New details on CEV

[gunsandrockets]

From the 56 page executive sumary of the ESAS report comes new details on the CEV.<br /><br />1) Some changes in the latest mass figures.<br /><br />The block 2 lunar capsule has creeped up to 9,506 kg. And the block 1A CEV for ISS missions is up to a full 22,900 kg almost the same as the block 2 lunar CEV, earlier the block 1A was reported at only 15,500 kg. The thinking is excess propellent can be used for reboosting the ISS and improving abort options.<br /><br />2) Sizing and development of capsule<br /><br />The CEV capsule has about 19 cubic meters of living volume. Why so big? They decided to size it as big as they could within the expected payload limits of the CLV (25 tonnes). The thinking is to bypass use of mission modules or new capsule development for possible future growth needs.<br /><br />I think it's instructive to compare the single module Apollo style CEV capsule with the two module Soyuz style casule of the Shenzou. The CEV capsule provides about 2 cubic meters of living space per tonne, while the Shenzou capsule provides about 3 cubic meters of living space per tonne. Interesting.

 

[gaetanomarano]

<br />Shenzhou is bell-shaped while CEV is a cone... why they have not used the bell-shape that works so good with Soyuz and Shenzhou?<br /><br />it's a "technical" choice or (only) they have fear that people may think they "copy" a '60 Soviet design?

 

[tomnackid]

Its a technical choice. The slope of the capsule walls allow it to bank during reentry--in effect the capsule "flies" at hypersonic speeds. If the walls were straighter, like the "gumdrop" shape of the Soyuz the capsule could not bank as much since parts of the walls would protrude into the reentry plasma. This ability to bank is not too important for reentry from earth orbit although it helps in hitting the landing site accurately. This capability is vital in returning from the moon however. Since the reentry speeds are much greater (25,000 mph vs. 18,000 mph) the ability to bank the the capsule and fly it reduces the g-forces to something tolerable for humans. In order for a Soyuz to reenter from lunar distances it has to accomplish a technically demanding "skip" maneuver to keep the g-forces below 20g. I think it might actually have to do several skips before actually reentering--someone else may have more info on this.<br /><br />Another factor is that NASA, for several reasons, wants to keep the heat shield on the bottom of the capsule only. One is that the g-forces are always coming from the same direction during launch and reentry. Another reason is that since the CEV is designed for long duration missions NASA wants to keep the heat shield covered up by the service module for as long as possible to prevent damage. A capsule with a TPS that wraps around can be any shape that is aerodynamically stable--a biconic was one proposed design, also T/space's "shuttle ****" design is another example, and of course LockMart's lifting body CEV is still another example.

 

[mikejz]

19 cubic meters, You know, add a modest consumables storage/crew habit module, and I could really see the CEV going to Mars.

 

[gaetanomarano]

<br />the CEV may slow its lunar speed with an SM engine burning toward earth<br /><br />the external part of a bell-shaped thermal shield may be protected with many different designs<br /><br />the advantages of a bell-shaped capsule are many... 1st: more internal space with less dimensions and weight<br /><br />also, a BIG bell-shaped capsule, my have space for an airlock without any (expensive and heavy) orbital extra-module

 

[nibb31]

Gaetano, you should read the ESAS report section 5, which has detailed information explaining why the CEV design is the way it is. <br /><br />You might actually learn something and understand that NASA engineers did not simply pull the CEV CM shape out of thin air.

 

[tomnackid]

OK genius: all those "creative" ideas add mass and/or are untested in actual space flight. The whole point of Project Constellation is to take the billions of dollars ALREADY invested in Mercury, Gemini, Apollo, and STS and use it to develop new more capable exploratory spacecraft.<br /><br />The CEV is plenty big enough for what it needs to do. It has a reentry shape that has been tested in actual space flight to and from the moon. How is it cost effective to waste time and money farting around with untested designs?

 

[gaetanomarano]

<br />I've no doubt they have their good reasons... but bell-shaped capsules exist (are not my invention...), fly (100+ times) and actually have ALL the advantages explained<br /><br />about the airlock... it's possible to have it with a bell-shaped CEV but (I can agree) it's clearly useless with CEV since that capsule will be used only to dock LSAM and ISS (and never will do or can do any Shuttle-like space-work)

 

[tap_sa]

<font color="yellow">"also, a BIG bell-shaped capsule, my have space for an airlock without any (expensive and heavy) orbital extra-module"</font><br /><br />Yes!!! And a VERY BIG bell-shaped capsule, my have space enough ... to SQUEEZE in not only 'one' ... but TWO big... fat... 'lunar' scientists ... INCREASING the 'number' of ... TRUE non-topGUN 'fatsos' on Moon surface by 69% ... or even 100%!

 

[tomnackid]

Thats just the point. They DON'T have an advantage when you look AT THE ENTIRE BIG PICTURE!!!!!!!!!!! <br /><br />The bell, or gumdrop, or headlight shape (take your pick) was first proposed to NASA by GE back in the late 50s, early 60s. It was looked at, tested, evaluated and determined that for going to the moon it just was not adequate. Boeing looked at the shape again for the Orbital Space Plane project then for the CEV project and again the negatives outweighed the positives when you LOOK AT THE ENTIRE BIG PICTURE!!!!!!!<br /><br />I'm not saying the shape doesn't have advantages, obviously it does. But just as obvious is the fact that those particular advantages are not important for exploring the moon.<br /><br />I can turn my washing machine into a spacecraft if I wanted to invest enough time and money in it, that doesn't mean its worth doing.

