CEV, going backwards one step at a time...

[najab]

><i>...the ISP figure refers to the engine efficiency in that, the higher the figure, the less propellant is needed or used to generate 'x' amount of thrust?</i><p>Uhm...not quite. The way I remember it is that the higher the Isp, the more delta-v you get per pound of propellant. Substitue 'momentum' for 'thrust' in your statement and you've got it.</p>

 

[trailrider]

"The 5 segment SRB will help a little however the second stage will have to get bigger to contain more propellant required by the lower Isp. "<br /><br />So is the new CLV Stage 2 config. one or 2xJ-2S? (I lost track in the higher signal-to-noise ratio!)<br /><br />Also, what is the current scuttlebut about whether they will try to recover the 5 segmen SRM?<br /><br />What are they going to do about roll control?<br /><br />Will the Stage 2 be the same diameter as the CEV (5.0 m)? (If so does anybody know where I can get ahold of some 1.3 inch dia. plastic tubing? I had a model of the original configuration all built, based on the 5.5 meter design! I have to change it before my next talk to young students.)<br /><br />Frodo, I hope you are right, though I'd take a Mars landing a couple years earlier. Shame us products of '42 can't participate more. But they only want young bucks to do this!<br /><br />Ad Luna! Ad Aries! Ad Astra!

 

[SpaceKiwi]

Okay, with you, thanks najaB. <div class="Discussion_UserSignature"> <p><em><font size="2" color="#ff0000">Who is this superhero?  Henry, the mild-mannered janitor ... could be!</font></em></p><p><em><font size="2">-------------------------------------------------------------------------------------------</font></em></p><p><font size="5">Bring Back The Black!</font></p> </div>

 

[JonClarke]

Has there been any clarification of the Isp for the J-2 variant being used? The original J-2S is quoted as having an Isp of 436, but the J-2S+ variant that is supposed to used has one as high as 453.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[mattblack]

Specific impulse:<br />It is the thrust produced per unit rate of consumption of propellants. It is expressed in pounds of thrust per pound of propellant consumed per second. <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>

 

[drwayne]

Good reference:<br /><br />http://www.braeunig.us/space/propuls.htm<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[scottb50]

See, I always thought that was the reason for computers, Google up a solution to any problem, so to speak. <div class="Discussion_UserSignature"> </div>

 

[SpaceKiwi]

Thanks Doc, your link was 'easier' to understand than the NASA one I originally Googled, though this is always relative for me when the dreaded algebraic equation makes an appearance.<br /><br />I thought the thrust profiles of the various solid fuel geometries were particularly interesting, but it was all good. <div class="Discussion_UserSignature"> <p><em><font size="2" color="#ff0000">Who is this superhero?  Henry, the mild-mannered janitor ... could be!</font></em></p><p><em><font size="2">-------------------------------------------------------------------------------------------</font></em></p><p><font size="5">Bring Back The Black!</font></p> </div>

 

[vt_hokie]

<i>In other words, I'll take what I can get, and hope for more later!</i><br /><br />Here's the problem with that logic: This politically motivated, antiquated system will cost so much to develop and to operate that, like the space shuttle, it will ensure that we don't get anything better for another 30 years!

 

[vt_hokie]

<i>No system (and I have actually worked on such engines for some 37.5 years before retiring from Rocketdyne in the year 2000) is EVER what it started out to be!</i><br /><br />Yeah, and as soon as there were problems and changes to X-33 (a program I worked on and actually believed in), this country gave up and killed it entirely. Where might we be today if that unfortunate decision hadn't been made, and we applied some of the technology demonstrated by X-33 to a two-stage system? SSTO was a mistake, but a fully reusable two stage to orbit vehicle is well within our capability.

 

[spacefire]

the SLI might have yielded fully reusable TSTO. That was cancelled as well.<br />NASA and the government have shown lack of vision and interest in furthering space exploration and exploitation.<br />Rather than this "we're happy with what we get, even if we're gonna get a lot less than promised" VSE, I'd rather see the US manned space program put on hold for a few years and all the money going to research of advanced spaceplanes and robotic exploration.<br />In 20 years this could yield a safe, viable launcher, and I'd rather see that than a tincan flying by the end of the decade. <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[mattblack]

>>I'd rather see the US manned space program put on hold for a few years and all the money going to research of advanced spaceplanes and robotic exploration. In 20 years this could yield a safe, viable launcher<<<br /><br />That couple of sentences beautifully outlines the flaw in part of your philosophy: Do little or nothing now, hope something better comes along later. The only way there'll be advanced spaceplanes from now on will be through private industry with Rutan and Co. DON'T expect U.S. taxpayers to fund spaceplanes: They've been chasing spaceplanes for more than 30 years, and look where it's got us?!<br /><br />Look; there isn't the money (for many reasons) and the fact that some of the VSE and CEV features are being whittled away at now just underlines that. We need to get to Moon & Mars A.S.A.P. otherwise there'll be 30 more years of mediocre rings-around-the-Earth with NO end in sight.<br /><br />(Shudder). <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>

 

[spacefire]

The approach worked, sorta: after Apollo, there was a bit of a hiatus and then the Shuttle appeard in 1980.<br />A spaceplane had been designed and it was way more performant than any existing manned spacecraft.<br />That the Shuttle proved to be expensive and unsafe can be attributed to poor management decisions which created a vehicle so heavy it had to forego full reusability and also rely on solid boosters and use an external tank, which in retrospect proved to be 'fatal' design criteria for the shuttle. <div class="Discussion_UserSignature"> <p>http://asteroid-invasion.blogspot.com</p><p>http://www.solvengineer.com/asteroid-invasion.html </p><p> </p> </div>

 

[vt_hokie]

<i>The only way there'll be advanced spaceplanes from now on will be through private industry with Rutan and Co.</i><br /><br />Time to disband NASA then, if it can't even be expected to pursue concepts at least as advanced as the small private industry innovators.

