A new thread over at a nasaspaceflight.com forum has new information about the NASA Lunar Surface Access Module (LSAM)...<br /><br />The new lunar lander<br /><br />...and in that a thread is a link to a 6.5mb pdf document with fascinating details.<br /><br />UPDATE section begin<br /><br />Here is a link to spaceref.com about the story...<br /><br />NASA Lunar Lander Project Office Presentation <br /><br />UPDATE section end<br /><br /><br />Highlights<br /><br />The LSAM is now simply refered to as the Lunar Lander.<br /><br />Concepts to improve the ESAS baseline 'spider' design have been boiled down to 7 basic configurations.<br /><br />Only one of those configurations is anywhere close to the baseline ESAS spider design.<br /><br />6 of the 7 configurations use a minimalist ascent module.<br /><br />3 of the 7 configurations use a crasher stage. Though NASA uses the blander term 'drop stage'.<br /><br />1 of the 7 configurations is all cryogenic and appears related to some Lockheed-Martin ideas described previously in this forum.<br /><br />1 of the 7 configurations is a 'horizontal lander' that appears similar to a Boeing concept.<br /><br />The JPL configuration has legs with wheels so it can move under it's own power to a new location after landing.<br /><br />Analysis<br /><br />Any of these concepts would be an improvement over the ESAS 'spider'. Some would be a big improvement. Gone is the forest of liquid hydrogen tanks in the baseline spider descent stage. (Almost) gone is the surface access EVA problem caused by the great height of the baseline spider configuration.<br /><br />The problem with re-using the Apollo-era Grumman lander design for the new Constellation-era moon mission is that the new mission is overmuch for the old spider configuration to cope with. All that the old spider had
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I still like the Lockheed concepts from last year, especially the "Eagle" lander. <div class="Discussion_UserSignature"> </div>
"I still like the Lockheed concepts from last year, especially the "Eagle" lander."<br /><br />Yes, the Lockheed dual-axis thrust lander, great stuff.<br /><br />Lockheed Martin reveal their three Lunar Lander Concepts<br /><br />The all cryogenic concept NASA lander looks almost exactly the same, except it uses a 'drop stage' which is underneath the ascent module rather than a descent module which was behind the ascent module of the dual-axis thrust lander.
I have to pick a fault with your simplistic conclusion<br /><br />"Stubbier (and therefore lower ISP) nozzles are neccessary for ground clearance"<br /><br />Nozzles (Laval nozzles) can have a high expansion ratio in a short distance. Because of the lower pressure downstream you don't have to worry about detached flow assuming a low enough exit pressure. In space exit pressure is near 0 so flow detachment shouldnt' be a problem.<br /><br />The only problem is you won't get an exactly uniform flow field on exit. (some exaust with be in other directions besides axial) meaning you loose a little thurst. <br /><br />Bell shaped nozzles can only be designed for on instance of chamber/exit pressures. Considering that the nozzle will be throttled up and down as it is landing you will never have a perfect set of conditions as it was designed. <br /><br />Therefore I doubt that you will see a significant performance degration over using a longer nozzle. At some point using a longer nozzle will result in losses due to friction.
"I have to pick a fault with your simplistic conclusion...Therefore I doubt that you will see a significant performance degration over using a longer nozzle. At some point using a longer nozzle will result in losses due to friction." <br /><br />Of the RL-10 family of liquid hydrogen/liquid oxygen engines...<br /><br />http://www.spaceandtech.com/spacedata/engines/rl10_specs.shtml<br /><br />...the stubby 42 inch long RL-10-A5 is the kind of engine that would be used in a spider style descent stage, it has an ISP of 365 seconds. The very long 163 inch RL-10-B2 is the kind of engine that a drop stage would use, and it has an ISP of 464 seconds. RL-10 variants which fall between those extremes in length, also fall between those extremes of ISP.<br /><br />Hmmm...my 'simplistic conclusion' seems to be backed up by real world evidence. How about that.
Great info.<br /><br />I liked the side launched ascent module concept.<br /><br />Don't like the mobile lander. <br /><br />Wonder if were asking too much for habitat conversion kits from tanks. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>
"Great info."<br /><br />Thanx! I'm surprised more people don't seem interested. This has been a low activity thread so far.<br /><br />"I liked the side launched ascent module concept."<br /><br />They tend to have the drawback though of requiring the lander to have two docking ports: one on the ascent module for LOR and another on the centerline of the lander for the TLI and LOC burns when the CEV and lander must be docked together. <br /> <br />"Wonder if were asking too much for habitat conversion kits from tanks."<br /><br />I agree. I don't really care for the 'habitank' lander concept.<br /><br />"Don't like the mobile lander."<br /><br />Here is some information on the ATHLETE mobility system...<br /><br />The ATHLETE Rover<br />
very true, but read my post again. during decent you will not be running continually at the optimum design settings. throttling up and down will change your operating Isp of the engine. The chart listed is a single design parameter. If you throttle down you will have to reduce CC pressure. lower pressure, lower exhaust velocity. <br /><br />Engineering is more than just looking at charts.
