Changes to Lunar Plans

[gunsandrockets]

Very interesting file, thanx for the link!<br /><br />From the report it looks like JPL has a winner with the Mobilander concept and ATHLETE suspension system.

 

[gunsandrockets]

<I'm a bit surprised to see them touting ATHLETE so much. I see some of the benefits but there are just so many places for the "fines" to damage the mechanisms.><br /><br />Hmmm... I don't think there is that much difference in the number of joints compared to a more conventional 'rocker-bogey' suspension. <br />

 

[gunsandrockets]

<Unfortunately, the space taken up by the suits eliminates spaces for windows that could be used by the crew to see how close the rover is to something.><br /><br />According to the slide file, NASA is looking at a top-mounted small dome window for all-round visibilty. (Even though no such window is visible in the illustration you are refering to)<br /><br />You don't want too many windows or too much rover area taken up by windows anyway because of the heavy mass of windows. The same reason why the windows on the original lunar module were so small and few.

 

[gunsandrockets]

<My question is how would they deliver these 'large modules'?><br /><br />With one Ares V launching one unmanned Lunar Lander loaded with cargo and no ascent module. <br /><br /><If you just use Ares V then you need some thruster with propellant to enter lunar orbit, and that would restrict available weight for your lander/cargo. /><br /><br />The Lunar Lander on an unmanned cargo mission would not brake into orbit but proceed to a direct landing instead. Plus the new Constellation spacecraft will use a different balance than the old Apollo spacecraft.<br /><br />With Apollo, the Command + Service Modules were the elephant and the Lunar Module was the fly. That's why the Apollo Service Module was used for braking the whole stack into lunar orbit.<br /><br />The Constellation reverses the Apollo arrangement and has a large Lunar Lander which brakes the whole Orion + Lander stack into lunar orbit. This was a deliberate choice on NASA's part to maximize cargo delivery to the lunar surface. And heavy cargo delivery is the major reason why the Lunar Lander's descent stage uses high performance LOX/LH2 rocket engines instead of hypergolic fueled engines. <br /><br /><If you use both Ares V and Ares I, you can maximize your cargo ferrying ability. IE launch Ares V with TLI booster, and lander with cargo, then launch Ares I with some more cargo and a service module for lunar orbit insertion. /><br /><br />The Ares I is an expensive and low capacity cargo delivery system and the Orion service module with it's mediocre rocket engine wouldn't add much payload capacity to the Lunar Lander.<br /><br />If you really want to boost the cargo capacity of the Ares V by EOR, a better option than the Ares I is the Delta IV.

 

[holmec]

<blockquote><font class="small">In reply to:</font><hr /><p>If you really want to boost the cargo capacity of the Ares V by EOR, a better option than the Ares I is the Delta IV.<p><hr /></p></p></blockquote><br /><br />Delta IV lifts less to LEO than Ares I, about 2000kg less. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[gunsandrockets]

<Delta IV lifts less to LEO than Ares I, about 2000kg less. ><br /><br />Maybe. If the Ares I completes it's development, however many billons of dollars down the road, we will see how close to it's promised capacity it actually delivers.<br /><br />And even if the Ares I delivers, it's still much more expensive than the Delta. Plus the figures you used only compared the Delta IV heavy configuration without SRB. If Delta IV SRB are included then the Delta IV heavy easily outlifts the Ares I.

 

[holmec]

<br /><blockquote><font class="small">In reply to:</font><hr /><p>Plus the figures you used only compared the Delta IV heavy configuration without SRB.<p><hr /></p></p></blockquote><br /><br />Don't think so:<br />Boeing's Delta IV<br /><br />Psst...the heavy doesn't have SRBs. Liquid fuel. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[jimfromnsf]

"Delta IV lifts less to LEO than Ares I, about 2000kg less."<br /><br />Not true. The Ares I doesn't lift it's payload into LEO, it is a suborbital trajectory<br />Also there will be a Delta IV heavy upgrade that will be fielded in 2011 with even more performance

 

[gunsandrockets]

<The [PDF file] rover is much more robust than the picture given to the media. Rear-deck access to the spacesuits, with Aux rover controls outside, an airlock/stormshelter and fixings for attachments. Good stuff.><br /><br />I wouldn't be surprised if the squarish rover is actually the earlier configuration and the round rover is the later one. <br /><br /><br /><br /><br /><SPRITE has the advantage of putting the external suit-mounts on the rear deck of the rover. The lop-sided design just proposed looks less functional (not that it wouldn't work) and might have viewport issues. I'd put the suits on a rear deck, or angled sidewards at the rear with the docking hatch between them directly rear. /><br /><br />Checking over the numbers of the SPRITE rover compared to the FRED rover, it's interesting to note the masses involved are nearly identical. Not a surprise since they appear so similar to each other. I hope NASA doesn't ignore the potential of their light-weight Rover to use Delta IV to get to the moon (as was proposed for the SPRITE). Use of other rockets in addition to the Ares V to deliver lunar cargo could help ease launch constraints.<br /><br />As for the 'lop-sided' rover, I think it might actually be the better option. Here's why...<br /><br />1) If the rover external steering controls are mounted at the side of the rover, then the EVA suited external driver has vision both forward and aft of the rover. Rear mounted controls are only practical for steering the rover backwards.<br /><br />2) The 'lop-sided' rover has an efficient cylindrical-shaped pressure vessel and much less window area and therefore would be much lighter than the squared-off rover.<br /><br />3) The very large hatch on the squared-off rover might be too large. I expect a smaller docking hatch like the one on the Shuttle will be selected instead. <br /><br />4) The side-mounted hatch on the squared-off rover might be harder to dock with than docking with an in-line forward or aft-mounte

 

[gunsandrockets]

<Psst...the heavy doesn't have SRBs. Liquid fuel. ><br /><br />Delta IV common core boosters can attach small solid rocket boosters. Even though the Delta IV heavy has flown so far only with three common-core liquid boosters, the Delta IV heavy can in addition add some small solid rocket boosters.<br /><br />But more importantly the Ares I is not cost effective as an unmanned cargo rocket.

 

[christine16]

Delta IV is good choice

 

[jimfromnsf]

"the Delta IV heavy can in addition add some small solid rocket boosters."<br /><br />Not so, that was only a study. D-IV currently can only attach SRM 's to the core in the same place the additional cores for the heavy are attached. The outboard cores of a heavy are unique and have no solid attach points, additionally the pad crane can't reach the outboard side of the outboard boosters. The study that added SRM's to the heavy found that 2 could be added to each core but only on the side that faces the MST

 

[nimbus]

That link is a 404 for me, does anyone have a mirror? <div class="Discussion_UserSignature"> </div>

 

[gunsandrockets]

<That link is a 404 for me, does anyone have a mirror?><br /><br />I had the same problem. Try this link instead...<br /><br />NASA ESMD Lunar Architecture Update<br /><br /><br />Be warned it's a big file, and if you have a dial-up connection as I do it takes a loooong time to load. It's worth it though.

 

[dreada5]

http://www.nasa.gov/mission_pages/exploration/mmb/lunar_architecture.html<br /><br />New graphic for future lunar rover concept (or at least new to me).