Thought a little bit over how a Lunar Program could be gradually built up, utilizing items often cited as "essential" such as the Lagrange points, ISRU, propellant depots, and even polar ice. Trick of course is putting this in a pill Congress can swallow and keeping it overall simple. What I lay out here would be a scheme akin to "Lunar Direct" that was a spinoff of "Mars Direct", but incorporating fuel depots and polar exploration in 3 phases, each with a differing yet complementary set of priorities that ends up with 2 useable bases and a propellant depot.Phase I - "Oceanus"Focusing on a straightforward return to the moon; "Oceanus" implies Oceanus Procellarum, as the initial site would be towards the lunar limb, whether it be the western or eastern. The initial and majority of the flights are cargo, delivering a habitat, a telescope and geologic gear, 5 "utility" robotic rovers (think MERs with snowplows and on steroids), 3 crew rovers (think updated Apollo rover), and twin sets of ISRU modules that would gradually produce "building blocks" and LOX from regolith dug up by the utility rovers. The crewed visits would range from a week to a full lunar day as the base components arrive, with their main purpose activating the outpost and local recon. All flights would be direct, any rendezvous strictly in LEO, and if reuseable the crewed vehicles using aerocapture to return to LEO at mission's end.Phase II - "Aquarius"Propellants begin to become the focus, as does utilizing cislunar space. Only 2 cargo flights are sent, the first being a self-contained LOX depot that's basically a flying H2 tank from SLS sent to wait at a LaGrange point. The more numerous crew flights initially are fully fueled, but first begin hauling LOX on the return trip, and then using the depot for LOX both inbound and outbound. While most flights revisit the equatorial limb base (ELB), 2 flights investigate other sites; one would be a "random" yet science-influenced site such as Copernicus or Aristarchus, while the second would be a polar region reasonably close to ice, such as Shackleton or Peary. The second cargo flight descends, delivering a habitat and rovers.Phase III - "Frigoris"With a habitat established at a pole, cargo flights descend to fully establish a smaller but water-focused Polar Base (PB). As water is tentatively harvested at PB, back at ELB a new cargo flight delivers equipment to upgrade the base and maximize LOX production. All crewed flights from the ELB stopover at the LOX Depot, refueling themselves but also restocking the supply before returning to LEO. By the end 2 regions on the Moon are thoroughly explored, 2 differing sources of LOX are extracted, and the seeds are planted for self-sufficiency.I will later add more to this thread, explaining the specifics of landers, ect. For now this is a would-be architecture for a glance-over.
So you want NASA to mine lunar regolith to get oxygen, next you want NASA to go the Moon's polar regionto mine lunar water.If mining regolith to get oxygen "works" why do you then want mine lunar water?
What I mean is mining water is for various uses as water, and one use is splitting water to make rocket fuel and that mostly gets oxygen- 8 kg of oxygen and 1 kg of hydrogen from 9 kg of water.I would think one want to start with mining water, then proceed to mining other metals and a by product of mining say iron, is you get some oxygen. So both pure iron and the oxygen has value.
Now, what I think NASA should do is explore the Moon to determine if it would be profitable to mine lunar water- commercially.
Quote from: gbaikie on 03/18/2014 11:59 pmSo you want NASA to mine lunar regolith to get oxygen, next you want NASA to go the Moon's polar regionto mine lunar water.If mining regolith to get oxygen "works" why do you then want mine lunar water?Because dry lunar regolith is more common than ice, but water with its hydrogen are inevitably only at the poles. One is more common but it'd be foolish not to harvest both.Quote from: gbaikie on 03/18/2014 11:59 pmWhat I mean is mining water is for various uses as water, and one use is splitting water to make rocket fuel and that mostly gets oxygen- 8 kg of oxygen and 1 kg of hydrogen from 9 kg of water.I would think one want to start with mining water, then proceed to mining other metals and a by product of mining say iron, is you get some oxygen. So both pure iron and the oxygen has value.That's one possibility many favor. The two disadvantages I see is that we don't yet know how hard to get the ice is and, when refined to hydrogen, hydrogen is a pain to store; even in lunar shadow there is bound to be some boil-off.
