Hillary is suffering from a serious, untreatable neurological condition
(some suggest Parkinson's) and will be unable to perform the duties
the Office of President of The United States requires.
Even if that's true, it won't change how the vast majority of people vote.
Most vote for a party, a platform, an ideology, or a pet policy issue - not for a person. If Hillary wins and cannot serve, she will be replaced by her Vice President. Since her VP is also a Democrat, it would make little difference to most voters which one actually ends up in power.
If anything, I think Trump's campaign would lose ground if it were to become known that Hillary could not serve, since there is a sizeable chunk of voters who can't stand either one and would jump at the chance to vote for anyone else - such as Tim Kaine.
Disclaimer: I am neither a Democrat or a Republican, and can't stomache either candidate. I'm making a prediction, not expressing a preference.
You're assuming a market similar to SpaceX's current market...
No, I'm not. The first and last sentences of my comment both explicitly acknowledge that the market could change dramatically.
You are the one who is "assuming" things by asserting not just that it could expand enough to support reusability, but that it actually will. My point is simply that it's going to cost the launch industry dearly IF that turns out to be the wrong bet.
I have not offered an opinion as to whether it is or isn't the right bet; I'm just pointing out the consequences if you're wrong...
I mean that it will slow down a ton relative to what would be required to launch the same payloads using only expendables. (Hopefully this is not a controversial statement.) I myself already raised the possibility that demand might increase in response to the lower launch price for reusable rockets.
Consider what reusability is going to do to Merlin engine production:
None of the second stages will be recovered
The second stage only needs one engine, so the fact that a new one is needed for every launch doesn't help that much to keep production rates up.
Not all first stages will be recovered
Based on present-day launch manifests, SpaceX should eventually be able to achieve nearly 100% first stage recovery - assuming that Falcon Heavy works, including core reuse. There are very few payloads launched each year which could not go up on a Falcon Heavy, even to GTO and with the performance penalty of recovering all three boosters.
Even recovered launch stages don't have an infinite life, they're only targeted for a few dozen launches
I will estimate the service life of a first stage at about ten launches (since accidents of some sort will probably destroy most before they actually wear out). That means that SpaceX will only need between one and three new engines for each flight, depending on whether most launches are Falcon 9, or Falcon Heavy. Added together with the one new engine needed for each second stage, we have a requirement of two to four new engines per flight - compared to at least ten today.
This implies that SpaceX will need to approximately triple its launch rate to justify the current engine production rate long-term. In each of the past three years, SpaceX launched about six missions. As the United States and Europe only made a total of 29 orbital launches in 2015, tripling SpaceX's rate would either require a massive expansion of the market, or for SpaceX to single-handedly capture about 60% of the market - leaving little for the other four major western launch providers to fight over.
All things considered, I stand by my original judgement: either the launch market is about to grow very quickly (in terms of annual up-mass, at least), or the industry is pouring a lot of money down the drain on excess capacity.
Some aspects of the Falcon design were designed to speed up the learning curve - and seem to have worked. Namely, the engines seem to have become quite reliable; part of the reason for going with so many engines was not just so that you can keep going after an engine failure, but also so that you're mass producing the engines and going through ten per flight; you're going to retire the risk a lot faster when using something in such large numbers. On the other hand, there's only two stages/pairs of tanks per flight, two COPVs, etc, so the learning curve is going to be - and has been - slower. . Falcon Heavy will help speed it up, of course, since there's four separate cores, all built similarly.
Full reusability is going to slow down that build rate a ton, though. Unless SpaceX can secure a much larger number of orders, they're in danger of losing much of the benefit of their mass production scheme in the near future.
Of course, it's not just a problem for SpaceX: the current glut of launch systems puts every provider at risk in this area - especially those pursuing reusability (SpaceX, Blue Origin, ULA, Airbus, ?). Either the launch market is about to experience massive growth, or there's a bubble about to pop...
And I originally wrote3THz to 300THz. THz, as in Tera Hertz.... Is that not Tera Hertz radiation?
No, it is not. You attempted to criticize the original article for misusing the phrase "terahertz radiation", but you are the one misusing it. Your definition is etymologically reasonable, but it's not the one used by the rest of the world, so it's wrong.
The Wikipedia article you cite seems to be semi confused about whether 300GHz-3THz is "Tremendously High Frequency" radiation (1mm - 100um) or "Terahertz" radiation.
And 3THz to 300THz most certainly does include near ultraviolet...
I said 300 GIGAhertz, not 300 TERAhertz.
Your confusion is understandable, given the unfortunate etymology of the phrase "terahertz radiation". But, etymology is often misleading.
Ultimately, the only way to be sure about the meaning of a term of art like this, is to look it up. While not every source I have found agree with the precise frequency range specified by the article I linked, all agree that the upper end of the band in question is somewhere in the infrared, and that it does not include visible light (let alone ultraviolet).
since you're mister snarky today
There is nothing sarcastic or mocking (the definition of "snark") in either of my comments in this thread. I simply pointed out your error. The fact that you automatically perceive that as "snarky" comes across either as proud or insecure (I will not speculate as to which).
The band commonly refered to as "terahertz radiation" is from 300 GHz to 3 THz. It overlaps the bottom end of the "far infrared" band on the chart you linked, just above EHF microwave - nowhere near the visible spectrum.
The thrust of the New Glenn is close enough to that of the Falcon Heavy that the higher specific impulse of the three-stage New Glenn will likely give it slightly greater payload capacity on high delta-V missions (GEO and beyond), despite the lower thrust at lift-off. So yes, it's only "slightly" less from a practical perspective.
More generally, "slightly" is an entirely subjective term, and in science and engineering it often makes more sense to compare things on a logarithmic, rather than linear, scale. On a log scale, 17.1 MN and 22.8 MN are barely distinguishable: the two rockets will directly compete with each other for payloads.
In the Garden of Eden, Adam and Eve are akin to children, and to top it off they didn't know right from wrong until after they had tasted the fruit from the tree of knowledge.
There is more than one kind of "knowledge". Adam and Eve were created as mature adults, both physically and intellectually (Genesis 2:15-25).
It is evident from the text that they knew very well - in the abstract - that eating from the Tree was unlawful and dangerous; that's why the woman (mis)quotes God's command to the tempting serpent, and why the serpent makes a point of denying the deadly warning in order to trick her. The Bible later states plainly that "Adam was not deceived" (1st Timothy 2:14); he ate of the Tree as an act of wilful rebellion, not childish naivete.
The effect of eating from the Tree was to transform that abstract knowledge into an intimate, practical knowledge of sin and its consequences, gained through experience. The fact they previously lacked such experience is no excuse; I don't need to actually try murdering someone to know that it would be evil and hurtful to both myself and others.
Nevertheless, if I did so, I would gain an understanding of some things that I can never understand otherwise (in this life, at least). But, humanity is better off leaving some things unlearned.
