I believe the reason its always been kept the same most places, is that the parents do not want a shift. Currently, at least everywhere I've ever been, K-5 start at least an hour after 6-8, which is again an hour after 9-12. This makes child care much easier since the parents can usually be home until the kids leave for school, or drop them off on the way to work -- then the older kids get home first so they can watch the younger ones.
I can't think of a good solution if you accept that those schedule conveniences for parents should be maintained; only things I can think of are matching the schooldays across age groups (which would require purchasing more buses), and lengthening the school day to match a typical 9-5 job.
I'd agree. I like my Kindle, in addition to novels, its great for weekly magazines that are mostly text as well (The Economist and Newsweek for me). However, it'll take a lot more to take over my physical textbooks.
Still, what would be nice is if I could pay an extra ~$10 for kindle or PDF versions -- while they can't replace a good physical copy, I like being able to have most of the things I need to do work in one bag. Since I move between home/office/coffee shops/out-of-town travel I have a bad habit of keeping all my references in my trunk...
On its closest approach, Saturn is about 7 AU away. The diameter of its rings are about 360,000 km. Doing the math, this means that best case scenario, the angular size of Saturn including its rings is around 1 arcminute. The 2-inch diameter Galileoscope has a diffraction limited angular resolution of 0.05 arcminutes. The gap between the rings and the planet (around 6000 km) is going to be about 0.02 arcminutes. This is all large enough we can safely ignore atmospheric seeing.
So basically this scope is going to be capable of seeing the rings of Saturn quite easily, although they won't be clearly distinguishable from the planet. This is exactly what early astronomers saw, and while it confused them at the time, any kid who has seen a picture is going to know immediately what it is. While the picture in a book or the view from a big expensive telescope is obviously going to be more impressive, there is something to be said for being able to see it at all with your own equipment in your own backyard. Personally, I bought myself a 5" newtonian for personal use even though my current work involves setting up and operating two 16" SCTs, for that very reason.
And I'm not sure what it being a refractor has to do with it. Tripod is definitely an issue though. I personally like the Celestron FirstScope http://www.celestron.com/c3/category.php?CatID=92 better for that reason, plus it has an extra inch of aperture - it is $50 vs. $20 though.
Actually I think you're referring to "liberalism" not "progressivism". They're actually not synonyms according to the rest of the world, despite modern American rhetoric. Liberalism refers to what you're discussing, the freedom from government interference wherever possible, and in modern social liberalism, freedom from inequalities and unnecessary suffering. (You might say we have two liberal parties, a progressive, social liberal party and a conservative, economic liberal party.)
Social progressivism, which often ends up sharing many goals with social liberalism, is more directly interested in eliminating inequalities and improving peoples lives based on modern understanding of science. Social progressivism isn't as attached to classic liberal ideals, and in fact one might argue from that point of view that banning the swastika is a step towards preventing past excesses and as such is a worthwhile policy.
Can you imagine the political difficulties in trying to reduce ITAR restrictions? Even if a politician does recognize that reform is needed, its unlikely they'll have the guts to do it, since the attack ads are so easy to write. Remember, ITAR stands for International Trade in Arms Restrictions. No one wants to be pro-proliferation.
We deal with the same things in the space industry, since rockets tend to resemble missiles. ITAR is ultimately a stranglehold on American businesses in a globalized world and needs to be reformed -- unfortunately reform is likely to be a complex, wonky issue, and one that is far too easy to be demonized.
Unfortunately, private ventures only make sense when theres a strong chance of profit. In those cases where exploration involved more than walking a little bit further (at which point a motivated individual could do it), it has always initially relied on government funding and support.
The great age of exploration in Europe was all initially government funded*. Only after routes were discovered and the land scouted out did for-profit groups begin to take charge -- even then they tended to be mercantilist public-private partnerships. This is part of why we form governments, to do those things that benefit society as a whole but do not profit individuals and require huge pools of resources (national defense being the most obvious example).
Where the X-Prize and other NewSpace efforts exist is in that space where groups like the British East India company existed in the past. That is, they are moving to take advantage of the initial government investment, and expand it now that the economic benefit of it is understood. The SS1 flight could never have happened without early developments like the X-15, and SpaceX wouldn't be where they are without previous government research. The innovations from these companies are in architecture and engineering practice, not fundamental theory.
NASA or something like it will always be needed to push the frontier, but they need to get out of the business of doing the same old stuff. Getting people and cargo to LEO is something they've done for 50 years, and there is clear economic benefit to doing so. Whether its using ULA launchers or newer, more exciting ones like Falcon 9 or Orbital Science's offerings, NASA should take advantage of what already exists and foster a more competitive market, so that they are able to perform their task, ground-breaking exploration, better and more cheaply. If there were a stronger, more competitive commercial market, the extra $3B may not have been necessary to request.
