The problem is that the only way to be 100% sure (or even 10% sure) of an impact risk is to send something out there to track it with proper radio science measurements.

Generally the approach any mission should take is not to prevent an impact, which implies that you will have something approaching good knowledge of whether or not it would pass through a keyhole, but rather to reduce the probability of impact. Because the center of the distribution from your knowledge (largely gaussian) is going to be offset from the keyhole, you need to nudge the asteroid further in that same direction to move it out past a 5-sigma or 6-sigma or 7-sigma ellipse, whatever your desired goal is.

The annoying truth about dealing with anything in deep space is that its all probabilistic. You never really know where anything is, and you always have to quote your certainty values.

I wonder if they've looked at predicting how this will play out with the new program in place -- they have the basic problem that they're affecting what they're observing, and thus will change what will happen.

If the algorithms predict crimes in certain areas, you'll end up with officers in the area, likely preventing a crime before it even happens. That is, the potential criminal will notice the police presence and decide its not a good time. Thus there would be some feedback from the prediction method back onto itself.

I can think of three ways it could go:
1. Predictable "waves" that roll across the city
2. Predictable but chaotic patterns reminiscent of a complex cellular automata or fractal
3. The software nullifies itself.

Anyone have any other thoughts or know if they've studied this problem?

Airbags scale by a factor of ~2.5 with mass. MSL is much larger than the MERs. Thus it can't be landed with airbags and fit on top of a launch vehicle.

The skycrane, ridiculous as it may seem, is probably really the best way to get something the size of MSL to the ground. Whether or not they wouldn't have been better off selecting a couple of MER sized machines is a different question...

I like how Boeing, ULA and ATK are listed as having no experience. This is neglecting the fact that no-experience applies less and less to SpaceX. You'd think being able to get a completely new good-sized vehicle flying with two successul test flights would speak to their capabilities.

When will these people realize that the old way of building spaceships hasn't produced a new vehicle in 30 years! Claiming NASA has the experience to build something new is disingenuous -- this is not to put the blame on NASA employees, but rather to point out that the current contracting structure, with its tendency to produce a One-Design-To-Rule-Them-All, and then have it be meddled with by congress, has proven to not be up to the task without Apollo-like external influences. I have trouble believing that any new NASA-designed launch vehicle would actually make it all the way to completion.

And their arguments are based largely on a miscomprehension of what is meant by 'commercial space'. It does not mean independence from a government market -- in fact only the wildest flights of fancy claim that an HSF market could exist without government demand. It means changing the contracting methods to something less prone to the abuses of cost-plus contracting, and allowing the companies that build new spaceships to sell their services to others as well. I really wish that we had chosen a less inflammatory name for the concept when it got pushed into the Obama budget -- I fear that the name makes the whole process sounds scarier than it actually is.

The problem with that is recognizing what code is going to be reused by others and what isn't.

I'm an aerospace engineer who writes a lot of code (and does so on the taxpayer's dime), and it is a struggle to find the right balance between getting something functional for the immediate task, and recognizing what will be useful for others later. Since its much more difficult to write the second variety (particularly if it needs to be generalized for as-yet unknown tasks,) its just as important to perform some tasks the quick way as it is to do others the right way. Otherwise I am wasting precious resources.

No. I'm sorry. No. Theres a difference between having fun with software names and this. It is incredibly misogynistic, and it is perfectly reasonable to be offended by it. The name refers to a non-consensual sexual intrusion, something you might consider light rape.

There's a big difference between this and something adolescent and immaturely sexual, but not horribly offensive like, oh, 'booblib'.

I see two clear differences between Facebook and Google+ that I think reduce the privacy issues.

1. Google has made a clear commitment to making sure you can export your data from all of their services, while Facebook is particularly shameless about lock-in. This makes the cost of shifting to a different service much lower if they start acting more evil.

2. The Circles feature makes it much easier to maintain privacy, not from Google, but from each other. By making different classes of friends/acquaintances core features of the system instead of Facebook's tacked-on Groups feature, it forces a user to consider whether they really need to share something with everyone. That's definitely a good thing.

Of course the fundamental issue that you can hide your information from Google or anyone that has a special arrangement with them is quite obviously still there. But I can't help but feel Google+ mitigates the issues much better.

Merely ideas before their time. Both nice in theory but ugly reality made them too ineffective for their roles.

Fortunately, we (as in civilization) have taken our lessons learned quite well. The Concorde was too inefficient relative to high subsonic aircraft (i.e. high fuel costs), and had very limited routes due to restrictions on supersonic land overflights. There is a lot of research going on now to reduce sonic booms to the point of elimination, as well as improving efficiency. The next supersonic commercial aircraft, whenever it is made, will be cost competitive and capable of flying more routes.

