NASA's budget has been increased, and unmanned missions such as this are doing just fine, with many new ones on the docket. What Obama did do is attempt to shut down Constellation, an expensive and unnecessarily complex manned program that tried to reconstruct the past glories of Apollo with no real purpose, and that was sucking the money out of unmanned missions. Commercialization is simply about finding an inexpensive way to get people to orbit so that NASA can get back to doing real exploration without having to find unsustainable amounts of money.
Actually, NASA JPL does most of their mission design work using Python (combining compiled C modules of course, just like NumPy and SciPy).
As I pointed out before: this isn't comparing SpaceX of the present to NASA of the 1960s, which would be a very unfair comparison for the reasons you're saying. Its comparing SpaceX to the NASA of now -- which can use exactly the same developed technologies. Somehow NASA has ended up doing things that cost 10x as much and are destined to be cancelled due to the realities of a system that is rooted in politics.
Many of us involved with the space program are simply fed up and want to try something, anything, different that might make things work better than the failure of the past 30 years to develop a viable launch vehicle using cost-plus contracts. This isn't gov't vs. corporations. Its behemoths that suckle at the gov't teat and profit off of the taxpayer vs. smaller entrepreneurial ventures. The people who get the most out of the current system are the higher-ups at Boeing, Lockheed and ATK, and the politicians who get the votes from bringing the pork home.
You can have good and bad gov't programs: the unmanned programs and aeronautical research are astounding at NASA. Its just that in manned spaceflight, the JSC/MSFC way of doing things has demonstrated itself as insufficient. For basic launch services, things that don't require new research and insane amounts of risk, we're better off going with a more standard contracting method: the government purchases a service for a fixed-price rather than paying for development and paying for overruns as well. Its not idealogical, its practical.
Then why isn't NASA simply using existing techniques and systems? Ares is unnecessarily complicated and poorly designed because Congress got involved in the design -- no one would want to continue to use solid boosters on a manned system if it didn't keep jobs in Utah. It isn't market-fundamentalist, its just simply logical.