Put simply, we still need NASA, but we need a smarter NASA.
------- *Yes, I'm aware of the dangers of relating things to European exploration, given the cultural destruction and exploitation that resulted. However, it still seems to me to be the best historical reference. Fortunately there are no natives most of the places we're talking about going now.
As someone who is color-blind (severely red/green), this news just astounds me.
The basic fact is that I have no idea, no point of reference to even understand what it is I don't see. It is impossible for me to imagine what "Purple" actually is, since to me it is merely a dark blue. Not hard to imagine, like an unusual experience is, but as far as I'm concerned impossible to imagine.
Until seeing this article today, I had assumed that I would never be able to understand what most people saw. Having the possibility open up is simply mind-blowing. Imagine what kind of leap that would be for more serious conditions like actual blindness.
While there's certainly room for improvement over NASA's methods, a two order-of-magnitude improvement from a startup seems absurdly optimistic, no matter what modular rockets and other mission design innovations they use.
However, I wish them the best of luck, and even if costs creep up to $8 million a person, then it will still be a worthwhile endeavor.
Living in Texas and following the tweets about it, I believe it was actually fairly windy yesterday. It was stormy and rainy across the state, and I know that they were much more worried about the rain than the wind.
That engine can thrust and vector a lot, and Dallas/Plano (their lab) and west Oklahoma (a common test site) aren't exactly known for their stellar weather, so they've always had to deal with wind.
Sadly I have no concrete numbers, but 10 mph seems like a pretty reasonable limit based on the environment.
That seems only marginally high for a technically-oriented summer internship. I made $3000/month the summer after my freshman year as an engineering student, and I think the company got pretty good value for my work. And this was in Tulsa, OK where that kind of money goes a lot further.
With another student we put together a parts manual for a product they were working on. It was rather tedious work, so it wasn't worthwhile to put the full-time engineers on, so they got their money's worth. It was also a great experience for us, doing technical documentation, and really getting to know how a rather complex aircraft system was put together -- I definitely feel it was a worthwhile summer that helped me a lot.
Certainly it makes more sense if you're starting from scratch. However, since we're not, the question becomes more complicated. On one side, you have the argument that we should make the best architecture possible for the sake of the future, with the disadvantage of long lead time, risk and high cost. On the other side you have the argument that we should build something that takes the most advantage of the currently in place manufacturing and infrastructure to minimize the gap and keep things running, but this leads to a long-term non-optimal solution. To me, Ares seems to be a 'worst of both worlds' compromise between the two, by limiting us to shuttle derived technology while still having to redesign it all in practical terms.
Personally, I feel something like DIRECT is better simply because it can be finished much more quickly than a completely new launch infrastructure, and is thus more likely to be finished before it gets cancelled. After this I would say slow development of a better series of vehicles should begin, although this seems less likely politically.
The summary makes one error, suggesting that Kepler is capable of detecting the gravitational 'wobble' caused by a moon. Rather, Kepler, or any system of similar sensitivity, is able to detect the transit of a moon, and recognize it as being distinct from that of the parent planet.
Understandable mistake, since all of the early exo-planet detections were made using the 'wobble' method (detecting the Doppler shift corresponding with a stars motion due to a heavy, close planet). However, the transit method, which measures small dips in the brightness as the planet passes in front of its parent star is far more sensitive, though more difficult to use due to noise constraints.
Basically, imagine if you were looking at our sun from another star system, and Jupiter stood out clearly as a dip in the light curve, reappearing every 8 or 9 years(?). With this, something like Io or Europa would show up as a smaller periodic variation overlaid on that larger dip. Only noise levels are standing in the way of detecting it, and apparently they think Kepler can handle it.
Actually, we evolved to fit into the savannas of Africa pretty well, everything after that has been colonization. Theres been some small scale evolution to adapt to new environments, but all of that was after we moved to the new areas, relying on the primary tool evolution gave us: intelligence.
If colonization of other worlds is possible, then its worthwhile. Not because we want to find a better Earth, but because we want to find more Earths. It may very well be that we adapt those worlds to suit us as those worlds adapt the settlers. However, its our adaptability through intelligence that will get us there, and that makes more and more environments suitable for us. The colonizers have never had it easy, but they have a history of adapting and making it better for following generations.
In this case, the ability to have an inexpensive, hackable e-paper device would allow the development of improved usage patterns for low-refresh rate devices.
Right now there are only a few e-paper devices out there, so there's only been a few groups working on the UIs. With the community hacking at it, its very possible someone will find new, better ways to do things that make e-paper devices less specialized. All the complaints about the rather poor web-browser are largely based on a lack of creativity and effort in the UI department... if one of these guys thinks they can do better I'd love to see what they can do.