The shuttle's failings are well documented, but the next generation of manned vehicles demonstrate the lessons learned quite well. All have the passenger cabin on top, separate crew and cargo functionality, seek simplicity and are truly reusable rather than merely refurbish-able. Additionally, by seeking multiple independent vendors we are avoiding the single string failures we encountered after Columbia, Challenger, and the current retirement plan.

We didn't get things right the first time out on either of these, but thats not necessarily a bad thing -- mistakes are often the best way to learn.

I work on NASA Science Mission Directorate missions, and while if JWST is not built, it will be in many ways a shame, but in other ways it will be a great relief.

JWST is facing potential cancellation not simply because it seems less important than military spending or other items, but because it is incredibly late, incredibly over budget, and taking funding from other missions. With MSL (the other SMD money sink) being launched soon, if JWST costs can be either constrained or repurposed we have a lot of opportunity to do a lot of new and interesting things which could be just as exciting.

While the US budget is certainly worth being questioned for its priorities (as is any county's, its only healthy), I don't think this is necessarily indicative of those issus.

As an engineer, that skycrane contraption sets off my alarms of being an extremely complicated and scary solution. It lacks the simplicity of earlier landers with a sequence of chutes, retro rockets, and airbag expansions. Though still being single point failures, they were not actively controlled and could use simple backup timers to make sure everything deployed if at all possible. (Full disclosure: I'm a JPL engineer, but not in EDL and not working on MSL, and of course my opinions are purely my own).

Of course for a mobile vehicle that large, I can't think of a better solution that could fit on a launch vehicle, so I'll give it the benefit of the doubt.

Given that, though, if it fails, i doubt it would be resurrected. MSL already has a bad track record of delays and problems, and a reputation as a money sink (though not as bad as JWST). Also, I have a bias towards more smaller and cheaper missions (and as a deep space navigator, rovers are quite dull for me professionally) so I would actually rather have the money spent on more New Frontiers and Discovery class missions.

The shuttle was designed and built in the 1970s. NASA (or more precisely the STS model of one vehicle to rule them all with politicians at the helm) has consistently failed to develop a replacement vehicle in the 40 years since then.

Time to try something new.

I hear this a lot, and I think the destination-oriented approach to the problem is the wrong way. As part of the Frontier movement, who whole-heartedly argue that settlement is the only economically justifiable reason for human exploration, we don't just want to go to the Moon, or an asteroid, or anywhere else. We want to go to all of these places, and more.

Destination-oriented approaches aren't going to open the solar system to us. They may ramp up public excitement a bit, but lets be honest, public excitement never got us very far. Don't fall for the myth that Apollo happened because of overwhelming public support, or because Kennedy really believed in it, or anything else -- it served a geopolitical agenda of demonstrating the superiority of the American model during the struggle to win the allegiances of the third world. As advocates of opening the frontier we need to learn to take what we're given and do the most we can with it.

And quite frankly, the ambiguous flexible path approach is the best way to do that. More than anything else, it doesn't require the critical step of "Get more money from congress." If we rebuild a solid infrastructure of multiple launch vehicles to get to LEO (with competitive pressures to improve performance and reduce cost) then in 5 years when a new administration may point in a new direction, they'll have a good starting point from which to redirect the program to accomplish something within 4-5 years (a new administration won't cancel something thats almost done). If in the process we find more new and profitable things to do further away from the Earth's economic sphere, then all the better, because commerce is always going to form a more stable base than the fickleness of feel-good politics. If our systems aren't designed only for the Moon, or for Mars or anywhere else, then we can go wherever it makes the most sense to go at the time.

30-year programs and custom one-off systems for a single mission are far more detrimental to human spaceflight than the passing political pressures or the vagaries of public opinion.

That conventional wisdom (which I have my own issues with, but I digress) only applies to projects that consume a large fraction of NASA's budget and are thus highly visible.

Plenty of small-ish projects get along just find without fear of national politics ending them. A small project just needs to stay on-time, on-budget, and not piss off the more immediate managers.

That sounds great. My least favorite part of meetings is sitting. If I'm stuck sitting there for more than an hour I get antsy.

I can work during meetings if it would otherwise be a waste of time for me to participate -- and I've learned which meetings are actually important after a year on the job. But sitting for that long, even if its worthwhile, just drives me up the wall.

I can't say for sure what they plan, but Earth-Moon L2 point is also a good hopping off point to to hit a lot of interesting places.

If you can match up the equal-energy contours in the Earth-Moon system with similar contours in the Earth-Sun system you can escape from the Earth system with a very modest maneuvers. The GRAIL mission launching in a few months is a good example of this (going the other way). This could make it pretty easy some new asteroids that have never been imaged before, and you could even potentially take these kinds of paths out to other planets -- this is the so-called Interplanetary Superhighway.

I'd imagine their intention is less to explore the L2 point, and more to explore *from* the L2 point.