Though God Himself has never committed it, yet He already possessed an intimate knowledge of moral evil, by virtue of His divine wisdom and foreknowledge: "for the Spirit searches all things" (1st Corinthians 2:10), and God has a deeper awareness of the inner life of every soul (past, present, or future; real or hypothetical) than we do ourselves (Psalm 139).
It is that knowledge - infinitely greater than that gained by Adam - which motivates His Law: both the parts that seem necessary to us, and those that offend. Humanity rejects the advice of infinite wisdom - and the commandments of unlimited power - at its own peril.
How could an omniscient god not know what Adam and Eve would do in that situation?
Although some Christians are unwilling to admit it, the Bible makes it quite clear that God knew exactly what Adam and Eve would do, before He even made anything. God would not plan that most costly sacrifice for mankind's sins (Revelation 13:8) and chose which people He would pursue unto salvation (Ephesians 1:4) "before the foundation of the world" unless He already knew that mankind would Fall.
Punishing all their descendants for that action is ridiculous and horribly unjust.
God is not punishing us for Adam and Eve's sin; this is a common misunderstanding of the doctrine of original sin.
When two dogs reproduce, what kind of creature will their offspring be? Cats? Roses? Of course not: they will be more dogs. Like begets like.
When Adam and Eve rebelled against God, they became sinners: broken, selfish, and partly crazy- in a word, spiritually "dead". We are all born in the likeness of our sinful parents. God is not punishing us for their sin, and He is not forcing us to sin, either. We simply lack the spiritual power and desire to be truly good, and so inevitably, predictably, commit sin ourselves.
Jesus said, "Why do you not know My speech? Because you cannot hear My word. You are of the Devil as father, and the lusts of your father you will do. He was a murderer from the beginning, and did not abide in the truth because there is no truth in him. When he speaks a lie, he speaks of his own, for he is a liar and the father of it. And because I tell you the truth, you do not believe Me." John 8:43-45
Is it unjust for God to punish us on account of our own corrupt nature, which we inherited rather than chose?
If you found a black mamba living in your house, would you let it stay? If not, why not? Deadly snakes don't choose to be deadly snakes; they just are
What kind of fancy cloak or rusty broken sword would that trade imply? This is the year 30 AD...
The price ranges for a real hand-made, genuine wool cloak versus a hand-forged carbon steel short-sword appear to overlap substantially today. Although the technology has changed somewhat in both cases, I don't see any fundamental reason to think the relative price difference would have been tremendously different back then.
I suspect they translated 'knife' into 'sword', but don't read enough greek or Aramaic to check.
The Greek word in Luke 22:36 is "machaira" (Strong's G3162), which in the New Testament is only ever used in reference to a weapon. Despite the widespread controversy (even among Christians) as to the moral intent of the verse, people who are actually qualified to translate Biblical Greek have consistently chosen "sword" as the best English word to represent it.
(Here's the complete list of verses, for anyone who wants to verify this: Matthew 10:34, 26:47, 26:52, 26:55, Mark 14:43, 14:48, Luke 21:24, 22:36, 22:38, 22:49, 22:52, John 18:10, Acts 12:2, 16:27, Romans 8:35, Hebrews 4:12, 11:34, 11:37, Revelation 6:4, 13:10)
Never did make a lot of sense to me.
There is a common misconception - one that I held to myself, for several years - that Jesus taught his followers to be pacifists. This really was not the case though. Briefly:
Jesus and the Apostles were very consistent in their teaching that Christianity is the continuation and fulfilment of the message of Moses and the Old Testament prophets, including warriors like Joshua and David. The ceremony, circumstances, and calling of the New Testament Church are different than that of the Old Testament nation of Israel, but the fundamental morality and theology is not.
"Do not think that I have come to destroy the Law or the Prophets. I have not come to destroy but to fulfill." Matthew 5:17
"For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh; so that the righteousness of the Law might be fulfilled in us, who walk not according to the flesh but according to the Spirit." Romans 8:3-4
So, any interpretation of the New Testament which makes its morality obviously and wildly inconsistent with that of the Old cannot represent the true intent of the writers. As I see it, there are two main sources of the legitimate confusion about Jesus' teachings on violence:
1) Unlike the nation of Israel, the Christian Church was not commissioned as an earthly government.
Both the New and the Old Testament consistently uphold the right of the State to enforce the law and defend its independence through violence. For example: "For the rulers are not a terror to good works, but to the bad. And do you desire to be not afraid of the authority? Do the good, and you shall have praise from it. For it is a servant of God to you for good. For if you practice evil, be afraid, for it does not bear the sword in vain; for it is a servant of God, a revenger for wrath on him who does evil. Therefore you must be subject, not only for wrath, but also for conscience' sake." Romans 13:3-5
The Old Testament generals, like Joshua and King David were the government, and so leading armies into battle was a part of their duties. On the other hand, when (before he was king) David found himself being unjustly hunted by the mad King Saul, he was very reluctant to fight back, even to save his life: "And he said to his men, Far be it from me, by the LORD, if I will do this thing to my lord, the LORD's anointed, to stretch forth my hand against him, since he is the anointed of the LORD." 1st Samuel 24:6.
In the New Testament, when Jesus famously said, "put up your sword again into its place; for all who take the sword shall peri
That line is from the end of 2nd Thessalonians. Paul tended to organize his letters (loosely) into two parts: theory, followed by application.
The theory part of 2nd Thessalonians corrects a misconception which had arisen: some were saying that Jesus would return to judge the world very soon - so soon, in fact, that some people decided to ignore everyday concerns and just focus on being spiritual (or pretending to be).
"For we hear that there are some who walk disorderly among you, not working at all, but being busybodies." 2nd Thessalonians 3:11
Paul corrects this by saying, in the theory part, that certain visible, earthly events must take place before Jesus comes back - notably, the appearance of a powerful new world leader in the Middle East who will blaspheme the God of the Bible and instead claim that he himself is a god, demanding (under penalty of death) to be worshipped. Until various such end-times prophecies begin to be fulfilled in earnest (which hasn't happened yet), Christians are not to suppose that Jesus is coming back tomorrow, or anything like that:
"Now we beseech you, my brothers, with regard to the coming of our Lord Jesus Christ and our gathering together to Him, that you should not be soon shaken in mind or troubled, neither by spirit, nor by word or letter, as through us, as if the Day of Christ is at hand. Let not anyone deceive you by any means. For that Day shall not come unless there first comes a falling away, and the man of sin shall be revealed, the son of perdition, who opposes and exalts himself above all that is called God, or that is worshiped, so that he sits as God in the temple of God, setting himself forth, that he is God." 2nd Thessalonians 2:1-4
In the application part, Paul basically says, "Therefore, stop being lazy and go earn your bread, like everyone else!" (That being my interpretation of 2nd Thessalonians 3:6-15 in context, not his actual words).
This instruction was necessary because Jesus and the Apostles taught that providing for the physical needs of fellow Christians was an essential duty of the church, and so those who chose not to work were able to free-load off of those who did work. But, that generosity was always intended for those who were disabled, elderly, sick, or shut out of the workplace by persecution - not for self-appointed monks and nuns.
