CEV & CLV moving target

[geminivi]

I saw this headline story in FlightInternational bolding asserting that the CLV will dictate the mass of the CEV. <br />http://www.flightglobal.com/Articles/2006/06/27/Navigation/200/207461/Crew+Launch+Vehicle+thrust+may+dictate+CEV+mass.html<br />Whoa really, the lift of a launcher dictates payload weight? Do tell.<br /> <br />But then I started to wonder.... <br />Given the shifting hardware in this program, 2.5 years after it was announced, how do the mass numbers look for a 5 meter CEV and a 5 segment CLV? I've heard that the SRB will have new propellant, different grain, increased weight and heavier parachutes. The shuttle engines have been swapped out for RS-68's and J2S-X's. Any chance NASA is getting heartburn with the new SRB's?

 

[nacnud]

IIRC the fuel for the 5 segment SRB reverted to the same type of fuel as in the Shuttle SRB.

 

[qso1]

geminiVI:<br />Given the shifting hardware in this program...<br /><br />Me:<br />shifting history in the early stages of a new program is nothing new. Look at Apollo and shuttles early history sometime.<br /><br />Excerpt from link:<br />The CLV has a five-segment solid rocket booster (SRB) first stage and a liquid oxygen/liquid hydrogen second-stage engine. Its thrust capability has not been revealed.<br /><br />Me:<br />Given the shuttle baseline SRB is around 3 million lbs thrust, I would expect an uprated version to max out at around 4 million lbs. Second stage thrust unknown. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[qso1]

A slight misnomer on my part. I wanted to more or less say the max probable thrust would probably be around 3.3 million but stated 4 million to account for any possible unforseen developments.<br /><br />I would agree that there probably won't be a redesign of the case, if you do that, may as well build a totally new launcher. <div class="Discussion_UserSignature"> <p><strong>My borrowed quote for the time being:</strong></p><p><em>There are three kinds of people in life. Those who make it happen, those who watch it happen...and those who do not know what happened.</em></p> </div>

 

[propforce]

<font color="yellow">The max thrust will not be as high as 4 million pounds. </font><br /><br />From NASA's briefings, it looks like the new thrust for the FSB is around 3.4M lbf.<br /> <div class="Discussion_UserSignature"> </div>

 

[propforce]

<font color="yellow">Any chance NASA is getting heartburn with the new SRB's? </font><br /><br />Oh Yeah.... like a $3 BILLION dollar heartburn to develop this FSB.<br /> <div class="Discussion_UserSignature"> </div>

 

[gunsandrockets]

"Given the shifting hardware in this program, 2.5 years after it was announced, how do the mass numbers look for a 5 meter CEV and a 5 segment CLV?"<br /><br />The original version of the CEV from the ESAS documents showed a 9.5 tonne 5.5m crew module and a 13.65 tonne LOX/CH4 propellant service module. For a time nasaspaceflight.com posted some documents that had numbers for the smaller CEV showing an 8.4 tonne 5m CM and a 12.9 tonne storable propellant SM.<br /><br />But the fact is the CEV design could afford to be even smaller than the 5m version and still work within the ESAS architecture plan. Recall that even the orginal Apollo capsule was designed for direct flight to the moon; not for the plan later adapted using a separate LM lunar landing spacecraft. In contrast the CEV is (supposedly) designed from the ground up for travel to the moon while mated with the enormous LSAM lunar landing spacecraft. Even with the CEV's larger crew of 4 (compared to the 3 crew of Apollo) the CEV capsule would work using same sized capsule as Apollo did.<br /><br />The only reasonable factor for using a CEV capsule larger than the Apollo capsule is the hypothetical need for the CEV as a six man ferry to a Mars Mission space ship even though the actual design or even the crew size of the Mars Mission ship is wildly speculative. Even taking the Mars goal into account a CEV crew capsule slightly larger than Apollo, let's say 4.5m diameter, should be more than adequate for the job.<br /><br />The jumbo sized CEV has never made any kind of sense; the original 5.5m CEV has three times the volume of the Apollo! Unless there is some burning need for a reentry vehicle to recover 10 or more men at the same time, that jumbo size doesn't make any sense. All it does is increase the mass of the capsule, thereby increasing the mass of the service module, thereby increasing the size of the CLV needed to send the CEV into orbit and also increasing the size of the EDS needed to send the CEV to t