If the only significant ice is in the deep polar craters then extracting it maybe a step to far initially. Whipple crater is 10,000 ft deep, take a look at 10,000 ft mountain range from sea level and see what we are up against. A base at 80% sunlight point on its crater rim is at highest point, any rover based exploring outside crater would require driving down steep outer crater rim first.Establishing a base where exploration is not limited by mountainous terrain, is a better option. Extracting LOX from regolith still gives you 80-90% of rocket fuel by weight.
Extracting LOX from regolith still gives you 80-90% of rocket fuel by weight.
I'm curious about this question: What are the first lunar surface capabilities that should be developed? I suggest they should be ones that will be "proximal" to current technology AND useful for a wide number of different approaches to lunar surface exploration.
At the exception of landing, what are the advantages of an equatorial station?No water, 2 weeks of continuous night wouldn't count as advantages. And now that we have a company that is working on pinpoint rocket landing in an atmosphere, I would guess that pinpoint landing on an airless body should not be a insurmountable problem.
What technologies do you take as "already developed sufficiently" ? For example, we've landed on the moon before, fairly accurately. But it was a long time ago and NASA has the Morpheus project... so must think refinement is justified.{snip}
I'll discuss the first element in my architecture: the cargo lander.All together, it would be the most straightforward spacecraft in that it is meant to fly directly from Earth to the Lunar surface. Much of my thinking about it stems from the Mars Direct Habitat. Unlike Altair or Boeing's current concept for a reusable lander, access to the surface is the priority so that the autonomous utility rovers can embark and crews unload equipment as well as enter the base hab. Fuel tanks, containing oxygen and methane, would sit atop either a habitat or container module with twin descent nozzles on either the sides or beneath the lander.Being a cargo vehicle, there is no concern about needing an emergency escape or separate sets of tanks for descent/ascent stages. The Altair engineering was impressive in coming up with ATHLETE as a means for offloading cargo from the descent stage, but it seems simpler just to put it low to the ground with the sides of the container unfolding into ramps. Naturally there are concerns for obstacle clearance, but given the thought that goes into site selection (including polar sites) and our increasing database (thanks chiefly to LRO, SELENE, ect.) a rock smaller than a foot isn't a show stopper. Fuel tanks and cargo, it would be a solid piece with minimal deployment mechanisms.
The math of course is the tricky part. Mark Zubrin's designs for Mars Direct's hab massed it around 25 tons for all major elements; Altair would have been about 50 tons with 26 of it propellant. While different designs, it implies that putting 25 tons on a one-way-moon-trip is possible. Regarding science gear, for comparison the Hubble weighs just under 12 tons, so the telescope for the Equatorial Limb Base could be nearly as large (more likely 2/3 as sized to be conservative) with plenty of room for anything from heliophysics to seismology. For items like the LOX and Foundry modules, I refer to Astronautics.com: http://www.astronautix.com/craft/lunox.htm Gear for tentative ISRU seems to be placed around 7 tons, so giving 10 for LOX and another toward Foundries seems reasonable, with room leftover for more rovers, spares, feedstock hydrogen, and things like solar panels.Whether or not orbiting/LaGrange elements are later employed, a one-way cargo lander should be a must for either Mars or Luna, just to ensure something long-lasting is established at the intended destination.
I'll discuss the first element in my architecture: the cargo lander.[...]Whether or not orbiting/LaGrange elements are later employed, a one-way cargo lander should be a must for either Mars or Luna, just to ensure something long-lasting is established at the intended destination.
Land 2 or 3 times at the same place and it becomes a spaceport. Once empty the lander becomes a man made rock messing up a prime landing area. The hazard needs removing. Something like the ATHLETE is needed to move the lander to the side of the crater awaiting recycling.
There are various VTVL machines that can be space-rated to land small cargoes, which would allow new machines on the Moon within 5 years.By putting several engines together you get a larger cargo lander.On Earth the VTVL melt their concrete landing pads. This heat will tend to damage any cargo near the nozzles.
Quote from: redliox on 03/31/2014 10:07 amI'll discuss the first element in my architecture: the cargo lander.[...]Whether or not orbiting/LaGrange elements are later employed, a one-way cargo lander should be a must for either Mars or Luna, just to ensure something long-lasting is established at the intended destination.Could you discuss the thinking behind this a bit? What provides your certainty that a non-reusable lander is required?
