There isn't a man-made object in space that could create a crater like that. The big ones like the ISS are too low density. The high density ones like the Russian Cosmos nuclear satellites aren't big enough. All of them would have a shallow entry angle that would result in a low velocity for anything that did hit the ground.
As you speculated, when events like this are reported, the various space agencies are usually very quickly able to identify possible satellites that may have entered during a given time frame. For example, a Russian booster entered over my home county about 10 years back. It had already been identified the next morning. Incidentally, it burned up completely. No crater.
Regarding a plutonium carrying satellite. Although I've mentioned such couldn't account for such a crater, there have been quite a few put into space. Cosmos 954, which failed to reach orbit and disintegrated over Canada (note that it was not designed to survive re-entry) is a notable example, but the Russians built dozens of these satellites. Actually, the Cosmos RORSATS were powered by uranium-fueled nuclear reactors, not plutonium RTG's. Anyway, when the RORSATS reached the end of their life, the fuel bundle was actually ejected by a small rocket into a 1000 km disposal orbit, which will delay their re-entry by several hundred more years. I suppose most of the satellite bodies themselves have already re-entered.
Interestingly, this has been found to be a rather major source of space debris, as some of the liquid sodium coolant was ejected simultaneously with but free from the core. Once free from the heat of the reactor, the liquid sodium hardens into little metal spheres.
I am not nitpicking when I point out that those are 7 out of 10 most polluted cities/areas, not the biggest polluters. Not the same thing.
But neither amd I nitpicking when I point out that there is a big difference between emission of CO2 and the release of stuff more commonly listed as pollutants such as lead, mercury, arsenic, sulfur dioxide, and nitrogen oxides, ozone, carbon monoxide and particulates. Not the same thing.
The US, Canada, and Europe have spent much of the last 100 years learning how to clean up those messes when we've made them and how to avoid making them in the first place. China and many other nations have been on a path of relearning all our old lessons on their own.
CO2 is not typically listed as a pollutant because it's very hard to create conditions where it will produce measurable harm. Physiologically, we're not even remotely close to dangerous atmospheric levels. It also doesn't form localized contaminations because it's a gas, and it doesn't bio-accumulate.
Before anybody responds with a global warming comment, note that the cause-and-effect is much different between dying in a hypothetical global warming-induced hurricane or from heat stroke because it's 2/3 of a degree warmer than it was 100 years ago, and dying of carbon dioxide poisoning.
You know that is a very good point. However, off the top of my head, I can't think of any organizations that stands to benefit financially in any significant way from meeting this challenge, either in the form of publicity or product development.
Maybe I'm wrong. It'd be really cool if I was. As I mentioned, I'd love to work on a project like this or even just see others do it. However, if you asked me to place a bet whether this prize will be won or not, I'd put money 10:1 against it.
I think the odds of this being won in the next 20 years (and they only have 5 years to do this) are pretty small. This is similar to Branson's prize he's offering for removing CO2 from the atmosphere at some rather significant rate; the challenge to be surpassed in meeting the qualifications are high enough that there is little chance of having to make a payout.
If they do have to make a payout, the publicity is huge, and it's certainly possible that they have some commercial return in mind...perhaps rights to the rover design. I think the field of contenders will be small and weak, because the challenge is significant and the prize amount is unlikely to match the cost. At least for the original X-prize there was a hypothesized market for system developed as a result.
Of course, if I'm going to say this on Slashdot, I'd better be prepared to back it up:
The guidelines are that it must soft-land on the moon by the end of 2012, roam 500+ meters, and send back video and pictures. The basic prize is $20 million. If it can be done by 2014, the prize is $15 million. There is an additional $5 million if a second lander (by any competitor) to land by 2014. There is a bonus $5 million for extra duties like roaming 5000+ meters, photographing existing man-made objects on the moon, surviving the 14 day lunar night, or discovering water-ice.
The requirements and bonus objectives are roughly inline with the design parameters of the Mars Exploration Rovers. I'm sure a private group can build a device with that kind of capabilities for less than $30 million. However, I'm positive they can't get it to the moon for that little.
Landing a meaningful payload on the moon requires a fairly decent-sized launch vehicle. If we assume a mass similar to the old Surveyor Lunar landers, which were about 1/3 as heavy as the MER's (landing mass, not mobile mass) and not mobile, then we can start looking at launch vehicles capable of sending it on it's way.
The Surveyors were launched on Atlas-Centaur rockets, which have an LEO payload of about 5000 pounds. There isn't anything directly comparable currently on the market. There's few offerings that are too small. A Falcon 1 ($8 million, 1500 pounds) won't cut it. A Falcon 9, on the other hand would be significant overkill, with 21,000 pound LEO capacity and a $35 million price tag.
A Russian Dnepr would probably be the best bet. These converted ICBM's are what Bigelow hired to launch his two prototype inflatable modules with. It has an 8000 pound LEO capacity and costs $15-20 million.
So you're left with $5-10 million (because the last $5 million are only available to a second mission) to develop and build the rover (piece of cake), but also a reliable landing platform and an earth departure stage. The latter can probably be adapted from existing upper stage products, but the first two are being done from scratch.
I just can't imagine that much work being accomplished, even with heavy use of volunteer labor, for that price.
However, if somebody out there has got the money to front and wants a mechanical engineer to work for peanuts part time on such a nerdy project, the above doesn't mean I'm not interested.
You'd be surprised how much operations costs. The rover operations team size has been reduced at least twice, but their last budget extension was still $8.5 million (I forget is that was for one year or 18 months).
Sure that's a lot less than a new mission, but it's not trivial.
Orbiters, by the way, have a special limitation. Once they run out of manuevering fuel, they eventually become completely useless, even if they're gyro stabilized (the gyros will become saturated). As a result, once the fuel gets low, it's not uncommon to do something crazy with them. To wit:
* Galileo plunged into Jupiter's atmosphere, recording data to the last. This was partially a protection measure to guarantee it would not contaminate Europa.
* Magellan did the same at Venus to develop the aerobraking technique.
* ESA Smart-1 hit the moon. The impact was studied from earth to look for water and study the geology. The same was done with Lunar Prospector.
* Stardust and Deep Impact both have been sent to visit additional comets.
* NEAR actually landed intact on the surface of the asteroid Eros. It was built as a mere orbiter.
They'll mostly be looking at geology. Just from a distance they already have noticed several distinct layers in the rocks exposed inside the crater. Examining those layers close up will give them comparisons to see similarities and differences and give them clues as to how they formed (volcanic, sedimentation). Victoria is a fantastic subject because it cuts over 60 feet into the local strata.
Sure there's ejecta outside the crater, but:
1.) Much of it is covered up by blowing sand and it's all scattered about as opposed to conveniently in one place inside the crater.
2.) Ejecta may be more metamorphed by the impact.
3.) You don't know which layer a piece of ejecta comes from.
4.) They've already studied several rocks on plains around the crater.
They're not realistically expecting to find signs of life. The rovers are ill-equipped for that, being primarily geology tools, but they may find more evidence for water and definitely will gather more information about Mars' geological past.
The team is well-aware that going into the crater may be the last thing Opportunity does. It may be stuck inside (although, notice the drive yesterday included a cautious backtrack most of the way out), something important may finally wear out, or the shelter from the wind may allow dust to accumulate on the solar panels to fatal levels. Opportunity has actually been at Victoria Crater, exploring the rim and surrounding area since the end of September...over 11 months ago. They wanted to be extra sure they got a clear picture of what was outside they crater before they move in.
I wouldn't worry about it being utterly boring (except to normal people). Going into the smaller Endurance Crater previously was as cool as anything they'd done before.