"Then the King shall say to those on His right hand, Come, blessed of My Father, inherit the kingdom prepared for you from the foundation of the world. For I was hungry, and you gave me food; I was thirsty, and you gave Me drink; I was a stranger, and you took Me in; I was naked, and you clothed Me; I was sick, and you visited Me; I was in prison, and you came to Me.
"Then the righteous shall answer Him, saying, Lord, when did we see You hungry, and fed You? Or thirsty, and gave You drink? When did we see You a stranger, and took You in? Or naked, and clothed You? Or when did we see You sick, or in prison, and came to You?
"And the King shall answer and say to them, Truly I say to you, Inasmuch as you did it to one of the least of these My brothers, you have done it to Me." Matthew 25:34-40
So, it really has nothing to do with class wars one way or the other, in the ordinary sense - although the Bible does have quite a lot to say about the structure of a just economy in other places.
Fences used to provide a decent amount of privacy, while allowing people the benefits of natural lighting and a view of the outside world. Low-flying camera drones are problematic because they can see into houses from angles that were previously inaccessible.
Still, shooting down trespassing drones really isn't a good solution, mostly because it's only sort-of reasonable for people who live in rural areas. Allowing people to fire guns into the air, without a proper backstop, is a really bad idea in more densely populated (sub)urban areas.
If the drone privacy problem isn't solved through regulation, perhaps we'll see a trend toward architectural mitigation - tinted windows and the like.
so that they could defend themselves from wild animals
Swords have never been the weapon of choice for hunting or defence against dangerous animals; people wanted something that would allow them to keep the animal at a distance, like a bow, spear/javelin, sling, or some kind of trap.
As a weapon, swords were almost exclusively for fighting people.
If they want this to be taken seriously as a simulated Mars mission, it should have been considerably longer - two to three years. With current propulsion technology, travel time alone could exceed a year, before you add in time actually spent on Mars exploring (and waiting for a favourable launch window to return).
Maybe they just figure that getting funding for an ultra-expensive, inefficient, all-chemical propulsion mission is politically impossible, anyway? (As it should be.)
Still, even with a high delta-V electric propulsion system, I would think that you'd want to design the system with enough life support longevity to allow a slow Hohmann transfer as a back-up plan.
Go look at the photos in the linked article: the astronauts in this test were stationed at high altitude, above the tree line in a desolate landscape of volcanic rock. It's fairly cold up there, despite being close to the equator.
Nowhere on Earth is actually similar to Mars, but the spot NASA chose is better than most. (Of course, I'm sure the support staff enjoyed the tropical climate found below.)
In what world is 300 litres (presumed at STP) per day of natural gas enough to power a car? Even in something rather efficient like a Honda Civic, that's still only enough for about 5 km per day, or ~2000 km per year.
[300 L/d of methane] * [0.0364 MJ/L of methane] / [34.2 MJ/L of gasoline] = [0.319 L/d of gasoline equivalent] [0.319 L/d of gasoline] / [6 L / 100 km (fuel economy of a modern compact sedan)] = [5.32 km/d]
Having said that, solar airships are subject to the square-cube law. The larger the airship, the less benefit it can derive from adding solar panels.
Actually, I'm not being entirely fair here - the propulsion power required during cruise depends not only upon the mass (cube scaling), but also upon the form drag (square scaling). So, the usefulness of adding solar cells does decrease for larger airships, but not as quickly as I implied.
Suppose we ditch the heavy batteries and replace them with a diesel generator that kicks in whenever there is insufficient sunlight:
Pros: Fuel consumption during daylight hours is reduced by around 50%. For multi-day trips, the reduction is closer to 25%.
Cons: The additional high-power electric motors, wiring, and power buffering together add substantial weight to the vehicle, as compared to a normal diesel-only model. This will reduce either the fuel load that can be carried, or the payload - maybe -1 ton?
Additionally, the cost of the airship will be increased by at least $3 million USD. (Reasoning: High efficiency thin-film solar cells cost something like $1 USD/Watt. Covering the top and sides of the envelope takes about 1.6 MW. The rest of the money covers motors, wiring, power buffering, profit margin, etc.)
Cost:Benefit analysis: Assuming an average duty cycle of 50% (probably an over-estimate), the lifetime fuel cost for the normal diesel-powered airship is around [480 kW average shaft power] / [40% engine efficiency] * [60 s/min] * [60 min/h] * [24 h/d] * [365.25 d/y] * [25 y] * [50% flying time] / [35.8 MJ/L of diesel] * [$1.20 USD / L of diesel] = $15.8 million USD.
A solar hybrid reduces that by [$15.8 million USD] * [30%] = $4.76 million USD - if we ignore the increased maintenance costs from the added complexity, and assume that the airship is kept very busy (in the air at least half of the time).
Conclusion: Upgrading the Airlander 10 to use a solar hybrid propulsion system isn't a good investment right now, unless you really want the modest range increase - but it's very close, and will probably become so within a decade or two, given the rapid pace of development for the key component: the thin-film solar cells.
Having said that, solar airships are subject to the square-cube law. The larger the airship, the less benefit it can derive from adding solar panels. The Airlander 10 is actually rather small compared to what most of the next-gen airship companies want to build, so it's unlikely that solar power will play a major role in the industry.
I think that Lighter Than Air vehicles have disadvantages that are very well known.
The Airlander 10 is actually somewhat heavier than air, and relies upon aerodynamic lift to stay aloft. Does this reduction in surface area and buoyancy, combined with modern technology, improve the concept enough to make it practical? I don't know, but it's already been built so there's no need to guess: just wait and see.
The people promoting these are usually True Believers who think those disadvantages don't matter. They are always wrong.
For the record, I am not a "True Believer", nor am I really trying to promote the airships. But, I do object to the idea that airships are strictly inferior to jets and trucks - they have, in theory, their own niche that cannot really be served by either of those alternatives.
If the resurgence of investment in airships doesn't lead anywhere useful, it will be because the revised designs fail to serve their target niche, not because they are out-competed by two technologies that can't serve the niche at all. The real competition is probably helicopters (despite their awful fuel efficiency) and smaller military cargo planes like the C-130, which can operate from much smaller, cheaper runways than a 747.
The blimp had to wait 3 days for calm air, it could only fly through a mountain pass, it could only be done at a specific time during the morning, and the pilots were on edge the entire crossing, concerned that the weather would change.
The Airlander 10 has a service ceiling about twice that of a typical blimp, and could cross the Rockies safely almost anywhere.
I don't know about the weather restrictions though; that is my biggest concern with airships, as well. But again, they've already started test flights, so they won't be able to hide it for very long if the restrictions are really severe.
It's an airship. It doesn't have to maintain power overnight. They can just turn the engines off and bob around for awhile.
Not this one: it's not actually lighter than air. Even at sea level, its displacement is only enough to lift about 94% of its weight. At cruising altitude, 40% of the lift must come from aerodynamic effects.
