AW&ST article on CEV [Lockheed goes for the extra point]

[mattblack]

>>We had a second Skylab ready to fly. It is sitting in the Smithsonian. We should have flown it also.<<<br /><br />After Apollo-Soyuz there were 4x flyable Block II CSM's left and perhaps two more that could have been upgraded to flight standard. Trouble is, there were only 2x Saturn 1b's left by this time, too. What would the remaining couple of CSM's have been launched on? America was nearly out of man-rated boosters by 1975. Could the remaining Saturn 1 also have been uprated to 1b standard?<br /><br />http://aesp.nasa.okstate.edu/fieldguide/pages/aaindex/home1.html<br /> <div class="Discussion_UserSignature"> <p> </p><p>One Percent of Federal Funding For Space: America <strong><em><u>CAN</u></em></strong> Afford it!!  LEO is a <strong><em>Prison</em></strong> -- It's time for a <em><strong>JAILBREAK</strong></em>!!</p> </div>

 

[mattblack]

I too think that Lifting Bodies should be left to private industry: The Rutan's and other clever folk. I'll say it again: capsules are cheaper and quicker to develop and far better for deep space. The dead weight of wings are useless at the Moon, and Mars would need far different shaped wings. Perhaps at Titan the LockMart CEV might have a chance!!<br /><br />Seriously, why are some folks getting this silly notion that capsules are silly, old-fashioned technology that should be abandoned? Just because a car has 4 wheels, suddenly 6 or 8 is better? Hey! stop those airplanes having wings; wings are SOOO 20th Century. You should take those wings off, they're so, gulp, OLD FASHIONED!!<br /><br />Russia has used casules for 40+plus years and they abandoned their winged craft. Why? 'CAUSE CAPSULES WORK.<br /><br />Get over it...<br /><br />Seriously; If my wishes were currency to spend, the T-Space CXV would be the bees knees for LEO transport to the ISS, a Tourist Hotel or any other LEO destination. In fact, the T-Space lunar CEV crew transport and tanker are great designs. If a SDHLV were used with a sufficiently large version, you could do Lunar-Direct mission architecture. <div class="Discussion_UserSignature"> <p> </p><p>One Percent of Federal Funding For Space: America <strong><em><u>CAN</u></em></strong> Afford it!!  LEO is a <strong><em>Prison</em></strong> -- It's time for a <em><strong>JAILBREAK</strong></em>!!</p> </div>

 

[botch]

Could the remaining Saturn 1 also have been uprated to 1b standard? <br /><br />The saturn 1 would have to be heavily modified to conform to the 1b spec. A saturn 1 has different shaped fins and is too thin at the top to accomodate the saturn IVB upper stage. Saturn 1 also has an appreciably heavier first stage.

 

[lunatio_gordin]

i think the biggest reason people dislike capsules is because they get discarded. Has anyone ever taken a capsule that landed, and then tried to refit it for flight? (i'm really asking here.)

 

[henryhallam]

<font color="yellow"><br />i think the biggest reason people dislike capsules is because they get discarded. Has anyone ever taken a capsule that landed, and then tried to refit it for flight? (i'm really asking here.)<br /></font><br />I don't believe this has ever actually been done but there were some serious studies towards doing this with the Apollo capsules. It was believed to be quite possible and might well have been undertaken if the full Apollo Applications Program had flown.

 

[lunatio_gordin]

Certainly, then, if it's possible and cost efficient to refit a capsule, that makes it the better vehicle. A capsule could probably be refit faster than something like the space shuttle, giving it a faster turnaround time.

 

[rogers_buck]

Thank you for your post.

 

[aaron38]

See MrMorris' Gemini capsule thread. Much has been said there on capsule re-useability. From what I gather, it's doable.<br /><br />http://uplink.space.com/showflat.php?Cat=&Board=businesstech&Number=68932&page=0&view=collapsed&sb=5&o=0&fpart=<br />

 

[botch]

You're right, my mistake: They did do some weight saving measures, but it probably wouldn't offset the increase in tank size.

 

[gunsandrockets]