The funny part will be the broken wedge and half a dozen divots right next to the golf ball.
This is a concern, but NASA considers the work the rovers are doing valuable enough to keep funding it.
NASA's budget for 2007 provides $85 million for rover operations, communications, and data processing. Obviously that's a non-trivial amount (roughly enough to employ 350 people full-time, standard cost ratios), even compared to the $820 million spent on designing, building, launching, and operating for the first year.
For comparision, Hubble is receiving $340 million this year. The entire NASA budget for Mars exploration for 2007 is about $700 million. Almost half of that goes towards building the 2009 Mars Science Laboratory rover. The rest is divided between the Spirit and Opportunity, Mars Global Surveyor (which died a couple months ago), Mars Odyssey (orbiter), Mars Reconnaissance Orbiter, the US contributions to Mars Express (orbiter), Phoenix Polar Lander (lander, en route), and a Scout-class mission scheduled for 2011.
* My numbers came from NASA's 2007 budget request. Some of them were changed for the actual allocation.
I had the same comment. NASA did not "rebuff" Russia. Since they released the Global Exploration Strategy, NASA has been pretty clear they're interested in international cooperation on the moon.
However, what they don't want is an exploration plan where our program becomes largely dependent upon other nations ability to meet their original committments. As a result, they're not looking to cooperate specifically on the Constellation program. NASA wants to develop the Constellation, get some actual hardware on the moon, then invite cooperation from other nations to assist in utilizing the outpost to its fullest potential. This could include not only sending their astronauts, but also their own exploration hardware, laboratory equipment, experiments, and even life support as desired. It would leave open the option for them to use our rockets or develop their own.
This, admittedly, tend to minimize the role of international partners compared to the International Space Station. However, it also somewhat avoids the sort of problems the ISS had when the Shuttle was grounded and Russia had to step up flights to support it, or prior to that, when the other nations were struggling to get their hardware completed in time for already completed but dependent hardware to launch. In both cases, some nations goals were being held up while others got in gear.
Russia apparently is hoping not to sit on their heals for 20 years waiting for us to hand them a minor role in developing a lunar base, so they're developing plans of their own. However, I don't think they really have the resources to develop a complete lunar program, which is part of the motivation for the Global Exploration Strategy as it now stands. NASA can work on theirs. Russia can work on theirs. At any point they can still share resources if it's beneficial.
I'm not sure if you're joking or not, so I'll reply anyways. From the paper:
A.) This is regularly detected at multiple nuclear plants, but is not caused by them. It is serendipitous because the plants already the gamma-ray detectors for operational monitoring.
B.) Superlatives like "lowest levels of radiation" are seldom meaningful in science. The detectors would have a minimum level they can reliably sense. Also, they can't determine the direction or frequency of the photons. The team that authored this paper set up a detector that can. Presumably they chose to set it up at that particular plant so they could correlate their detailed observations with those from the plant's detectors.
C.) The research was conducted by the University of Tokyo and the Japanese Space Agency (and others). The effect is not unique to Japan, rather the work was done in Japan. And yes, Japan does have magic special super clouds, but they are licensed to the makers of the Final Fantasy series.
Lastly, the effect was first suggested in 1925, but hasn't been investigated much since. Again, it's not caused by the nuclear plant (the submitter wasn't very clear about that). The plant just happened to be a convenient laboratory.
This is really cool to read and compare to the NY Times profile of the Large Hadron Collider at CERN. The feature popped up on Slashdot a few months back.
While the LHC is much bigger and has more advanced detectors, the basic ideas are similar. Both take free protons, then send them through multiple accellerators, finally delivering them to the big circular accellerators for the collisions.
The LHC is 17 miles around, while the Tevatron is only about 4 miles. The LHC will cause collisions at 14 TeV compared to Tevatron's 2 TeV. The LHC is completely underground, while the Tevatron is visible on the surface.
Once the Tevatron is decommissioned, there will still be the Relativistic Heavy Ion Collider in New York doing high energy particle physics in the US, and I understand Fermilab and other American institutes will be involved in processing the deluge of data produced by LHC.
You obviously don't live in an area with many teenagers.
They don't merely sound louder without turning up the volume (which the record companies want), they also sound louder (duh) when you do turn up the volume (which probably 90% of car stereo buyers who think volume==quality want). They want to be able to crank the volume up and both drown out the outside world completely and let everyone else know how sweet their stereo must be since you can hear it from three blocks away.
There is a minor advantage to that when you're listening to music in a noisy environment, because the low volume portions of the song are still audible over the background noise. But then when you hear it in a decent environment or actually listen to it instead of merely using it as a more favorable background sound or a soundtrack for life, it sounds dull.
Imagine listening to the 1812 Overture where the cannon aren't any louder than the trombones. It just sounds cheesy.
Well, obviously it wasn't [Chernobyl]. The question is how close was it?
Chernobyl had a lot more mass of fuel, already hot, contained in a pressurized vessel. When the reaction got out of hand, it superheated the water causing a steam explosion that blew the top off the vessel, spewing part of the reactor contents into the air and also causing a graphite fire that released even more radioactive material. Since the fuel was in solid form, the bulk of it was not easily mobile, allowing it to stay at a critical mass and density while it heated to a lava-like state and melted it's way downward into the ground while keeping the graphite fire burning.
This incident involved 9 gallons uranium and an unspecified solvent at an unspecified concentration and occurred at a processing plant, not a reactor. Had a critical mass pooled, it would have started heating up as the reaction rate increased. This would have caused the solvent to boil, mobilizing some of the radioactive particles but keeping the pool somewhat dispersed, in turn reducing the reaction rate...a sort of natural moderation effect. Actually, this is pretty much the main challenge to overcome in detonating a fission bomb. They like to sputter themselves apart before you get an effective yield.
Because of the self-moderating effect and the lack of any way to build up pressure, there could be no explosion from this spill. It might start a fire, however, which could be expected to increase the amount that becomes airborne, and of course cause additional hazards if the fire spread. A fire can be fought, by the way, although you want to take extra care not to spread the uranium to places where it's harder to clean up.
The increased radiation and perhaps irradiation from the reaction would be a hazard to anyone working in the immediate area. The NRC said there was a possibility of one worker receiving a fatal dose of radiation had it gone critical. The actual uranium that might become airborne is a surprisingly minor hazard. In fact, the wikipedia article has a picture of someone holding U-235 pellets in their hand. It is highly toxic and this is the main threat, but you still need to get a sufficient dose to cause problems. Its radioactivity is actually very low when not in a chain reaction, with a half life of 700 million years. The bigger concern is the daughter isotopes created by its decay with shorter half lives, like radon, but these of course only form at the rate the uranium decays, so it's typically only a problem with very large deposits.
Also, if you read the article in full, you will see that the Nuclear Regulatory Commission already did an investigation (part of what was classified) and gave the company a list of required operational changes to help prevent this sort of thing from happening in the future and mitigate damage if it does.
That wasn't the attitude though. The NRC classified the information as "For Official Use Only," based on (no doubt excessive) blanket security concerns, meaning relevant people need a relevant reason to have access to the information, and it was classified as part of a larger policy change, not to cover-up the incident.
It clearly wasn't a case of "what they don't know can't hurt them" because the NRC followed up on the spill, providing a list of required improvements to the plant, and after review, decided that the policy of disclosure in the nuclear industry was more important than whatever little security concern they had.
The statement "if anything seeps into the wild it will be a catastrophe" is a exaggerated rhetoric. The danger is in the dose. Don't forget uranium exists in non-trivial quantities in the wild. The difference with enriched uranium is the dose is higher relative to anything its diluted in. It may still be a problem, but the scope depends on a lot more.
