the LSAM shape to come

[gunsandrockets]

Having recently read the Aviation Week & Space Technology article on NASA's plans for a polar Moon base, I noted some factoids buried in the story I haven't seen mentioned elsewhere. The NASA plans for lunar operations are already shaping the LSAM in interesting ways.<br /><br />[The decision to work from a base on the Moon, instead of dispersed sortie missions on the Apollo model, is already shaping hardware planning for surface exploration. From the beginning, each human mission to the Moon will leave behind hardware that future missions will incorporate into a larger base. That approach will guide the design of the lunar lander NASA plans to build as the final leg of the surface-to-surface U.S. lunar transportation infrastructure.] <br /><br />["We thought it was important to really maximize the capability to bring payload down to the Moon when you brought crew, and to leave that payload there after you left," says Tony Lavoie, head of the NASA team that developed the lunar surface architecture. Unlike Apollo, the new strategy will be "to make the ascent module small, to make the descent module small, and to maximize the payload-carrying capability. From a notional point of view, from a point of departure, we're on the order of 6,000 kg. (13,228 lb.) in that landed-mass envelope."] <br /><br />http://www.aviationnow.com/avnow/search/autosuggest.jsp?docid=362108&url=http%3A%2F%2Fwww.aviationnow.com%2Favnow%2Fnews%2Fchannel_space_story.jsp%3Fview%3Dstory%26id%3Dnews%2Faw121106p2.xml<br /><br />NASA administrator Griffin once boasted that a key feature of the LSAM/Ares V combination would be the ability to land more than 20 metric tons of cargo on the lunar surface. That assumed a cargo-only unmanned version of the LSAM to supplement the 7-day s

 

[subzero788]

<br />"Now with the current NASA moonbase build up plan, it appears there will only be one version of the LSAM with minimal life-support capability but additionally able to carry 6,000 kg of cargo."<br /><br />I was under the impression that the LSAM vechicle was going to be modular, with cargo and crew versions. Where did NASA say they would make only one version?

 

[gunsandrockets]

"I was under the impression that the LSAM vechicle was going to be modular, with cargo and crew versions. Where did NASA say they would make only one version?"<br /><br />That comes from reading the NASA lunar flight program as currently described. NASA has gone into significant detail as to what moon base components will be carried by each LSAM during the first five years of manned landings. There is no description of any cargo-version LSAM taking any part of that schedule. <br /><br />The only unmanned LSAM mission described is the very first LSAM landing and that's only because it's a test flight of the combo manned/cargo LSAM. The test flight will drop cargo on the surface and the ascent module will fly back up to lunar orbit as a complete flight test of the LSAM. A pure cargo LSAM won't have an ascent module, the whole point of a pure cargo LSAM is to maximize cargo mass by shedding all mass related to manned flight.

 

[gunsandrockets]

" there was no need to discuss that [pure cargo LSAM] in the general over view." <br /><br />Well that's odd. If a cargo LSAM fits into the lunar program, how does it fit? When does it first fly? What moonbase component will it carry, and when? Why no mention of any pure cargo flights?<br /><br />And more importantly why try to squeeze so much cargo out of the manned LSAM if an unmanned pure cargo LSAM is going to be used to any significant extant? Five years of manned LSAM flights would deliver 60,000 kg of cargo. Only three pure-cargo LSAM would be needed to match that, a factor that would significantly alter the manned lunar flight program and the time needed to build up the lunar base.<br /><br />If a cargo LSAM is part of the program it makes much more sense to land the cargo LSAM first and which carries a fairly large self-contained base, such as a BA-330 inflatable. Yet the NASA plan describes an incremental base build up using cargo accumulated from multiple manned flights of the LSAM.

 

[gunsandrockets]

Where does a pure cargo LSAM fit into the NASA plan as reported?<br /><br />Excerpt from the link in my first post in this thread...<br /><br />[...Once the site is selected, the notional concept for planting a base envisions two missions a year. The first mission will be an unmanned test of the lander, but it will deliver a solar power unit and an unpressurized rover that will be used to connect the growing lunar power grid as more missions arrive. The test lander will also carry an ascent module that will be sent back to lunar orbit to rendezvous with the Orion crew exploration vehicle that accompanied it to the Moon.] <br /><br />[The first four-member crew will arrive for a seven-day stay, with the first habitation element for the base. A second human landing in the first year will deliver two more power units and a crawler/carrier that will allow the following mission to connect the original habitat with a second one that it will bring. ]<br /><br />["And there we have the beginnings of the outpost," Lavoie says, noting that the concept--designated 5A--is already out of date as plans evolve.] <br /><br />[The second mission in the second year brings more power elements, each able to deliver about 6 kw. when the Sun is shining. When it isn't, the base will use 2-kw. power-storage units. The first launch in the third year would deliver another habitation element, and the addition of more power units later that year would allow stays of 14 days. In the fourth year, crews would deliver a fourth habitation element, and a module for ISRU experiments.] <br /><br />["We intend to be aggressively pursuing this capability because it is really attempting to break the supply chain to Earth," Lavoie says.] <br /><br />[Crews could stay as many as 30 days in the fourth year, and by the end of the fifth year, six-month stays would be possible,...]

 

[gunsandrockets]

There is a reason why NASA might prefer to avoid a pure cargo version of the manned LSAM aside from development costs.<br /><br />Previous NASA studies for large cargo landers all seemed to come to the same conclusion, that a lunar-crasher stage was the best configuration for a lander. A crasher-stage configuration could be used with a manned LSAM yet NASA has already voiced reservations that such a design would be more dangerous than a more conventional layout (a debatable point).<br /><br />But a large cargo lander which is modified from a manned lander of conventional configuration begins to run into all the problems that made a crasher-stage attractive in the first place; a top heavy lander with no good means of lowering it's cargo to the lunar surface.<br /><br />So to dodge the headache of trying to use the same basic LSAM design for a manned lander and a pure cargo lander, NASA may have decided to combine both functions into a single design. NASA already has said the LSAM will have a 'minimal descent module' to maximize cargo. That tells me the cargo is most likely to be carried level with the descent module. Designing the LSAM to accomodate 6,000 kg of cargo inside the descent module shouldn't be that challenging, and a lot less challenging than figuring out how to handle 20,000 kg of cargo perched on top of the descent module.

 

[gunsandrockets]

"The standard manned LSAM leaves as much mass on the surface as possible. The ascent module is very small. It is not the version shown earlier where the ascent stage included the large pressurized module and airlock."<br /><br />That was covered in the article I linked to in the very first post.<br /><br />"The cargo version adds the mass of the ascent vehicle as cargo that remains on the surface."<br /><br />Not entirely true. A pure cargo version of the LSAM could add much more cargo than just the mass of a missing ascent module.<br /><br />An unmmaned cargo mission of the Ares V would be missing the ~23 tonne mass of the CEV. And the unmanned cargo LSAM wouldn't need to brake that missing CEV into lunar orbit. That missing CEV mass translates into increased payload that a pure cargo version of the LSAM could land on the lunar surface.<br /><br />That's how a manned LSAM with 6 tonnes of cargo gets to an unmanned LSAM with more than 20 tonnes of cargo.

 

[radarredux]

> <i><font color="yellow">That's how a manned LSAM with 6 tonnes of cargo gets to an unmanned LSAM with more than 20 tonnes of cargo.</font>/i><br /><br />Nice summary. Thanks!</i>