If all you're trying to do is maintain altitude, it is certainly possible to extend the battery life by flying much slower and lower - but the lower you fly, the more vulnerable the airship is to weather-induced accidents. Maybe you could make it through the night, if the weather was good, but there wouldn't be nearly enough safety margin for routine operations, I think.
For loitering missions, that's true. However, for cargo - and especially sky crane - missions, I'm pretty sure that a human crew will be required for many years to come. Safely and quickly handling arbitrary cargo while squeezing as much capacity as possible out of the vehicle is a complex task (both mentally and physically) that can't really be automated yet.
Still, at least for the military, the future 50+ ton capacity models should require far fewer crew members per cargo ton-kilometer than ground convoys, if only because the armed escort can be (mostly) eliminated.
Would it be at all feasible to cover the top of this thing with thin and semi-flexible solar panels? If Solar Impulse can make it around the planet using just the solar energy hitting its thin little lifting surfaces then surely the surface area of this magnificent flying backside should be able to gather enough energy to shove it across the sky, right?
The vehicle is powered by "4 x 325 hp" diesel engines, for a combined peak power of about 960 kW. Most vehicles do not cruise at peak power continuously, so I will estimate the average power requirement at half of that: 480 kW. (This ratio would be approximately correct for a large subsonic jet; if someone knows what it should be for a diesel-powered lifting-body airship instead, please leave a comment.)
The useful surface area of the Airlander 10 is approximately [92 m long] * [43.5 m wide] = [4000 m^2]. (The exact number depends upon the latitude, the time of day, and the craft's heading, but it turns out that its shape is such that the answer doesn't change much, except near the poles.) Peak solar irradiance (direct sunlight at high noon) at ground level is about 1 kW / m^2, and current thin film solar panels are under 15% efficient. Solar power conversion circuitry is around 90% efficient, and an appropriate electric motor with its controller is about 88% efficient. Therefore, a maximum of [4000 m^2] * [1kW / m^2] * [15%] * [90%] * [88%] = [475 kW] of shaft power could be generated by solar-electric means.
So, a solar-powered Airlander 10 could work - but not very well. Under ideal daylight conditions, it could fly about as well as the hydrocarbon-powered version. However, airships are sufficiently slow and long-range that they are expected to routinely fly through the night. Thus, the average power available must be at least cut in half, to 238 kW. Cloud shadowing (airships can fly over some clouds, but far from all) and dust will further reduce that number.
Additionally, a solar-powered airship needs to carry heavy batteries in order to avoid catastrophic power loss when passing through clouds. One hour's worth of lithium-ion power would mass [475 kW*h] / [86% charge/discharge efficiency] / [200 W*h / kg] / [80% - 20% depth of discharge range limit] = [4600 kg]. As the total mass of the Airlander 10 is only 20 metric tons, it cannot carry much more battery power than that without cutting into the payload.
At cruise, nearly all of the Airlander 10's power is devoted to fighting drag. Since subsonic drag scales with the square of airspeed, a solar-powered version could quadruple its battery-powered run time by halving its speed. (It can't really go any slower than that though, as it needs to be able to overcome typical headwinds to be useful.) Four hours of battery time is still woefully inadequate for an overnight flight though, so a solar-powered version would be limited to daytime flights only, and consequently to overland flights only.
TLDR: A solar-powered version of this airship is possible, but it would be considerably slower and incapable of crossing oceans. Supplemental charging on the ground wouldn't help much at all.
It targets two major use cases, neither of which can be serviced by a conventional cargo jet or a road vehicle:
1) Ferrying heavy cargo (and possibly people) to or from a land-locked location that lacks a suitable runway or road/rail connection. This is of special interest to the military, but also has civilian applications.
For the military, truck transport through enemy territory is extremely dangerous for obvious reasons - possibly even more dangerous than using an airship, depending on what technology the enemy has access to. An airship may be a big target, but it can also fly high enough that most ground weapons can't even hit it. If it does get hit, a few small holes in the envelope (say, from a machine gun) won't immediately end the mission. A large one is also at least twice as fast as a military ground convoy, and has more tactical options available for avoiding the enemy, since it doesn't need to follow roads.
Truck transport through neutral territory is safe - for the military convoy. It's not safe for the neutral country though, as allowing military convoys to pass their borders may be considered an act of war by the enemy. For this reason, it can be very difficult to get permission from neighbouring countries to use ground transport into a land-locked war zone. Air transport is less problematic (I do not say problem-free) in this regard.
As for conventional cargo jets like the 747 - their survivability probably isn't as much better than an airship as you might think. Big subsonic jets are easy to shoot down for anyone who has access to large 1970s anti-aircraft missiles, like the Sidewinder or the S-300. So, cargo jets won't last long unless the user has air dominance in the area of operations. A lifting-body airship should still be able to fly high enough to keep out of range of small arms like machine guns, and arguably is not that much more vulnerable than a 747 in practice. It would have to stay a bit further from the front lines though, because it cruises low enough to be at risk from short-range stuff like Stinger missiles, and maybe auto cannons.
For any user (whether military or civilian), the advantage of an airship is that it doesn't need a huge, expensive concrete runway at each end of the journey. For the military, taking weeks or months to build such a runway isn't always an option. Even when a suitable runway is available, it could be disabled by the enemy at any time with a few bombs or artillery rounds. For civilian users, there are projects set in remote areas for which the expense and/or environmental impact of installing a city-grade runway is just not worth it. Dirt roads are usually (though not always) an option, but some exceptionally heavy, bulky cargo can't reasonably be moved via a steep, narrow, windy, muddy road.
2) Because airships can stay aloft so much longer before they need to refuel, they are well-suited to loitering over an area to provide a communications relay or an observation platform. This has civilian applications, as well as military. If you only need to cover a relatively small area (hundreds of square kilometres, rather than thousands), they are much cheaper than satellites. The ability to easily relocate them and swap or upgrade the payload makes them more flexible.
Even for military users, their greater vulnerability isn't always a problem: the military is tasked not only with taking enemy territory, but also with patrolling friendly territory. An enemy trying to sneak in cannot shoot down a patrolling airship without revealing his presence.
There's only one way that a 2017 Tesla will be brand new in 5 years and then put up for sale in 2017
I have no idea what confusion was going through your mind when you wrote that sentence, as it doesn't seem to have any logical connection to what I actually said.
This is not complicated, and should not controversial: WindBourne stated above that the Tesla Model 3 will be affordable for "90%" of American drivers "next year" (2017). This is clearly nonsense, and none of your bizarre replies are helping his case.
Car depreciation rates are not that mysterious. There's only one way that the Tesla Model 3 will be widely available (in good condition) for $16,800 in 2017: if it turns out to be such a piece of junk that the original buyers hate it, and are willing to take a 50% loss on a brand new car just to get rid of it. Surely no one would claim such a disastrous product launch as evidence that electric cars had now become affordable.
Slashdot Mirror
Hillary is suffering from a serious, untreatable neurological condition (some suggest Parkinson's) and will be unable to perform the duties the Office of President of The United States requires.