The decision sort of already is with the crew. They may have nerves of steel, but I seriously doubt any of them are going to blindly take the risk unnecessarily.
If the crew didn't trust the engineers on the ground, they don't have to re-enter. Ground control can't get the shuttle down remotely without the crew prepping it (landing gear control needs to be hooked up to the computer, thrusters need to be powered on, docking hatch has to be sealed). They can raise a fuss and holler, and NASA will get them down by their altnernate means (Soyuz or rushed rescue shuttle). Sure, outright rebellion would be the end of their careers, but these are smart people, and a career doesn't mean much if you're dead.
So the crew is implicitly in the decision loop. They might not have all the info, but at the very least you know they've seen the damage. The general public probably doesn't really appreciate how much the crew, especially the pilot and commander, are very familiar with the inner workings of the shuttle. They definitely know enough to be able to make intuitive assessments of various situations, such as aircraft pilots passed on your work as an avionics specialist, and possibly numerical ones too (since about half the crew has engineering degrees).
Assuming ground control has fully briefed them, which there is not really any reason to doubt, they recognize there is an added risk to re-entering as-is, and there is a risk to sending astronauts out-of-sight underneath the shuttle where there's potential for them to cause further damage if they're not careful. They've said in several interviews they're aware of the damage, but trust the assessment from the ground.
I personally thought this would be an outstanding opportunity to do a real test of their repair method, but obviously people more familiar with it don't find the payoff equal to the added risk.
I'm sure you understand this, but your wording has incorrect implications that I think should be cleared up:
... impossible to evolve away from this without immense changes... ...almost impossible to mutate away from... ...it's unlikely the bug can mutate in time...
A germ couldn't mutate away from or evolve to face a threat as some sort of active response (well, let's hope not anyway). If a singular bacterium that is vulnerable to one of the above threats encounters it, it's pretty much screwed.
The risk is that within a species or strain of bacteria, some may already exist that just happen to have a beneficial mutation that makes them resistant to these threats. So when the population encounters the threat, primarily the mutated ones survive. This also reduces their competition for resources, often allowing these survivors to flourish as a new strain that uniformly has this mutation.
The concern is that we will have then accomplished an accidental form of selective breeding that fosters the creation of bacteria-cide resistant "superbugs" that will enslave humanity and suck our brains. This may have already happened with cable TV.
It's also possible that no such mutations occur and the bacteria-cide remains effective indefinitely. It's hard to guess the chances.
Of course, the big advantage of bacteria-cides is they're generally not harmful to us. You can probably drink anti-bacterial soft-soap, and it'd be the basic soap would probably kill you before you got enough anti-biotic to harm you. If you drink bleach...well...you've got problems.
There is no solution that wins across the board because each design has different strengths and weaknesses.
Buran was generally similar to the shuttle, and yes it did have some similar vulnerabilities as a result. The payload sits in a side-stack configuration, leaving it exposed to potential debris (no foam, but possibly ice) falling off the core stage or a core stage explosion. Also, their hypergolic fuel was very corrosive and more of an explosive hazard on the pad (as evidenced by the SS-18 program) than the SRB's on ours.
Other architectures aren't unilaterally better. They're better by specific criteria...and worse by others. Some of the advantages of the shuttle is that it's a versatile work platform (performed 3 Hubble service missions), it can return large cargos from orbit (multiple spacelab missions and a few satellite retrievals), it doesn't require a separate launch and rendezvous for missions requiring cargo and crew together, and it has much more control during landing. Only the SST and the Buran have/had these capabilities. Even the Kliper, if it ever does get built, will only have a similarly controlled landing. NASA has had several similar proposals, but none got funding.
It's hard to fairly compare the Soyuz or other capsules to the shuttle for these reasons. Heck, an entire Soyuz (actually, two of them by mass, but together they would be too long) with its 3 man crew could be lofted by the shuttle...along with it's own 7 crew.
The Space Shuttle's inability to be landed remotely was actually a safety feature reflecting the intent to only launch it manned. Since the landing gear can not be retracted in flight (same for the Buran, as far as I know), the controls for lowering them are operated manually so a computer bug can not trigger them. The "upgrade" to allow automatic control was a cable that connects the computer to the landing gear relays.
Lastly, I want to note that launching larger segments of the station by Energia would not be trivial due to their modular nature. Of course, this is partially a result of function but largely a result of their being designed around available launchers.
The argument that private citizens should have equal access to this is an interesting one. Historically, satellite imagery from the NRO has been closely guarded on grounds of national security, because releasing it reveals details that might be useful to unsavory people about our satellites capabilities, orbits, and operating practices. There is of course, the additional issue of privacy. After all, not just any private citizen can have access to a wire-tap. Then again, a wiretap requires (in theory anyways) a warrant.
This doesn't quite strike me as uncharted territory. A satellite image is not fundamentally much different from an aerial photo (most people don't seem to realize that the majority of high resolution imagery on Google Earth comes from USGS camera-equipped aircraft). In fact, aircraft usually have the advantage of better resolution, the ability to schedule observations much more conveniently, and longer loiter times (you can't look at the same target for very long moving at 17,500 mph). The main drawbacks are they don't scan as large of areas, and your target can more easily see them, although it's hard to be sure if a plane is watching you or just doing flight training. Oh, and not many airplanes can fligh high enough to avoid an SA-2.
Actually, the Wall Street Journal author seems to have done a good job covering each of these issues in the article.
Regarding two-way transparency, if someone is being underhanded in exploiting that, it once again becomes unbalanced unless you have the resources to identify and address that problem. Net result: someone is still screwing with you, but you have less privacy.
Besides, we theoretically have checks and balances built into the system, but that doesn't stop people from using the system for their own purposes. If the system isn't perfect as is, I highly doubt it will improve by removing all restrictions on either side.
First of all, I'm with the vaporware claims on this.
Secondly, I'd rather see billionaires spending their money creating high paying, high tech jobs building stuff in space than buying hookers, drugs, wigs, and contrived and boring talk or reality tv shows.
Third, you can throw all the money you want at the problem spots in the world, but until someone figures out how to fix the incredibly messed up politics of those places, most of that money will continue to be used to buy more guns/diamonds/sex slaves/burquas. Sure you can just buy food and medicine, but the dictators/warlords/extremist sect leaders only prefer money over food and medicine as wealth to distribute in support of their positions because money is more portable and easily traded for guns/drugs/hookers/hitmen.
Well, I'm not a plasma physicist, so I'm not intimately familiar with all the details, but one thing that jumps out at me right away is the distinction between energy and power.
Energy is the ability to do work. Power is the rate at which work is done or energy is extracted.
The plasma contains a great amount of thermal energy with a tendency to do work (by difussing to the reactor walls), so you have to set up a barrier to accomplishing that work. This is analogous to a dam holding back water. The water, due to it's elevation, has a lot of potential energy, but no power is required to hold it back. Power is extracted as it's let through the turbines.
It's a little more complicated for a plasma. A charged particle moving through a varying magnetic field (like that surrounding the reactor) does work and thereby loses energy. As a result, there is a tendency, although less definite than with a dam and water, for the hydrogen ions to only move around in the reactor along lines of constant magnetic field strength.
Once a magnetic field is established, it ideally takes no energy to maintain, except as charged particles move through it. So power only has to be supplied to the electromagnets to account for their inefficiency (0 under ideal conditions in a superconducting Tokamak) or as work is done on the field by charged particles escaping. Since most of the energy from the reactions is carried away by neutrons, which have no electric charge and therefore don't affect the field, the containment power is sufficiently smaller than the reaction power that this is theoretically feasible as a power plant.
