Perhaps a better understanding of c is the 'speed of information'.

Actually college administrator salaries have increased far above (IIRC more than double) the rate of college tuitions (which is about three times the overall inflation rate), while professor pay has languished and benefits have been decreased, to the point where universities in particular have resorted to eliminating tenured and full time positions, keeping large teams of part-time instructors, kept judiciously below the number of teaching hours that would trigger full time benefits - shades of fast food!

The pay inflation of college presidents has far exceeded that of the average for corporate executives. This difference largely tracks the inflation of federal subsidies for higher education - in other words, the administrations have succeeded in rent-seeking at the expense of students and taxpayers. Today, with grants and loans, it is as hard for a family to pay for college as it was before the federal subsidies were expanded, while the taxpayer now has to toss in an additional large amount. The net result of the expansion of federal money has done nothing but line the presidential pockets.

Looking at the data, the increase in the pay for college administrators closely follows the increase in federal grants and loans to students, while the pay for instructors and professors has stagnated. The result is that the cost of college has skyrocketed, making it just as hard for a family to pay for college today, with the loans and grants, as it was before the explosion in college funding.

This idea of "Let's put _everyone_ through college with our unlimited federal funds!" does nothing but move money from taxpayers to rent-seeking college administrators (and a few more fancy buildings), reduces the overall quality of college students, and reduces the general efficiency of college classes while impoverishing college teachers.

This is yet another example of how a primitive 'do-good' methodology - unlimited federal funding for everyone to go to college - breaks the feedback loop of costs vs. benefits that act when a family unit must choose how to spend their limited resources.

A further negative consequence is that the pressure is reduced for high schools to make sure that their students are competent, while superfluous requirements for college degrees for every job proliferate. The result is beneficial in a sense - people are kept out of the workforce for an additional four to six years, improving the jobless rate.

My interpretation has been that the French helped with the Revolution to keep a large fraction of British forces occupied 'over there', so the French wouldn't have to fight them at home.

Also, it's a little-recognized point, but it's quite arguable that George Washington, as a fairly new officer in the British Army, accidentally started what we call the French and Indian war. He was tasked with building a fort at the confluence of the Allegheny and Monongehela rivers, which join to become the Ohio, in what is now Pittsburgh. A French force wandered by, on the way toward (IIRC) Virgina. Washington's force attacked and killed most of them (again, IIRC). As it turned out this was not, as Washington had thought, a raiding party but a diplomatic one. Oops.

But the Revolution was in fact more significant than what you propose, for at least two reasons. 1) This was the first country where Rousseau's and Locke's ideas about the sovereignty of the individual 'man' over the government were explicitly defined in the fundamental law of the nation - Britain had gone some way in that direction, but primarily only with respect to the relations between the King and the aristocracy. Even Hamilton was aghast at the prospect of the great unwashed masses actually being able to vote. 2) This was the first country that was defined not by ethnicity or geography but by the founding principle.

As various people said at the time, democracy has generally not been successful - at that time no democracy had ever survived more than about 200 years, as the two forces of people voting themselves largesse out of the public till, and the influential continually manipulating the system and the people to give themselves absolute power (sometimes using 'bread and circuses' - a term going back to Pericles, who caused the eventual destruction of Athens a few decades later) will eventually bankrupt the nation, which will then turn to military rule or defeat by a nearby enemy. From Greece and Rome to Argentina and Venezuela, we see this happen over and over again.

One complication - hydrostatic equilibrium also is somewhat dependent on local conditions, i.e. composition of the body. A hypothetical planet made entirely of Mercury, for instance, might be/have been in HE when only 5 feet in diameter (before it froze solid, or orbiting close enough to a heat source to remain liquid). That's of course an absurd extreme, so there's probably an example somewhere out there in the universe! :)

So IMHO, HE is a necessary criterion, but may not be sufficient. I read an article a few months ago that asserted another criterion to go with HE but I don't recall what it was. In any case, I generally agree with what you say, for what it's worth.

No, that's pretty much always been the way it was.

Flow batteries are already in use in many places, mostly in large scale installations, where it is desired to store 1/2 day's worth of energy at a utility plant. They have some differences/advantages compared to other batteries: 1) there are no issues with the battery 'wearing out' like any solid-based battery - the electrolyte fluid(s) is(are) pumped past the membrane, so there's no need for ions to migrate onto/off of a plate. It is possible for the membrane separating the two sides to get messed up but that can be relatively easy and cheap to replace; 2) because the total capacity of the battery is determined by the size of the tanks, and the current potential is determined by the size of the membrane, these two factors are now completely separated. You can customize your battery for the optimum combination of total capacity (Watt-hours) and power (Watts).