Even if that's true, it won't change how the vast majority of people vote.
Most vote for a party, a platform, an ideology, or a pet policy issue - not for a person. If Hillary wins and cannot serve, she will be replaced by her Vice President. Since her VP is also a Democrat, it would make little difference to most voters which one actually ends up in power.
If anything, I think Trump's campaign would lose ground if it were to become known that Hillary could not serve, since there is a sizeable chunk of voters who can't stand either one and would jump at the chance to vote for anyone else - such as Tim Kaine.
Disclaimer: I am neither a Democrat or a Republican, and can't stomache either candidate. I'm making a prediction, not expressing a preference.
You're assuming a market similar to SpaceX's current market...
No, I'm not. The first and last sentences of my comment both explicitly acknowledge that the market could change dramatically.
You are the one who is "assuming" things by asserting not just that it could expand enough to support reusability, but that it actually will. My point is simply that it's going to cost the launch industry dearly IF that turns out to be the wrong bet.
I have not offered an opinion as to whether it is or isn't the right bet; I'm just pointing out the consequences if you're wrong...
Not necessarily.
I mean that it will slow down a ton relative to what would be required to launch the same payloads using only expendables. (Hopefully this is not a controversial statement.) I myself already raised the possibility that demand might increase in response to the lower launch price for reusable rockets.
Consider what reusability is going to do to Merlin engine production:
None of the second stages will be recovered
The second stage only needs one engine, so the fact that a new one is needed for every launch doesn't help that much to keep production rates up.
Not all first stages will be recovered
Based on present-day launch manifests, SpaceX should eventually be able to achieve nearly 100% first stage recovery - assuming that Falcon Heavy works, including core reuse. There are very few payloads launched each year which could not go up on a Falcon Heavy, even to GTO and with the performance penalty of recovering all three boosters.
Even recovered launch stages don't have an infinite life, they're only targeted for a few dozen launches
I will estimate the service life of a first stage at about ten launches (since accidents of some sort will probably destroy most before they actually wear out). That means that SpaceX will only need between one and three new engines for each flight, depending on whether most launches are Falcon 9, or Falcon Heavy. Added together with the one new engine needed for each second stage, we have a requirement of two to four new engines per flight - compared to at least ten today.
This implies that SpaceX will need to approximately triple its launch rate to justify the current engine production rate long-term. In each of the past three years, SpaceX launched about six missions. As the United States and Europe only made a total of 29 orbital launches in 2015, tripling SpaceX's rate would either require a massive expansion of the market, or for SpaceX to single-handedly capture about 60% of the market - leaving little for the other four major western launch providers to fight over.
All things considered, I stand by my original judgement: either the launch market is about to grow very quickly (in terms of annual up-mass, at least), or the industry is pouring a lot of money down the drain on excess capacity.
Some aspects of the Falcon design were designed to speed up the learning curve - and seem to have worked. Namely, the engines seem to have become quite reliable; part of the reason for going with so many engines was not just so that you can keep going after an engine failure, but also so that you're mass producing the engines and going through ten per flight; you're going to retire the risk a lot faster when using something in such large numbers. On the other hand, there's only two stages/pairs of tanks per flight, two COPVs, etc, so the learning curve is going to be - and has been - slower. . Falcon Heavy will help speed it up, of course, since there's four separate cores, all built similarly.
Full reusability is going to slow down that build rate a ton, though. Unless SpaceX can secure a much larger number of orders, they're in danger of losing much of the benefit of their mass production scheme in the near future.
Of course, it's not just a problem for SpaceX: the current glut of launch systems puts every provider at risk in this area - especially those pursuing reusability (SpaceX, Blue Origin, ULA, Airbus, ?). Either the launch market is about to experience massive growth, or there's a bubble about to pop...
And I originally wrote3THz to 300THz. THz, as in Tera Hertz. ... Is that not Tera Hertz radiation?
No, it is not. You attempted to criticize the original article for misusing the phrase "terahertz radiation", but you are the one misusing it. Your definition is etymologically reasonable, but it's not the one used by the rest of the world, so it's wrong.
The Wikipedia article you cite seems to be semi confused about whether 300GHz-3THz is "Tremendously High Frequency" radiation (1mm - 100um) or "Terahertz" radiation.
It's both. Like many things, that band has more than just one name.
And 3THz to 300THz most certainly does include near ultraviolet...
I said 300 GIGAhertz, not 300 TERAhertz.
Your confusion is understandable, given the unfortunate etymology of the phrase "terahertz radiation". But, etymology is often misleading.
Ultimately, the only way to be sure about the meaning of a term of art like this, is to look it up. While not every source I have found agree with the precise frequency range specified by the article I linked, all agree that the upper end of the band in question is somewhere in the infrared, and that it does not include visible light (let alone ultraviolet).
since you're mister snarky today
There is nothing sarcastic or mocking (the definition of "snark") in either of my comments in this thread. I simply pointed out your error. The fact that you automatically perceive that as "snarky" comes across either as proud or insecure (I will not speculate as to which).
The band commonly refered to as "terahertz radiation" is from 300 GHz to 3 THz. It overlaps the bottom end of the "far infrared" band on the chart you linked, just above EHF microwave - nowhere near the visible spectrum.
The thrust of the New Glenn is close enough to that of the Falcon Heavy that the higher specific impulse of the three-stage New Glenn will likely give it slightly greater payload capacity on high delta-V missions (GEO and beyond), despite the lower thrust at lift-off. So yes, it's only "slightly" less from a practical perspective.
More generally, "slightly" is an entirely subjective term, and in science and engineering it often makes more sense to compare things on a logarithmic, rather than linear, scale. On a log scale, 17.1 MN and 22.8 MN are barely distinguishable: the two rockets will directly compete with each other for payloads.
In the Garden of Eden, Adam and Eve are akin to children, and to top it off they didn't know right from wrong until after they had tasted the fruit from the tree of knowledge.
There is more than one kind of "knowledge". Adam and Eve were created as mature adults, both physically and intellectually (Genesis 2:15-25).
It is evident from the text that they knew very well - in the abstract - that eating from the Tree was unlawful and dangerous; that's why the woman (mis)quotes God's command to the tempting serpent, and why the serpent makes a point of denying the deadly warning in order to trick her. The Bible later states plainly that "Adam was not deceived" (1st Timothy 2:14); he ate of the Tree as an act of wilful rebellion, not childish naivete.
The effect of eating from the Tree was to transform that abstract knowledge into an intimate, practical knowledge of sin and its consequences, gained through experience. The fact they previously lacked such experience is no excuse; I don't need to actually try murdering someone to know that it would be evil and hurtful to both myself and others.
Nevertheless, if I did so, I would gain an understanding of some things that I can never understand otherwise (in this life, at least). But, humanity is better off leaving some things unlearned.
Though God Himself has never committed it, yet He already possessed an intimate knowledge of moral evil, by virtue of His divine wisdom and foreknowledge: "for the Spirit searches all things" (1st Corinthians 2:10), and God has a deeper awareness of the inner life of every soul (past, present, or future; real or hypothetical) than we do ourselves (Psalm 139).
