Very cool AWST article on CEV, Delta IV-H, Atlas V

[redgryphon]

AWST article<br /><br />Some interesting points:<ul type="square"><li>NASA is going for a 4-person CEV for under 20 MT<li>The 60k lb cryogenic upper stages are in development and may be coming back onto the table<li>The astronaut office is skeptical of human rating the EELVs. <li>Boeing has many different options for upgrading the D IV-H, some at simple as modifying the flight path, right up to bigger diameter CBCs. Some of these options were hinted at in this pdf but it's good to see the options being fleshed out.<br /></li></li></li></li></ul><br />As for the 7-CBC cluster variants - imagine the hydrogen fireball just before liftoff on that one! Toasty. <img src="/images/icons/cool.gif" />

 

[mikejz]

I think that so long as the LV is strickly liquid, the need to 'man rate' it should be minimized in relation to the boosters proven track record. <br /><br />I would rather go up on an Atlas that has a long history behind it rather then a new man-rated booster with little history. <br /><br />I really am against using a Delta-Heavy however. <br /><br />$200 Million per flight+costs of CEV+costs of upgrades!<br /><br />In the end we will have a program that costs as much as the shuttle, but delivers less crew and cargo to orbit!

 

[mattblack]

All good points, mikejz. I too prefer the Atlas V and it's derivatives. Imagine having all that liquid hydrogen burning away at the insulation, it scares me to death despite the assurances that this is "normal". Also, I think that clustering a bunch of RD-180 engines in any future corestage would take up less room with Lox/Kerosene than huge quantities of bulky Hydrogen. I could imagine a cluster of 7x RD-180 powered corestages with an upper stage powered by an RS-68. This could, if supplied with sufficient propellant, be a Earth-escape stage. With Aluminium-Lithium used in the stages and all engines perhaps uprated, would anyone agree payload figures of about 90-metric tons to LEO and 40-metric tons Earth escape might be achieved? Are there any studies showing the Atlas V heavy upgrade path? <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>

 

[no_way]

<blockquote><font class="small">In reply to:</font><hr /><p> I too prefer the Atlas V and it's derivatives<p><hr /></p></p></blockquote><br />Why tie the CEV to a particular launch vehicle in the first place ? Just restrict weight and size of it, so that any medium launcher on the market could launch it.<br /><br />Zenit, Proton, Ariane, Long March, all of them should be suitable.<br />

 

[mikejz]

I wounder why Boeing decided to take the risk of dumping and burning tons of Hydrogen to being with? It seems safer to have some sort of a chilldown system on the pad using liquid helium/nitrogen.

 

[mrmorris]

<font color="yellow">"I wounder why Boeing decided to take the risk..."</font><br /><br />Some people paint flames on the sides of their vehicles to make them look fast. Boeing just decided to go for the real thing. <img src="/images/icons/smile.gif" />

 

[no_way]

An interesting post i found on sci.space.policy, by Jorge R. Frank<br /><blockquote><font class="small">In reply to:</font><hr /><p><br />..a year-by-year comparison between CEV and shuttle funding, suitably corrected for inflation. <br /><br />Shuttle (actual) <br />1970 50.2 <br />1971 300.3 <br />1972 365.3 <br />1973 694.9 <br />1974 1550.2 <br />1975 2357.5 <br /> ------ <br /> 5318.6 <br /><br />CEV <br />2004 922.8 (actual) <br />2005 526.0 (actual) <br />2006 1103.5 (requested) <br />2007 1530.6 (projected) <br />2008 1448.8 (projected) <br />2009 1855.4 (projected; last Bush budget) <br /> ------ <br /> 7387.2 <br /><br />(all figures in constant-year FY2005 dollars in millions; totals may not add due to rounding) <p><hr /></p></p></blockquote><br /><br />STS was initially developed for _less_ money than what is projected for CEV ??? There has _got_ to be something very wrong here.<br />I dont have the source for these numbers, but it should be pretty easy to look up and verify.

 

[grooble]

Give Grooble $1b and i'll build a ultra-cannon, and fire payloads direct to the moon! <br /><br />Yeah, its one of my goals in the next 20 years, to build the most powerful cannon in history, perhaps launch millions of canisters to the moon and mars which contain water and other materials, metals, tools, pre-fab building components, space ship components, fuel.<br /><br />So by the time humans get there, they'd be 100,000s of tons of useable resources!<br /><br />Perhaps launch 1% of the earths ocean to mars.<br /><br /><img src="/images/icons/laugh.gif" />

 

[radarredux]

> <i><font color="yellow">STS was initially developed for _less_ money than what is projected for CEV</font>/i><br /><br />I don't understand the point of the numbers. Shuttle development did not stop in 1975 (it was another 6 years before she flew), nor will CEV development stop in 2009.<br /><br />Also keep in mind that each vehicle had different missions. The shuttle was designed as a single vehicle to take cargo up to LEO and back down, while the CEV is part of a constellation of technologies to move humans beyond LEO. Different goals, requirements, missions, etc.</i>

 

[padrat]

I think Jorge was referring to the dates of Critical Design Review, the point in a project's development when the builder is ready to actually bend metal.<br /><br />-Pad Rat-

 

[rogers_buck]

Actually, I think they should only worry about man-rating the escape tower with liquid stages. If they can escape through the entire flight profile, then what the hell?