A couple of false limitations here. First, NASA isn't the only group capable of leaving the Earth ("Space is a place, not a program"): there are other countries, cooperative ventures with other countries and private ventures, etc.
Second, its not that no one is willing to fund NASA to do it, its that NASA isn't willing/able to find a way to do it within the budget they're given. Every moon plan is always predicated on the president saying that more money will be there. If NASA is ever going to break the Apollo barrier in a sustainable way, the plans must take into account that funding WILL drop back to the post-Apollo average, if its ever actually raised in the first place. Complain all you like about us needing to take a longer view of the future (I agree), its pretty clear that this is the politically sustainable budget level, and there's no indication that will change in the future.
Also I'd guess that its not so much as a slow news day as that there are ton of rumors and different ideas swirling around right now with the Augustine commission closed but unpublished. I expect the large number of similar stories will die down in a month, but at this point I think the discussion is great, even if some of the ideas (like this one) are less than politically feasible.
The biggest concern isn't the cost so much as the existence of a domestic supplier, whether it be Orbital, SpaceX or the big old guys.
Of course the other important part of COTS is encouraging the development of a fixed-price contract system for orbital launches instead of the cost-plus system that dominates vehicle development right now, a change that does have the implication of leading to lower costs.
True, if you only have the two bodies interacting with each other. However, in this case, the asteroid is in a heliocentric orbit, and also has a very close flyby of the Earth in 2029, which makes the picture very different.
Whenever you propagate the equations of motion forward over multiple orbits, very small errors at the present time grow much larger errors in the future. This is what makes it so hard to know where these small object are going to be: an estimate of the current state thats accurate to within a kilometer and ~0.1 meter/second right now translates to 10s of Earth radii in 2036.
Though Apophis is as guaranteed not to impact in 2029 (all right, 1e-30 or 1e-40, or something absurdly small), the big worry is that it will pass through a gravitational 'keyhole', a set of regions in space around Earth few hundred meters wide that would cause it to return on an impact trajectory in the next 7 years. Basically, this indicates that the close flyby (within the GEO Belt) acts as a huge modifier on any minor modification and error.
The goal of the mission isn't to directly move the asteroid many Earth radii away, but to move it just enough so that the natural forces carry it away from an Earth impact. In order to move it a few hundred meters by the 2029 close approach, you only have the move the asteroid by 10-20 meters if you start modification in 2022. The hard part isn't changing the orbit so much as knowing how you want to change it. Any mitigation mission would also need to do very precise measurements to get the orbital tracking precision down to the order of around ten meters to before beginning any significant modification, because there is a danger of actually making things worse rather than better if you're not careful.
Hope that explains the confusion, I should have been more clear before.
A 500 kg spacecraft hovering at around ~300 meters from the CM of the asteroid is sufficient to alter the trajectory if 99942 Apophis by ~50 Earth radii by 2036, if applied in the early 2020s for a period of a year. Note that Apophis is 2e10 kg, so a 1 ton asteroid would be incredibly easy to move. The force imparted is around 1/100 of a Newton. The key for getting the most out of such small forces is to use them early and use the orbital tendencies of the asteroid to magnify your result. The close flyby of Apophis in 2029 acts as a huge multiplier for any minor modification of the trajectory.
This sized spacecraft with the requisite Delta-V during the minimum energy window that corresponds with the close approach can easily be fit on board a Delta, Atlas or Falcon 9.
Obviously this isn't an option for a short-lead time object, but hopefully the NEO project funding gets worked out so we will have ample warning in the future to use these kind of long-term mitigation methods. Larger objects would require heavier, more expensive systems, but fortunately those are going to be easier to track and understand, so you wont have the huge uncertainties that make dealings with small objects like Apophis so difficult. A 10% chance of impact is a lot easier to sell to congress than a 1/30,000 chance, and a world-destroyer is likely to get plenty of funding.
Note that I pulled these numbers from numerical simulations in a project I'm currently working on, so I can't really write out the equations or cite any papers. Sorry... you'll just have to believe I have no reason to lie and am reasonably competent.
Windows: People who want something standard, is fairly inexpensive (compared to Mac hardware), and that works well enough. Also for power users who already know Windows well. OS X: People who want something highly polished, and are willing to spend money for less hassles (assuming they don't have compatibility issues). Also good for UNIX power-users who don't want to put in the maintenance/setup time for Linux/BSD. Linux/BSD: Good for those who like free software (in both senses), those that like to tinker with their systems, or UNIX users who don't like Apples closed system and would rather use commodity hardware.
