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Supposedly the hangup in the new space policy is finding a way to get to the moon without susbstantially increasing the NASA budget. However, this should not be too difficult.
General Dynamics Early Lunar Access
ELA is the cheapest option that requires practically no new hardware. HLR will require some new investment, but looks to be more sustainable. But both plans can be implemented without new boosters.
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Well, George II/et al. aren't going to have much of a base with either ELA or HLR concepts! Not enough reuseability, crews are too small, and no real orbital or surface infrastructure... Nasa would have quite a bit of money if they cut Shuttle/ISS loose and managed to keep LockMart/Boeing from price gouging.
Somthing like the Drake plan would be preferable, with some modification, that would permit long term serious habitation (i.e. more people than will fit in one OSP). The basic idea is to use ion powerd tugs to get modest cargoes from LEO to the Lunar orbit, where landers fueled by Lunar water-LOX/LH would go up to get them. My variation is discussed in another NewMars thread under Interplanetary Transportation (The Moon As Fuel Source).
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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HLR has much reusability built into it. The transfer vehicles aerocapture back into earth orbit, and they can be refuelled by the FGB. The option C even puts a space station in lunar orbit, von Braun style.
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HLR is a step up from the ELA plan, but still not quite enough with the Plan A's manned section being a one-shot capsule, Plan C not establishing a Lunar surface base, and all the plans sound like awfully low-payload concepts without Lunar refueling.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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I think everybody concedes that we won't be able to do a lunar base on our first trip. We'll have to make several landings to build infrastructure and gain confidence. What I like most about HLR is that aerocapture is tested in earth orbit, paving the way to aerocapure at Mars.
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Of course not, but considering the sizes of the payloads and rockets involved, it doesn't make sense to make tiny unreuseable or underpowerd ships like HLR when we don't need ships a great deal bigger for a real base. Again, if we don't go with building a base in mind as soon as possible, there isn't going to be a base, and it will become Apollo II.
I still have some doubts about aerobraking being preferable to propulsive capture too... you have to lug that shield along, and have a high degree of insertion accuracy. The extra fuel for propulsive capture might also permit direct abort.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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In a crash program I am sure we could mount a lunar vehicle on the Shuttle launcher in place of it; for further exploration we will need 200+ ton Cheap boosters
Perhaps an evolution of the proven Saturn design, like the V-4X?
Then we will need nonchemical rockets with 4 digit ISPs or more to truely open up the stars.
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Aerocapture shields add 15% to the total mass, which is less than the fuel needed otherwise, and precise flying to hit the atmosphere at the right angle does not strike me as that difficult with advanced computers, especially if one uses GPS (and we will need a GPS system for Mars eventually, anyway). Of course, if one wants to fly to Mars in less than 140 days, you hit the thin Martian atmosphere too fast for aerobrkaing and have to use propulsion to slow down. That may be practical once refueling is possible at Mars.
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Aerobraking is easily the superior theoretical method from a fuel mass standpoint, its the engineering i'm worried about.
-An effective shield must be large, probobly much larger than the 5M limit on an EELV or the Shuttle bay. Will an inflatable, folding, or orbital-built shield be safe/reliable enough?
-Since you can't use GPS beyond the orbit of the GPS satelites (their signals only point down at Earth), can your ship really be precise enough time after time with the small margin of error? Propulsive capture permits much more generous orbital insertion and course correction flexibility.
-Is your ship going to carry enough fuel for direct abort anyway? This would probobly be almost enough for propulsive capture in the first place.
As for a MARS aerobraking, that likewise makes me a little nerveous with the required entry accuracy. Maybe for maximum-payload cargo ships perhaps, but propulsive capture sounds safer. It would as you say also enable faster transit with the aid of a powerful engine, like should be developed anyway. Faster trips to Mars are certainly preferable from a radiation, deconditioning, and mechanical reliablility point of view.
A large megarocket is also not needed for a Lunar expedition, and might even be unfavorable given the low payloads any near-future lander could haul. Any base on the Moon will all but require a reuseable ship(s) that can be refueled, so you don't need a "whole thing at once" direct launch with a megarocket. The SDV or a revived Energia are the best way to launch any needed large cargoes.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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On the official Energia website, they depict a circular aerobrake riding laterally on the Energia rocket. I guess that would be the best way to launch the aerobrake, and it would be more difficult to modify an SDV to do this than it would be to put it on an Energia. If neither option was available, the shield would have to be assembled in orbit. The 90-day plan called for this to occur at Space Station Freedom. Conceivably, an aerobrake could have petals that folded up and collapsed it into a smaller structure, but I suppose it would need some kind of strengthening at the hinges.
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-Since you can't use GPS beyond the orbit of the GPS satelites (their signals only point down at Earth), can your ship really be precise enough time after time with the small margin of error? Propulsive capture permits much more generous orbital insertion and course correction flexibility.
10,800 miles is their orbits
precise flying to hit the atmosphere at the right angle does not strike me as that difficult with advanced computers, especially if one uses GPS (and we will need a GPS system for Mars eventually, anyway
Part of GPS position is based off of the refraction of the L-Band radio waves in the atmosphere.. never heard of many space based uses of GPS, most of those systems have their own their own navigation systems. GPS has a three fold purpose. The two that would effect things like this is obviously it's positions systems, and it's timing distribution of UTC.
Shuttle C is a great launch setup, and is an upgradable launch setup. With the possibilities of evolving SRBS and the tank, with the proper equipment.
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Okay, someone in the know on such mathmatical things:
You have 14 tons to work with, is that enough space/weight limit to work with to get to the Moon? How many people could you get to the moon with a 14 ton vehicle?
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Fifteen English Standard tons is not much to work with... the Apollo Lunar Lander (which could concieveably seat three) weighed in at around 16 tons with about 11 of that being decent stage, and it was essentially "disposeable" (a bad thing). If the thing were LOX/LH powerd, I imagine it might be lighter, but thats not much headroom.
My twist on the Drake plan, tailored for EELV HLV sized payloads, in another thread "The Moon as Fuel Source" in Interplanetary Transportation page 2.
[i]"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw[/i]
[i]The glass is at 50% of capacity[/i]
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