 

[edkyle98]

The payload is still supposed to be 25 tonnes to the specified transfer orbit, last I heard. The key limiting factor isn't going to be first stage thrust, it is going to be second stage specific impulse. The yet-to-be-developed J-2X second stage engine has to come through with substantially better ISP than the old J-2 or J-2S designs, or the CLV/CEV project will be in trouble.<br /><br /> - Ed Kyle

 

[frodo1008]

The ISP is to some extent dependent upon the propellents used. In the case of all the J2 designs that is liquid oxygen and liquid hydrogen. There are some other factors, but if NASA is expecting to get a far greater isp out of these engines it is indeed in very big trouble. <br /><br />However, if it is just a matter of needing additional thrust, I think Rocketdyne can indeed provide that possibility.

 

[gunsandrockets]

"The payload is still supposed to be 25 tonnes to the specified transfer orbit...The yet-to-be-developed J-2X second stage engine has to come through with substantially better ISP than the old J-2 or J-2S designs, or the CLV/CEV project will be in trouble."<br /><br />The only thing threatened is the elephantine size of the CEV. The CEV could easily perform the required missions for much less mass than 23 tonnes (or 25 tonnes or whatever other ridiculous mass is quoted for it recently). <br /><br />

 

[vt_hokie]

One thing that's becoming increasingly clear is that "CEV" will not be safe, simple, or soon!

 

[gofer]

Yeah, well, it's always been clear that the CEV would need to be heavy enough to keep the G's in line with the manned cargo of the CLV. Since the CLV is just a dumb firecracker with some predefined grain profile, you gotta keep it down, or the feisty ****** will just plaster the astros all over the capsule. The CEV and the CLV go hand in sweaty hand. By design. A pair made for each other. No wonder.

 

[cuddlyrocket]

"The only reasonable factor for using a CEV capsule larger than the Apollo capsule is the hypothetical need for the CEV as a six man ferry to a Mars Mission space ship...."<br /><br />Don't forget that the CEV is also supposed to be able to act as a crew-ferry and lifeboat for the ISS, should a private-sector alternative not be available. A six-man crew is specified for that mission profile, I believe.

 

[gofer]

The Big Gemini had capacity of 9 people (!) + 2.5tonne supplies (!!!) within the MOL program, and was lighter than the current CEV (15 tonnes total for the BigG vs. 21+ for the CEV) Launched on the then Titan. Can't say we couldn't do better now. Say, what rockets could launch a 15 tonnes CEV? .... I can count at least 5.

 

[geminivi]

Since the motivation for swapping out the SSME's for the RS-68 was cost of manufacturing has anyone seen what the manufacturing costs for a 4 segment and a 5 segment SRB are? How about comparing either to the cost of a Delta 4 Heavy?

 

[propforce]

I've heard cost numbers anywhere from $6 billion to $10 billion for NASA to build the CLV, while it would only cost $1 billion each to "man-rate" the Delta IV or the Atlas V, and would cost far less to launch from either one of them. <div class="Discussion_UserSignature"> </div>

 

[josh_simonson]

>he Big Gemini had capacity of 9 people (!) + 2.5tonne supplies (!!!) within the MOL program, and was lighter than the current CEV (15 tonnes total for the BigG vs. 21+ for the CEV) Launched on the then Titan. Can't say we couldn't do better now.<br /><br />Not when you include a SM that can do TEI. You're comparing apples and oranges.