Personally, I run an Ubuntu desktop and an Ubuntu media server, but prefer to use an OS-X laptop because the better hardware integration is nice (I've had some painful linux laptop experiences). Windows annoys me to use personally, so I avoid it -- I feel technically inclined enough to deal with whatever incompatibilities with the rest of the world that causes. Of course, its all about different priorities for different people, what works for me may not work for you. No need to rely on stereotypes and start holy wars (not that the parent post was necessarily doing that).
My backgrounds in space mission design, not geology.. pretty sure the cost to benefit ratio is going to show I'm better off working on asteroid deflection while the geologist down the street gets to work looking at mitigating supervolcanoes. And of course the automotive engineers over there on the other side of town are probably best off developing newer, more efficient cars, and my friends in aerodynamics should working on more efficient aircraft and better wind turbines.
Lots of problems in the world, but also lots of people with lots of different skills
I'm curious what it being weaker than the weak and strong nuclear forces and the electromagnetic forces has to do with it. If the design works, it works. I'm curious to see your equations if you think it won't work. Also gravity is the only purely attractive force, and the one thats hardest to explain, which is why we really pay attention to it.
The advantage of a gravity tractor is that you don't have to land, because landing is a *VERY* hard problem on an asteroid. The biggest problem is that its very difficult to latch on, since you can't rely on gravity to hold you in place. Since you don't hae a good idea of the surface before you arrive, its rather difficult to design a solution thats going to work for all the different possibilities.
This leads one to consider how can you manage to deflect an asteroid without landing, and a gravity tractor is an obvious elegant solution. Note also that in this case you're still using the vaunted ion thrusters to impart the force on the asteroid. Considering the spacecraft and asteroid as two separate systems you have to use the thrust to maintain your standoff distance; considering them as one system (my preferred analysis), you have the thrusters moving the whole system, with internal gravity keeping the whole thing together. The only difference between it and landing, as far as thrust is concerned, is that you are limited to a maximum thrust by the gravity bond: the same sized ion thruster on a landed spacecraft and on a gravity tractor will have exactly the same effect.
The only time it would make sense to land is if you wanted to do a very high-thrust chemical burn (or maybe something like VASMIR, which would only be in the emergency case. Of course, in that case, the costs become irrelevant ($50B for a mission or wiping out Europe isn't a hard decision to make) and you're more likely to seek to impart a maximum impulse by doing a high-risk/high-reward method such as a kinetic impactor or nuke (and multiples as backup).
Though technically correct, it all still comes down to the UI paradigm. You can have Mac programs that require a window open (CoolBook I'm looking at you), and you can have Windows programs that operate effectively without a main window (IM apps as you suggest). However, these are the outliers of the system, and programs on both systems tend to follow the suggested paradigms pretty well. Consider MS Word:
Windows Version: Double click on the icon, you usually get a blank document window. You decide you really don't want to write that report right now, and close the window, and Word is no longer running. OS X Version: Open Word from the Dock or from Spotlight, and the menu comes up on the 'menu bar to rule them all', and a blank document opens up. Decide you'd rather not write that same report again, and close the window. In this case word is still happily running, and you could start a new document with a simple Command+n.
Which one you like more, or find more productive is a matter of personal preference. I think that the App-centric model (OS X) allows more control and seems more natural than the Doc-centric model (Windows), but the Doc-centric model keeps you from accidentally leaving a lot of stuff open unnecessarily and might be more efficient. I prefer the app-centric mode, and am very happy using OS X, but of course, thats just me.
While I can't say one way or the other in the long-term, I'd imagine that air-superiority is going to be the last air combat role to be replaced by drones. As I understand it, the biggest difference between piloting a drone and being in the cockpit yourself is the situational awareness. Flying something like a Predator or Raptor you're not going to be relying on your peripheral vision to notice something going on off in the distance, or flipping your head around very quickly when your wingman tells you something is behind you. While technology may very well make these kind of things easier, there will be both real and imagined differences (the pilots don't want to lose the cockpit), that will put up a lot of resistance.
Bombing, observation, cargo and escort runs are easier to do without the same level of situational awareness, so I'd imagine that it'll be quite a while after those all fall to UAVs before air superiority goes to the drones. Of course, as others point out, the dogfighting and numerical advantages of being unmanned may cancel it out... but I'd be willing to bet the resistance of pilots (based on possibly questionable objections around situational awareness) will be the dominant factor.
Keep in mind my background is Aerospace Engineering, not military doctrine, so I can't claim to be anything more than an interested observer.
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I believe the reason its always been kept the same most places, is that the parents do not want a shift. Currently, at least everywhere I've ever been, K-5 start at least an hour after 6-8, which is again an hour after 9-12. This makes child care much easier since the parents can usually be home until the kids leave for school, or drop them off on the way to work -- then the older kids get home first so they can watch the younger ones.