 

[nibb31]

"I've no doubt they have their good reasons... but bell-shaped capsules exist (are not my invention...), fly (100+ times) and actually have ALL the advantages explained"<br /><br />And also ALL the disadvantages that have also been explained.<br /><br />For the second time, I urge you to read the ESAS report and look at the figures provided by NASA. Once you have achieved a decent understanding of that section 5, you might be able to discuss the issues at the correct level. Until then, you are not qualified to have an opinion.<br /><br />The ESAS report is located here:<br />http://www.spaceref.com/news/viewsr.html?pid=19094<br /><br />Regarding the airlock, there is not much point in adding an airlock to the CEV because EVA will not be a part of most CEV mission profiles. ISS missions will use the airlocks available on the ISS. If an EVA is needed during lunar transit, it can probably be done from the LSAM. As shuttle_guy mentioned, if a contingency EVA is ever needed on a standalone CEV, it can be done. No big deal, and not worth adding the extra weight of an airlock.

 

[rubicondsrv]

I would suggest that you ignore getano as he dose not care about anything but his twisted opinions. <div class="Discussion_UserSignature"> </div>

 

[gaetanomarano]

<br />despite do science don't need so much body-motion... not all scientists are "fat"... but "don't be fat" is not sufficient for risky and complex space missions<br /><br />astronauts must have (FIRST) the great experience of flight/spaceflight and very strong "steel-nerves" that only a few (very selected) military pilots actually have... since they are trained to risk his life every time they fly from an aircraft carrier... for war or not<br /><br />many studies medicine... some become surgeons... a few become great surgeon... the reason is the same... great (specific) experience and "steel-nerves"<br />

 

[gaetanomarano]

<br />do you post here from America or North Korea?<br />

 

[gaetanomarano]

<br />following your opinion... we must claim that all (100+) bell-shaped Soyuz and Shenzhou launched still are in orbit since they can't reenter...<br /><br />the advantages FOR MOON are many!<br /><br />a bell-shaped CEV may have great part of a cone-CEV volume with less weight and dimensions<br /><br />less weight and dimensions mean a reduced SM<br /><br />a reduced CEV/SM mean a reduced CLV<br /><br />a reduced CEV/SM/CLV mean less cost and weight per launch<br /><br />less weight per launch mean more weight on LSAM for longer and better missions<br /><br />less cost mean MORE (longer and better) moon missions<br /><br />more, longer and better moon missions mean 3, 4, 5, 10 more science and exploration on the moon <br /><br /><br />(do you REALLY want MORE and BETTER missions, science and exploration on the moon or ONLY a big CEV/CLV to build?)<br />

 

[tomnackid]

?????????????? what the hell are you high on? <br /><br />Once again a blithering idiot ruins a thread on Space.com (sigh). And you ARE a blithering idiot--make no mistake about it. Don't bother arguing that this is a personal attack. I know its a personal attack--and it is one that a blithering idiot like you richly deserves. I keep hoping that you will eventually get bored or annoyed with having your ignorance constantly thrown in your face by your betters. I'm just a space enthusiast, you don't have to listen to me. I have a couple of masters degrees in science, but not in engineering or aerospace. But when people who DO do this for a living try to straighten you out and you discourteously and blithely ignore them, or when you ignore reference materials that people try to steer you toward so you won't look quite so foolish (a lost cause at this point) just to try and make your incoherent points over and over and over and over again you are abusing this message board and giving a slap in the face to all who are here to learn something.<br /><br />

 

[gaetanomarano]

<br />if I understand your slang... I come from the well-suggested-and-designed-spacecrafts-and-perfect-missions' HEAVEN<br />

 

[gaetanomarano]

<br />thank you for the link with the full report<br /><br />I've already read some parts linked in another thread these days (and more in next days)... but, frankly, no one MUST read that plan BEFORE have "any" opinion about CEV or to make a comparison between an UNEXISTING vehicle (that will fly in 2015!) with a capsule that have ALREADY done 100+ successful missions!!!<br /><br />about the airlock... I agree with you (read my previous post here) ...unfortunately some think (and say here) that CEV may be the Shuttles' replacement...

 

[tap_sa]

<font color="yellow">"I come from the well-suggested-and-designed-spacecrafts-and-perfect-missions' HEAVEN "</font><br /><br /><img src="/images/icons/rolleyes.gif" />

 

[tomnackid]

"...but, frankly, no one MUST read that plan BEFORE have "any" opinion about CEV..."<br />-----------------------------------------------------------<br />Your right. You can NOT read the report and have a really STUPID and UNINFORMED opinion about the CEV...and you do! Congratulations you must be very proud!<br /><br />

 

[drwayne]

I found section 6 to be fascinating reading.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[gaetanomarano]

<br />don't forget that many CEV details (dimensions, weight, versions, use, launchers, etc.) was already known from weeks (and some used or linked in my posts)<br />

 

[gaetanomarano]

<br />many world's countries/politicians/companies have 1000+ times the "power" of NASA, ESA, etc. but press and people talk and discuss of them while they can't change absolutely NOTHING<br /><br />if we can't talk and give our opinion about nothing, we must ask a freezing-company to hibernate our mind...

 

[tomnackid]

many world's countries/politicians/companies have 1000+ times the "power" of NASA, ESA, etc. but press and people talk and discuss of them while they can't change absolutely NOTHING <br /><br />if we can't talk and give our opinion about nothing, we must ask a freezing-company to hibernate our mind... <br />-----------------------------------------------------------<br />Anybody care to parse this for me?????

 

[gaetanomarano]

<br />read my posts<br /><br />I've suggested to use the SM engine to slow the bell-CEV speed on earth return (after an uncrewed test, of course)<br /><br />if this will never tested and used we never can send out of earth nothing than cones, cones, cones, cones<br /><br />never different and bigger vehicles... never a ferry... nothing...