Al_ said:
How many of those have been outside Earth?
I don't say that there is no progress, but those approaches are still far away from being used outside Earth.
Al_ said:
A small drone rocket could get a payload of precious metal and fuel and launch from the Moon to LLO. Then it's ion drive takes a month or so to transfer it to LEO. It does a quick de-orbit burn, releases it's payload, and a quick burn to get back to orbit. The payload re-enters the atmosphere and hard lands in the desert. The drone then uses it's ion drive and takes a couple weeks or so to transfer to LLO. Another rocket burn takes it down to a pre-arranged spot on the Moon. Here, the robots load it up with another payload and more fuel.
Then you have to carry all the landing fuel, the engine and so on to Earth and back. If rockets are used at all, two different systems look more efficient. One system brings stuff to LLO, another system cycles between LLO and Earth.
I would try to avoid big rockets completely. Build a lunar space elevator. A practical cable can be as light as 50 tons and can be built with existing materials. You can produce it on Earth, a single Falcon Heavy or SLS launch can deliver it to Low Earth Orbit, other rocket launches can then bring it to L1 (SLS Block 2 might have that capability in a single launch, ITS will laugh at that payload). Add a counterweight and Moon ground infrastructure.
Delta_v between space elevator and atmosphere-grazing highly eccentric Earth orbit: ~600 m/s.
You still have to invent a largely autonomous mining industry on Moon, with everything either produced locally (how?) or shipped to Moon (expensive).
Mark Harder said:
Isn't there supposed to be lots of Helium-3 on the lunar surface? I recall seeing that somewhere, perhaps here. The idea being that fusion power sources are much easier to design and build using He-3. But I wouldn't want to make a home of the moon.
By far the easiest fusion reaction is D+T. We don't have power plants based on that yet. Even in the most optimistic case, fusion with He-3 is much more challenging, and it is unclear if it can work at all.
The surface of Moon has
up to 10 parts per billion He-3 by mass. You would have to process a whole cubic kilometer for ~20 tons of He-3. Fused with lithium or deuterium*, that gives 10
19 J, about 1/3 of that would go to electricity. If we let the fuel cost 2cent/kWh, our cubic kilometer of regolith gives He-3 for $20 billion dollars worth of electricity.
As comparison: A poor gold mine on Earth has 1 grams per ton, filtering a cubic kilometer of rock on Earth gives gold for a market price of $100 billion. Good mines have more than 10 times that concentration.
Even if we would have fusion reactors that could use He-3, filtering it out of cubic kilometers of rock
on the Moon would be extremely expensive.
He-3 from the Moon is a nice science fiction story, but the numbers don't work out.*there is also the option of He-3 He-3 fusion: it might give a better conversion rate to electricity, but it also needs twice the fuel per energy released, so it doesn't change the conclusion
sophiecentaur said:
I would say that the amount of money spent on Aid should be at least as great as that spent on fundamental Science and Space research.
$25 billions/year are directly spent on humanitarian assistance (
source, for 2014,
$22bn in 2013).
The total NASA budget is $17.5 billion (
2014, 2015), but a significant fraction of that is for Earth observation, Sun observation, material science for Earth-based applications and so on. It is impossible to find a number "not Earth-related".
Total ESA budget is $5.6 billion (
2016), same problem here.
Roscosmoc has a budget of about $3 billion (2015,
I don't speak Russian but the budget should be 186.5 billion rubles)
India spends $1.1 billion (http://www.isro.gov.in/sites/default/files/article-files/budget-accounts/outcomebudget2016-2017.pdf )
The Chinese don't seem to make their numbers public.
All other space agencies are negligible. Currency conversions done with the current exchange rates.
Global government funding for space agencies combined (and see above: a good fraction is science for Earth) is at the level of direct humanitarian aid. That does not include research that helps other countries and various other forms of aid.