I can't think of a good solution if you accept that those schedule conveniences for parents should be maintained; only things I can think of are matching the schooldays across age groups (which would require purchasing more buses), and lengthening the school day to match a typical 9-5 job.
I'd agree. I like my Kindle, in addition to novels, its great for weekly magazines that are mostly text as well (The Economist and Newsweek for me). However, it'll take a lot more to take over my physical textbooks.
Still, what would be nice is if I could pay an extra ~$10 for kindle or PDF versions -- while they can't replace a good physical copy, I like being able to have most of the things I need to do work in one bag. Since I move between home/office/coffee shops/out-of-town travel I have a bad habit of keeping all my references in my trunk...
On its closest approach, Saturn is about 7 AU away. The diameter of its rings are about 360,000 km. Doing the math, this means that best case scenario, the angular size of Saturn including its rings is around 1 arcminute. The 2-inch diameter Galileoscope has a diffraction limited angular resolution of 0.05 arcminutes. The gap between the rings and the planet (around 6000 km) is going to be about 0.02 arcminutes. This is all large enough we can safely ignore atmospheric seeing.
So basically this scope is going to be capable of seeing the rings of Saturn quite easily, although they won't be clearly distinguishable from the planet. This is exactly what early astronomers saw, and while it confused them at the time, any kid who has seen a picture is going to know immediately what it is. While the picture in a book or the view from a big expensive telescope is obviously going to be more impressive, there is something to be said for being able to see it at all with your own equipment in your own backyard. Personally, I bought myself a 5" newtonian for personal use even though my current work involves setting up and operating two 16" SCTs, for that very reason.
And I'm not sure what it being a refractor has to do with it. Tripod is definitely an issue though. I personally like the Celestron FirstScope http://www.celestron.com/c3/category.php?CatID=92 better for that reason, plus it has an extra inch of aperture - it is $50 vs. $20 though.
Actually I think you're referring to "liberalism" not "progressivism". They're actually not synonyms according to the rest of the world, despite modern American rhetoric. Liberalism refers to what you're discussing, the freedom from government interference wherever possible, and in modern social liberalism, freedom from inequalities and unnecessary suffering. (You might say we have two liberal parties, a progressive, social liberal party and a conservative, economic liberal party.)
Social progressivism, which often ends up sharing many goals with social liberalism, is more directly interested in eliminating inequalities and improving peoples lives based on modern understanding of science. Social progressivism isn't as attached to classic liberal ideals, and in fact one might argue from that point of view that banning the swastika is a step towards preventing past excesses and as such is a worthwhile policy.
As far as I know, pardons are for lifting criminal charges and/or the shortening of punitive measures.
The immunity provisions, I believe, were targeted at civil suits, not criminal charges, so a presidential pardon wouldn't apply.
Can you imagine the political difficulties in trying to reduce ITAR restrictions? Even if a politician does recognize that reform is needed, its unlikely they'll have the guts to do it, since the attack ads are so easy to write. Remember, ITAR stands for International Trade in Arms Restrictions. No one wants to be pro-proliferation.
We deal with the same things in the space industry, since rockets tend to resemble missiles. ITAR is ultimately a stranglehold on American businesses in a globalized world and needs to be reformed -- unfortunately reform is likely to be a complex, wonky issue, and one that is far too easy to be demonized.
Unfortunately, private ventures only make sense when theres a strong chance of profit. In those cases where exploration involved more than walking a little bit further (at which point a motivated individual could do it), it has always initially relied on government funding and support.
The great age of exploration in Europe was all initially government funded*. Only after routes were discovered and the land scouted out did for-profit groups begin to take charge -- even then they tended to be mercantilist public-private partnerships. This is part of why we form governments, to do those things that benefit society as a whole but do not profit individuals and require huge pools of resources (national defense being the most obvious example).
Where the X-Prize and other NewSpace efforts exist is in that space where groups like the British East India company existed in the past. That is, they are moving to take advantage of the initial government investment, and expand it now that the economic benefit of it is understood. The SS1 flight could never have happened without early developments like the X-15, and SpaceX wouldn't be where they are without previous government research. The innovations from these companies are in architecture and engineering practice, not fundamental theory.
NASA or something like it will always be needed to push the frontier, but they need to get out of the business of doing the same old stuff. Getting people and cargo to LEO is something they've done for 50 years, and there is clear economic benefit to doing so. Whether its using ULA launchers or newer, more exciting ones like Falcon 9 or Orbital Science's offerings, NASA should take advantage of what already exists and foster a more competitive market, so that they are able to perform their task, ground-breaking exploration, better and more cheaply. If there were a stronger, more competitive commercial market, the extra $3B may not have been necessary to request.