 

[edkyle98]

"I've heard cost numbers anywhere from $6 billion to $10 billion for NASA to build the CLV, while it would only cost $1 billion each to "man-rate" the Delta IV or the Atlas V, and would cost far less to launch from either one of them."<br /><br />You must not have heard that EELV costs have nearly doubled, so that an EELV Heavy launch, which still isn't enough rocket to handle CEV, now costs nearly as much as the horrendously costly Titan it replaced. You must not have noticed that the EELV program cost the Pentagon $550 million last fiscal year, even though only ONE EELV launch was performed for the Pentagon during that time (the Delta 4 Heavy launch). The Pentagon is asking for nearly $1 billion for EELV next year, for maybe two or three launches. You must not have read the reports that Boeing and Lockheed have been losing money on their EELV efforts. You must not have noticed that both companies were eager to dump their rockets into a consortium effort in order to attempt to limit the fiscal bleeding. You must not have read the ESAS report, which showed very clearly that it will cost LESS to launch CEV on CLV than on an EELV-derived launcher.<br /><br /> - Ed Kyle

 

[gunsandrockets]

"One thing that's becoming increasingly clear is that "CEV" will not be safe, simple, or soon!"<br /><br />As much as I am a critic of the ESAS plan and it's dependence on an HLV, I disagree with you.<br /><br />At first blush the ESAS plan had all kinds of holes in it, but NASA is showing a comendable willingness to dump stupider aspects of the plan if it costs too much. NASA has already canned the SSME and the 5.5m CEV, so dumping the 5-segment SRB and switching to an even smaller CEV wouldn't surprise me anymore.

 

[gunsandrockets]

"Yeah, well, it's always been clear that the CEV would need to be heavy enough to keep the G's in line with the manned cargo of the CLV. Since the CLV is just a dumb firecracker with some predefined grain profile, you gotta keep it down, or the feisty ****** will just plaster the astros all over the capsule. The CEV and the CLV go hand in sweaty hand. By design. A pair made for each other. No wonder."<br /><br />Actually the mass of the second stage is the important thing, not the mass of the CEV, for keeping acceleration down to acceptable levels.

 

[gunsandrockets]

"Don't forget that the CEV is also supposed to be able to act as a crew-ferry and lifeboat for the ISS, should a private-sector alternative not be available. A six-man crew is specified for that mission profile, I believe."<br /><br />Not right. Surprisingly the CEV is not required to fill the permanent lifeboat role of the old X-38 Crew Rescue Vehicle, so no need for six crew. In the ISS ferry role the CEV is only required to carry three people (which makes sense for ISS crew rotation since you only need to replace 1/2 the maximum crew of the ISS at a time).

 

[propforce]

<font color="yellow">You must not have heard that EELV costs have nearly doubled, so that an EELV Heavy launch, which still isn't enough rocket to handle CEV, now costs nearly as much as the horrendously costly Titan it replaced.</font><br /><br />You're right, I have not hear. Can you provide the link referencing the cost of EELV ?<br /><br />BTW, the CEV launch requirement is 25 MT. That is well within the EELV (DIV-H and future Atlas V heavy) capability. <br /><br /><br /><font color="yellow">You must not have noticed that the EELV program cost the Pentagon $550 million last fiscal year, even though only ONE EELV launch was performed for the Pentagon during that time (the Delta 4 Heavy launch). </font><br /><br />Let's see if we can get some clarification on just what that $550 millions provide? Does all that money goes to the contractors, or does that support the DoD staffs/ NRO staffs, etc. as well? Does it support mission engineering for future launches? Does it support the Mission Assurance effort in the EELV program? Does pay for anything other than a single DIV-H launch?<br /><br />BTW, if you think a single CLV launch will cost anything less than $550 million you're gravely mistaken.<br /><br /><font color="yellow">You must not have read the reports that Boeing and Lockheed have been losing money on their EELV efforts. You must not have noticed that both companies were eager to dump their rockets into a consortium effort in order to attempt to limit the fiscal bleeding.</font><br /><br />Oh I can assure you that I am aware of this development quite well <img src="/images/icons/wink.gif" />. As an engineer I hate to see this consortium happens. But from a business perspective I must grudgingly admit that both companies have no choice but stop the bleeding. Why continue to put money into a unprofitable operation? If the customer(s) want to have this product, then they should pay for it. Afterall, both companies are not in this busi <div class="Discussion_UserSignature"> </div>