 

[tomnackid]

What do you mean by advanced? As far as I know no private company has yet put a manned spacecraft in orbit, much less sent one to the moon and back. Power Point presentations and glossy brochures made for the benefit of venture capitalists won't get us into space.

 

[rfoshaug]

<blockquote><font class="small">In reply to:</font><hr /><p>As far as I know no private company has yet put a manned spacecraft in orbit, much less sent one to the moon and back. Power Point presentations and glossy brochures made for the benefit of venture capitalists won't get us into space.<p><hr /></p></p></blockquote><br /><br />Excactly! Making a small 3-seat suborbital craft is nowhere near the challenge NASA is facing. <div class="Discussion_UserSignature"> <p><font color="#ff9900">----------------------------------</font></p><p><font color="#ff9900">My minds have many opinions</font></p> </div>

 

[josh_simonson]

> The only way there'll be advanced spaceplanes from now on will be through private industry with Rutan and Co.<br /><br />Rutan's way over-rated. What will happen is the spaceplane will be shelved until tps, propulsion and structural technologies are sufficiently developed to make rolling one out a less risky proposition. Between NASA, civilian aerospace, and the military, there's a lot of hypersonic research going on in the area of scramjets and PDEs. It's not like things aren't moving along, they're just not trying to shoehorn it into an aircraft yet.

 

[vt_hokie]

There is absolutely no reason that an X-38/CRV class lifting body wouldn't be feasible with existing technology.

 

[nacnud]

True, but would it be able to cope with the re-entry velocites from the Moon/Mars and will it be cheaper than a capusle.<br /><br />Mainly is that a risker shape than a capsule in terms of technology development, crew safety and buget?

 

[vt_hokie]

<i>True, but would it be able to cope with the re-entry velocites from the Moon/Mars and will it be cheaper than a capusle.</i><br /><br />I don't know about re-entry velocities for a direct lunar or Mars return, but Lockheed Martin apparently felt that their lifting body CEV could handle it, before that design was killed by NASA's capsule requirement.<br /><br />I'm beginning to think that the CEV will not be simple, safe, or soon! <img src="/images/icons/wink.gif" /> It certainly won't be affordable. If SpaceDev estimates that it could build the orbital version of its HL-20 derived "Dreamchaser" transport for $100 million, then why does NASA need billions of dollars for its Apollo command module revival?

 

[nacnud]

Because that's what Boemart will charge them?

 

[john_316]

If you sit back and think about it for a moment! Burt Rutan could build the CM itself and probably cheaper than Boemart and Company and more of them for the same price. Prime contractors should also look at that and not making a 10 fold profit but rather start their own 10 fold profit private space access because they will be challenged now that Virgin Galactic will start up here in a couple of years..<br /><br />I am just saying the CM itself. I don't think his company has the facility to build the Service Module and I think its time we stop going freaking gung ho with 200 acronyms with the CEV.<br /><br />CEV=Crew Exploration Vehicle (as a whole)<br />CM=Command Module <br />SM=Service Module <br />CLV=Crew Launch Vehicle<br /><br />Ok is that simple enough without another 20 acronyms? I mean what is the official naming conventions now? Geez this is getting ubsurd.....<br /><br />LOL <img src="/images/icons/smile.gif" /><br />

 

[mattblack]

Everybody's overrated!! Still, Rutan and those behind Russia's "Kliper" are the only spaceplane shows in town. <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>

 

[barf9]

I love the new HLV based on shuttle parts, 125 tons in orbit!! but how does NASA'a new plan get us closer to a moon colony? All I'm hearing is it's going to Plant more footprints in the dust and wave the flag, we already did that part, what about the moon base?

 

[spacester]

I love that line - "Everybody's overrated!" - I'm gonna remember that one.<br /><br />BUT for perhaps the first time ever <img src="/images/icons/laugh.gif" /> mattblack said something I disagree with <img src="/images/icons/wink.gif" /><br /><br /><font color="yellow">. . . the only spaceplane shows in town.</font><br /><br />I just got a news alert from rocketsaway.net that Rocketplane Limited, Inc. has signed a Space Act Agreement with NASA for a loan of an RS-88 engine for 3 years. From the news release - which I find nowhere else on the web (!!!):<br /><br /><i>The RS-88 engine is capable of 50,000 pounds of thrust. It was designed and built by The Boeing Company's former Rocketdyne Propulsion & Power unit for use on Lockheed Martin's Pad Abort Demonstration vehicle. In 2003, NASA tested the RS- 88 in a series of 14 hot-fire tests, resulting in 55 seconds of successful engine operation. </i><br /><br />These guys in Oklahoma are looking more legit every year. Their XP vehicle has passed a design review and is in the detailed design stage right now.<br /> <div class="Discussion_UserSignature"> </div>