"I too think that Lifting Bodies should be left to private industry: The Rutan's and other clever folk. I'll say it again: capsules are cheaper and quicker to develop and far better for deep space. The dead weight of wings are useless at the Moon, and Mars would need far different shaped wings. Perhaps at Titan the LockMart CEV might have a chance!!"<br /><br />First off lifting bodies don't have the 'dead weight of wings' because lifting bodies are wingless. That's why they are called lifting bodies, they generate lift from their bodies instead of using wings.<br /><br />More importantly the purpose of lifting bodies, or of semi-ballistic capsules, is for landing on Earth, not landing on the Moon, Mars or Titan. Note that return to Earth speeds from deep space are much higher than the reentry speed from LEO. G loads in a capsule can reach as high as 16 when returning from Mars. It's because of the needs of deep space missions that Lockheed-Martin went with a lifting body design in the first place, in order to reduce those high G loads.<br /><br /> "Russia has used casules for 40+plus years and they abandoned their winged craft. Why? 'CAUSE CAPSULES WORK.<br /><br /> Get over it... "<br /><br />Hmmm...I seem to recall that Russia wants to replace the capsule design Soyuz spacecraft with the lifting body design Kliper spacecraft. Isn't that funny?<br /><br />"Seriously, why are some folks getting this silly notion that capsules are silly, old-fashioned technology that should be abandoned? "<br /><br />Nope. Everything has it's place and purpose. Semi-ballistic capsules are just fine for reentering the Earth's atmosphere from LEO. It's just that lifting bodies are better for returning from farther out. And sure an Apollo capsule was used for returning from the Moon but that doesn't mean a capsule is the best way to return from the Moon, it was just the fastest way to win the Moon Race. Just as the Vostok pure ballistic capsule was used to return from LEO, it wasn't the be

 

[space_dreamer]

gunsandrockets, couldn't have put it better my self!<br />

 

[gunsandrockets]

"Really? Please explain this statement. <br />The lifting body is best from LEO so that you have more landing options in an emergency. That is not needed when returning from the Moon or further out. The lifting capsule can target it's landing site with a burn on the way back. "<br /><br />I'm afraid I don't understand the point you are trying to make. Are you claiming that lifting bodies are superior to semi-ballistic capsules for LEO missions? Or are you claiming that semi-ballistic capsules are superior to lifting bodies for missions beyond LEO? Or both?<br /><br />In any case the G loading factor seems more important than crossrange. 16 gees when returning to Earth from Mars seems an awfully high burden to accept for the sake of a 'lighter cheaper' capsule.<br /><br />And as far as crossrange issues, have you noted the t/Space claims for the crossrange of their (LEO missions) CXV capsule design? They claim, "The landing site can be selected with a certain degree of accuracy by propulsive maneuvers during the vehicle's initial descent which provide a crossrange of more than 400 nmi."<br /><br />http://64.78.33.215/index.cfm?fuseaction=projects.view&workid=CCD3097A-96B6-175C-97F15F270F2B83AA

 

[henryhallam]

Where do you get the idea that a capsule returning from Mars would have to decelerate at 16g? The Apollo capsules returning from the Moon had a maximum deceleration of approx. 6g. Mars return is faster than lunar but not by all that much. Modification of the descent profile (e.g. "skipping" once or twice) can reduce the g load further still. I think a ~5g return from Mars is quite doable with a skip approach.<br /><br />All else being equal, a lifting body can use its lift to stay higher in the atmosphere, thus spending a longer time decelerating and hence the peak g force will be somewhat lower - but I don't think it will be enough of a difference to make this the deciding factor of which format to choose for a spacecraft.<br /><br />A lifting body does not have wings but its shape is less efficient in terms of volume per unit surface area. So it will weigh more than a capsule for the same volume, mass that could be used for other things. Of course some lifting bodies are more out-of-shape than others so there is a bit of a sliding scale involved.<br /><br />As shuttle_guy said, when returning from interplanetary distances a small burn can easily adjust the coarse position of the landing site, and capsules are quite steerable during descent as well (due to the center of lift being offset from the center of mass) for fine tuning. Even the relatively crude computer control used by the Apollo capsules could land within 1km of the target point. <br /><br />All but the most outlandish lifting body designs use parachutes for landing anyway, same as a capsule.

 

[gunsandrockets]

"Where do you get the idea that a capsule returning from Mars would have to decelerate at 16g?"<br /><br />I get it from the AW&ST article that was the basis of the start of this thread. Here is the link...http://uplink.space.com/showflat.php?Cat=&Board=missions&Number=224877&fpart=1&PHPSESSID=<br /><br /> "The Apollo capsules returning from the Moon had a maximum deceleration of approx. 6g. Mars return is faster than lunar but not by all that much."<br /><br />Maybe. The AW&ST article doesn't seem to agree with that. Perhaps you have another article or source about Mars return you could bring to our attention?<br /><br /> "Modification of the descent profile (e.g. "skipping" once or twice) can reduce the g load further still. I think a ~5g return from Mars is quite doable with a skip approach."<br /><br />Perhaps. But isn't a skip approach riskier? How many skips? And What if the first skip is too high and doesn't slow the capsule below escape velocity, or places the capsule into a very long duration orbit that delays reentry for days? And how accurate is a multi-skip approach? Wouldn't the footprint of the landing zone dramatically increase with every skip? How difficult or expensive would the develpment cycle be to iron out these skip issues?<br /><br />"All else being equal, a lifting body can use its lift to stay higher in the atmosphere, thus spending a longer time decelerating and hence the peak g force will be somewhat lower - but I don't think it will be enough of a difference to make this the deciding factor of which format to choose for a spacecraft."<br /><br />It was enough of a difference for Lockheed-Martin to choose a modest lifting body shape in order to improve lift-to-drag from the Apollo style capsule l/d of 0.3 to the necessary l/d of 1.0.<br /><br />"A lifting body does not have wings but its sh

