ancient discredited NERVA/ROVER program which began in 1956 and dragged on to a miserable failed end in 1973
You mean the discredited program that produced working engines and test-fired them on vacuum stands, proving they are practical and work? You might also note another program that was terminated in 1972: Apollo. Oh my, what an abominable failure that one was...
the fact that any rocket has to carry and throw away a vast load of reaction mass
And how else would you propose to move in space? Mr Newton might have something to say here.
But the actual raw energy needed to lift 118 tonnes to 200 km is...
If you think the difficulty in achieving orbit is just lifting something sufficiently high up, you're more dense than I thought... Here's an idea, first learn about something, then start lecturing about it.
No other mode of transportation has to carry its own reaction mass and throw it away. Not bicycles, cars, trains, ships, submarines, or airplanes.
Please note that all of the above modes of transportation have one thing in common: they only work on the Earth. Or when was the last time you last saw a car drive through outer space?
I don't how great a source it is
Apparently not a very good one. Google maps says that the optimal driving distance from SF to BOS is about 3000 miles, which, on a 30mpg car, results in 100 gallons of fuel burn. Gasoline is typically around 0.75kg/L, so that comes to 284kg of fuel. Unless your vehicle manages to break the laws of physics somehow, you're never going to emit 930 kg of just greenhouse gases per vehicle. Now the same trip using a plane is about 2700 miles (from a real flight plan). A typical Airbus A320 or Boeing 737 comes to about 0.03L/km/seat, and given that Jet-A is typically around 0.82kg/L, this comes to ~100kg per seat.
So it really comes down to occupancy. A nearly fully-booked plane wins over a single-occupancy car hands down easily. The break even point is at about 2-3 passengers per car, so a car can be more efficient, assuming you car pool. One thing frequently forgotten in these comparisons, though, is the cost of time. The flight is 6 hours. The drive is 4 days of non-stop driving. In any case, just wanted to let your know that the source you cited is quite off.
Your weight estimates could be correct but there is no way you're gonna fit a 140-seat glider in the Falcon 9 fairings.
Of course it won't and I explicitly said to replace the entire second stage as well. I would have hoped it to be obvious that I was talking about reengineering large parts of the system.
Anyways 5 minute weightless suborbital flight is so 1961. I would just make a stretched version of Dragon that seats 20 people (no cargo) and send them into orbit for $50k each.
Or to Mars for perhaps $500k, I agree. I was just thinking out loud about the possibilities here, just to show that Virgin Galactic's system is an overpriced toy that could be done much cheaper by the likes of SpaceX.
Real zero-g (not Vomit Comet or theme park rides) would be pretty damn cool.
Well, the Vomit Comet is exactly the same as LEO zero-g, it's just much shorter. All the Virgin Galactic guys are doing is extending that time from 30s to 300s. And at tremendous cost, I might add.
As for 140 people for a suborbital flight on Falcon 9, that sounds about right, maybe even a bit pessimistic. By my reckoning, the second stage with propellant and max payload masses somewhere in the vicinity of 100 tons, more than the MTOW of a Boeing 737-800 and at that mass, the first stage is enough to give them around 2 km/s at burnout and an arc of well above 100km. And that includes the spare fuel to fly the spent booster back to the launch pad and land it, so no loss there either. So replace the entire second stage & payload with a hypersonic glider and you're done, basically. It might even be conceivably possible to use this to actually travel somewhere at hypersonic speeds without having to muck about with all that ramjet/scramjet business, though I'm not sure it'd be worth it.
Assuming capital costs per flight of $1M (20% of which is fuel, the rest being O&M, equipment amortization and profit), one such ticket could cost as little as ~$5k. Not chump change by any means, but still 20x lower than what Virgin Galactic are charging. It's about 1st class-type money on some long-haul flights.
The process uses a liquid that allows the hydrogen to be locked up in a liquid-based inorganic fuel. By using a liquid sponge known as a redox mediator that can soak up electrons and acid we’ve been able to create a system where hydrogen can be produced in a separate chamber without any additional energy input after the electrolysis of water takes place.
He focused on energy sources, and his point that the increase in usage of brown coal is neglegtible, is correct.
In that respect, that is correct, the increase might indeed be just noise.
You focus on TWh production of elictricity, where you clearly see there is a noticeable increase in terra watt hours of electricity produced
This data is pretty hard to come by, I agree, so I had to make some assumptions (elaborated below). Can you cite your sources?
so bottom line the "record usage" of brown coal is still nearly 20% below the 1990 level (in primary energy) and roughly 10% below 1990 level in electric power production
While it is true that some efficiency offsets might be made, your numbers simply do not add up to the graph Dunkelfalke linked. It lists lignite at 3201 TJ in 1990 and 1645 TJ in 2012. That is not "[usage] of brown coal is still nearly 20% below the 1990 level (in primary energy)", that is a 50% reduction in primary energy. All of that also happened before the year 2000 - since then, pretty much no reduction in lignite use has occurred. If powerplant efficiency were indeed rising while electrical generation remained mostly flat during the 2000-2011 period, that would imply that a rising proportion of that input lignite energy (which flatlined during that time period too) is being used for heating and other uses. However that doesn't appear to be the case either (coal use outside of electricity is falling rapidly) - this leads me to believe that there hasn't been such a dramatic increase in efficiency as to be able to confidently say that the recent increase in generation is due to an increase in powerplant efficiency. Also, how can you claim use in electrical generation is 10% below 1990, when even you said yourself just a few moments before that "no one can deduce how much more brown coal was used for that". I'd really appreciate if you could cite your sources, that would allow us to clear up the situation. If you have access to figures on lignite consumption by coal fired power plants, that would be great. Otherwise, the only reliable thing we can say is that electrical generation from lignite is at an all time high since 1990.
The key elements in human thinking are not numbers but labels of fuzzy sets. -- L. Zadeh