Reuseable for crews is applicable, but for the moment I discuss the cargo vehicle [capable of] bringing a 25 ton habitat down.
Unless you have a reason to return to Earth, it is more cost effective to put it on a one-way trip.
I'm beginning to understand your perspective! You seem to be saying, "For this architecture let's take as a given the use of an expendable, 25 t payload, cargo lander." Discussing what could be accomplished with such a vehicle, and at what cost, is definitely fun and probably worthwhile.QuoteUnless you have a reason to return to Earth, it is more cost effective to put it on a one-way trip.That's possibly a straw-man argument. Proponents of reusable lunar landers rarely propose returning them to Earth. They are usually seen as doing purely "surface to orbit and back" duty.
It's going to be hard enough to build one base, so don't propose building two. Remember also, that there is plenty of regolith available at the poles for ISRU demos along those lines.
Most of the mass to maintain a Space Station is unmmaned, so I think that the best approach is to use a ion tug and use only Earth-LEO conventional transport and use some ion ultraefficient tugs to reach the final destination. Xenon could be refilled.
Otherwise regarding ion propulsion it may not be necessary for landers. An SLS in either the 105 or 130 range can send a payload to the Moon on a 3 day trip directly whereas SEP demands weeks of slow boating. Once the landers begins descent furthermore, it needs a chemical system to touchdown, and even in lunar gravity some of the giant solar arrays would be as frail as butterfly wings.I'm a fan of SEP, but if there's a simple, clean way to reach the Moon in under a week use that avenue.
Quote from: redliox on 04/02/2014 02:42 pmOtherwise regarding ion propulsion it may not be necessary for landers. An SLS in either the 105 or 130 range can send a payload to the Moon on a 3 day trip directly whereas SEP demands weeks of slow boating. Once the landers begins descent furthermore, it needs a chemical system to touchdown, and even in lunar gravity some of the giant solar arrays would be as frail as butterfly wings.I'm a fan of SEP, but if there's a simple, clean way to reach the Moon in under a week use that avenue.Ion is not appropriate for manned, but weeks is not a problem for unmanned cargo.The idea is to try avoid to create new expensive rockets that we could not use for other thing instead massive and costly missions.
Quote from: JohnFornaro on 04/02/2014 01:11 pmIt's going to be hard enough to build one base, so don't propose building two. Remember also, that there is plenty of regolith available at the poles for ISRU demos along those lines.The truly hard part, if any, is convincing an administration to return to the Moon.I suggest 2 bases because there is more than one region to study and mine; some 99% of the Moon is nothing like the poles. If 99% of the Moon is dry, we must work with it. Ice or not, I don't think isolating flights to one site alone is the best way to return. Suggesting a dozen bases is unpractical, but proposing one primary base supplemented by a smaller base combines the strengths of 2 regions.
There is one major problem an ion drive would encounter within Cis-Lunar space: the Van Allen radiation belts. Smart-1 used it in similar fashion but had to pass through the belts numerous times, and this was a factor in it's design. Even with an improved set of thrusters, cargo sized for human expeditions would take even longer with the risk of damaging elements needed at the Moon like electronics and solar panels. Given the choice, I would pick a swift path to the Moon versus the slow SEP.
{snip}I'll give a dry description. The core would be a crew cabin akin to a slightly enlarged ISS module, except for the fact it would be octangular, not cylindrical, in cross-section. At the base of the core cabin would be a single oxygen tank with a single LOX/CH4 main engine. Meshing with 4 sides of the core's octagon are 4 slightly skinny methane tanks, each with a fuel line running to the main engine. A separate line for oxygen runs vertically up one side of the core cabin, meeting with a port on top near the docking adaptor atop the vehicle to allow for LOX transfer between the lander and the LOX depot. 4 landing legs are spaced under each methane tank, though not directly supporting them. The core cabin would be split into 2 parts internally: the upper part with the docking port and crew rooms while the lower part is storage and the airlock for lunar excursions.{snip}
If you are willing to use 4-5 engines instead of one the prototype LOX/CH4 engine was flying around KSC last week.