Actually, the biggest power demand in a Tokamak as I understand is for heating the plasma to a temperature where fusion will take place. The hotter it gets, the faster fusion occurs, eventually reaching a breakeven point energy is released by fusion faster than it is carried away by escaping neutrons and gamma rays. Then the plasma can sustain itself. We haven't gotten there yet.
Sorry, the dam analogy isn't great and talking about charged particles in a magnetic field is a little abstract. Hope this helps.
In fact, the stellarator design is almost as old as the Tokamak design. The first one was built in 1951.
Somebody over at physorg got a little too excited about a fairly low-impact paper from NYU. If you read the abstract, you'll see that the paper just deals with the design of the coils for a stellarator.
Most likely, this is for the National Compact Stellarator Experiment (NCSX) being built at nearby Princeton, which will be the first stellarator designed with a computer optimized plasma geometry. I think it will also be the largest stellarator to date, with 12 MW of heating capacity. In contrast, the JET Tokamak has 37 MW and the ITER Tokamak will have 110 MW of heating. Unlike ITER, NCSX will not be capable of break-even operation.
Stellarators often get mentioned in fusion power discussions because they provide a more stable containment design, whereas a Tokamak needs one extra set of electromagnets to deal with the fact that the magnetic field is weaker at the outside of a torus of magnets than at the inside. Although a stellarator is therefore a little simpler in that regard, the geometry and plasma modelling is much more complex, and this in turn creates problems for designing the coils and the exhaust diverter. Because of this, most of the funding and research effort has gone to the Tokamaks.
It's probably not clear from the submission or perhaps even the article, but the same effect is being described in both.
When a nuclear reaction occurs, energy is released primarily in two ways:
1.) Kinetic/thermal energy carried away the reaction products and free neutrons and electrons.
2.) Radiation (mostly x-rays and gamma rays) emitted directly or by secondary effects like Bremsstrahlung (collisions of particles from method 1).
If there's a lot of extra matter around, like an atmosphere, it absorbs most of this energy, thereby converting it to more conventional effects like a shock wave, and UV/infrared/visible light.
However, in space there's little to absorb and re-emit the radiation or collide with and be displaced by the moving matter, so a far greater amount of the nuclear energy is carried away as radiation. As you said, this heats and vaporizes a thin layer of the surface. The vaporized material flies away, giving an equal and opposite impulse to the bulk of the asteroid. A minor drawback is that most of the energy is wasted, since the radiation is emitted 360 degrees around the warhead.
A similar concept would have a super-powerful laser vaporize small amounts of surface material gradually. This has an advantage of being aimable to get some steering benefit but would require much more forewarning.
I thought it interesting that they proposed six smaller warheads instead of one big one (a 10 MT bomb is not out of the question), but that not only allows them to use existing warheads, but also to have some extra control. I could see them parking the warheads in a safe position a few thousand miles from the asteroid and sending them in one at a time. After each blast, you determine the effect on its orbit, then detonate the next one at an optimized angle and distance to account for uncertainties in the position of the last warhead and the composition and density of the asteroid.
I'm a little curious how they ended up studying "laser printer emissions." Perhaps it was a specific finding of a larger workplace particle assessment?
Regardless, the really important thing the article doesn't do is identify any harms. It mentions that the toner is "potentially" able to cause respiratory issues, and they're telling the Australian government they need to regulate this, but they don't say anything about what is a known harmful level or how what they found compared. They most certainly don't refer to any cases of health problems specifically attributed to office-level exposure of toner. Presumably the toner makers have to produce an MSDS on the material, so it's not like this information is impossible to find.
Is this worth regulating? I think a lot more information is in order before we start fretting about a product that has been in our offices for 20+ years. Or perhaps we better start regulating dihydrogen monoxide exposure in the break room, too.
"No employee shall be internally exposed to more than 10 liters of dihydrogen monoxide during an eight hour shift. Following internal exposure exceeding regulatory limits, cardio-pulmonary resuscitation is to be administered..."
Ok, not to diminish the validity of the "Scotty method" of project estimating, but someone should probably once again join this discussion to clarify this point:
The mission plans called for a minimum of 90 days operations and a certain amount of driving (400 meters IIRC). This was not a prediction of the actual performance, but the criteria for mission success. Less than that would be considered only partially successful.
However, they did expect the rovers to last longer, based on the performance of Pathfinder and Sojourner, and therefore included an operations budget extension of 90 days in the budget. Not exactly a secret. By this time they figured it was about 50/50 whether dust accumulation would have robbed them of too much power or something would've broken, so the budget had an allowance for another extension of 180 days just in case.
At this point, they were pretty sure the rovers would be dead. NASA actually had to get special approval from congress to fund an additional one year of operations funding. Well guess what happened when that year was up. Yep.
So now they've gone 14 times the mission success criteria and 3-1/2 times NASA's best predictions. Opportunity has had a disabled heater on its infrared spectrometer for a while, Spirit has had a dead wheel motor for well over a year, and both of the rock abrasion tools are worn out from so much use, but they're still ticking. Of course, there is a real danger from the dust storm currently enveloping the planet, but I've got my fingers crossed.
You're going to have a lot harder time landing on a body with no surface (or at least it's so deep we don't know where it becomes solid).
I'm a little bothered that the article dismisses as useless components that in actuality will probably be used for landing on Mars and are unrelated to the problem addressed in the article, and it tends to treat each idea as a complete solution, rather than pieces of a multistate solution.
The problem is not touching down on the surface. It's that first bit of decelleration during which you cover most of the distance to the ground. You've got to bleed off a lot of speed really fast, and Mars atmosphere isn't very conducive to accomplishing that. The article does cover this part well.
Previous landers, especially the Mars Exploration Rovers, have used multiple stages. The first is the heat shield. Because of their small size, the MER's have a high surface area/mass ratio. The heat shield slowed them down to mach 2 and a supersonic parachute deploys. Then retrorockets fired, slowing it to a complete stop a little ways above the ground, and lastly, the cable cut, dropping it relatively gingerly onto the airbags.
So just for the little MER's, there were actually 4 stages involved: heat shield, parachute, retro-rockets, and airbags. Although the article on focus on the airbags in its discussion of the MER, those were really only to allow a margin of error for the retrorockets (although a needed one), and were unrelated to the supersonic transition part.
The hypercone is basically a specially-shaped parachute, but it still won't slow a lander sufficiently to survive hitting the ground. I'm expecting the final solution if we ever commit to it will include heat shield, hypersonic chute, possible a middle stage chute, main chute, retrorockets, and airbags.
Also, you mention lighting a rocket in a supersonic airstream is hard (I'm not sure about that...the combustion chamber is static), and the article claims it would be better if Mars had no atmosphere. Regardless, if you're committing to rockets for anything more than what a modestly sized parachute leaves you travelling, then it doesn't much matter if you use the rockets down near the ground, or as part of a longer de-orbit burn. Either way you're getting rid of KE.
The military has also showed an interest in bio-fuels. In fact, I believe that was part of the impetus for this Boeing project.
Of course, the military's interest is not ecological, but strategic. They need oil to operate and want a backup for foreign oil. The military investing in bio-fuels is win-win-win because:
1.) It secures their supply
2.) It makes the civillian supply less affected by military demand
3.) Processes and technology the military develops for it are likely to work their way into the civillian market if proven feasible.
In fact, because the military is a little less risk averse, a lot of the initial qualification of blended fuels for aircraft will likely be driven by the Air Force.
