It doesn't have to be "much" cheaper, though. That's the entire point: if they can undercut it by even 5%, it's worth it. Plus, you can then fill up the Progresses and ATVs with more useful stuff.

The launch rate of ISS supply ships is constrained by more than just money, but also things like launch windows, vehicle availability etc.

Ordering some water from an on-orbit supplier is overall much simpler, from a logistics as well as monetary standpoint.

I'm generally pretty skeptical of private sector influence or expansion in most areas but space exploration isn't one of them. I think it's pretty clear Federally based space exploration is going nowhere fast. Whether that's from lack of funding or lack of interest doesn't really seem to matter anymore. Guys like Burt Rutan, Virgin Galactic, and now Planetary Resources or whatever show more motivation to do it than any government organization for now.

I actually read that laws and oversight of private space exploration will fall on the FAA, rather than NASA.

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Best care anywhere.

What is Project Zohar?

It's not so much motivation, I think; it's that no one can order them to drop what they're doing and go use their (limited) budget on something else. This has been killing the manned space exploration side of NASA- they don't have an externally imposed objective, haven't had one for a long time, and whenever they decide for themselves what they want to do, someone forces their hand and changes their mind... or just refuses to allocate the money.

You can sell fuel for refueling so that the satellites last longer.
If fuel costs are lowered then companies might choose to build more GEO satellites for whatever reason.

Satellites use hypergolics for long-term storability, so this won't work.

a LH2-LOx space tug can go there and gently push them around so they don't have to use their own engines.
It's a slightly modified centaur upper stage (has celestial navigation systems). Nothing earth-shaking.

I can't think transferring fuel from lunar orbit (correct me if I am wrong) to LEO is going to be very efficient in many cases.

The more interesting proposals are to produce fuel on, for instance, the moon, so that rockets exploring the rest of the solar system do not need to be nearly as large. But this is obviously not something the market is crying out for right now.

The point you should keep in mind, is that while these guys are likely to not be repayed from the initial investment (especially development costs), the infrastructure they put up is likely to make enough money (and be useful enough) to grant its survival one way or another.

I'd like to know the reasoning behind this. The delta-v needed is a fucking order of magnitude less. All other things (like docking and refuelling/pushing) remain equal.

The delta-v is so small that you can do a round trip LEO/GEO-Moon Orbit without staging. From moon surface it would require staging (or two different vehicles, slightly smarter). From Earth is completely ludicrous, but can still make economic sense if you use crappier cheaper rockets from Ex-Soviet Ukraine to lift the fuel.

Also this way moon missions just require you to lift from Earth something like this since you can refuel it where you need it (LEO and then moon orbit). Which is doable without having to design and build (and pay for) another Saturn V.


Hell, rockets are awesome in Earth orbit and Moon if you have a refuelling facility up there.

Let's put it this way: out of 3000 tonnes of the Saturn V, only 45 made it to lunar orbit ; After all was said and tone, the CSM could return to Earth all by itself.

Literally 96% of the Saturn V's launch mass was spent just getting it off Earth. Think about it for a minute.

Let me put it this way - just 30 years ago:

But who would buy the access? This 'Darpanet' thing has only 150 computers connected to it. If you are trying to send a letter, very few ones ever go beyond needing what telegraph offers. At the prices they suggest it is not really much cheaper than sending it by post office.

Yes, there is no need to invest into routers and stuff, that whole 'net' thing will surely never catch on nor make any money

Actually, they're shifting over to ion thrusters or Green non toxic storable propellants. Handling hydrazine is not fun.

I didn't know that, but this hardly affects their refuelability with hydrogen/oxygen

Because it's inefficient to use it, now. But if you know that you can simply order a 'refill' in orbit, the simple H/O drive will become a feature in new satellites. You don't even have to send it up fueled, saves another couple of k$...

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The Greeks are somewhat undependable allies when it comes to keeping promises. I am sure the fleet of 300 galleys they promised will turn out to be 3 guys in an oversized cooking pot. (Thanas, revealing the plans for German world domination)

I do archery skeet. With a Trebuchet.

Another service they could make is provide a space tug to move sattelites from LEO to GEO. That would allow smaller and cheaper rocket because sattelites that currently need Proton or Ariane 5 could be launched on Zenit, Falcon 9 or Soyuz since rocket wouldn't have to carry fuel to get from LEO to GEO.
In the future availability of fuel in space may make it easier for NASA to pull of missions that require large amounts of fuel. For example a manned Mars mission would become much cheaper if only hardware has to be placed in LEO and fuel for departure could be supplied from orbital refueling facility.