Ares IV

[j05h]

<i>>> "Modify the EDS propulsion -with storable propellants- ... is easier than creating a new man-rated launcher ... isn't it ?"<br /><br /> /> This would require a substantially bigger launch vehicle. Replacing the LH2/LOX in the Ares 4 upper stage with UDMH/N2O4 storable propellants would cut translunar payload capacity by more than half.<br />...<br />High energy propellants are essential for human lunar exploration missions. <br /></i><br /><br />Sounds like a job for a VASIMR transfer stage, assuming Dr. Chang-Diaz' engine works as advertised. With ARES IV or another HLV, getting the stage and reactor into orbit should be easy enough. <br /><br />Also, to the secondary post, the EDS doesn't even exist yet. For near-term uses, think of what can be done with current hardware. <br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>

 

[nyarlathotep]

<font color="yellow">This would require a substantially bigger launch vehicle. Replacing the LH2/LOX in the Ares 4 upper stage with UDMH/N2O4 storable propellants would cut translunar payload capacity by more than half. Using hydrogen peroxide and ethlyene would result in a TLI payload that was less than 25% of the LH2/LOX version.</font><br /><br />Much smaller vehicle actually, it's a very dense propellant combination. For the same payload you have just over three times the mass of propellant, but a much smaller tank. You just need a semi-reliable really cheap big dumb rocket to boost the fuel. The fuel payloads are neither expensive nor time-critical, so cut as many corners in vehicle margin as you can. If you lose 10% of your deliveries, oh well, pull another booster from the shelf.<br /><br />I believe this guy Andrew Beal was working on one in the 20T to LEO class, but gave up in 2000 when teledesic and skybridge went bankrupt and he couldn't find another suitable market. Perhaps if there now was a market, someone might think about developing one.

 

[edkyle98]

""This would require a substantially bigger launch vehicle. Replacing the LH2/LOX in the Ares 4 upper stage with UDMH/N2O4 storable propellants would cut translunar payload capacity by more than half. Using hydrogen peroxide and ethlyene would result in a TLI payload that was less than 25% of the LH2/LOX version.""<br /><br />"Much smaller vehicle actually, it's a very dense propellant combination. For the same payload you have just over three times the mass of propellant, but a much smaller tank. You just need a semi-reliable really cheap big dumb rocket to boost the fuel. The fuel payloads are neither expensive nor time-critical, so cut as many corners in vehicle margin as you can. If you lose 10% of your deliveries, oh well, pull another booster from the shelf."<br /><br /><br />I should have said "heavier" rather than "bigger", but "heavier" means much more thrust, which means much more money. A scaled up Ares V with a storable propellant EDS would need to produce nearly 7,000 tonnes (15.4 million lbs) of liftoff thrust - as much as two Saturn Vs. The alternative would be to launch the mission in smaller pieces, taking advantage of the on-orbit storage capability - but that would require a dozen EELV Heavy or Ares I launches per mission, eating up the equivalent of NASA's annual shuttle budget and then some for each lunar mission just for the launch. <br /><br />"Big Dumb Booster" doesn't exist. Not in the U.S. or in any other country. It hasn't existed during the entire history of the space age. BDB is a pipe dream - like the failed plan to build monorails instead of highways to solve traffic jams in Seattle. In the real world it costs money to reach orbit, lots of it, and the cash requirement scales with launch vehicle mass. Using high energy propellants in upper stages reduces launch vehicle mass, saving money. <br /><br /> - Ed Kyle

 

[nyarlathotep]

Why the heck would you use the stupidly expensive EELVs, Ares V's or Ares Is to transfer fuel? Are you insane? Just put out an order to the Ukraine for 100 Zenits, and launch them from either a second oil rig or an east coast pad.<br /><br />Perhaps if you were using Zenits instead of currently non-existant cheap BDBs, or stupidly expensive Ares I's, you could consider a marginally more difficult to handle warm cryogenic like C3H8/LOX. Propane is dense enough when prechilled, has a decent ISP and you'd fit a good amount of it in a WBC diameter tank. A hundred watt stirling cryocooler could keep the EDS frosty indefinitely. <br /><br />The mission hardware (LSAM, cargo lander, etc) is going to be by an order of magnitude more expensive than the EDS and fuel delivered to it. It would be idiotic to risk that sort of capital just to save a few pennies by not using a storable EDS.

 

[radarredux]

> <i><font color="yellow">Why the heck would you use the stupidly expensive EELVs, Ares V's or Ares Is to transfer fuel? Are you insane? Just put out an order to the Ukraine for 100 Zenits, and launch them from either a second oil rig or an east coast pad.</font>/i><br /><br />I am not convinced that lots of launches with lots of in-space rendezvouses is a good idea. It sounds complicated, and complicated sounds dangerous.</i>

 

[scottb50]

They will need one anyway as it will take months to get to Mars and so they will need to store propellant for the braking manouveres when they get there.....<br /><br />That's why its easier to take water and break it down as it is needed using Solar energy. <div class="Discussion_UserSignature"> </div>

 

[edkyle98]