Slashdot Mirror
There isn't a man-made object in space that could create a crater like that. The big ones like the ISS are too low density. The high density ones like the Russian Cosmos nuclear satellites aren't big enough. All of them would have a shallow entry angle that would result in a low velocity for anything that did hit the ground.
As you speculated, when events like this are reported, the various space agencies are usually very quickly able to identify possible satellites that may have entered during a given time frame. For example, a Russian booster entered over my home county about 10 years back. It had already been identified the next morning. Incidentally, it burned up completely. No crater.
Regarding a plutonium carrying satellite. Although I've mentioned such couldn't account for such a crater, there have been quite a few put into space. Cosmos 954, which failed to reach orbit and disintegrated over Canada (note that it was not designed to survive re-entry) is a notable example, but the Russians built dozens of these satellites. Actually, the Cosmos RORSATS were powered by uranium-fueled nuclear reactors, not plutonium RTG's. Anyway, when the RORSATS reached the end of their life, the fuel bundle was actually ejected by a small rocket into a 1000 km disposal orbit, which will delay their re-entry by several hundred more years. I suppose most of the satellite bodies themselves have already re-entered.
Interestingly, this has been found to be a rather major source of space debris, as some of the liquid sodium coolant was ejected simultaneously with but free from the core. Once free from the heat of the reactor, the liquid sodium hardens into little metal spheres.
But neither amd I nitpicking when I point out that there is a big difference between emission of CO2 and the release of stuff more commonly listed as pollutants such as lead, mercury, arsenic, sulfur dioxide, and nitrogen oxides, ozone, carbon monoxide and particulates. Not the same thing.
The US, Canada, and Europe have spent much of the last 100 years learning how to clean up those messes when we've made them and how to avoid making them in the first place. China and many other nations have been on a path of relearning all our old lessons on their own.
CO2 is not typically listed as a pollutant because it's very hard to create conditions where it will produce measurable harm. Physiologically, we're not even remotely close to dangerous atmospheric levels. It also doesn't form localized contaminations because it's a gas, and it doesn't bio-accumulate.
Before anybody responds with a global warming comment, note that the cause-and-effect is much different between dying in a hypothetical global warming-induced hurricane or from heat stroke because it's 2/3 of a degree warmer than it was 100 years ago, and dying of carbon dioxide poisoning.
You know that is a very good point. However, off the top of my head, I can't think of any organizations that stands to benefit financially in any significant way from meeting this challenge, either in the form of publicity or product development.
Maybe I'm wrong. It'd be really cool if I was. As I mentioned, I'd love to work on a project like this or even just see others do it. However, if you asked me to place a bet whether this prize will be won or not, I'd put money 10:1 against it.
I think the odds of this being won in the next 20 years (and they only have 5 years to do this) are pretty small. This is similar to Branson's prize he's offering for removing CO2 from the atmosphere at some rather significant rate; the challenge to be surpassed in meeting the qualifications are high enough that there is little chance of having to make a payout.
If they do have to make a payout, the publicity is huge, and it's certainly possible that they have some commercial return in mind...perhaps rights to the rover design. I think the field of contenders will be small and weak, because the challenge is significant and the prize amount is unlikely to match the cost. At least for the original X-prize there was a hypothesized market for system developed as a result.
Of course, if I'm going to say this on Slashdot, I'd better be prepared to back it up:
The guidelines are that it must soft-land on the moon by the end of 2012, roam 500+ meters, and send back video and pictures. The basic prize is $20 million. If it can be done by 2014, the prize is $15 million. There is an additional $5 million if a second lander (by any competitor) to land by 2014. There is a bonus $5 million for extra duties like roaming 5000+ meters, photographing existing man-made objects on the moon, surviving the 14 day lunar night, or discovering water-ice.
The requirements and bonus objectives are roughly inline with the design parameters of the Mars Exploration Rovers. I'm sure a private group can build a device with that kind of capabilities for less than $30 million. However, I'm positive they can't get it to the moon for that little.
Landing a meaningful payload on the moon requires a fairly decent-sized launch vehicle. If we assume a mass similar to the old Surveyor Lunar landers, which were about 1/3 as heavy as the MER's (landing mass, not mobile mass) and not mobile, then we can start looking at launch vehicles capable of sending it on it's way.
The Surveyors were launched on Atlas-Centaur rockets, which have an LEO payload of about 5000 pounds. There isn't anything directly comparable currently on the market. There's few offerings that are too small. A Falcon 1 ($8 million, 1500 pounds) won't cut it. A Falcon 9, on the other hand would be significant overkill, with 21,000 pound LEO capacity and a $35 million price tag.
A Russian Dnepr would probably be the best bet. These converted ICBM's are what Bigelow hired to launch his two prototype inflatable modules with. It has an 8000 pound LEO capacity and costs $15-20 million.
So you're left with $5-10 million (because the last $5 million are only available to a second mission) to develop and build the rover (piece of cake), but also a reliable landing platform and an earth departure stage. The latter can probably be adapted from existing upper stage products, but the first two are being done from scratch.
I just can't imagine that much work being accomplished, even with heavy use of volunteer labor, for that price.
However, if somebody out there has got the money to front and wants a mechanical engineer to work for peanuts part time on such a nerdy project, the above doesn't mean I'm not interested.
You'd be surprised how much operations costs. The rover operations team size has been reduced at least twice, but their last budget extension was still $8.5 million (I forget is that was for one year or 18 months).
Sure that's a lot less than a new mission, but it's not trivial.
Orbiters, by the way, have a special limitation. Once they run out of manuevering fuel, they eventually become completely useless, even if they're gyro stabilized (the gyros will become saturated). As a result, once the fuel gets low, it's not uncommon to do something crazy with them. To wit:
* Galileo plunged into Jupiter's atmosphere, recording data to the last. This was partially a protection measure to guarantee it would not contaminate Europa.
* Magellan did the same at Venus to develop the aerobraking technique.
* ESA Smart-1 hit the moon. The impact was studied from earth to look for water and study the geology. The same was done with Lunar Prospector.
* Stardust and Deep Impact both have been sent to visit additional comets.
* NEAR actually landed intact on the surface of the asteroid Eros. It was built as a mere orbiter.
They'll mostly be looking at geology. Just from a distance they already have noticed several distinct layers in the rocks exposed inside the crater. Examining those layers close up will give them comparisons to see similarities and differences and give them clues as to how they formed (volcanic, sedimentation). Victoria is a fantastic subject because it cuts over 60 feet into the local strata.
Sure there's ejecta outside the crater, but:
1.) Much of it is covered up by blowing sand and it's all scattered about as opposed to conveniently in one place inside the crater.
2.) Ejecta may be more metamorphed by the impact.
3.) You don't know which layer a piece of ejecta comes from.
4.) They've already studied several rocks on plains around the crater.
They're not realistically expecting to find signs of life. The rovers are ill-equipped for that, being primarily geology tools, but they may find more evidence for water and definitely will gather more information about Mars' geological past.
The team is well-aware that going into the crater may be the last thing Opportunity does. It may be stuck inside (although, notice the drive yesterday included a cautious backtrack most of the way out), something important may finally wear out, or the shelter from the wind may allow dust to accumulate on the solar panels to fatal levels. Opportunity has actually been at Victoria Crater, exploring the rim and surrounding area since the end of September...over 11 months ago. They wanted to be extra sure they got a clear picture of what was outside they crater before they move in.
I wouldn't worry about it being utterly boring (except to normal people). Going into the smaller Endurance Crater previously was as cool as anything they'd done before.