"...but read my post again..."<br /><br />I did read your post carefully. I was giving you the benefit of the doubt that you had read my original post carefully. I was wrong.<br /><br />"...during descent you will not be running continually at the optimum design settings. throttling up and down will change your operating Isp of the engine. The chart listed is a single design parameter. If you throttle down you will have to reduce CC pressure. lower pressure, lower exhaust velocity."<br /><br />And I pointed out in my original post (something which you apparently overlooked) that a drop stage woudn't NEED to throttle; that a drop stage could afford to run at a single level of highest effeciency, unlike a descent stage which must throttle.<br />
[Engineering is more than just looking at charts]<br /> <br />"Right. Gynsandrockets (sic) has not grasped that concept yet. "<br /><br />Gee SG, can't we all get along? Why be so hostile?<br />
"And I pointed out in my original post (something which you apparently overlooked) that a drop stage woudn't NEED to throttle; that a drop stage could afford to run at a single level of highest effeciency, unlike a descent stage which must throttle. "<br /><br />I don't like to start flame wars, but I too am having a crappy week. You are asking me to look at a partial statement of information from your original post<br /><br />"Another very important advantage of a liquid hydrogen drop stage is it can be specialized for minimum weight and maximum ISP. Lightweight structure and a single RL-10 engine with a very large expansion nozzle can be used. But if RL-10 have to power a landing all the way to touchdown then all kinds of compromises are neccessary. <br />"<br /><br />and come up to the same line of thoughts as you? If you wish me not to missunderstand you then you really should explain it all out. Effective comunication comes from completely explaining yourself.
Hey, how about something a little goofy just to break the tension. <img src="/images/icons/laugh.gif" /> <img src="/images/icons/wink.gif" /><br /><br />The interesting idea here in my mind is the possibility of a dual-mode landing strategy.<br /><br />Played eagle Lander much? It's been a while but I mastered it, and it has real physics behind it. One can get a pretty darn good feel for Lunar gravity and operational possibilities within that particular field. Yeah, I know, this sounds silly so far, still one can run some basic experiments on it.<br /><br />One way to land on the moon is an extreme way but instructional. I call it the Bugs Bunny approach. You drop like a stone and only at the last possible moment before disaster do you fire your engines at 110% <img src="/images/icons/laugh.gif" /> thrust and come to zero vertical velocity 3 feet above the surface. Not highly recommended, but it minimizes propellant use. It cannot be done more efficiently. Stupid, but instructive.<br /><br />OK, so what if you do the bugs bunny thing down to 1000 m above the surface, and you kill all your (substantial) horizontal velocity with the same burn? Well that leaves you with a high-thrust engine that needs to be throttled WAY down for the final landing maneuvers. Another bad idea, but instructive.<br /><br />See where I'm going with this? Two sets of engines on our Lunar Lander, bigguns delivering 2.3 km/s dV and littluns giving you terrific maneuverability and capability, with tankage that can be partially filled for mission-specific dV configuration. RL-10s and Armadillo. It's a hopper between landing missions. It's a true spaceship.<br /><br />Both sets could be propelled by LUNOX and Earth-fuel (but not necessarily the same fuel). The Lander's first mission would of course be all earth-sourced but then the pre-staged fuel for the following landing missions is loaded up, along with the LUNOX, and taken to the HLO or LaGrange point depot. Once a couple of landers are in place, we can stop <div class="Discussion_UserSignature"> </div>
"I don't like to start flame wars,..."<br /><br />Then why persist in baseless criticism. First you claimed I made a simplistic assumption about RL-10 engines. Now you claim you can't understand what I write.<br /><br />You say, "If you wish me not to missunderstand you then you really should explain it all out. Effective comunication comes from completely explaining yourself."<br /><br />Ever looked at your own mangled syntax and spelling? Loose for lose and thurst for thrust? Someone who sits inside a glass house should not throw stones.<br /><br />And how could you possibly have misunderstood what I wrote? Sentences such as, "Wheras a drop stage engine only needs to turn on and off at full thottle", which appeared in my very first post or the sentence, "...a drop stage woudn't NEED to throttle; that a drop stage could afford to run at a single level of highest effeciency, unlike a descent stage which must throttle", in the post where I defended myself.<br /><br />You say, "You are asking me to look at a partial statement of information from your original post and come up to the same line of thoughts as you?". <br /><br />NO! I merely pointed out that you didn't comprehend that my original post covered the issue of throttling. Your criticism based on throttling was attacking a straw man of your own creation. You aren't arguing with me, you are arguing with yourself. <br /><br /><br /><br />I don't intend to flame anyone, but I don't regret defending myself from erroneous attack. If anyone ever wants to correct me when I have made a mistake, I welcome that. The only thing that matters to me is the truth. But it is extremely irritating to be a subject of criticism when that criticism is based on a misreading or bad oversight by the person making the criticism. If you are going to the trouble of correcting someone be damn sure you are reading an actual mistake! It's not my job to read for you or spoon feed you information. Heck I remember on one occasion I had to rep