"Why the heck would you use the stupidly expensive EELVs, Ares V's or Ares Is to transfer fuel? Are you insane? Just put out an order to the Ukraine for 100 Zenits, and launch them from either a second oil rig or an east coast pad. "<br /><br />It would take perhaps 22 Zenits, plus a couple extras to replace the failures, to do a single lunar mission. A maneuvering upper stage that would probably cost more than the first two stages would need to be added. NASA would run out of money on this scheme quickly, not to mention the political nonstarter of outsourcing these multiple billions of dollars. Human spaceflight is all about national prestige, after all. It wouldn't be very prestigious for the U.S. to have to depend completely on Russo-Ukrainian rockets to get back to the Moon. *That* would be insane. <img src="/images/icons/wink.gif" /><br /><br /> - Ed Kyle

 

[holmec]

Started a thread on storable propellants <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[josh_simonson]

>"Big Dumb Booster" doesn't exist. Not in the U.S. or in any other country. It hasn't existed during the entire history of the space age. BDB is a pipe dream - like the failed plan to build monorails instead of highways to solve traffic jams in Seattle. In the real world it costs money to reach orbit, lots of it, and the cash requirement scales with launch vehicle mass. Using high energy propellants in upper stages reduces launch vehicle mass, saving money.<br /><br />This isn't really right, while bigger rockets are generally more expensive, all else (exchange rates...) equal, the marginal cost of additional payload in larger rockets is lower. In fact the only reliable means of reducing the per/lb cost of spacelaunch is to use larger vehicles. Case in point, Aries 1 has a horrendous $/lb metric. However, Aries V which is also built by NASA (all else equal...) should at least come out even with EELV, and with enough flights could fly for less than half as much per pound. Same thing with the Falcon 1 and Falcon 9. Bigger rockets cost less/lb. The Futron report on launch price trends in the 90's showed this very clearly.<br /><br /><br />A way to avoid the boiloff issues that the 1.5 launch archetecture is dealing with is to switch to lunar orbit (or EML1) rendevous. That way the high energy EDS propellant is used immediately rather than stored in LEO, which is the worst possible place to store LOX/LH2. It costs more to keep Aries 1 around than it costs to launch on Aries IV/V instead anyway. Might as well use that capability to simplify the missions and improve performance.

 

[holmec]

Here is a rendition of Ares IV<br /> <div class="Discussion_UserSignature"> <p> </p><p><font color="#0000ff"><em>"SCE to AUX" - John Aaron, curiosity pays off</em></font></p> </div>

 

[nyarlathotep]

<font color="yellow">It would take perhaps 22 Zenits, plus a couple extras to replace the failures, to do a single lunar mission.</font><br /><br />Wow. Just Wow. Did you lose a decimal point there or something? The EDS and LSAM combined have about 90T of LOX. It would take seven zenits to ferry that to a fuel depot. If one looked at the mass of the Zenit second stage and went gee, why don't we put a lockheed WBC on there (thanks jon goff), you could loft that in half the number.<br /><br />If we can't perform a simple task of berthing a fuel tank to a fuel depot, what hope have we of building a reliable man rated lunar lander? It's centuries off. It simply can't be done with todays technology.

 

[john_316]

<b><font color="red"> "Big Dumb Booster" doesn't exist. Not in the U.S. or in any other country. It hasn't existed during the entire history of the space age. BDB is a pipe dream </font>/b> <br /><br /><br /><br />It may not exist but it could have depending on what you actually want it to do or what you plan on putting on it to launch it. The closet things would be the Saturn-V and Energia if you can compare them. At least the lift-weight capacity was there. <br /><br />I imagine a BDB could be built just to lift a very heavy cargo into a GEO orbit of the earth without all the bells and whistles attached. However that’s just to get said cargo into orbit and circle around without changing orbits and all. I am talking about a small computer system to operate such a large mostly non-computerized machine. A BDB!! <br /><br />Fundamentally I think you would agree that with smaller computers, less excessive extras a rocket could be built with a nice clean sheet in mind? Even an ET of a shuttle with 2 SRB and a 100ton cargo capacity can be called a BDB in a lot of ways, as long as the cargo is confined to the top of the ET and the rocket doesn't need more redundant systems than a shuttle does. <br /><br />I think Ares-V can achieve something along this magnitude of being a simplistic rocket (of course we hope). It’s not perfect but I think the idea does have a merit. The upper stages will be the complex parts. <br /><br />I read that the machining is still available for the Saturn-V so that in essence tells me if we had too we could build a up rated Saturn-V if we needed too. However I'm realistic here and I want to see us achieve all the goals at once but we know that doesn't happen that way. So I have to see Ares-I in test flights then see what they can do with the Ares-V later in the coming years. <br /><br />It would be nice to see Ares-I erected on the pad like Delta-4H and keep the crawler used for the Ares-V. If that would save some money great because I don't think it</b>

 

[nyarlathotep]

<font color="yellow">Even an ET of a shuttle with 2 SRB and a 100ton cargo capacity can be called a BDB in a lot of ways,</font><br /><br />You're right. Most of us can agree that NASA's frankenrocket is both big and dumb. It is also by definition a booster.<br /><br />I had in mind a different type of big and dumb though, one centered around both minimum unit and operations cost, not maintaining a 5000 strong standing army.

 

[josh_simonson]

Well, it's still more cost effective if that 5000 man army is launching 100+t payloads at a time rather than 20t payloads.

 

[john_316]

Good point!!!!<br /><br /><br />Empty erected weight versus solid grain SRM...<br /><br /><br /><br /><img src="/images/icons/smile.gif" /><br />