The funny part will be the broken wedge and half a dozen divots right next to the golf ball.
This is a concern, but NASA considers the work the rovers are doing valuable enough to keep funding it.
NASA's budget for 2007 provides $85 million for rover operations, communications, and data processing. Obviously that's a non-trivial amount (roughly enough to employ 350 people full-time, standard cost ratios), even compared to the $820 million spent on designing, building, launching, and operating for the first year.
For comparision, Hubble is receiving $340 million this year. The entire NASA budget for Mars exploration for 2007 is about $700 million. Almost half of that goes towards building the 2009 Mars Science Laboratory rover. The rest is divided between the Spirit and Opportunity, Mars Global Surveyor (which died a couple months ago), Mars Odyssey (orbiter), Mars Reconnaissance Orbiter, the US contributions to Mars Express (orbiter), Phoenix Polar Lander (lander, en route), and a Scout-class mission scheduled for 2011.
* My numbers came from NASA's 2007 budget request. Some of them were changed for the actual allocation.
I had the same comment. NASA did not "rebuff" Russia. Since they released the Global Exploration Strategy, NASA has been pretty clear they're interested in international cooperation on the moon.
However, what they don't want is an exploration plan where our program becomes largely dependent upon other nations ability to meet their original committments. As a result, they're not looking to cooperate specifically on the Constellation program. NASA wants to develop the Constellation, get some actual hardware on the moon, then invite cooperation from other nations to assist in utilizing the outpost to its fullest potential. This could include not only sending their astronauts, but also their own exploration hardware, laboratory equipment, experiments, and even life support as desired. It would leave open the option for them to use our rockets or develop their own.
This, admittedly, tend to minimize the role of international partners compared to the International Space Station. However, it also somewhat avoids the sort of problems the ISS had when the Shuttle was grounded and Russia had to step up flights to support it, or prior to that, when the other nations were struggling to get their hardware completed in time for already completed but dependent hardware to launch. In both cases, some nations goals were being held up while others got in gear.
Russia apparently is hoping not to sit on their heals for 20 years waiting for us to hand them a minor role in developing a lunar base, so they're developing plans of their own. However, I don't think they really have the resources to develop a complete lunar program, which is part of the motivation for the Global Exploration Strategy as it now stands. NASA can work on theirs. Russia can work on theirs. At any point they can still share resources if it's beneficial.
I'm not sure if you're joking or not, so I'll reply anyways. From the paper:
A.) This is regularly detected at multiple nuclear plants, but is not caused by them. It is serendipitous because the plants already the gamma-ray detectors for operational monitoring.
B.) Superlatives like "lowest levels of radiation" are seldom meaningful in science. The detectors would have a minimum level they can reliably sense. Also, they can't determine the direction or frequency of the photons. The team that authored this paper set up a detector that can. Presumably they chose to set it up at that particular plant so they could correlate their detailed observations with those from the plant's detectors.
C.) The research was conducted by the University of Tokyo and the Japanese Space Agency (and others). The effect is not unique to Japan, rather the work was done in Japan. And yes, Japan does have magic special super clouds, but they are licensed to the makers of the Final Fantasy series.
Lastly, the effect was first suggested in 1925, but hasn't been investigated much since. Again, it's not caused by the nuclear plant (the submitter wasn't very clear about that). The plant just happened to be a convenient laboratory.
This is really cool to read and compare to the NY Times profile of the Large Hadron Collider at CERN. The feature popped up on Slashdot a few months back.
While the LHC is much bigger and has more advanced detectors, the basic ideas are similar. Both take free protons, then send them through multiple accellerators, finally delivering them to the big circular accellerators for the collisions.
The LHC is 17 miles around, while the Tevatron is only about 4 miles. The LHC will cause collisions at 14 TeV compared to Tevatron's 2 TeV. The LHC is completely underground, while the Tevatron is visible on the surface.
Once the Tevatron is decommissioned, there will still be the Relativistic Heavy Ion Collider in New York doing high energy particle physics in the US, and I understand Fermilab and other American institutes will be involved in processing the deluge of data produced by LHC.
You obviously don't live in an area with many teenagers.
They don't merely sound louder without turning up the volume (which the record companies want), they also sound louder (duh) when you do turn up the volume (which probably 90% of car stereo buyers who think volume==quality want). They want to be able to crank the volume up and both drown out the outside world completely and let everyone else know how sweet their stereo must be since you can hear it from three blocks away.
There is a minor advantage to that when you're listening to music in a noisy environment, because the low volume portions of the song are still audible over the background noise. But then when you hear it in a decent environment or actually listen to it instead of merely using it as a more favorable background sound or a soundtrack for life, it sounds dull.
Imagine listening to the 1812 Overture where the cannon aren't any louder than the trombones. It just sounds cheesy.
Chernobyl had a lot more mass of fuel, already hot, contained in a pressurized vessel. When the reaction got out of hand, it superheated the water causing a steam explosion that blew the top off the vessel, spewing part of the reactor contents into the air and also causing a graphite fire that released even more radioactive material. Since the fuel was in solid form, the bulk of it was not easily mobile, allowing it to stay at a critical mass and density while it heated to a lava-like state and melted it's way downward into the ground while keeping the graphite fire burning.
This incident involved 9 gallons uranium and an unspecified solvent at an unspecified concentration and occurred at a processing plant, not a reactor. Had a critical mass pooled, it would have started heating up as the reaction rate increased. This would have caused the solvent to boil, mobilizing some of the radioactive particles but keeping the pool somewhat dispersed, in turn reducing the reaction rate...a sort of natural moderation effect. Actually, this is pretty much the main challenge to overcome in detonating a fission bomb. They like to sputter themselves apart before you get an effective yield.
Because of the self-moderating effect and the lack of any way to build up pressure, there could be no explosion from this spill. It might start a fire, however, which could be expected to increase the amount that becomes airborne, and of course cause additional hazards if the fire spread. A fire can be fought, by the way, although you want to take extra care not to spread the uranium to places where it's harder to clean up.
The increased radiation and perhaps irradiation from the reaction would be a hazard to anyone working in the immediate area. The NRC said there was a possibility of one worker receiving a fatal dose of radiation had it gone critical. The actual uranium that might become airborne is a surprisingly minor hazard. In fact, the wikipedia article has a picture of someone holding U-235 pellets in their hand. It is highly toxic and this is the main threat, but you still need to get a sufficient dose to cause problems. Its radioactivity is actually very low when not in a chain reaction, with a half life of 700 million years. The bigger concern is the daughter isotopes created by its decay with shorter half lives, like radon, but these of course only form at the rate the uranium decays, so it's typically only a problem with very large deposits.
Also, if you read the article in full, you will see that the Nuclear Regulatory Commission already did an investigation (part of what was classified) and gave the company a list of required operational changes to help prevent this sort of thing from happening in the future and mitigate damage if it does.
That wasn't the attitude though. The NRC classified the information as "For Official Use Only," based on (no doubt excessive) blanket security concerns, meaning relevant people need a relevant reason to have access to the information, and it was classified as part of a larger policy change, not to cover-up the incident.
It clearly wasn't a case of "what they don't know can't hurt them" because the NRC followed up on the spill, providing a list of required improvements to the plant, and after review, decided that the policy of disclosure in the nuclear industry was more important than whatever little security concern they had.
The statement "if anything seeps into the wild it will be a catastrophe" is a exaggerated rhetoric. The danger is in the dose. Don't forget uranium exists in non-trivial quantities in the wild. The difference with enriched uranium is the dose is higher relative to anything its diluted in. It may still be a problem, but the scope depends on a lot more.