 

[najab]

><i>If they can escape through the entire flight profile...</i><p>Which would mean that they'd have to carry the tower all the way to orbit...</p>

 

[padrat]

>>Which would mean that they'd have to carry the tower all the way to orbit... <<<br /><br />Well, no, not really. Escape towers are needed when the spacecraft propulsion is insufficient for the task of abort. In later stages of flight, an upper stage or the spacecraft itself could provide the necessary impulse to successfully abort.<br /><br />In the end, though, what's really needed is a reliable malfunction detection system that tells the spacecraft - in sufficient time to do something - that there's a need to get off the rocket. "Man rating the tower", whatever that's supposed to mean, is not enough.<br /><br />-Pad Rat-

 

[scottb50]

Which would mean that they'd have to carry the tower all the way to orbit...<br /><br />The vehicle needs maneuvering and rendevous capability while in orbit and the second stage engines of the Delta are too powerful. Why not have a maneuvering stage that doubles as an escape system during launch, it would provide escape capability from the surface to docking and return capabillity if docking is unsuccesful. <div class="Discussion_UserSignature"> </div>

 

[najab]

<blockquote><font class="small">In reply to:</font><hr /><p>In the end, though, what's really needed is a reliable malfunction detection system that tells the spacecraft - in sufficient time to do something - that there's a need to get off the rocket. "Man rating the tower", whatever that's supposed to mean, is not enough.<p><hr /></p></p></blockquote>That was the point I was making. If the escape tower is the <b>only</b> 'man rating' provision, then it has to be carried all the way to orbit. 'Man rating' doesn't end at 100,000 feet!<br />

 

[mikejz]

Of course you could do what Mmorris and the Klipper design does and instead of an escape tower--use solids as a the final kick stage/deorbit engine. If fired together they would provide enought power to propel the capsule away from the booster, that way they are not simply dead weight if not used

 

[padrat]

>>About the only common thing beweeen the Atlas V and the Atlas is the name.<<<br /><br />Let's see....there's the engine (granted, it's only common to Atlas III), a lot of the avionics and the Centaur.<br /><br />-Pad Rat-

 

[rogers_buck]

I like what the Russians propose doing. Use the escape tower burn during the final stage boost to add delta vee. The tower is no longer needed to abandon a stricken vehicle so they make good use of the thrust it can provide.

 

[najab]

><i>...[T]here's the engine (granted, it's only common to Atlas III), a lot of the avionics and the Centaur. </i><p>Well the Atlas III wasn't <i>really</i> an old-school Atlas - it was more a beta-test of the Atlas V <img src="/images/icons/smile.gif" />. <p>More important is what's different from the old Atlas, and that's a lot. The V is an entirely new booster that happens to use a few of the same components as the old one.</p></p>

 

[padrat]

First-stage structure is just about the only new thing on the vehicle, and structure is a fairly simple engineering issue. There is a tremendous amount of Atlas heritage present in Atlas V, and its results to date speak to that.<br /><br />-Pad Rat-

 

[najab]

><i>First-stage structure is just about the only new thing on the vehicle, and structure is a fairly simple engineering issue.</i><p>If it was a simple increase in diameter or length, I'd agree. But the switch from pressure-stabilised to structurely stabilized is a <b>BIG</b> difference. That alone makes it a totally new booster. Add to that the fact that they use a throttleable engine instead of a booster/sustainer combo...I stand by what I said earlier - it's a new vehicle with a few old parts.</p>

 

[padrat]

>>So you are telling me they build a new vehicle with 40 year old avionics. I find that difficult to believe.<<<br /><br />Believe it. Avionics development is EXPENSIVE. There are some new boxes, and Block II avionics are on the way, but there are a lot of heritage boxes on the bird.<br /><br />-Pad Rat-

 

[padrat]

>>But the switch from pressure-stabilised to structurely stabilized is a BIG difference<<<br /><br />Yes, and easier to accomplish than pressure-stabilized tanks by a long shot.<br /><br />Trust me, most of the parts that count are heritage. Flight-tested and proven, the key to success.<br /><br />-Pad Rat-

 

[padrat]

>>But I would believe that changes happened often during those 40+ years. One little "improvement", (change anyway) at a time, until the last Atlas to fly probably had little or no electronics in common with John Glenn's D Model.<<<br /><br />True. But that adds up to a impressive flight test record. The boxes in Atlas V are proven. For that matter, Delta IV uses the RIFCA out of Delta II, with a few appropriate adjustments, so it has significant heritage, too.<br /><br />-Pad Rat-

 

[scottb50]

I was thinking more of a module that attaches to the Docking adapter and is removed at a base station when it would not be needed any longer. The problem with the Kilpler concept is the mounting system would be cumbersome to transport and attaching to base of the vehicle adds another avenue of complexity that can fail. <br /><br />What I have in mind is a liquid propellant tank with an engine mounted on either end, docked to the passenger launch/re-entry vehicles docking adapter, this is based on a Geminin type vehicle. It would maneuver the second stage to dock to a station. There would always be a use for a tank in orbit and the engines could be used for other things, say maneuvering engines for Tugs, which would be re-fueled second stages. <div class="Discussion_UserSignature"> </div>