"Played eagle Lander much?"<br /><br />No. Sounds like fun. I remember an old arcade game, I think was called lunar lander, which was pretty fun but damned hard.<br /><br />"OK, so what if you do the bugs bunny thing down to 1000 m above the surface, and you kill all your (substantial) horizontal velocity with the same burn? Well that leaves you with a high-thrust engine that needs to be throttled WAY down for the final landing maneuvers. Another bad idea, but instructive. See where I'm going with this? Two sets of engines on our Lunar Lander, bigguns delivering 2.3 km/s dV and littluns..." <br /><br />That is basically the landing mode of the unmanned Surveyor lunar landing probe. The drop stage killed the Surveyor's velocity at some altitude and then the drop stage was dropped(!) to lighten the final load.<br /><br />"Two sets of engines on our Lunar Lander, bigguns delivering 2.3 km/s dV and littluns giving you terrific maneuverability and capability, with tankage that can be partially filled for mission-specific dV configuration. RL-10s and Armadillo. It's a hopper between landing missions. It's a true spaceship."<br /><br />You have just described the Lockheed-Martin dual axis thrust lunar lander! Covered in detail in another thread, linked to here...<br /><br />Lockheed Martin reveal their three Lunar Lander Concepts <br /> <br /><br /><br /><br />
<img src="/images/icons/laugh.gif" /> <img src="/images/icons/laugh.gif" /> Yeah, I know. I'm in love with the design. Thanks for the reply 
<div class="Discussion_UserSignature"> </div>
<div class="Discussion_UserSignature"> </div>"Yeah, I know."<br /><br />Alrighty then.<br /><br />"I'm in love with the design."<br /><br />What strikes me is how much imagination and creative design NASA is applying to the Lunar Lander. It's a great contrast to the mundane and pedestrian approach taken with the Orion CEV. <br /><br />
Yes it is pretty cool. Lets hope that NASA does fund it properly. The design over time can evolve to be adaptable to other solar system bodies, other than the Moon.<br /><br />Thank you for sharing this with us. A great development.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>
I think the U.S. needs to do the funding better.<br />As far as I remember, I keep hearing NASA going to the government for more money<br />and I keep hearing of budget cuts.<br /><br />Not too long ago I read an article, actually I'm including the link.<br />It states the following: <br /><font color="yellow">' Agency worries the U.S. could lose the lead it has over Russia and China'</font><br /><br /><br />so from thins I can see that the agency[NASA] is very concerned, you see, the U.S is not<br />worried that NASA could lose the lead it has over Russia and China<br /><br />my personal opinion is that NASA needs to be professionally funded. <br /><br /><br /><br />here's the link to the article by CNN dot com<br /><br />http://www.cnn.com/2007/TECH/space/03/30/space.flight.gap.ap/index.html <div class="Discussion_UserSignature"> </div>
I'm not worried that the 4 year gap will result in the US losing manned space access forever, but it is a little embrassing. I think that Congress will be much more likely to keep the funds flowing if we don't have a current operating vehilcle. <br /><br />Everybody's favortie white elephant the X-33 would likely have flown if it was a current project under todays political climate
> <i><font color="yellow">verybody's favortie white elephant the X-33 would likely have flown if it was a current project under todays political climate</font>/i><br /><br />I have often used the X-33 (eventually leading the the Venture Star) as an example of NASA's failures, but it is also worth keeping in mind that the amount of money poured into the X-33 was only about 3 months the Shuttle's budget. I am not sure how much has gone into the Ares program yet, but I bet if it hasn't already, it will soon pass the amount that went into the X-33 program.<br /><br />On the other hand... Venture Star had a planned payload capability of only about 59,000 pounds, or less than 1/4 that of Ares V. I think it would be difficult to build a Lunar or Mars program out of Venture Star-class payloads.</i>
<blockquote><font class="small">In reply to:</font><hr /><p>I'm not worried that the 4 year gap will result in the US losing manned space access forever, but it is a little embrassing. I think that Congress will be much more likely to keep the funds flowing if we don't have a current operating vehilcle. <p><hr /></p></p></blockquote><br /><br />Never thought about it that way, but I think you have a point. <img src="/images/icons/smile.gif" />
Do you think that NASA will be left with an uncrewed vehicle for 4 years, or could the retirement of the Space Shuttle be postponed until 2014? <br /><br />This would remove a lot of the pressure to meet 'deadlines' which as we know all too well can lead to disaster. After all it is a fully functioning largely successful system.<br /><br />Just a thought.<br /><br />I do hope that this new Lunar Lander will be operational as timelined. <br /><br />We need to go back to the Moon & do some real science that Apollos, 15, 16 & 17 started in earnest (11, 12 & 14 were technology demonstrators IMO, although some good science came from them). Also the capability of high latitude lunar landings as well as the lunar farside is appealing (although far side landings obviously will need a 'comsat' of some sort).<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>
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