 

[gunsandrockets]

"Another point to consider is the duration of the heat pulse. A longer period of lower heat MAY be just as bad, or worse than a shorter pulse of higher temperature. "<br /><br />Relevant to that is this interesting tidbit I found on the web...<br /><br />"Beginning in 1954 and continuing through 1958, Allen and two associates, Alfred J. Eggers, Jr., and Stanford E. Neice, examined the relative merits of three types of hypersonic spacecraft - ballistic, skip, and glide. They prepared in early 1954 a theoretical discussion of the alternative configurations that could be used for manned spacecraft, "A Comparative Analysis of the Performance of Long-Range Hypervelocity Vehicles." For manned satellite missions, any of the three craft could be boosted to orbital velocity by a rocket and then be separated from the launch vehicle for either free flight or earth orbit. The skip vehicle, which would reenter the atmosphere by an intricate series of dips and skips, would require the greatest boost capacity, and would encounter excessive aerodynamic heating during reentry."<br /><br />http://www.hq.nasa.gov/office/pao/History/SP-4209/ch3-4.htm

 

[mattblack]

>>A lifting body does not have wings but its shape is less efficient in terms of volume per unit surface area. So it will weigh more than a capsule for the same volume, mass that could be used for other things.<<<br /><br />BRILLIANT!!! And quite true. I have no particular dislike of Lifting Bodies. In fact, I was very dissapointed when the X-38 was cancelled. But Lifting Bodies are best for LEO-to-ground vehicles, not coming back from 25,000 mph+ ballistic re-entries. The extra lift-over-drag ratio of a Lifting Body would be problematic at those speeds: aero-surface thermal stresses and design challenges for it's TPS, coupled with a Lifting Body's tendency to want to "fly" itself back out of the atmosphere means that you'd probably have to do a re-entry inverted in respect to the Earth, just to fly it into the atmosphere. In other words, a "pitch-up" with the Earth ABOVE your windows, not below it as in a Shuttle re-entry. <div class="Discussion_UserSignature"> <p> </p><p>One Percent of Federal Funding For Space: America <strong><em><u>CAN</u></em></strong> Afford it!!  LEO is a <strong><em>Prison</em></strong> -- It's time for a <em><strong>JAILBREAK</strong></em>!!</p> </div>

 

[holmec]

Shuttle_guy, all planes bodies have lift. If you are going to use the atmoshere to assist in reentry, a lifting body design, or modified, could work. As far as I see it a dart design is the most effecient for reentry since it would have auto orientation of the craft. Lockheed's lifting body will not take off from a runway. So it doesn't need all that much lift for reentry. I do not see the equivelance of cost with the design of a lifting body. The shape of the craft is what were talking here. Its how you put the rest of the functional parts together that will dictacte the cost not neccesarily the shape of the craft. that is heat shield, controls, payload, fuel.<br /> <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[holmec]

>The lifting body design will be much more expensive to develop<<br /><br />Than what?? Since the Gruman is an unknown, what are you comparing? <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[holmec]

> "Russia has used casules for 40+plus years and they abandoned their winged craft. Why? 'CAUSE CAPSULES WORK.<br /><br />Get over it... " <<br /><br />So how come the russians are returning to the lifting body CEV like craft? Hmm... maybe because you can only use a capsule once. <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[nacnud]

There is no reason why capsules can't be made reuseable. Perhaps in the case of the Soyuz it is cheaper just to build another one.<br /><br />The Kliper is twice the size of the Soyuz, it might be cheaper to resuse than build anotherone, the test will be to see if one Kliper flight is more or less costly than two Soyuz flights.

 

[mrmorris]

<font color="yellow">"Perhaps in the case of the Soyuz it is cheaper just to build another one. "</font><br /><br />Yep -- very little of the 'guts' of the Soyuz are in the return module. It's only 1/3 of the craft and only contains about 1/8th of the hardware. Most of the stuff that would be worth reusing burns up on re-entry.

 

[gunsandrockets]

update<br /><br />Small article on CEV in the July 2005 edition of Spaceflight magazine. No details on Northrop-Grumman CEV but on page 253 there was some on the Lockheed-Martin CEV.<br /><br />The CEV crew module is described as having a length of 6.7 meters. The CEV plus the MM plus the TEIM is described as 21 meters in length and a mass of 40 metric tons.