IIRC a San Diego professor has a flow battery that uses organic quinones for the electrolyte. Quinones are (relatively?) non-toxic organic molecules that are cheap and easy to produce. So IMHO this would be a better direction than Lithium.

CAVEAT: IANA battery guy, only an interested follower, so all of the above may only be relatively close to the facts. (I have a cruising sailboat, am interested in the future potential for using flow batteries in my boat. This would require about 5KWH capacity, and peak draw of about 1-2KW but the peak could be handled by some intermediating hardware.)

No, that's the common carrier thing that the cable guys have tried to avoid. Common carriers are not liable in most circumstances. But information providers can be without the safe harbor provided by common carrier status. They've been trying for years to get it both ways.

I tend to agree, though IANA planetary geologist. Folks tend to forget the value of things like nickel-iron, which could become one of the primary materials for constructing machines in space. It may well be that simple in-space products such as water and its constituents hydrogen and oxygen will become the largest economic activity for some time. Platinum is attractive in part because of the "Gold syndrome" - "OMG it's like GOLD! And it's just laying around out there, ins SPACE!" It does get people's attention. And I hope it's true - the entire space development industry or community or whatever is going to change forever with the first "killer app".

Regardless of the fun, I expect that an entire branch of metallurgy and materials engineering will arise around the use of nickel-iron and other available materials. Where many materials processes on Earth are based on liquid-phase chemistry, I expect that space materials processing will be much more based on solar (thermal and electric) powered vapor-phase methods, with additive manufacturing for actual components. Earth has some advantages - gravity, atmosphere, large amounts of water for solvent chemistry and cooling, etc. Space has different advantages.

For those who aren't familiar, some of the best types of steel, and other iron alloys, are basically nickel + steel + other things - see Iron Nickel Alloy.) I am not sure of the abundance of Aluminum in asteroids, but it's quite possible that the abundance of nickel steel in space may actually result in space-built hardware being made of these steels and steel-like alloys. Steel is traditionally iron + carbon, but the actual amount of carbon is on the order of 0.02% to 2%. The definition 's not that simple, but suffice it to say that nickel-iron alloys are valuable resources in space, though unprofitable for shipment down to Earth.

The big difference between the 1989 Plan and this one is that from the beginning this Plan is intended to incorporate the fact of some 40 national space programs (Ecuador and Kenya both have nascent space programs), and that the path to space is no longer a single plan but a herd - for lack of a better word - of different entities with different goals, motivations and theories, but some common goals. Many entities want a lunar outpost for various kinds of research, including research on requirements for a future permanent habitation. There is strong disagreement on almost every aspect of that project. Nobody can say for certain that the first outpost will done by one government, international group of governments, commercial entities, or a combination thereof.

But some things are obviously true. The project will require various items, including a reliable contained space with air and other necessities of life, protection from cosmic rays, a way to produce food and recycle wastes as soon as possible, communications, various tools and materials for construction, maintenance, research, etc., probably some robotics to do the initial construction before we send people - and of course, a launch system to get the packages to the location. I tend to include the economic, financial, and political requirements as well. All of these pieces can be defined with projected costs, development times, and other aspects including their second-order requirements (what technical capability must be ready to put robots on the Moon?). And then we can connect the pieces up in various ways as a precedence graph - somewhat simpler than what Google Maps does to figure out your best route - to determine one or more 'best' routes based on criteria of cost, time, difficulty, probability of failure, etc.

So that's the new Plan - a comprehensive online tool for generating precedence graphs based on the various relations between elements. If the Raptor methane engine is required for the Falcon Heavy, and the schedule for the Raptor gets pushed, then so also does Falcon Heavy, and thus all the planned flight schedules, and thus all of the business or government activities that depend on them. The 2015 ISP poster is just a snapshot, limited by space, time, resources, and a lack of information. In today's world of space development, there are many, many different significant projects and so many different 'critical paths' - but the common goal is to get us, and Earth Life, into space and off the planet.

One of the biggest changes in focus between the old plan and the new one is the de-emphasis on "NASA does all". As the online version of the Plan evolves, this will continue to change. I can't say when the commercial space budget will exceed NASA's, but it will be happen if all goes well. This may be a terrible example, but it kinda fits - Thomas Jefferson sent Lewis and Clark to explore and map the Louisiana Purchase, and continue on to the Pacific Ocean, to learn what might be learned.
Per this article, Jefferson originally asked for $2500 from Congress, but ultimately the cost was closer to $50,000, a 20 to 1 cost overrun that outdoes any modern overrun.

Lewis and Clark took two years and were actually given up for dead. But today, I can drive approximately the same route in three days. The point is that IMHO we are on the cusp of the transition from pure government financed exploration to the first 'trappers and hunters' going out to see what they could make of an opportunity. So either NASA will become less and less important and cease exploring, or more likely, will continue to transition their activities in support of the next phase.