The decision sort of already is with the crew. They may have nerves of steel, but I seriously doubt any of them are going to blindly take the risk unnecessarily.
If the crew didn't trust the engineers on the ground, they don't have to re-enter. Ground control can't get the shuttle down remotely without the crew prepping it (landing gear control needs to be hooked up to the computer, thrusters need to be powered on, docking hatch has to be sealed). They can raise a fuss and holler, and NASA will get them down by their altnernate means (Soyuz or rushed rescue shuttle). Sure, outright rebellion would be the end of their careers, but these are smart people, and a career doesn't mean much if you're dead.
So the crew is implicitly in the decision loop. They might not have all the info, but at the very least you know they've seen the damage. The general public probably doesn't really appreciate how much the crew, especially the pilot and commander, are very familiar with the inner workings of the shuttle. They definitely know enough to be able to make intuitive assessments of various situations, such as aircraft pilots passed on your work as an avionics specialist, and possibly numerical ones too (since about half the crew has engineering degrees).
Assuming ground control has fully briefed them, which there is not really any reason to doubt, they recognize there is an added risk to re-entering as-is, and there is a risk to sending astronauts out-of-sight underneath the shuttle where there's potential for them to cause further damage if they're not careful. They've said in several interviews they're aware of the damage, but trust the assessment from the ground.
I personally thought this would be an outstanding opportunity to do a real test of their repair method, but obviously people more familiar with it don't find the payoff equal to the added risk.
I'm sure you understand this, but your wording has incorrect implications that I think should be cleared up:
A germ couldn't mutate away from or evolve to face a threat as some sort of active response (well, let's hope not anyway). If a singular bacterium that is vulnerable to one of the above threats encounters it, it's pretty much screwed.
The risk is that within a species or strain of bacteria, some may already exist that just happen to have a beneficial mutation that makes them resistant to these threats. So when the population encounters the threat, primarily the mutated ones survive. This also reduces their competition for resources, often allowing these survivors to flourish as a new strain that uniformly has this mutation.
The concern is that we will have then accomplished an accidental form of selective breeding that fosters the creation of bacteria-cide resistant "superbugs" that will enslave humanity and suck our brains. This may have already happened with cable TV.
It's also possible that no such mutations occur and the bacteria-cide remains effective indefinitely. It's hard to guess the chances.
Of course, the big advantage of bacteria-cides is they're generally not harmful to us. You can probably drink anti-bacterial soft-soap, and it'd be the basic soap would probably kill you before you got enough anti-biotic to harm you. If you drink bleach...well...you've got problems.
There is no solution that wins across the board because each design has different strengths and weaknesses.
Buran was generally similar to the shuttle, and yes it did have some similar vulnerabilities as a result. The payload sits in a side-stack configuration, leaving it exposed to potential debris (no foam, but possibly ice) falling off the core stage or a core stage explosion. Also, their hypergolic fuel was very corrosive and more of an explosive hazard on the pad (as evidenced by the SS-18 program) than the SRB's on ours.
Other architectures aren't unilaterally better. They're better by specific criteria...and worse by others. Some of the advantages of the shuttle is that it's a versatile work platform (performed 3 Hubble service missions), it can return large cargos from orbit (multiple spacelab missions and a few satellite retrievals), it doesn't require a separate launch and rendezvous for missions requiring cargo and crew together, and it has much more control during landing. Only the SST and the Buran have/had these capabilities. Even the Kliper, if it ever does get built, will only have a similarly controlled landing. NASA has had several similar proposals, but none got funding.
It's hard to fairly compare the Soyuz or other capsules to the shuttle for these reasons. Heck, an entire Soyuz (actually, two of them by mass, but together they would be too long) with its 3 man crew could be lofted by the shuttle...along with it's own 7 crew.
The Space Shuttle's inability to be landed remotely was actually a safety feature reflecting the intent to only launch it manned. Since the landing gear can not be retracted in flight (same for the Buran, as far as I know), the controls for lowering them are operated manually so a computer bug can not trigger them. The "upgrade" to allow automatic control was a cable that connects the computer to the landing gear relays. Lastly, I want to note that launching larger segments of the station by Energia would not be trivial due to their modular nature. Of course, this is partially a result of function but largely a result of their being designed around available launchers.
The argument that private citizens should have equal access to this is an interesting one. Historically, satellite imagery from the NRO has been closely guarded on grounds of national security, because releasing it reveals details that might be useful to unsavory people about our satellites capabilities, orbits, and operating practices. There is of course, the additional issue of privacy. After all, not just any private citizen can have access to a wire-tap. Then again, a wiretap requires (in theory anyways) a warrant.
This doesn't quite strike me as uncharted territory. A satellite image is not fundamentally much different from an aerial photo (most people don't seem to realize that the majority of high resolution imagery on Google Earth comes from USGS camera-equipped aircraft). In fact, aircraft usually have the advantage of better resolution, the ability to schedule observations much more conveniently, and longer loiter times (you can't look at the same target for very long moving at 17,500 mph). The main drawbacks are they don't scan as large of areas, and your target can more easily see them, although it's hard to be sure if a plane is watching you or just doing flight training. Oh, and not many airplanes can fligh high enough to avoid an SA-2.
Actually, the Wall Street Journal author seems to have done a good job covering each of these issues in the article.
Regarding two-way transparency, if someone is being underhanded in exploiting that, it once again becomes unbalanced unless you have the resources to identify and address that problem. Net result: someone is still screwing with you, but you have less privacy.
Besides, we theoretically have checks and balances built into the system, but that doesn't stop people from using the system for their own purposes. If the system isn't perfect as is, I highly doubt it will improve by removing all restrictions on either side.
First of all, I'm with the vaporware claims on this.
Secondly, I'd rather see billionaires spending their money creating high paying, high tech jobs building stuff in space than buying hookers, drugs, wigs, and contrived and boring talk or reality tv shows.
Third, you can throw all the money you want at the problem spots in the world, but until someone figures out how to fix the incredibly messed up politics of those places, most of that money will continue to be used to buy more guns/diamonds/sex slaves/burquas. Sure you can just buy food and medicine, but the dictators/warlords/extremist sect leaders only prefer money over food and medicine as wealth to distribute in support of their positions because money is more portable and easily traded for guns/drugs/hookers/hitmen.
Well, I'm not a plasma physicist, so I'm not intimately familiar with all the details, but one thing that jumps out at me right away is the distinction between energy and power.
Energy is the ability to do work. Power is the rate at which work is done or energy is extracted.
The plasma contains a great amount of thermal energy with a tendency to do work (by difussing to the reactor walls), so you have to set up a barrier to accomplishing that work. This is analogous to a dam holding back water. The water, due to it's elevation, has a lot of potential energy, but no power is required to hold it back. Power is extracted as it's let through the turbines.
It's a little more complicated for a plasma. A charged particle moving through a varying magnetic field (like that surrounding the reactor) does work and thereby loses energy. As a result, there is a tendency, although less definite than with a dam and water, for the hydrogen ions to only move around in the reactor along lines of constant magnetic field strength.
Once a magnetic field is established, it ideally takes no energy to maintain, except as charged particles move through it. So power only has to be supplied to the electromagnets to account for their inefficiency (0 under ideal conditions in a superconducting Tokamak) or as work is done on the field by charged particles escaping. Since most of the energy from the reactions is carried away by neutrons, which have no electric charge and therefore don't affect the field, the containment power is sufficiently smaller than the reaction power that this is theoretically feasible as a power plant.