Put simply, we still need NASA, but we need a smarter NASA.
-------
*Yes, I'm aware of the dangers of relating things to European exploration, given the cultural destruction and exploitation that resulted. However, it still seems to me to be the best historical reference. Fortunately there are no natives most of the places we're talking about going now.
As someone who is color-blind (severely red/green), this news just astounds me.
The basic fact is that I have no idea, no point of reference to even understand what it is I don't see. It is impossible for me to imagine what "Purple" actually is, since to me it is merely a dark blue. Not hard to imagine, like an unusual experience is, but as far as I'm concerned impossible to imagine.
Until seeing this article today, I had assumed that I would never be able to understand what most people saw. Having the possibility open up is simply mind-blowing. Imagine what kind of leap that would be for more serious conditions like actual blindness.
While there's certainly room for improvement over NASA's methods, a two order-of-magnitude improvement from a startup seems absurdly optimistic, no matter what modular rockets and other mission design innovations they use.
However, I wish them the best of luck, and even if costs creep up to $8 million a person, then it will still be a worthwhile endeavor.
Living in Texas and following the tweets about it, I believe it was actually fairly windy yesterday. It was stormy and rainy across the state, and I know that they were much more worried about the rain than the wind.
That engine can thrust and vector a lot, and Dallas/Plano (their lab) and west Oklahoma (a common test site) aren't exactly known for their stellar weather, so they've always had to deal with wind.
Sadly I have no concrete numbers, but 10 mph seems like a pretty reasonable limit based on the environment.
That seems only marginally high for a technically-oriented summer internship. I made $3000/month the summer after my freshman year as an engineering student, and I think the company got pretty good value for my work. And this was in Tulsa, OK where that kind of money goes a lot further.
With another student we put together a parts manual for a product they were working on. It was rather tedious work, so it wasn't worthwhile to put the full-time engineers on, so they got their money's worth. It was also a great experience for us, doing technical documentation, and really getting to know how a rather complex aircraft system was put together -- I definitely feel it was a worthwhile summer that helped me a lot.
Certainly it makes more sense if you're starting from scratch. However, since we're not, the question becomes more complicated. On one side, you have the argument that we should make the best architecture possible for the sake of the future, with the disadvantage of long lead time, risk and high cost. On the other side you have the argument that we should build something that takes the most advantage of the currently in place manufacturing and infrastructure to minimize the gap and keep things running, but this leads to a long-term non-optimal solution. To me, Ares seems to be a 'worst of both worlds' compromise between the two, by limiting us to shuttle derived technology while still having to redesign it all in practical terms.
Personally, I feel something like DIRECT is better simply because it can be finished much more quickly than a completely new launch infrastructure, and is thus more likely to be finished before it gets cancelled. After this I would say slow development of a better series of vehicles should begin, although this seems less likely politically.
The summary makes one error, suggesting that Kepler is capable of detecting the gravitational 'wobble' caused by a moon. Rather, Kepler, or any system of similar sensitivity, is able to detect the transit of a moon, and recognize it as being distinct from that of the parent planet.
Understandable mistake, since all of the early exo-planet detections were made using the 'wobble' method (detecting the Doppler shift corresponding with a stars motion due to a heavy, close planet). However, the transit method, which measures small dips in the brightness as the planet passes in front of its parent star is far more sensitive, though more difficult to use due to noise constraints.
Basically, imagine if you were looking at our sun from another star system, and Jupiter stood out clearly as a dip in the light curve, reappearing every 8 or 9 years(?). With this, something like Io or Europa would show up as a smaller periodic variation overlaid on that larger dip. Only noise levels are standing in the way of detecting it, and apparently they think Kepler can handle it.
Actually, we evolved to fit into the savannas of Africa pretty well, everything after that has been colonization. Theres been some small scale evolution to adapt to new environments, but all of that was after we moved to the new areas, relying on the primary tool evolution gave us: intelligence.
If colonization of other worlds is possible, then its worthwhile. Not because we want to find a better Earth, but because we want to find more Earths. It may very well be that we adapt those worlds to suit us as those worlds adapt the settlers. However, its our adaptability through intelligence that will get us there, and that makes more and more environments suitable for us. The colonizers have never had it easy, but they have a history of adapting and making it better for following generations.
In this case, the ability to have an inexpensive, hackable e-paper device would allow the development of improved usage patterns for low-refresh rate devices.
Right now there are only a few e-paper devices out there, so there's only been a few groups working on the UIs. With the community hacking at it, its very possible someone will find new, better ways to do things that make e-paper devices less specialized. All the complaints about the rather poor web-browser are largely based on a lack of creativity and effort in the UI department... if one of these guys thinks they can do better I'd love to see what they can do.