NASA has been doing some very cool things to support commercial space entities and save money in the process - despite the less-than-sane meanderings of congressional politics. A case in point - the President's Commercial Crew Program 2017 budget, presently in negotiations in Washington, is being cut by $300 million, necessitating that NASA spend $600 additional million to buy launch services from Russia and delaying a return to US manned launches by four years.

(According to this inflation calculator, that $50,000 was equivalent to $1,027,500 today.)

I haven't looked into this recently. This is a good example why it's difficult to get traditional investment entities like VCs to invest in these highly speculative ventures - nobody really knows what's out there. Platinum is fun to talk about, but IMHO the markets for in-space re-fueling, satellite maintenance, possibly space tourism, a robotic lunar research facility (prototype self-constructing system), and similar more mundane aspects have higher near-term probabilities.

OTOH, platinum on Earth is extremely problematical. It's a horrible environmental mess, it's a horrible human mess with workers one step above slaves, direct mining takes huge amounts of ore to make a few grams of platinum. (I think more is produced as a by-product of copper smelting.) A high grade platinum source may be less than 0.5 ppm. 2010 production was 245 tonnes. Potential global demand at $10 per ounce may well be more than 1000 times that.

Part of the theoretical justification for platinum in asteroids is that, as a very dense metal, nearly all of it on Earth has sunk into the core. But many asteroids appear to be the remnants of proto-planets (proto-dwarf-planets?) that partially differentiated concentrating the heaviest elements toward their core, similarly to Earth, then were broken apart in collisions. We know that many asteroids are mostly nickel-iron (which in the long run will also be quite valuable as raw material for space manufacturing), and as such _should_ have platinum in veins, in solution with the iron, and/or in chunks from the deepest part of those cores.

One argument against asteroid platinum mining is the purported cost. However the negative cost estimates I've seen assume a full Earth->asteroid->Earth travel cycle, which is incorrect. If I were building a system, it would be launched once, then operated and maintained in space for 15 years at least. I would try to do as much refining at the asteroid as feasible, and return the concentrate or pure material to LEO (possibly via multiple intermediate steps), where it could be brought back piggy-backed on another return vehicle. Returning need not take anything like as much resources - fuel or anything - as launching. (A Falcon 9 launch involves about $300K of fuel but $10 million for the first stage hardware, used once.)

Some of the numbers and discussion here.

Sigh. "copies" => "companies". And the other one to mention is Deep Space Industries. There are some others as well.

There are two copies actively engaged. The one that AFAIK is farthest ahead is Planetary Resources. I think their investors include James Cameron and Tom Hanks. :) I quote from their page on Asteroid Composition:

I recall that the head of PR was asked if bringing so much platinum back to Earth would crash the market, and he said he expected it. He thought they could make money at $10 to $100 per ounce (the present price is around $1300 per ounce). Platinum is especially interesting because it is a hugely useful industrial metal but its application has been minimal because of the cost. The catalytic converter in your care probably has an infinitesimal amount of Platinum. If it were cheaper, it could even be used to build catalytic converters for coal fired power plants! So this one item could improve industrial efficiencies and reduce pollution, improving the standard of living on Earth.

PR's first testbed launch is in space now - Arkyd testbed platform launched in July. They're still developing the technology.

PR is also looking strongly at the H2O market. Water in space is valuable as the raw material to make hydrogen for rocket engines. SInce the cost of shipping from Earth is presently on the order of $20,000 per pound, retrieving it in space from the Moon or an asteroid could be very profitable, and would reduce costs.

There is a communications satellite owned by IntelSat that failed some time ago. It was determined that the cause of the failure was that a thermal blanket popped loose on one end, probably due to a fastener failure, and draped across the solar panels. So that $150 million satellite has been moved to a 'graveyard' parking orbit. But if a small robotic satellite could get to it, pull the blanket back away and stick it down with some glue or something, that satellite would be ready to go. That's a trip worth at least $10 million.

These are just a few examples.

To Dani's comment, I'll just add that, the day that an asteroid assay is done and proves that the thing is actually more than 1% platinum, or any other of the many proposed ways to make space economically interesting proves out, the land rush will be on. Private investment by institutions today is difficult because many of the business models are speculative, the terrain is unknown, the payout time frame of 10-20 years is way too long for VCs, who want to get paid in five or less. As soon as somebody shows that their business is more than a pipe dream, things will happen fast. But already the angel investors are working about a dozen deals per year in space-related startups. Many of these are for small companies that are already profitable or cash flow positive but don't have the cash to go to the next step. I look forward to when the majority of launches to LEO and beyond are for private commercial purposes.