 

[propforce]

<font color="yellow">At first blush the ESAS plan had all kinds of holes in it, but NASA is showing a comendable willingness to dump stupider aspects of the plan if it costs too much. NASA has already canned the SSME and the 5.5m CEV, so dumping the 5-segment SRB and switching to an even smaller CEV wouldn't surprise me anymore. </font><br /><br />Just in case anyone thinks that I am anti-NASA from reading my post above, I too; want to commend NASA for the willingness to make changes from the ESAS report as facts become clear on what better path to take on the CEV, CLV and perhaps CaLV.<br /><br />The reason we voice our opinions is in part that we hope someone in NASA with cooler heads and technically savy enough would consider what we're saying and perhaps see the merits of our opinions. Make changes where it makes sense is a good thing. America's space program will be better and further along as a result. <div class="Discussion_UserSignature"> </div>

 

[gunsandrockets]

"Since the motivation for swapping out the SSME's for the RS-68 was cost of manufacturing has anyone seen what the manufacturing costs for a 4 segment and a 5 segment SRB are? How about comparing either to the cost of a Delta 4 Heavy? "<br /><br />I don't know the manufacturing cost, but the development cost for the 5-segment SRB for use in the Crew Launch Vehicle is now 3 billion dollars. The original estimate for the 4-segment SRB was 1 billion dollars. I don't know if the change in cost estimation is due to switching to a 5-sement SRB though that must have some effect.<br /><br />As I recall the original projected development budget for the CEV was 5 billion dollars, for the CLV another 5 billion dollars, and for the HLV 5-10 billion dollars. 20 billion dollars total just for development costs, anything for manufacturing or operations is not included in that 20 billion total. <br /><br />The development cost of both the Atlas V and the Delta IV combined was around 1 billion dollars (though 'man-rating' those boosters is claimed by critics to be expensive).<br /><br />http://www.nasawatch.com/archives/2006/04/clv_cost_escala.html

 

[gunsandrockets]

"The Big Gemini had capacity of 9 people (!) + 2.5tonne supplies (!!!) within the MOL program, and was lighter than the current CEV (15 tonnes total for the BigG vs. 21+ for the CEV) Launched on the then Titan."<br /><br />Josh Simonson is right here. Comparing the Big Gemini to the CEV really isn't fair because most of the mass of the CEV is rocket propellant, unlike the Big Gemini. The CEV as currently conceived carries enough propellant for 1.7 km/s delta vee! If NASA were to change from low-lunar-orbit-rendezvous (LLOR) to Lagrange-Point-One-Rendevous (LPR1) the amount of propellant the CEV would need could be cut almost in half. The block 2 lunar mission CEV would then more closely resemble the block 1 ISS mission CEV too if that change were made.<br /><br />"...Say, what rockets could launch a 15 tonnes CEV? .... I can count at least 5."<br /><br />Yep. If the CEV had both a smaller capsule and only had to return from L-1 instead of low-lunar-orbit than the CEV could be made even smaller than 15 tonnes, maybe as small as 13 tonnes.<br /><br />One of the main criticisms of using the EELV instead of the SRB for the Crew-Launch-Vehicle was that the EELV use of a 'lofted trajectory'. Well with a smaller CEV an EELV wouldn't have to fly a 'lofted trajectory' to have enough payload to deliver the CEV into orbit.