It is that knowledge - infinitely greater than that gained by Adam - which motivates His Law: both the parts that seem necessary to us, and those that offend. Humanity rejects the advice of infinite wisdom - and the commandments of unlimited power - at its own peril.
How could an omniscient god not know what Adam and Eve would do in that situation?
Although some Christians are unwilling to admit it, the Bible makes it quite clear that God knew exactly what Adam and Eve would do, before He even made anything. God would not plan that most costly sacrifice for mankind's sins (Revelation 13:8) and chose which people He would pursue unto salvation (Ephesians 1:4) "before the foundation of the world" unless He already knew that mankind would Fall.
Punishing all their descendants for that action is ridiculous and horribly unjust.
God is not punishing us for Adam and Eve's sin; this is a common misunderstanding of the doctrine of original sin.
When two dogs reproduce, what kind of creature will their offspring be? Cats? Roses? Of course not: they will be more dogs. Like begets like.
When Adam and Eve rebelled against God, they became sinners: broken, selfish, and partly crazy- in a word, spiritually "dead". We are all born in the likeness of our sinful parents. God is not punishing us for their sin, and He is not forcing us to sin, either. We simply lack the spiritual power and desire to be truly good, and so inevitably, predictably, commit sin ourselves.
Jesus said, "Why do you not know My speech? Because you cannot hear My word. You are of the Devil as father, and the lusts of your father you will do. He was a murderer from the beginning, and did not abide in the truth because there is no truth in him. When he speaks a lie, he speaks of his own, for he is a liar and the father of it. And because I tell you the truth, you do not believe Me." John 8:43-45
Is it unjust for God to punish us on account of our own corrupt nature, which we inherited rather than chose?
If you found a black mamba living in your house, would you let it stay? If not, why not? Deadly snakes don't choose to be deadly snakes; they just are
What kind of fancy cloak or rusty broken sword would that trade imply? This is the year 30 AD...
The price ranges for a real hand-made, genuine wool cloak versus a hand-forged carbon steel short-sword appear to overlap substantially today. Although the technology has changed somewhat in both cases, I don't see any fundamental reason to think the relative price difference would have been tremendously different back then.
I suspect they translated 'knife' into 'sword', but don't read enough greek or Aramaic to check.
The Greek word in Luke 22:36 is "machaira" (Strong's G3162), which in the New Testament is only ever used in reference to a weapon. Despite the widespread controversy (even among Christians) as to the moral intent of the verse, people who are actually qualified to translate Biblical Greek have consistently chosen "sword" as the best English word to represent it.
(Here's the complete list of verses, for anyone who wants to verify this: Matthew 10:34, 26:47, 26:52, 26:55, Mark 14:43, 14:48, Luke 21:24, 22:36, 22:38, 22:49, 22:52, John 18:10, Acts 12:2, 16:27, Romans 8:35, Hebrews 4:12, 11:34, 11:37, Revelation 6:4, 13:10)
Never did make a lot of sense to me.
There is a common misconception - one that I held to myself, for several years - that Jesus taught his followers to be pacifists. This really was not the case though. Briefly:
Jesus and the Apostles were very consistent in their teaching that Christianity is the continuation and fulfilment of the message of Moses and the Old Testament prophets, including warriors like Joshua and David. The ceremony, circumstances, and calling of the New Testament Church are different than that of the Old Testament nation of Israel, but the fundamental morality and theology is not.
"Do not think that I have come to destroy the Law or the Prophets. I have not come to destroy but to fulfill." Matthew 5:17
"For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh; so that the righteousness of the Law might be fulfilled in us, who walk not according to the flesh but according to the Spirit." Romans 8:3-4
So, any interpretation of the New Testament which makes its morality obviously and wildly inconsistent with that of the Old cannot represent the true intent of the writers. As I see it, there are two main sources of the legitimate confusion about Jesus' teachings on violence:
1) Unlike the nation of Israel, the Christian Church was not commissioned as an earthly government.
Both the New and the Old Testament consistently uphold the right of the State to enforce the law and defend its independence through violence. For example: "For the rulers are not a terror to good works, but to the bad. And do you desire to be not afraid of the authority? Do the good, and you shall have praise from it. For it is a servant of God to you for good. For if you practice evil, be afraid, for it does not bear the sword in vain; for it is a servant of God, a revenger for wrath on him who does evil. Therefore you must be subject, not only for wrath, but also for conscience' sake." Romans 13:3-5
The Old Testament generals, like Joshua and King David were the government, and so leading armies into battle was a part of their duties. On the other hand, when (before he was king) David found himself being unjustly hunted by the mad King Saul, he was very reluctant to fight back, even to save his life: "And he said to his men, Far be it from me, by the LORD, if I will do this thing to my lord, the LORD's anointed, to stretch forth my hand against him, since he is the anointed of the LORD." 1st Samuel 24:6.
In the New Testament, when Jesus famously said, "put up your sword again into its place; for all who take the sword shall peri
context
That line is from the end of 2nd Thessalonians. Paul tended to organize his letters (loosely) into two parts: theory, followed by application.
The theory part of 2nd Thessalonians corrects a misconception which had arisen: some were saying that Jesus would return to judge the world very soon - so soon, in fact, that some people decided to ignore everyday concerns and just focus on being spiritual (or pretending to be).
"For we hear that there are some who walk disorderly among you, not working at all, but being busybodies." 2nd Thessalonians 3:11
Paul corrects this by saying, in the theory part, that certain visible, earthly events must take place before Jesus comes back - notably, the appearance of a powerful new world leader in the Middle East who will blaspheme the God of the Bible and instead claim that he himself is a god, demanding (under penalty of death) to be worshipped. Until various such end-times prophecies begin to be fulfilled in earnest (which hasn't happened yet), Christians are not to suppose that Jesus is coming back tomorrow, or anything like that:
"Now we beseech you, my brothers, with regard to the coming of our Lord Jesus Christ and our gathering together to Him, that you should not be soon shaken in mind or troubled, neither by spirit, nor by word or letter, as through us, as if the Day of Christ is at hand. Let not anyone deceive you by any means. For that Day shall not come unless there first comes a falling away, and the man of sin shall be revealed, the son of perdition, who opposes and exalts himself above all that is called God, or that is worshiped, so that he sits as God in the temple of God, setting himself forth, that he is God." 2nd Thessalonians 2:1-4
In the application part, Paul basically says, "Therefore, stop being lazy and go earn your bread, like everyone else!" (That being my interpretation of 2nd Thessalonians 3:6-15 in context, not his actual words).
This instruction was necessary because Jesus and the Apostles taught that providing for the physical needs of fellow Christians was an essential duty of the church, and so those who chose not to work were able to free-load off of those who did work. But, that generosity was always intended for those who were disabled, elderly, sick, or shut out of the workplace by persecution - not for self-appointed monks and nuns.