A couple of false limitations here. First, NASA isn't the only group capable of leaving the Earth ("Space is a place, not a program"): there are other countries, cooperative ventures with other countries and private ventures, etc.
Second, its not that no one is willing to fund NASA to do it, its that NASA isn't willing/able to find a way to do it within the budget they're given. Every moon plan is always predicated on the president saying that more money will be there. If NASA is ever going to break the Apollo barrier in a sustainable way, the plans must take into account that funding WILL drop back to the post-Apollo average, if its ever actually raised in the first place. Complain all you like about us needing to take a longer view of the future (I agree), its pretty clear that this is the politically sustainable budget level, and there's no indication that will change in the future.
Also I'd guess that its not so much as a slow news day as that there are ton of rumors and different ideas swirling around right now with the Augustine commission closed but unpublished. I expect the large number of similar stories will die down in a month, but at this point I think the discussion is great, even if some of the ideas (like this one) are less than politically feasible.
The biggest concern isn't the cost so much as the existence of a domestic supplier, whether it be Orbital, SpaceX or the big old guys.
Of course the other important part of COTS is encouraging the development of a fixed-price contract system for orbital launches instead of the cost-plus system that dominates vehicle development right now, a change that does have the implication of leading to lower costs.
True, if you only have the two bodies interacting with each other. However, in this case, the asteroid is in a heliocentric orbit, and also has a very close flyby of the Earth in 2029, which makes the picture very different.
Whenever you propagate the equations of motion forward over multiple orbits, very small errors at the present time grow much larger errors in the future. This is what makes it so hard to know where these small object are going to be: an estimate of the current state thats accurate to within a kilometer and ~0.1 meter/second right now translates to 10s of Earth radii in 2036.
Though Apophis is as guaranteed not to impact in 2029 (all right, 1e-30 or 1e-40, or something absurdly small), the big worry is that it will pass through a gravitational 'keyhole', a set of regions in space around Earth few hundred meters wide that would cause it to return on an impact trajectory in the next 7 years. Basically, this indicates that the close flyby (within the GEO Belt) acts as a huge modifier on any minor modification and error.
The goal of the mission isn't to directly move the asteroid many Earth radii away, but to move it just enough so that the natural forces carry it away from an Earth impact. In order to move it a few hundred meters by the 2029 close approach, you only have the move the asteroid by 10-20 meters if you start modification in 2022. The hard part isn't changing the orbit so much as knowing how you want to change it. Any mitigation mission would also need to do very precise measurements to get the orbital tracking precision down to the order of around ten meters to before beginning any significant modification, because there is a danger of actually making things worse rather than better if you're not careful.
Hope that explains the confusion, I should have been more clear before.
Fair enough. In my view \vec{f}=-(GMm)/r^3 \vec{r}... none of your fancy physics for me.
A 500 kg spacecraft hovering at around ~300 meters from the CM of the asteroid is sufficient to alter the trajectory if 99942 Apophis by ~50 Earth radii by 2036, if applied in the early 2020s for a period of a year. Note that Apophis is 2e10 kg, so a 1 ton asteroid would be incredibly easy to move. The force imparted is around 1/100 of a Newton. The key for getting the most out of such small forces is to use them early and use the orbital tendencies of the asteroid to magnify your result. The close flyby of Apophis in 2029 acts as a huge multiplier for any minor modification of the trajectory.
This sized spacecraft with the requisite Delta-V during the minimum energy window that corresponds with the close approach can easily be fit on board a Delta, Atlas or Falcon 9.
Obviously this isn't an option for a short-lead time object, but hopefully the NEO project funding gets worked out so we will have ample warning in the future to use these kind of long-term mitigation methods. Larger objects would require heavier, more expensive systems, but fortunately those are going to be easier to track and understand, so you wont have the huge uncertainties that make dealings with small objects like Apophis so difficult. A 10% chance of impact is a lot easier to sell to congress than a 1/30,000 chance, and a world-destroyer is likely to get plenty of funding.
Note that I pulled these numbers from numerical simulations in a project I'm currently working on, so I can't really write out the equations or cite any papers. Sorry... you'll just have to believe I have no reason to lie and am reasonably competent.
I'd rephrase/revise your categories slightly.
Windows: People who want something standard, is fairly inexpensive (compared to Mac hardware), and that works well enough. Also for power users who already know Windows well.
OS X: People who want something highly polished, and are willing to spend money for less hassles (assuming they don't have compatibility issues). Also good for UNIX power-users who don't want to put in the maintenance/setup time for Linux/BSD.