Actually, the biggest power demand in a Tokamak as I understand is for heating the plasma to a temperature where fusion will take place. The hotter it gets, the faster fusion occurs, eventually reaching a breakeven point energy is released by fusion faster than it is carried away by escaping neutrons and gamma rays. Then the plasma can sustain itself. We haven't gotten there yet.
Sorry, the dam analogy isn't great and talking about charged particles in a magnetic field is a little abstract. Hope this helps.
In fact, the stellarator design is almost as old as the Tokamak design. The first one was built in 1951.
Somebody over at physorg got a little too excited about a fairly low-impact paper from NYU. If you read the abstract, you'll see that the paper just deals with the design of the coils for a stellarator.
Most likely, this is for the National Compact Stellarator Experiment (NCSX) being built at nearby Princeton, which will be the first stellarator designed with a computer optimized plasma geometry. I think it will also be the largest stellarator to date, with 12 MW of heating capacity. In contrast, the JET Tokamak has 37 MW and the ITER Tokamak will have 110 MW of heating. Unlike ITER, NCSX will not be capable of break-even operation.
Stellarators often get mentioned in fusion power discussions because they provide a more stable containment design, whereas a Tokamak needs one extra set of electromagnets to deal with the fact that the magnetic field is weaker at the outside of a torus of magnets than at the inside. Although a stellarator is therefore a little simpler in that regard, the geometry and plasma modelling is much more complex, and this in turn creates problems for designing the coils and the exhaust diverter. Because of this, most of the funding and research effort has gone to the Tokamaks.
A little more info here: http://en.wikipedia.org/wiki/Stellarator
Anybody care to bet on whether this shows up on CNN's tech page in a day or two as some major "recent design enhancement?"
It's probably not clear from the submission or perhaps even the article, but the same effect is being described in both.
When a nuclear reaction occurs, energy is released primarily in two ways:
1.) Kinetic/thermal energy carried away the reaction products and free neutrons and electrons.
2.) Radiation (mostly x-rays and gamma rays) emitted directly or by secondary effects like Bremsstrahlung (collisions of particles from method 1).
If there's a lot of extra matter around, like an atmosphere, it absorbs most of this energy, thereby converting it to more conventional effects like a shock wave, and UV/infrared/visible light.
However, in space there's little to absorb and re-emit the radiation or collide with and be displaced by the moving matter, so a far greater amount of the nuclear energy is carried away as radiation. As you said, this heats and vaporizes a thin layer of the surface. The vaporized material flies away, giving an equal and opposite impulse to the bulk of the asteroid. A minor drawback is that most of the energy is wasted, since the radiation is emitted 360 degrees around the warhead.
A similar concept would have a super-powerful laser vaporize small amounts of surface material gradually. This has an advantage of being aimable to get some steering benefit but would require much more forewarning.
I thought it interesting that they proposed six smaller warheads instead of one big one (a 10 MT bomb is not out of the question), but that not only allows them to use existing warheads, but also to have some extra control. I could see them parking the warheads in a safe position a few thousand miles from the asteroid and sending them in one at a time. After each blast, you determine the effect on its orbit, then detonate the next one at an optimized angle and distance to account for uncertainties in the position of the last warhead and the composition and density of the asteroid.
I'm a little curious how they ended up studying "laser printer emissions." Perhaps it was a specific finding of a larger workplace particle assessment? Regardless, the really important thing the article doesn't do is identify any harms. It mentions that the toner is "potentially" able to cause respiratory issues, and they're telling the Australian government they need to regulate this, but they don't say anything about what is a known harmful level or how what they found compared. They most certainly don't refer to any cases of health problems specifically attributed to office-level exposure of toner. Presumably the toner makers have to produce an MSDS on the material, so it's not like this information is impossible to find.
Is this worth regulating? I think a lot more information is in order before we start fretting about a product that has been in our offices for 20+ years. Or perhaps we better start regulating dihydrogen monoxide exposure in the break room, too.
"No employee shall be internally exposed to more than 10 liters of dihydrogen monoxide during an eight hour shift. Following internal exposure exceeding regulatory limits, cardio-pulmonary resuscitation is to be administered..."
Ok, not to diminish the validity of the "Scotty method" of project estimating, but someone should probably once again join this discussion to clarify this point:
The mission plans called for a minimum of 90 days operations and a certain amount of driving (400 meters IIRC). This was not a prediction of the actual performance, but the criteria for mission success. Less than that would be considered only partially successful.
However, they did expect the rovers to last longer, based on the performance of Pathfinder and Sojourner, and therefore included an operations budget extension of 90 days in the budget. Not exactly a secret. By this time they figured it was about 50/50 whether dust accumulation would have robbed them of too much power or something would've broken, so the budget had an allowance for another extension of 180 days just in case.
At this point, they were pretty sure the rovers would be dead. NASA actually had to get special approval from congress to fund an additional one year of operations funding. Well guess what happened when that year was up. Yep.
So now they've gone 14 times the mission success criteria and 3-1/2 times NASA's best predictions. Opportunity has had a disabled heater on its infrared spectrometer for a while, Spirit has had a dead wheel motor for well over a year, and both of the rock abrasion tools are worn out from so much use, but they're still ticking. Of course, there is a real danger from the dust storm currently enveloping the planet, but I've got my fingers crossed.
You're going to have a lot harder time landing on a body with no surface (or at least it's so deep we don't know where it becomes solid).
I'm a little bothered that the article dismisses as useless components that in actuality will probably be used for landing on Mars and are unrelated to the problem addressed in the article, and it tends to treat each idea as a complete solution, rather than pieces of a multistate solution.
The problem is not touching down on the surface. It's that first bit of decelleration during which you cover most of the distance to the ground. You've got to bleed off a lot of speed really fast, and Mars atmosphere isn't very conducive to accomplishing that. The article does cover this part well.
Previous landers, especially the Mars Exploration Rovers, have used multiple stages. The first is the heat shield. Because of their small size, the MER's have a high surface area/mass ratio. The heat shield slowed them down to mach 2 and a supersonic parachute deploys. Then retrorockets fired, slowing it to a complete stop a little ways above the ground, and lastly, the cable cut, dropping it relatively gingerly onto the airbags.
So just for the little MER's, there were actually 4 stages involved: heat shield, parachute, retro-rockets, and airbags. Although the article on focus on the airbags in its discussion of the MER, those were really only to allow a margin of error for the retrorockets (although a needed one), and were unrelated to the supersonic transition part.
The hypercone is basically a specially-shaped parachute, but it still won't slow a lander sufficiently to survive hitting the ground. I'm expecting the final solution if we ever commit to it will include heat shield, hypersonic chute, possible a middle stage chute, main chute, retrorockets, and airbags.
Also, you mention lighting a rocket in a supersonic airstream is hard (I'm not sure about that...the combustion chamber is static), and the article claims it would be better if Mars had no atmosphere. Regardless, if you're committing to rockets for anything more than what a modestly sized parachute leaves you travelling, then it doesn't much matter if you use the rockets down near the ground, or as part of a longer de-orbit burn. Either way you're getting rid of KE.
The military has also showed an interest in bio-fuels. In fact, I believe that was part of the impetus for this Boeing project.
Of course, the military's interest is not ecological, but strategic. They need oil to operate and want a backup for foreign oil. The military investing in bio-fuels is win-win-win because:
1.) It secures their supply
2.) It makes the civillian supply less affected by military demand
3.) Processes and technology the military develops for it are likely to work their way into the civillian market if proven feasible.
In fact, because the military is a little less risk averse, a lot of the initial qualification of blended fuels for aircraft will likely be driven by the Air Force.
NY Times Article on Air Force Bio-Fuel