"Then the King shall say to those on His right hand, Come, blessed of My Father, inherit the kingdom prepared for you from the foundation of the world. For I was hungry, and you gave me food; I was thirsty, and you gave Me drink; I was a stranger, and you took Me in; I was naked, and you clothed Me; I was sick, and you visited Me; I was in prison, and you came to Me.
"Then the righteous shall answer Him, saying, Lord, when did we see You hungry, and fed You? Or thirsty, and gave You drink? When did we see You a stranger, and took You in? Or naked, and clothed You? Or when did we see You sick, or in prison, and came to You?
"And the King shall answer and say to them, Truly I say to you, Inasmuch as you did it to one of the least of these My brothers, you have done it to Me." Matthew 25:34-40
So, it really has nothing to do with class wars one way or the other, in the ordinary sense - although the Bible does have quite a lot to say about the structure of a just economy in other places.
But someone invented curtains instead
Fences used to provide a decent amount of privacy, while allowing people the benefits of natural lighting and a view of the outside world. Low-flying camera drones are problematic because they can see into houses from angles that were previously inaccessible.
Still, shooting down trespassing drones really isn't a good solution, mostly because it's only sort-of reasonable for people who live in rural areas. Allowing people to fire guns into the air, without a proper backstop, is a really bad idea in more densely populated (sub)urban areas.
If the drone privacy problem isn't solved through regulation, perhaps we'll see a trend toward architectural mitigation - tinted windows and the like.
so that they could defend themselves from wild animals
Swords have never been the weapon of choice for hunting or defence against dangerous animals; people wanted something that would allow them to keep the animal at a distance, like a bow, spear/javelin, sling, or some kind of trap.
As a weapon, swords were almost exclusively for fighting people.
If they want this to be taken seriously as a simulated Mars mission, it should have been considerably longer - two to three years. With current propulsion technology, travel time alone could exceed a year, before you add in time actually spent on Mars exploring (and waiting for a favourable launch window to return).
Maybe they just figure that getting funding for an ultra-expensive, inefficient, all-chemical propulsion mission is politically impossible, anyway? (As it should be.)
Still, even with a high delta-V electric propulsion system, I would think that you'd want to design the system with enough life support longevity to allow a slow Hohmann transfer as a back-up plan.
Why Hawaii? Mars is not a tropical romper room.
Go look at the photos in the linked article: the astronauts in this test were stationed at high altitude, above the tree line in a desolate landscape of volcanic rock. It's fairly cold up there, despite being close to the equator.
Nowhere on Earth is actually similar to Mars, but the spot NASA chose is better than most. (Of course, I'm sure the support staff enjoyed the tropical climate found below.)
In what world is 300 litres (presumed at STP) per day of natural gas enough to power a car? Even in something rather efficient like a Honda Civic, that's still only enough for about 5 km per day, or ~2000 km per year.
[300 L/d of methane] * [0.0364 MJ/L of methane] / [34.2 MJ/L of gasoline] = [0.319 L/d of gasoline equivalent]
[0.319 L/d of gasoline] / [6 L / 100 km (fuel economy of a modern compact sedan)] = [5.32 km/d]
Having said that, solar airships are subject to the square-cube law. The larger the airship, the less benefit it can derive from adding solar panels.
Actually, I'm not being entirely fair here - the propulsion power required during cruise depends not only upon the mass (cube scaling), but also upon the form drag (square scaling). So, the usefulness of adding solar cells does decrease for larger airships, but not as quickly as I implied.
Why does it have to be all or nothing?
Suppose we ditch the heavy batteries and replace them with a diesel generator that kicks in whenever there is insufficient sunlight:
Pros: Fuel consumption during daylight hours is reduced by around 50%. For multi-day trips, the reduction is closer to 25%.
Cons: The additional high-power electric motors, wiring, and power buffering together add substantial weight to the vehicle, as compared to a normal diesel-only model. This will reduce either the fuel load that can be carried, or the payload - maybe -1 ton?
Additionally, the cost of the airship will be increased by at least $3 million USD. (Reasoning: High efficiency thin-film solar cells cost something like $1 USD/Watt. Covering the top and sides of the envelope takes about 1.6 MW. The rest of the money covers motors, wiring, power buffering, profit margin, etc.)
Cost:Benefit analysis: Assuming an average duty cycle of 50% (probably an over-estimate), the lifetime fuel cost for the normal diesel-powered airship is around [480 kW average shaft power] / [40% engine efficiency] * [60 s/min] * [60 min/h] * [24 h/d] * [365.25 d/y] * [25 y] * [50% flying time] / [35.8 MJ/L of diesel] * [$1.20 USD / L of diesel] = $15.8 million USD.
A solar hybrid reduces that by [$15.8 million USD] * [30%] = $4.76 million USD - if we ignore the increased maintenance costs from the added complexity, and assume that the airship is kept very busy (in the air at least half of the time).
Conclusion: Upgrading the Airlander 10 to use a solar hybrid propulsion system isn't a good investment right now, unless you really want the modest range increase - but it's very close, and will probably become so within a decade or two, given the rapid pace of development for the key component: the thin-film solar cells.
Having said that, solar airships are subject to the square-cube law. The larger the airship, the less benefit it can derive from adding solar panels. The Airlander 10 is actually rather small compared to what most of the next-gen airship companies want to build, so it's unlikely that solar power will play a major role in the industry.
I think that Lighter Than Air vehicles have disadvantages that are very well known.
The Airlander 10 is actually somewhat heavier than air, and relies upon aerodynamic lift to stay aloft. Does this reduction in surface area and buoyancy, combined with modern technology, improve the concept enough to make it practical? I don't know, but it's already been built so there's no need to guess: just wait and see.
The people promoting these are usually True Believers who think those disadvantages don't matter. They are always wrong.
For the record, I am not a "True Believer", nor am I really trying to promote the airships. But, I do object to the idea that airships are strictly inferior to jets and trucks - they have, in theory, their own niche that cannot really be served by either of those alternatives.
If the resurgence of investment in airships doesn't lead anywhere useful, it will be because the revised designs fail to serve their target niche, not because they are out-competed by two technologies that can't serve the niche at all. The real competition is probably helicopters (despite their awful fuel efficiency) and smaller military cargo planes like the C-130, which can operate from much smaller, cheaper runways than a 747.
The blimp had to wait 3 days for calm air, it could only fly through a mountain pass, it could only be done at a specific time during the morning, and the pilots were on edge the entire crossing, concerned that the weather would change.
The Airlander 10 has a service ceiling about twice that of a typical blimp, and could cross the Rockies safely almost anywhere.
I don't know about the weather restrictions though; that is my biggest concern with airships, as well. But again, they've already started test flights, so they won't be able to hide it for very long if the restrictions are really severe.
It's an airship. It doesn't have to maintain power overnight. They can just turn the engines off and bob around for awhile.
Not this one: it's not actually lighter than air. Even at sea level, its displacement is only enough to lift about 94% of its weight. At cruising altitude, 40% of the lift must come from aerodynamic effects.