Linux/BSD: Good for those who like free software (in both senses), those that like to tinker with their systems, or UNIX users who don't like Apples closed system and would rather use commodity hardware.
Personally, I run an Ubuntu desktop and an Ubuntu media server, but prefer to use an OS-X laptop because the better hardware integration is nice (I've had some painful linux laptop experiences). Windows annoys me to use personally, so I avoid it -- I feel technically inclined enough to deal with whatever incompatibilities with the rest of the world that causes. Of course, its all about different priorities for different people, what works for me may not work for you. No need to rely on stereotypes and start holy wars (not that the parent post was necessarily doing that).
Can't we do both at once?
My backgrounds in space mission design, not geology.. pretty sure the cost to benefit ratio is going to show I'm better off working on asteroid deflection while the geologist down the street gets to work looking at mitigating supervolcanoes. And of course the automotive engineers over there on the other side of town are probably best off developing newer, more efficient cars, and my friends in aerodynamics should working on more efficient aircraft and better wind turbines.
Lots of problems in the world, but also lots of people with lots of different skills
I'm curious what it being weaker than the weak and strong nuclear forces and the electromagnetic forces has to do with it. If the design works, it works. I'm curious to see your equations if you think it won't work. Also gravity is the only purely attractive force, and the one thats hardest to explain, which is why we really pay attention to it.
The advantage of a gravity tractor is that you don't have to land, because landing is a *VERY* hard problem on an asteroid. The biggest problem is that its very difficult to latch on, since you can't rely on gravity to hold you in place. Since you don't hae a good idea of the surface before you arrive, its rather difficult to design a solution thats going to work for all the different possibilities.
This leads one to consider how can you manage to deflect an asteroid without landing, and a gravity tractor is an obvious elegant solution. Note also that in this case you're still using the vaunted ion thrusters to impart the force on the asteroid. Considering the spacecraft and asteroid as two separate systems you have to use the thrust to maintain your standoff distance; considering them as one system (my preferred analysis), you have the thrusters moving the whole system, with internal gravity keeping the whole thing together. The only difference between it and landing, as far as thrust is concerned, is that you are limited to a maximum thrust by the gravity bond: the same sized ion thruster on a landed spacecraft and on a gravity tractor will have exactly the same effect.
The only time it would make sense to land is if you wanted to do a very high-thrust chemical burn (or maybe something like VASMIR, which would only be in the emergency case. Of course, in that case, the costs become irrelevant ($50B for a mission or wiping out Europe isn't a hard decision to make) and you're more likely to seek to impart a maximum impulse by doing a high-risk/high-reward method such as a kinetic impactor or nuke (and multiples as backup).
Though technically correct, it all still comes down to the UI paradigm. You can have Mac programs that require a window open (CoolBook I'm looking at you), and you can have Windows programs that operate effectively without a main window (IM apps as you suggest). However, these are the outliers of the system, and programs on both systems tend to follow the suggested paradigms pretty well. Consider MS Word:
Windows Version: Double click on the icon, you usually get a blank document window. You decide you really don't want to write that report right now, and close the window, and Word is no longer running.
OS X Version: Open Word from the Dock or from Spotlight, and the menu comes up on the 'menu bar to rule them all', and a blank document opens up. Decide you'd rather not write that same report again, and close the window. In this case word is still happily running, and you could start a new document with a simple Command+n.
Which one you like more, or find more productive is a matter of personal preference. I think that the App-centric model (OS X) allows more control and seems more natural than the Doc-centric model (Windows), but the Doc-centric model keeps you from accidentally leaving a lot of stuff open unnecessarily and might be more efficient. I prefer the app-centric mode, and am very happy using OS X, but of course, thats just me.
While I can't say one way or the other in the long-term, I'd imagine that air-superiority is going to be the last air combat role to be replaced by drones. As I understand it, the biggest difference between piloting a drone and being in the cockpit yourself is the situational awareness. Flying something like a Predator or Raptor you're not going to be relying on your peripheral vision to notice something going on off in the distance, or flipping your head around very quickly when your wingman tells you something is behind you. While technology may very well make these kind of things easier, there will be both real and imagined differences (the pilots don't want to lose the cockpit), that will put up a lot of resistance.
Bombing, observation, cargo and escort runs are easier to do without the same level of situational awareness, so I'd imagine that it'll be quite a while after those all fall to UAVs before air superiority goes to the drones. Of course, as others point out, the dogfighting and numerical advantages of being unmanned may cancel it out... but I'd be willing to bet the resistance of pilots (based on possibly questionable objections around situational awareness) will be the dominant factor.
Keep in mind my background is Aerospace Engineering, not military doctrine, so I can't claim to be anything more than an interested observer.