Talk:Size of Infrastructure

The assemblers need not be nano. Self-replicating factories will at first be very big. A good way to simplify the replication process is to have shared components^marsp.

As for HLVs, do not fixate on Ares V, constellation and NASA. One example is Sea Dragon. Sea Dragon had a payload capacity of 500 tons or so. HLVs have ~100, MLVs, say, ~20 tons. How hard would it be to scale down Sea Dragon to the size of an HLV or MLV?

If it is not vital to have a HLV for lunar return, it would certainly be preferred. Just not a NASA monstrosity. T.Neo 09:39, 7 September 2008 (UTC)

• As far as I know there is no need for HLVs to start a lunar colony. The costs of maintaining launch facilities for HLVs are outsized just as the rockets are outsized. Since HLVs are infrequently launched, the annual maintenance costs are spread over few launches making HLVs expensive per pound of payload. Eliminating an entire unneeded class of launch vehicle results in savings that should not be missed.--Farred 14:24, 22 October 2008 (UTC)

Robert Bigelow has said that he plans to assemble mutiple Bigelow modules in LEO, then land them on the moon. For non-inflatable, rigid shell habitats, HLV's may be necessary. Using less costly, commercially available rockets is one of the advantages of the Bigelow approach. - Jarogers2001 15:16, 22 October 2008 (UTC)

I see your point, Farred. However, the whole concept behind BDB (Big Dumb Boosters) like Sea Dragon is to reduce those costs throught simplicity. For example, how about using room temperature propellants such as H2O2 and kerosine/hydrocarbon instead of cryogenics like Lox/LH2? I do think, However, that below a certain point, sea launch becomes too costly, and it would probably be better to do a conventional land launch. We ship cargo in bulk on huge container ships, not one-by-one on rowboats.

We also need smaller launchers, I am not saying that we don't. It is a pity BDB was never applied to smaller launchers. T.Neo 22:35, 22 October 2008 (UTC)

The problem with H2O2 is its instability. The safeguards to protect against/prevent violent decomposition tend to be more expensive than going with LOX. BDB should probably be applied with LOX/Kerosene. SpaceX is trying to take this route. - Jarogers2001 00:59, 23 October 2008 (UTC)

Not even "real" kerosine. I am talking about something more like Jet A. The OTRAG project used plain gasoline, if I remember correctly. What about propane/MAPP gas/natural gas? Could these be used as room temperature, self pressurizing propellants? With room temperature oxidisers, nitrogen tetroxide is used often, and nitric acid of several varieties have been considered. These two are toxic and volatile, so how do they stand up to H2O2? Which is cheaper: Lox/H2O2?

• Cost per litre
• Cost of handling equipment
• Cost of maintaining handling equipment
• Cost in weight, of fill/drain and other handling systems on board the LV
• Cost in terms of Hi-tech materials used both on the pad and on the vehicle
• Also, if empty stages were to spill residual propellants, or the rocket went off course, H2O2 would quickly dilute into the water into low levels thatare tolerable. N204/Nitric acid would do terrible things, but LOX would just go boom.

SpaceX disappoints me with the amount of "Hi-Tech" components on their LVs, like the turbopump driven Merlin (First stage Falcon1, both stages Falcon9) and the niobium nozzle on the Kestrel engine. I am talking "down and dirty" technology, rugged, off the shelf, cheap. Like OTRAG.

A big dumb booster concept, the Beal BA-2, used jet fuel/H2O2 in all stages. It failed because, like I said before, it started out too big. T.Neo 08:23, 23 October 2008 (UTC)