If all you're trying to do is maintain altitude, it is certainly possible to extend the battery life by flying much slower and lower - but the lower you fly, the more vulnerable the airship is to weather-induced accidents. Maybe you could make it through the night, if the weather was good, but there wouldn't be nearly enough safety margin for routine operations, I think.
For loitering missions, that's true. However, for cargo - and especially sky crane - missions, I'm pretty sure that a human crew will be required for many years to come. Safely and quickly handling arbitrary cargo while squeezing as much capacity as possible out of the vehicle is a complex task (both mentally and physically) that can't really be automated yet.
Still, at least for the military, the future 50+ ton capacity models should require far fewer crew members per cargo ton-kilometer than ground convoys, if only because the armed escort can be (mostly) eliminated.
Would it be at all feasible to cover the top of this thing with thin and semi-flexible solar panels? If Solar Impulse can make it around the planet using just the solar energy hitting its thin little lifting surfaces then surely the surface area of this magnificent flying backside should be able to gather enough energy to shove it across the sky, right?
Going off the Airlander 10 specs:
The vehicle is powered by "4 x 325 hp" diesel engines, for a combined peak power of about 960 kW. Most vehicles do not cruise at peak power continuously, so I will estimate the average power requirement at half of that: 480 kW. (This ratio would be approximately correct for a large subsonic jet; if someone knows what it should be for a diesel-powered lifting-body airship instead, please leave a comment.)
The useful surface area of the Airlander 10 is approximately [92 m long] * [43.5 m wide] = [4000 m^2]. (The exact number depends upon the latitude, the time of day, and the craft's heading, but it turns out that its shape is such that the answer doesn't change much, except near the poles.) Peak solar irradiance (direct sunlight at high noon) at ground level is about 1 kW / m^2, and current thin film solar panels are under 15% efficient. Solar power conversion circuitry is around 90% efficient, and an appropriate electric motor with its controller is about 88% efficient. Therefore, a maximum of [4000 m^2] * [1kW / m^2] * [15%] * [90%] * [88%] = [475 kW] of shaft power could be generated by solar-electric means.
So, a solar-powered Airlander 10 could work - but not very well. Under ideal daylight conditions, it could fly about as well as the hydrocarbon-powered version. However, airships are sufficiently slow and long-range that they are expected to routinely fly through the night. Thus, the average power available must be at least cut in half, to 238 kW. Cloud shadowing (airships can fly over some clouds, but far from all) and dust will further reduce that number.
Additionally, a solar-powered airship needs to carry heavy batteries in order to avoid catastrophic power loss when passing through clouds. One hour's worth of lithium-ion power would mass [475 kW*h] / [86% charge/discharge efficiency] / [200 W*h / kg] / [80% - 20% depth of discharge range limit] = [4600 kg]. As the total mass of the Airlander 10 is only 20 metric tons, it cannot carry much more battery power than that without cutting into the payload.
At cruise, nearly all of the Airlander 10's power is devoted to fighting drag. Since subsonic drag scales with the square of airspeed, a solar-powered version could quadruple its battery-powered run time by halving its speed. (It can't really go any slower than that though, as it needs to be able to overcome typical headwinds to be useful.) Four hours of battery time is still woefully inadequate for an overnight flight though, so a solar-powered version would be limited to daytime flights only, and consequently to overland flights only.
TLDR: A solar-powered version of this airship is possible, but it would be considerably slower and incapable of crossing oceans. Supplemental charging on the ground wouldn't help much at all.
So can someone explain what the point is?
It targets two major use cases, neither of which can be serviced by a conventional cargo jet or a road vehicle:
1) Ferrying heavy cargo (and possibly people) to or from a land-locked location that lacks a suitable runway or road/rail connection. This is of special interest to the military, but also has civilian applications.
For the military, truck transport through enemy territory is extremely dangerous for obvious reasons - possibly even more dangerous than using an airship, depending on what technology the enemy has access to. An airship may be a big target, but it can also fly high enough that most ground weapons can't even hit it. If it does get hit, a few small holes in the envelope (say, from a machine gun) won't immediately end the mission. A large one is also at least twice as fast as a military ground convoy, and has more tactical options available for avoiding the enemy, since it doesn't need to follow roads.
Truck transport through neutral territory is safe - for the military convoy. It's not safe for the neutral country though, as allowing military convoys to pass their borders may be considered an act of war by the enemy. For this reason, it can be very difficult to get permission from neighbouring countries to use ground transport into a land-locked war zone. Air transport is less problematic (I do not say problem-free) in this regard.
As for conventional cargo jets like the 747 - their survivability probably isn't as much better than an airship as you might think. Big subsonic jets are easy to shoot down for anyone who has access to large 1970s anti-aircraft missiles, like the Sidewinder or the S-300. So, cargo jets won't last long unless the user has air dominance in the area of operations. A lifting-body airship should still be able to fly high enough to keep out of range of small arms like machine guns, and arguably is not that much more vulnerable than a 747 in practice. It would have to stay a bit further from the front lines though, because it cruises low enough to be at risk from short-range stuff like Stinger missiles, and maybe auto cannons.
For any user (whether military or civilian), the advantage of an airship is that it doesn't need a huge, expensive concrete runway at each end of the journey. For the military, taking weeks or months to build such a runway isn't always an option. Even when a suitable runway is available, it could be disabled by the enemy at any time with a few bombs or artillery rounds. For civilian users, there are projects set in remote areas for which the expense and/or environmental impact of installing a city-grade runway is just not worth it. Dirt roads are usually (though not always) an option, but some exceptionally heavy, bulky cargo can't reasonably be moved via a steep, narrow, windy, muddy road.
2) Because airships can stay aloft so much longer before they need to refuel, they are well-suited to loitering over an area to provide a communications relay or an observation platform. This has civilian applications, as well as military. If you only need to cover a relatively small area (hundreds of square kilometres, rather than thousands), they are much cheaper than satellites. The ability to easily relocate them and swap or upgrade the payload makes them more flexible.
Even for military users, their greater vulnerability isn't always a problem: the military is tasked not only with taking enemy territory, but also with patrolling friendly territory. An enemy trying to sneak in cannot shoot down a patrolling airship without revealing his presence.
There's only one way that a 2017 Tesla will be brand new in 5 years and then put up for sale in 2017
I have no idea what confusion was going through your mind when you wrote that sentence, as it doesn't seem to have any logical connection to what I actually said.
This is not complicated, and should not controversial: WindBourne stated above that the Tesla Model 3 will be affordable for "90%" of American drivers "next year" (2017). This is clearly nonsense, and none of your bizarre replies are helping his case.
What point are you trying to make?
Car depreciation rates are not that mysterious. There's only one way that the Tesla Model 3 will be widely available (in good condition) for $16,800 in 2017: if it turns out to be such a piece of junk that the original buyers hate it, and are willing to take a 50% loss on a brand new car just to get rid of it. Surely no one would claim such a disastrous product launch as evidence that electric cars had now become affordable.